Transportation of milk and dairy products, Is a very important intermediate stage between the manufacturer and the end consumer, as it requires compliance with very strict rules for the transportation of this type of food.

No food can be compared with milk and dairy products in terms of calcium content, which is easily absorbed by our body. In addition, milk contains many vitamins, as well as micro and macro elements. All this makes this product very valuable.

But, along with this, dairy products are perishable. They have a limited shelf life and transportation, and also need to comply with transportation requirements with a guarantee of the safety of the delivered goods for the health of consumers.

Therefore, milk and dairy products must be transported promptly - in a very short time!

Dairy products mean kefir, yogurt, sour cream, cream, butter, cottage cheese, cheese, etc.

The company "RefPorevozka" has been engaged in the transportation and delivery of various types of goods, including milk and dairy products, for a considerable time. We have both experience and our own vehicles for transportation of temperature cargo, as well as partnerships with other reliable carriers. This allows us to offer not only prompt delivery of milk and dairy products, but also beneficial cooperation.

Conditions for the carriage of milk and dairy products

There are a number of requirements and nuances in the transportation of milk and dairy products that must be strictly observed. It also requires experience and increased attention to temperature conditions.

For example, a vehicle for the transportation of dairy products must necessarily comply with the established GOSTs, undergo mandatory sanitary and veterinary inspections, and also have the suitability of power plants and units in the technical part.

Before use, the transport undergoes mandatory cleaning and washing of previously transported cargo with the issuance of the necessary certificates of suitability for the transportation of dairy products.

There are also requirements for storage times and transportation, for containers and packaging, etc.

In addition, since dairy products also have increased acidity, their transportation and ventilation temperatures also differ. Plus, seasonality is also important.

The last point is a separate topic, but in general, during the transportation of dairy and fermented milk products, the temperature inside the vehicle should be from +2 to +4 o C. In more detail, the temperature regime of a particular dairy product can be found in the following table:

Moreover, it is also important to take into account the issue of commodity proximity, in which it is unacceptable that many other food products are transported in a vehicle along with dairy products.

There are a number of other points that are important to consider and observe in the transportation of products of this type. In the future, we plan to prepare a number of articles on this topic.

Transport for the delivery of milk and dairy products

Depending on the type of dairy products, cargo volume, distance distance and a number of other factors that are clarified during the processing of the application, we can offer different delivery options.

We have our own refrigerated containers and refrigerated sections, which we can use for transportation, including dairy products, throughout Russia, from Moscow to Vladivostok and back.

In addition, we have established reliable partnerships with other carriers. Therefore, we can always organize the delivery of your cargo with a minimum empty mileage.

If you need to transport milk in bulk, we will promptly select the delivery option that suits you, depending on the volume and route, - we will find a car with the required carrying capacity, the number of sections and the volume of the tank.

We also deliver milk and dairy products to stores and retail chains in the city of Moscow by road.

For more information about transport and delivery routes, see the sections: How do we transport and Where do we transport.

We will transport your dairy products promptly and profitably

Why do cargo owners choose to cooperate with RefPorevozka in the transportation of milk and dairy products?

In this regard, at least 5 reasons can be distinguished, namely:

1. We have practical experience multiple shipments of perishable products, including milk and dairy products.
2. We own and enjoy own and... We have our own isothermal composition, which allows us to offer favorable terms of transportation for our clients.
3. We have built partner network with other carriers, and we continue to work in this direction. This makes it possible to quickly find suitable carriers from among our partners, even if our own resources are all busy at the moment.
4. We provide full cargo escort... Our experts will help prepare all the necessary documents for transportation, as well as resolve issues related to forwarding, insurance, etc.
5. You can get from us full range of services according to the "door-to-door" scheme. We organize fast loading and / or unloading of dairy products.

We invite you to cooperate with our company in the transportation of your milk and dairy products! We are always glad to both new and regular partners and clients!

In the process of long-term storage of milk on farms at a temperature of 3-5 ° C for 2-5 days and transportation to dairies, almost all the main components of milk and its properties change to one degree or another. Fat and proteins undergo more significant changes, less significant vitamins and salts. The structure of lipid and protein components is disturbed, and this worsens the organoleptic and technological properties of milk. So, fat goes from liquid to solid during storage of milk, which increases its viscosity, acidity increases by 0.5-2T.

In the process of storing and transporting milk, the structure of the shells of fat globules is disturbed and fat is hydrolyzed under the action of native and bacterial lipases - lipolysis. Hydrolysis leads to milk rancidity. When milk is stored at low temperatures, bacterial mitases play an insignificant role in lipolysis. Under certain conditions, native lipases cause 2 types of lipolysis: spontaneous (spontaneous) and induced (induced).

The first type occurs when milk is cooled, which is prone to rancidity. Plasma lipase binds to the membranes of fat globules and causes its hydrolysis. Spontaneous lipolysis is characteristic of old milk and mastitis.

Induced occurs when the membranes of fat globules are strongly destroyed, thereby increasing the activity of lipase. This happens during transportation, repeated stirring and pouring during long-term storage at low temperatures. The content of FFAs, which cause a rancid taste of milk, increases at a concentration of more than 20 mg%. Dairy products made from such milk have taste and odor defects. To prevent them, it is necessary to eliminate the causes of their appearance and control the degree of lipolysis before processing milk chemically and organoleptically.

Proteins in raw chilled milk during long-term storage are decomposed by proteinases. Native ones are associated with micelles - casein and a small amount of them is in the plasma. Proteases from bacteria in the initial stage of proteolysis have an effect on casein similar to the action of native milk proteases. At low temperatures and long-term storage (2 days or more) of milk, the amount of Y-casein and proteose peptone fraction increases in it, which negatively affect rennet coagulation, synergetic properties of protein clots, heat resistance of milk, and other technological properties.

Vitamins and Salts. During storage and transportation of milk, the amount of vitamins does not decrease, except for vitamin C: within two days it is destroyed by 18%; within 3 days by 67%. Salt is a redistribution of their forms.

Milk transportation rules

Comparative table of requirements and rules for the transportation of dietary (therapeutic and prophylactic) drinks - jelly and compotes "Under harmful working conditions" and milk

15.1. For the transportation of milk and dairy products, specialized transport should be allocated.

15.2. Transportation of milk and dairy products should be carried out in sealed refrigerators, specialized milk tanks, machines with insulated bodies. Delivery of milk and cream from farms must be carried out in sealed milk tanks or flasks.

15.3. Transport used for the transportation of milk and dairy products must be clean, in good condition, the car body must have a hygienic coating that can be easily washed and markings on the sides of the body, corresponding to the transported products. The transport must have a sanitary passport issued by territorial bodies and institutions carrying out state sanitary supervision for each vehicle for a period of not more than 6 months. A car without a sanitary passport is not allowed on the territory of the enterprise.

The administration of the enterprise appoints a person responsible for monitoring the state of transport. Loading is not allowed without inspection of the transport by the responsible person and his permission.

15.4. It is forbidden to transport dairy products together with raw products (meat, poultry, fish, eggs, vegetables, fruits), semi-finished products, as well as in vehicles that previously transported pesticides, gasoline, kerosene and other strong-smelling and toxic substances.

15.5. During the warm period of the year, the period of loading, delivery and unloading of perishable whole milk products during their transportation in refrigerators should not exceed 6 hours (in the absence of temperature-recording devices). It is allowed to use insulated vehicles for transportation over short distances, the above period in such cases should not exceed 2 hours. When shipment of perishable dairy, fermented milk products and milk, the company makes a note in the accompanying documents about the start time of the dispensing.

15.6. The driver-freight forwarder (freight forwarder) must have a personal medical book with marks on the passage of medical examinations and hygienic training, sets of sanitary and overalls, strictly observe the rules of personal hygiene and the rules for transporting dairy products. The issuance and change of sanitary clothing must be organized by the dairy processing enterprise (when unloading milk), as well as by the enterprise producing raw milk and cream (when loading) and carried out at least once a week.

15.7. Sanitary treatment of vehicles intended for the non-starter transportation of milk, as well as flasks, must be carried out at dairy factories in accordance with the "Instructions for the Sanitary Treatment of Equipment at Dairy Industry Enterprises." A note is made about the processing carried out in the waybill; without this mark, the car is not released from the territory of the plant.

Section 16

Occupational hygiene

16.1. When designing and reconstructing dairy enterprises, it is necessary to take into account the sanitary and hygienic norms and rules for the organization and hygiene of labor, as well as those established by these SanPiN.

16.2. Control over working conditions should include an assessment of production factors (microclimate parameters; industrial noise and vibration, electric field strength of industrial frequency currents at workplaces; natural and artificial lighting; air pollution of the working area with aerosols and gases; psychophysiological factors associated with the nature of work; household conditions at work; catering and medical services) with a hygienic assessment of working conditions.

16.3. The microclimate of the premises (temperature, relative humidity, air velocity) must comply with SanPiN "Hygienic requirements for the microclimate of industrial premises".

16.5. The levels of noise and vibration, as well as the intensity of the electric field of industrial frequency currents in the workplaces of industrial premises must comply with the requirements of the current SanPiN.

16.6. The value of the coefficients of natural lighting (KEO, SK) and illumination of working surfaces with artificial lighting must comply with the requirements of the current SNB "Natural and artificial lighting" and "Sanitary requirements for the design of dairy enterprises", taking into account the characteristics of visual work.

16.7. At enterprises of the dairy industry, household premises must be provided in accordance with the requirements of SNiP "Administrative and domestic buildings" and "Standards for technological design of enterprises of the dairy industry" (see section 6 of these SanPiN).

16.8. The administration is obliged to organize meals for workers (canteen, buffet, dining rooms). The mode of operation of a catering establishment is established taking into account the number of work shifts, their duration, and the time of the lunch break.

16.9. Persons exposed to harmful and unfavorable production factors are subject to mandatory preliminary and periodic medical examinations in accordance with the Resolution of the Ministry of Health of the Republic of Belarus dated 08.08.2000 No. 33 "On the procedure for conducting mandatory medical examinations."

16.10. Medical workers of medical and sanitary units, health centers of the enterprise, together with specialists of territorial bodies and institutions carrying out state sanitary supervision, should analyze the health status of workers based on the study of morbidity with temporary disability, occupational morbidity and the results of periodic medical examinations. Based on the results of the study of the state of health, a plan of health-improving measures is being developed.

16.11. The administration is obliged to provide workers with a full set of overalls in accordance with current regulations. Workers exposed to harmful production factors must be provided with personal protective equipment.

16.12. All workshops must be provided with first aid kits for first aid.

Section 17

Personal hygiene

17.1. Each employee of a dairy enterprise is responsible for compliance with the rules of personal hygiene, the condition of his workplace, strict compliance with technological and sanitary requirements at his site.

17.2. Persons applying for work and working at the enterprise must undergo preliminary and periodic medical examinations in accordance with the "List of Occupational Diseases", Resolution of the Ministry of Health of the Republic of Belarus dated 08.08.2000 No. 33 "On the procedure for conducting compulsory medical examinations".

17.3. According to epidemiological indications, by decision of territorial bodies and institutions carrying out state sanitary supervision, an unscheduled bacteriological examination of workers can be carried out.

17.4. For each employee, upon admission to work, a medical book must be drawn up, in which the results of all medical examinations and studies, information about the transferred infectious diseases, data on the origin of training in the hygienic training program are entered.

Personal medical records should be kept in the health center or at the head (foreman) of the workshop.

17.5. Persons suffering from the following diseases (or carrying bacteria) are not allowed to work:

typhoid fever, paratyphoid fever, salmonellosis, dysentery;

hymenolepiasis, enterobiasis;

syphilis in the infectious period;

infectious skin diseases: scabies, trichophytosis, microsporia, scab, actinomycosis with ulceration or fistula on open parts of the body;

infectious and destructive forms of pulmonary tuberculosis;

extrapulmonary tuberculosis with fistulas, bacteriuria;

tuberculous lupus erythematosus of the face and hands;

pustular diseases.

17.6. Persons who have not passed a timely medical examination may be suspended from work in accordance with applicable law.

17.7. Workers of production shops are obliged to inform the administration about this if signs of gastrointestinal diseases, fever, suppuration, symptoms of other diseases appear and contact the health center of the enterprise or other medical institution to receive appropriate treatment.

17.8. Persons who have infectious patients in the family or apartment in which they live are not allowed to work until special anti-epidemic measures are taken and a special certificate is submitted from bodies and institutions exercising state sanitary supervision.

17.9. Coming to work, each worker of the shop must sign in a special magazine that he and his family members have no intestinal diseases.

17.10. To identify persons with pustular skin lesions and catarrhal phenomena, the medical workers of the enterprise should check the hands and throat of the personnel daily, with an entry in a special journal, which indicates the date of the inspection, the last name, first name, patronymic of the employee, the results of the examination and the measures taken.

In the absence of a medical worker on the staff of the enterprise, such a procedure should be carried out by a sanitary post (specially assigned and trained worker) of the enterprise or by a workshop foreman.

17.11. All newly admitted workers must complete a compulsory hygiene training program and pass the exam with a note of this in the appropriate journal and in the personal medical record. In the future, all employees must undergo training and testing of hygienic knowledge once every two years, employees of the starter department - annually. Persons who have not passed the hygienic training exam are not allowed to work.

17.12. Specially created commissions with the participation of bodies and institutions carrying out state sanitary supervision once in two years should certify executives and specialists for their knowledge of sanitary rules and norms and the basics of hygienic and anti-epidemic requirements for the production of milk and dairy products.

17.13. Before starting work, workers in production shops should take a shower, put on clean sanitary clothes so that they completely cover their personal clothes, pick up their hair under a kerchief, cap (hat), wash their hands thoroughly with warm water and soap and carry out an antiseptic treatment.

17.14. Each worker of the production department must be provided with 4 sets of sanitary clothes (workers of the shops for the production of children's products - 6 sets); clothes are changed daily and as they become dirty. It is forbidden to enter production halls without sanitary clothing. Washing and disinfection of sanitary clothes is carried out at the enterprises on a centralized basis; it is prohibited to wash sanitary clothes at home.

17.15. Locksmiths, electricians and other workers engaged in repair work in the production and warehouse premises of the enterprise are required to follow the rules of personal hygiene, work in workshops in sanitary clothes (have 2 sets), carry tools in special closed boxes with handles.

17.16. When leaving the building on the territory and visiting non-production premises (toilets, dining room, first-aid post, etc.), sanitary clothes must be removed; it is forbidden to put any outer clothing on the sanitary clothes.

17.18. Smoking is allowed only in designated areas.

17.19. Eating is allowed only in canteens, canteens, dining rooms or other food outlets located on or near the enterprise.

17.20. Workers should be especially careful to keep their hands clean. Fingernails should be cut short and not varnished. Hands should be washed and antiseptic before starting work and after each break in work, when moving from one operation to another, after touching contaminated objects. The workers of the starter culture departments should be especially careful to wash and antiseptically treat their hands before fermenting milk, separating kefir fungi and before draining the starter culture.

To improve the efficiency of hand treatment, it is recommended that hands be antiseptic before and after washing.

After visiting the toilet, hands should be washed and antiseptic twice: in the airlock after visiting the toilet before putting on a dressing gown and at the workplace, just before starting work.

Antiseptic treatment of hands should be carried out with antiseptic solutions approved by the Ministry of Health in concentrations equivalent to an active chlorine content of 150 mg / l.

When leaving the toilet, disinfect your shoes on a disinfecting mat. Disinfectant solutions must be replaced daily.

17.21 Rules for handrub are given in Appendix 4

17.22. The cleanliness of the hands of each worker is checked at least 3 times a month by a microbiologist of the factory laboratory (without prior warning), before starting work, after visiting the toilet, especially for those workers who are in direct contact with products or clean equipment. Hand cleanliness is controlled by the methods described in the "Instructions for microbiological control of production at dairy enterprises". The cleanliness of the hands with the help of the iodine starch test is monitored once a week. The iodine-starch test is carried out by a specially assigned and trained worker (sanitary post).

Disinsection, deratization

18.1. Flies, cockroaches, rodents and other insects are not allowed in the dairy industry.

18.2. To carry out disinsection, deratization works, the administration of the enterprise must conclude an agreement with the department of preventive disinfection of the territorial center of hygiene and epidemiology or with another specialized enterprise licensed to carry out these works.

The contracts must be renewed annually.

18.3. The enterprises must create the necessary conditions for the effective conduct of pest control and disinfestation work, exclude the possibility of contact of chemicals with manufactured products, auxiliary, packaging materials, containers.

18.4. To control flies in the dairy industry, the following preventive measures should be taken:

thorough and timely cleaning of the premises;

timely collection of food waste and garbage in containers with tight-fitting lids;

timely removal of food waste and garbage with subsequent washing and disinfection of containers with solutions approved by the Ministry of Health of disinfectants;

sweeping of all openable windows and doorways for the spring and summer period.

Extermination of flies in flight form is carried out in accordance with the current "Methodological guidelines for the fight against flies" approved by the USSR Ministry of Health and instructions.

18.5. In order to prevent the appearance of cockroaches, it is necessary to close up all the cracks in the walls, partitions, to prevent the accumulation of crumbs, food debris. If cockroaches are found, it is necessary to thoroughly clean the premises and disinfest with permitted means.

18.6. To protect raw materials and finished products from rodents, the following measures should be taken:

closing windows in basement floors with metal bars, hatches - with tight covers;

closure of ventilation openings and channels with metal grids with cells of no more than 0.25 x 0.25 cm;

filling holes, cracks in floors, near pipelines and radiators with bricks, cement, metal shavings or sheet metal;

upholstery of warehouse doors with iron.

18.7. During the reconstruction and repair of workshops of enterprises, it is necessary to fully carry out construction and technical measures to protect buildings and premises from the penetration of rodents.

18.8. In the event of the appearance of rodents, mechanical methods of destruction are used (top, traps). Carrying out work on the destruction of insects and rodents by chemical means is allowed only by the forces of exterminators and exterminators.

18.9. It is forbidden to use bacteriological methods of rodent control in the dairy industry.

18.10. When carrying out disinsection measures, the production of dairy products is not allowed.

If milk cannot be sent quickly to a processing plant, it is stored in milk tanks, tubs, vats and jars. For storage of milk, closed thermos tanks are also used. In closed tanks, milk is protected from foreign odors and mechanical impurities.

Storing milk at low temperatures only slows down the development of microbes, but does not eliminate the possibility of their spread. The lids of the flasks must be open to allow gases to escape. The neck of the flasks is covered with gauze to prevent dirt from getting in. It is not economically viable to store milk in jars. For long-term storage, use the tank TOM-2A, cooling tanks RPO-1.6 RPO-2.5. Milk can be stored for up to 48 hours in vertical and horizontal tanks or VO-1000 vats. During a 20-hour storage period, the temperature of milk rises by 1-2 0 С when the temperature difference between the ambient air and the product is equal to 24 0 С. Do not mix chilled milk with warm milk and milk of different milk yields if the temperature difference exceeds 2 0 С. When storing milk 12-18 hours the temperature of the cooled milk should be 6-8 0 C, within 18-24 hours - 5-6 and within 36-48 hours - 1-2 0 C.

When transporting milk to processing plants, it is necessary to preserve its original qualities as much as possible. In the republic, milk is mainly transported by milk tankers in special isothermal milk tanks. They have two, sometimes three, well insulated sections. During the summer period, during transportation to a distance of up to 100 km, the milk temperature rises only by 1-2 0 C. Each section of the tank is filled with milk of uniform quality and completely so that it does not churn. When transported in winter, milk is protected from freezing. Milk obtained from cows suffering from mastitis, tuberculosis, brucellosis, leukemia and other diseases is delivered in a separate container.

When selling milk, a consignment note is drawn up for the dispatch of milk and dairy products, which indicates the mass of the product, its quality, temperature and time of dispatch. The dairy returns a copy of the invoice, which shows the actual accepted weight and quality of the product, as well as the test weight based on the conversion to basis fat content.

PASTEURIZED, STERILIZED

MILK & CREAM

4.1. Structure of milk processing in Belarus

According to human nutrition standards, milk and dairy products in the annual diet should be 433.6 kg, including whole milk 130 kg, butter - 6, cottage cheese - 8.9, sour cream - 7.3, cheese - 5.8 and low-fat products - 16.7 kg. To provide the population of the Republic of Belarus with dairy products in accordance with these consumption rates, 4.2 million tons of milk are required per year.

Formed material and technical base of enterprises in the 60-80s. does not meet modern requirements. Many enterprises of the republic do not meet the sanitary and veterinary requirements of the countries of the European Community. Compared to developed countries, Belarus has always had a low level of industrial processing of raw milk - less than 60%.

The structure of milk processing in Belarus is largely traditional, it has survived from the times when the bulk of dairy raw materials were processed into butter and milk powder - long-term storage products with the possibility of transporting them to remote regions of the USSR. Of the total volume of state procurements in the processing structure, 50-53% of milk was used for the production of butter, 14-17% for the production of fatty cheeses, and 30-34% for the production of whole milk and other products. Due to the low quality of milk (only 8% of milk produced in the republic is cheese-grade) and insufficient capacity, very little cheese is produced.

One of the main areas of work of the dairy industry is the production of combined dairy products using raw materials of animal and vegetable origin. The biological value of dairy products is supposed to be increased by enriching them with a complex of vitamins; natural and synthetic flavoring additives will be widely used.

Dairy processing enterprises receive a large volume of so-called secondary milk raw materials: skim milk, buttermilk, and whey. These foods contain many valuable nutrients, especially lactose and protein. The energy value of skim milk and buttermilk is half that of whole milk. When processing a product such as milk, there should be no waste. Therefore, it is necessary to move from the technology for the production of individual dairy products (butter, cheese, cottage cheese, etc.) to the technology of complete processing into food, i.e. to carry out waste-free processing of milk.

4.2. Homogenization, pasteurization and sterilization of milk

Homogenization- crushing (dispersing) fat globules into smaller ones and their uniform distribution in milk due to high pressure (15-20 MPa) in homogenizers. It is carried out at a temperature of 65-95 ° C and an exposure of about 15-20 s. up to 10-15 minutes. The degree of homogenization reaches 80-85%, and the size of the balls decreases by about 10 times (Fig. 2). Homogenizing milk prevents fat from settling. The product becomes more homogeneous, the loss of fat with whey is reduced, the consistency of the cheese mass and the miscibility of the components are improved. Homogenized milk is easier and more fully assimilated, and its shelf life is increased. Homogenization is used in the production of drinking milk, fermented milk products, cream, sour cream, canned milk and milk replacer. Homogenization is the most energy-intensive process in the dairy industry.

Pasteurization- heating milk from 63 0 С and slightly below the boiling point. The purpose of pasteurization is to destroy microflora, especially disease-causing microflora, and to extend the shelf life of milk. It destroys 99.9% of vegetative microflora and is the main method of milk neutralization. Milk is pasteurized when sent to retail chains and canteens.

Thanks to pasteurization, milk acquires relative stability for a certain period of time and processors have the opportunity to produce a safe and sound product.

Rice. 2. Fat globules under the microscope:

a - non-homogenized milk; b - homogenized milk

Three modes of milk pasteurization are used: long-term pasteurization at a temperature of 63-65 0 С for 30 minutes is used in public catering, short-term - at a temperature of 72-76 0 С milk is kept for 15-20 s, used in cheese making and in the preparation of whole milk products, instant - milk is heated to a temperature of 85-90 0 С without holding (no more than 2 s) when preparing butter and cheeses. Each type of product has its own pasteurization modes. For example, in the production of rennet cheeses, the pasteurization temperature is set at 72-76 ° C, in the preparation of fermented milk products - up to 95 ° C. After pasteurization, milk is most often subjected to immediate cooling.

During pasteurization, some components of the milk are partially changed. Albumin begins to denature at a temperature of 60-65 ° C. At temperatures above 85 ° C, calcium is cleaved from casein. At the same temperature, milk acquires a specific taste and aroma. During pasteurization, the loss of vitamin B 12 reaches 90%, vitamin C - 30 and vitamin B 1 - 15%. Heating milk contributes to the destruction of some enzymes, and at temperatures above 80 0 C, there are no enzymes in milk. Soluble phosphate salts become insoluble.

Sterilization (boiling)- heating milk above the boiling point. It is used to destroy not only vegetative, but also spore forms of microorganisms, which significantly increases the shelf life of finished products at room temperature. In practice, the following sterilization modes are used: I - in bottles in batch autoclaves at a temperature of 103-108 0 С for 14-18 minutes; II - in bottles in continuous sterilizers at a temperature of 117-120 0 С for 15-20 minutes; III - instantaneous at a temperature of 140-142 0 С with aseptic filling into paper bags. In the process of sterilization, the rennet coagulation of milk deteriorates. In a hermetically sealed container, sterilized milk can be stored for a long time at room temperature.

4.3. Separation of milk

Separation- a method of mechanical processing of milk, allowing it to be divided into two fractions - cream and skim milk, as well as used for cleaning it from contamination. Separation of milk is based on the use of centrifugal force arising in a rapidly rotating drum - the main working element of the separator. Under the influence of this force, milk is divided into fractions depending on their density. Skim milk with an average density of 1033 kg / m 3 is thrown to the edges of the drum, while fat globules with a lower density collect in the form of cream and move towards the axis of rotation and concentrate in the central part. Somatic cells, mechanical impurities, as heavier, are thrown to the wall of the drum and settle in the mud space. Cream and skim milk leaves the separator in a cleaned state.

Separators-milk purifiers, separators-cream separators, separators for obtaining high-fat cream and universal ones with replaceable drums are distinguished according to their purpose. The weight ratio between cream and skim milk after separation can vary over a very wide range - from 1: 3 to 1:12, i.e. you can get cream of a certain fat content.

All separators consist of the following main components: drum, drive mechanism, inlet and outlet device, milk dishes and bed. On small and medium-sized farms, SOM-7-600 and SOM-3-1000 are used. Separator SOM-7-600 operates from a drive and can be manually operated, and SOM-3-1000 - from a 1 kW electric motor. Separators SPFM-200 and OSB can be used on large farms and dairy complexes.

For a more complete skimming of milk, the following conditions must be observed:

· The temperature of milk should be 40-45 0 С, while the release of small fat globules is facilitated;

With heavy contamination of milk, the mud space quickly fills, mucus begins to settle on the drum plates, the separation of milk worsens, the transition of fat to the return increases;

· The larger the fat globules, the higher the degree of defatting, and the fat globules less than 1 micron, almost all remain in the waste (approximately 0.02-0.05% fat);

· High acidity of milk negatively affects the separation process, as it promotes partial coagulation of milk proteins, which fill the space and gaps between the plates;

· Correct assembly of the drum ensures a reduction in the transition of fat to skim milk;

· It is necessary that the number of cymbals in the drum strictly corresponds to the passport requirements;

· The duration of separation should be no more than 1.5-2 hours, after which the drum is disassembled and cleaned of impurities.

Before starting milk separation, the necessary calculations are made. To do this, you need to know the amount of milk (M) intended for separation, and the fat content in it (LM). Then it is determined what amount of cream (C) of a given fat content (Ls) can be obtained from the milk intended for separation, taking into account the fat content in the skimmed milk (Zho). The calculation is carried out according to the following formula:

4.4. Pasteurized milk

According to the physiological norm, a person should consume 50% of all dairy products in the form of drinking milk. It is assumed that in the future, profound changes will take place in the technology of drinking milk, primarily related to the shelf life, which must be extended to 30-40 days. For this, it is planned to use more widely the ultra-high-temperature processing of milk (sterilization) and its packaging under aseptic conditions. The production of products with a reduced energy value and the use of various kinds of flavors and flavoring additives will be expanded. But for this it is necessary to solve the problem of the quality of dairy raw materials, since it is impossible to obtain high-quality products from raw materials of poor quality.

The republic produces many types of drinking pasteurized milk with different fat content, SNF, different fillers. According to the fat content, milk can be whole (natural not skimmed), natural normalized with the addition of skim milk and cream, skim or protein, in which fat is completely or partially removed during separation. Milk is called normalized, in which the proportion of fat is brought to certain indicators (1.5%, 2.5, 3.2%). According to the method of processing, milk is produced as pasteurized, pasteurized vitamin, reconstituted and baked milk. For the production of pasteurized drinking milk, natural cow and skim milk, buttermilk with an acidity of not more than 19 0 T, whole and skim milk powder, cream are used.

Pasteurized milk is produced according to the following scheme: acceptance and quality assessment, cleaning at a temperature of 35-40 0 С, immediate cooling to 2-4 0 С, redundancy, fat normalization, heating to 45-65 0 С, homogenization at a pressure of 12-15 MPa, pasteurization (74-78 0 С, 15-20 s), cooling to 4-6 0 С, container preparation, filling, capping and marking, storage and transportation.

Pasteurized milk is packaged in plastic and paper bags. The paper bags are covered with paraffin on the outside, and inside with polyethylene. Packaged milk is transferred for sale at a temperature not higher than 7 0 C or sent to storage in refrigerating chambers for a period not exceeding 18 hours with a temperature not higher than 8 0 C and a humidity of 85-90%. Milk is sold not more than 36 hours from the date of manufacture.

The quality of pasteurized milk is controlled by temperature, acidity, fat content, taste and smell, pasteurization test, bacterial contamination and E. coli titer.

Protein milk characterized by a high content of dry skimmed substance due to the addition of condensed skim milk. In terms of organoleptic properties, it fully corresponds to whole pasteurized milk, and in terms of biological value it surpasses it.

Protein milk is produced according to the following technological scheme: acceptance of raw materials, preparation, normalization, purification, pasteurization under various modes, homogenization (65 0 С), cooling (4-6 0 С), bottling, storage. During the preparation process, the feedstock is double-normalized in terms of fat and dry matter content. For the production of protein milk, milk is used with an acidity not higher than 19 0 T. The finished product contains 4.5% protein, acidity not higher than 25 0 T.

Reconstituted milk is produced in whole or in part from dry whole or skim milk obtained by spray drying, by dissolving it in good-quality drinking water at a temperature of 45-50 0 С and normalizing to the required fat content. Hotter or colder water slows down the dissolution of dry matter. During the aging process, the proteins swell and the dry matter dissolves better. In terms of biological value, it is not inferior to normalized pasteurized milk. After reconstitution, the milk is quickly cooled to 6-8 ° C and kept for 3-4 hours. The reconstituted milk must be homogenized to prevent the appearance of fat droplets on the surface. The technological scheme of milk production is as follows: purification, homogenization, pasteurization and cooling. Before pasteurization, milk is heated to 70-80 ° C, homogenized at a pressure of 12 MPa. Recovered milk in winter is quite often used in human nutrition, especially in large industrial centers. This is due to the pronounced seasonality of milk production, since in the summer period, which lasts about 5 months, almost half of the gross annual milk production is produced.

Fortified milk are prepared by enriching pasteurized milk with vitamin C, since it is easily destroyed due to its easy oxidizability during processing and transportation. The technological process for obtaining fortified milk is the same as for ordinary pasteurized milk. Vitamin C is added to milk after pasteurization to reduce its loss. In the production of fortified milk, homogenization is mandatory. Ready fortified milk is stored at a temperature not exceeding 8 0 С, since at elevated temperatures vitamin C is destroyed. According to its chemical composition, organoleptic properties and physicochemical indicators, it is the same as pasteurized whole milk.

Baked milk obtained according to the following technological scheme: acceptance of raw materials, quality assessment, cleaning, normalization, pasteurization (95-99 0 С) using tubular pasteurizers, heating in closed containers for 3-4 hours until a brown color appears, cooling to 8 0 С, pour storage. The temperature regime during the heating period should not be lower than 95 0 C. Every hour for 2-3 minutes the milk is stirred to avoid the formation of a layer of protein and fat on the surface. Due to high temperatures, milk components change significantly. Baked milk has a creamy color with a brownish tint, a uniform consistency without sediment, a specific taste and smell of pasteurized milk. Its acidity should not exceed 21 0 T.

1.1.1. Milk transportation methods

and dairy products

The method of transporting raw materials to a dairy plant significantly affects the quality and cost of the resulting product.

Milk is transported over long distances in flasks and various containers called transport tanks. Inside the factories, milk is transported through milk pipelines.

When transporting milk from farms to processing plants, flasks, tank trucks and milk pipelines are used. In large volumes (1000 liters and more) milk is transported in tanks using road, rail and water transport.

Small quantities of milk are transported in flasks by trucks. With this method, labor costs are high for loading and unloading operations and milk losses, and the transportation conditions do not meet the sanitary and hygienic requirements for food products. At the same time, it is used to transport liquid products (sour cream, condensed milk, etc.) to a retail network, a public catering network.

Tank trucks. The tank truck consists of one or more elliptical sections with spherical bottoms. Outside, the sections are covered with thermal insulation, wood cladding and parchment tom, on top of which a protective casing made of sheet carbon or stainless steel is installed. The wooden cladding protects the thermal insulation material (most often mipora or molding foam) from mechanical damage, and the casing protects from moisture penetration. The thermal insulation layer covering the sections prevents the milk from heating up and freezing during transport. The section made of food grade aluminum sheet or food grade stainless steel, depending on the brand of the tanker, has a capacity of 0.9 to 6.55 m3 of milk (Table 1.1).

Tab. 1.1. Technical characteristics of tank cars

In the places of attachment to the chassis of a car or trailer, the sections are equipped with supporting belts made of wooden bars fastened together.

For washing and inspection of the working container in the section, a hatch is used, which is hermetically closed by a cover with a sealing ring rubber gasket. On the inner surface of the mouth of the hatch there are circular marks indicating the milk level when the section is filled with it. Each section is equipped with one valve located at the end of the bottom and connected to the milk pipe by means of a fitting for pouring and unloading milk. Using special equipment, hoses are connected to the fittings, for storage of which the tank is equipped with a luggage carrier. So that the unions in the transport position do not get dirty, they are tightly closed with plugs. The valves are manually operated by means of handwheels mounted on the valve stems and equipped with protective cases.

The section is filled with milk due to the vacuum created by an autonomous vehicle filling system or by a pump installed at the milk collection point. Since the cistern is filled from below through the milk pipe, the milk does not froth. Milk is drained from the tank by gravity or pumped by a dairy pump.

To control the milk level in the sections, most tanks are equipped with an electrical alarm system consisting of a panel, an induction coil, a reverse current relay, switches and a float lever. When the section is filled with milk, the float device closes the circuit and a sound signal is turned on.

Small tankers are flushed by pumping water and detergents inside through the dairy pipeline. Tank trucks with a capacity of more than 10 m3 are also washed from the pipeline of the plant. However, in this case, the washing process itself is not carried out manually, but with the help of special washing heads, which rotate during operation and thus ensure high-quality washing of tanks.

Milk pipelines. Of particular interest is the use of a milk pipeline system for transporting milk to processing enterprises of small and medium capacity in the case when they are slightly removed from dairy farms. Experience has shown a whole number of advantages of such delivery over all other methods: a high operational reliability, simplicity and ease of maintenance, the ability to use in off-road conditions, and a reduction in the duration of milk transportation.

In mountainous areas, due to the height difference between the points of reception and collection of milk, gravity milk pipelines made of polyethylene pipes with a diameter of 16, 20 or 25 mm are economical. In accessible places, they are laid in the ground to a depth of 40 ... 70 cm, and in gorges, on steep slopes, above water barriers, they are attached to intermediate supports or steel wire tightly stretched between the supports.

Pressure systems include milk pipelines laid on flat terrain in the ground below the soil freezing zone. The underground pressure milk pipe consists of two parallel polyethylene pipes, through one of which milk is supplied, through the other - compressed air. Milk line equipment includes a thermos tank, pump, milk meter, scales and milk collection tank. The air line consists of a compressor, oil separator, air cooler, spray trap and filter.

The underground milk pipeline works as follows. The milk is pumped by a centrifugal pump through the meter into the milk line. Then insert a cork made of porous food grade rubber. Compressed air from the compressor, supplied to the milk line, moves the plug and displaces milk from the pipeline into the pan of the milk receiving scale.

1.1.1. Methods for transporting milk and dairy products

factory. In this case, the rubber stopper is retained in the catcher. Thus, the operation of an underground milk pipeline consists of three periods: filling the pipeline with liquid, moving the liquid, and emptying the pipeline.

Long milk pipelines are usually made of polyethylene pipes. They are frost-resistant, retain their flexibility even in the range from -30 to -60 ° C. The liquid in these pipes freezes 3 ... 4 times slower than in metal ones. When the liquid freezes, the pipes do not collapse, but due to their elasticity, they increase in diameter and, after the liquid thaws, regain their previous shape. Pipes with an outer diameter of 15 ... 50 mm are supplied by the industry rolled into coils. The length of the pipe in the bay can be up to 250 m, which makes it possible to lay a milk pipeline with a minimum number of butt joints and completely mechanize the laying process.

Polyethylene pipes can be connected both by contact method (welding) and by means of detachable joints.

The range of pipes made of low density polyethylene is given in table. 1.2.

Tab. 1.2. Characteristics of polyethylene pipes

Flasks. Flasks (Fig. 1.1) must be hermetically sealed, easy to carry, loading, unloading and washing, durable and hygienic.

1.1. Transportation of milk to dairy factories, acceptance and storage

Rice. 1.1. Flask:

1 - case; 2- plank; 9-handle; 4- upper hoop; 5-carbine; 6 - funnel; 7- neck; 8 - hinge; 9 - rubber ring; 10 - on the loop; 11 - clamping bar; 12 - lower hoop

Flasks are made primarily of sheet steel; all seams are welded; Tinned by two-, three-fold immersion in molten tin.

Recently, aluminum flasks have become widespread, but milk should not be stored and cooled in them.

Flasks are also made of stainless steel. Such flasks differ from tinned and aluminum ones in greater wear resistance and hygiene.

The technical characteristics of the flasks are given in table. 1.3.

Tab. 1.3. Technical characteristics of flasks

1.1.1. Methods for transporting milk and dairy products

Tab. 1.3. Technical characteristics of flasks (end)

To transport the flasks, trolleys can be used (Fig. 1.2 and Fig. 1.147, page 329).

Rice. 1.2. Flask trolleys (without lifting platform):

1 - pipe; 2 - handle; 3 - meadows; 4 - wheels; 5 - coupling

It consists of a gas pipe 1 with a diameter of 1 ", smoothly bent at an angle of 90 ° and has a handle 2 at one end and a welded arc 3 made of the same pipe at the other end. Wheel axles are welded at the ends of the arc. 4 The wheels are fitted with solid rubber tires. for quiet running.

On the pipe 1 there is a coupling 5 with two hooks located at different heights. Two hooks on the sleeve are provided due to the presence of flasks with handles located on different

1. 1. Transportation of milk to dairy factories, acceptance and storage

height. There are two cutouts in the lower end of the sleeve allow the sleeve to be installed in two positions, turning one or the other hook towards the flask.

The pipe 7 has a transverse pin that goes into the cutouts of the coupling 5 and holds it on the pipe in a certain place.

The filled flask is crocheted by the handle, lifting the handle 2 of the trolley, as shown in the figure with a dotted line. When lowering the handle of the trolley, the flask rises by 2 ... 4 cm and is transported. A little effort is required to move the flask on a smooth floor. When unloading the cart, the handle 2 is raised, as a result of which the flask is placed on the floor and the cart is rolled away.

The carts described are applicable in narrow aisles where large carts cannot be used.

The flasks can also be transported on conventional cargo trolleys. To empty the flasks, special devices are used - flask dumpers, which are a metal frame with which the flask can be easily rotated on a hinge,

passing near the center of gravity of the flask.

Basic safety rules for the operation of equipment for the transportation and storage of milk. Tank trucks and containers must have protective earthing. It is necessary to check the reliability of the fastening of the tank hatches in order to avoid their possible opening during operation. Hatches and agitators of containers must have blocking devices that exclude the possibility of turning on the agitator when the hatch is open. It is necessary to take precautions when using a ladder, container for inspecting the agitator drive (with its top position).

In installations for cooling milk on farms, the container, housing, compressor, electric motors and starting equipment must be reliably grounded. It is necessary to systematically check the serviceability of the grounding devices. To carry out work on the compressor, mixer and pump, the entire installation must be de-energized. The freon pipeline and the entire cooling system of the baths are not allowed to be disassembled, as this can cause the loss of freon. The compressor relief valve should be checked systematically.

1.1.2. Reception and storage of milk

and dairy products

Tank equipment is one of the common types of equipment for storage and processing of milk. Capacitive equipment is designed to perform various technological operations in the processing of milk and dairy products: accumulation and storage, heating, cooling, normalization, fermentation, pasteurization, ripening, etc. Capacitive equipment refers to batch process apparatuses.

In terms of functionality, capacitive equipment can be divided into three groups: storage tanks, capacitive devices and universal tanks.

The main elements of the capacitive equipment are a housing with a heating and cooling system, mixing and washing devices, a control panel with devices for monitoring and regulating the technological process, a platform and a service ladder. Several containers of the same type, usually have one common service platform and one or two ladders. There are also removable ladders included in the equipment set for the installation and repair of the container components located inside the case.

The main requirements for tank equipment are reduced to the creation of optimal conditions for the processing of milk and dairy products in accordance with the required technological process while maintaining the quantity and quality of the feedstock and finished product.

The main technological parameters of the tank equipment include:

The nominal volume of the vessel body V is the nominal volume of the inner cavity of the vessel body. In other words, this is the largest volume of milk filling the body of the container or

1.1. Transportation of milk to dairy factories, acceptance and storage

product, in which the operation of the container is ensured with the fulfillment of all the requirements imposed on it.

The actual volume V L is the volume of the internal cavity of the container, determined by the actual dimensions of the manufactured product, minus the volume occupied by the internal devices.

The pressure of the product in the container body is usually atmospheric. The product temperature is maintained depending on the need

temperature parameters and properties of the processed product. Capacitive equipment used for processing milk and dairy products usually allows the process to be carried out at different temperatures from 4 to 95 ° C.

The temperature of the heat and coolant also depends on the technological process of product processing and is, respectively, 140 ° С (steam), (25 ± 2) ° С (warm water) and 0.5 ... 3 ° С (ice water).

The rotation frequency of the mixer of rotary mechanical mixing devices is 10 ... 180 rpm. For circulating jet mixing devices, the rotor speed on the pump reaches 2800 rpm.

Along with the listed main parameters, the capacitive equipment is characterized by overall dimensions (length, width, height, occupied area) and weight.

In the manufacture of capacitive equipment, ferrous and non-ferrous metals, alloys and other materials, including polymeric ones, are used as construction materials. Parts of equipment in contact with milk and dairy products should not corrode and degrade under the influence of technical detergents and disinfectants. Cleaning of product residues should not be difficult. Various paints and varnishes and enamels with high protective properties are used to protect structural materials from corrosion. At present, cladding made of corrosion-resistant steel or combined metallization-varnish-and-paint or polymer coatings (up to 5 ... 6 layers) are increasingly used. Rubber and rubber-woven plates that are not in contact with food are used as seals for various parts, and in places in contact with food, plates made of special types of rubber operating in the temperature range from -30 to + 110 ° C are used.

1.1.2. Reception and storage of milk and dairy products

To reduce heat loss to the environment and lower the temperature of the outer surfaces of the capacitive equipment, heat insulating materials are used that meet the following basic requirements: have low thermal conductivity and heat capacity, low density, high heat resistance, sufficient strength, low hygroscopicity, biostability, anticorrosion, harmlessness, be cheap and easy to install. These properties are satisfied, for example, by filling phenol-formaldehyde foam FRP-1.

Capacitive technological equipment (capacitive devices) are often included in the complete set of technological lines for the production of butter, drinking milk, fermented milk products, children's dairy products, cottage cheese, etc. providing the required temperature regime. Moreover, in each apparatus it is possible to carry out one or several technological processes. In addition to the general requirements for storage containers, vessels must meet the following requirements. The heating and cooling system must be capable of recirculating scale and dirt removal using chemical agents.

Large capacity equipment is mainly used for receiving, accumulating and storing milk. Storage tanks also include milk coolers designed for short-term storage of milk on farms and livestock complexes.

Pumps are the most common and most important type of processing equipment in dairies. The quality of milk and dairy products, as well as the course of the technological process, largely depend on the operation of the pumps. In this regard, it is of great importance to select the correct pump that meets the conditions and characteristics of the technological process for the production of various types of dairy products.

In the dairy industry, pumps are used mainly for pumping milk into milk storage tanks when receiving it from road, railway tanks and other containers, for transporting milk and liquid dairy products on the territory of a plant or workshop, as well as in continuous technological schemes for milk processing and production of various products for feeding and pushing the product through other devices, for example, through plate, tube pasteurizers and coolers, filters, hermetic separators, spray nozzles and other devices.

The pumps are used to set up and regulate the operating modes of machines and devices that do not have special devices for this purpose. In this case, the pumps are supplied with a drive or devices for smooth regulation of parameters: capacity, head. Pumps are used in the production of almost all types of dairy products.

In general, the following basic requirements are imposed on the design of pumps for milk and dairy products and their operation:

During operation, the pump should have the least possible mechanical effect on the product, not change its natural properties, for example, not cause a noticeable change in the fat phase of milk, not lower the viscosity (consistency) of kefir, sour cream and other products below the permissible level;

1.1.3. Pumping milk and dairy products

working bodies of pumps in contact with the product must be made of stainless steel or other materials approved by the Ministry of Health of the Russian Federation for contact with dairy products;

the design of the pumps should provide CIP cleaning or quick and easy disassembly for cleaning;

pumps should be easy to connect to pipelines;

pumps must ensure the highest flow when pumping milk from one container to another and create the required pressure when pumping the product through the devices of the technological scheme with a stable flow;

pumps for dosing milk and other dairy products

goods must ensure an even flow of the product. Such pumps must have drive mechanisms that allow to change the speed of rotation of the pump working bodies and thereby regulate the product flow.

Pumps used in the dairy industry, according to the principle of action, can be divided into the following types: vane (centrifugal), vortex, axial and positive displacement.

V vane (centrifugal) pumps, the pressure in the liquid is created by the centrifugal force arising from the rotation of the vane wheels. For pumpingwhole milk, cream, defatted other dairy products, the viscosity of which is comparatively low, as well as for the supply of detergent solutions,

v mainly centrifugal pumps.

V positive displacement pumps, a pressure difference arises when a liquid is displaced from a closed space by bodies moving reciprocating or rotational. Pumps of this type include piston, gear with external and internal gearing, rotary, cam, vane, diaphragm, screw. Dairy products with high viscosity (condensed milk, high-fat cream, cottage cheese, cheese pastes, fermented milk products) are pumped by volumetric pumps: rotary, gear, diaphragm and screw.

For transportation of products of a delicate consistency, for example, kefir, sourdough, sour cream, homemade cheese, pumps are used that have a minimum mechanical effect on the product and have a certain selected parameters.

1.1. Transportation of milk to dairy factories, acceptance and storage

The use of plunger pumps is limited, they are mainly used for generating high pressure, for example for homogenizing milk and forcing condensed milk through spray nozzles of dryers.

To supply milk under pressure through other machines, it is necessary to select pumps that provide the required head, uniform flow and consistent performance. When pumping milk from one container to another, it should be used on the pumps of the highest capacity and with a low pressure.

Most centrifugal milk pumps are designed so that they can be installed without a foundation and can be positioned with the discharge nozzle by 90 °, 180 ° and 270 °.

The main parameters of the pumps. A pump of any type, in accordance with its purpose, is characterized by the following parameters: flow rate, pressure, head, power and efficiency.

Innings. The pump flow is characterized by the amount of liquid that the pump can pump per unit of time. It can be volumetric (l / h, m3 / h, m3 / s) or mass (t / h, kg / s). Mass flow G is related to the volumetric Q ratio

where β is the density of the liquid, kg / m3.

The volumetric flow of centrifugal pumps depends on the head (as the head increases, the volumetric flow decreases) and on the viscosity of the product (when pumping a liquid of high viscosity, the pump flow decreases due to an increase in friction losses). The volumetric flow rate of positive displacement pumps does not change significantly when the pressure changes to the viscosity of the product.

Pump pressure. The pump pressure in the general case is the value determined by the relationship

p = pk -pn + p (θ to 2 - θ Η 2) / 2 + pg (ZK - ZH),

where p K and p H - pressure at the outlet and inlet of the pump, Pa; θκ ​​and θн - velocity of the liquid medium at the outlet and at the inlet of the pump, m / s; g - gravitational acceleration, m / s2; Ζκ and ZH - height of the center of gravity of the pump outlet and inlet section, m.

Pump head. The pump head is the increment of mechanical energy that the pump imparts to 1 kg of fluid that conducts

1.1.3. Pumping milk and dairy products

through it, that is, the head is the difference in specific energies when leaving the pump and when entering it. The head is measured in meters and shows how high the pump can lift the liquid. If the pump is used not to raise the liquid, to increase the pressure, then the head is expressed in atmospheres

In the general case, the pressure is called the value determined by the dependence

The head is determined depending on the installation and purpose of the pump and is calculated as follows:

H = M0 + B0 + (θ n 2 -θ in 2) / 2g,

where М 0, В 0 are the indicators of the manometer and vacuum gauge reduced to the pump axis, m column of the supplied liquid; θΗ and θv are the fluid flow rates at the points of connection of the manometer and vacuum gauge tubes, m / s.

In the case of pump operation with a head, the total head is determined by the dependence

where M 0 m -V 0 v are the readings of the manometer and vacuum gauge on the port and inlet pipes of the pumps, reduced to the pump axis, m.

Let's consider the general scheme of the pumping unit. Milk from the collecting tank 1 (Fig. 1.3) is sucked in by the pump 7 through the suction pipeline2 and is fed under pressure through the delivery pipeline4 to the tank5. If the pressures in tank 1 and reservoir 5 are not the same (we will designate them as p1 and p2), then the total head Н of the pump is spent on lifting the liquid to the full geometric height Hr overcoming the pressure difference in the reservoir and the receiving tank (p2 - p1), hydraulic resistances on suction h n.in c and dischargeh n.on pipelines:

H = Hg + (p2 -p1) / pg + hn,

where hп _ total resistance of pipelines (hl = hp.ws + hpn); Hg = Hvs + Hn where H sun H n - suction and discharge heights, m.

If the pressures in the receiving tank and the reservoir are the same

Rice. 1.3. Pumping unit diagram:

1 - receiving container; 2 - suction pipeline;

3 - vacuum gauge; 4 - discharge pipeline; 5 - reservoir; 6 - pressure gauge; 7 - pump

1.1. Transportation of milk to dairy factories, acceptance and storage

When pumping liquid through a horizontal pipeline, Η = h p.

The suction of liquid by the pump occurs under the influence of the pressure difference in the receiving tank p 1 and the pump VS or under the influence of the pressure difference

p1 / pg-pbc / pg.

The suction lift can be determined from the equation

The suction height increases with an increase in the pressure p, in the receiving tank and decreases with an increase in the pressure p ps, the liquid velocity θws, and the head loss hpws in the suction pipeline. If the liquid is pumped from an open container, torus 1 is equal to atmospheric pressure and the pressure at the pump inlet VS must be greater than the pressure p 1 of saturated pumping steam.

liquid at the suction temperature, since otherwise the liquid in the pump will begin to boil and due to the generated vapor, the flow may be ruptured and the suction lift may decrease to zero. Hence,

suction lift depends on the value of atmospheric pressure, speed of movement, density of the pumped liquid and its temperature

1.1.3. Pumping milk and dairy products

peratures. In general, the vacuum suction lift is a value determined by the relationship

where p 0 is the ambient pressure, Pa (the rest of the designations of the quantities are indicated above).

When pumping hot, highly viscous liquids, the pump should be installed below the level of the collection tank or pressurized in it.

When determining the suction height, it is necessary to take into account not only the head loss due to friction and overcoming local resistances, but also the inertial losses (for piston pumps) or cavitation (for centrifugal pumps). Cavitation - a violation of the continuity of a liquid - occurs at high speeds of rotation of the impellers of centrifugal pumps and when pumping hot liquids in conditions when intense vaporization occurs in the liquid. In this case, the vapor bubbles enter the high pressure region, where they instantly condense. Vacuum is formed. The liquid rapidly fills the formed cavities, which is accompanied by hydraulic shocks, noise, pump shaking. During cavitation, the flow and head of the pump sharply decrease, and its wear accelerates. Cavitation occurs when the suction head is zero.

To create normal operating conditions for the pump, it is necessary to provide a certain suction margin at the suction, that is, the minimum permissible excess of pressure over the vapor pressure of the pumped liquid. In this case, the suction head must be equal to

The cavitation reserve is determined by the dependence

where Δh is the permissible cavitation margin, which ensures the operation of the pump without changing the main technical parameters; p p is the vapor pressure of the liquid medium, Pa.

1.1.

V In piston pumps, the inertial forces of the fluid moving continuously behind the piston have a significant effect on the suction lift. If the maximum permissible number of double strokes is exceeded, then the liquid, possessing significant inertia, will not flow behind the piston. Intensive release of vapors from the pumped liquid and the separation of the piston from the liquid will begin, cavitation will occur, and the pump will stop working.

The inertial head losses hin are determined by the formula

where LB is the length of the suction pipeline, m, n is the number of double strokes; r is the radius of the crank, m.

The permissible suction head can be determined from the expression

where hv is the pressure loss to overcome the resistance when the liquid passes through the suction pipeline and valve (determined by the formulas of hydraulics), m.

In practice, the suction lift of pumps when pumping water does not exceed the following values:

Power. The power consumed by the pump is spent on communicating kinetic energy and pressure energy to the liquid, the sum of which is the liquid head. Much of the power is spent on mechanical and hydraulic losses in the pump itself. Net powerΝ, significantly less than the energy consumed by the pump. The power imparted by the pump to the supplied liquid medium is determined by the dependence

where Q is the pump flow rate, m3 / s; ρ is the pump pressure, Pa.

Through the mass flow, the power can be determined by the formula

Nп = qQH / 102 [kW],

where q is the density of the liquid medium, kg / m3; H is the head, m.

1.1.3. Pumping milk and dairy products

The power consumed by the pump N c is greater than the net power. It takes into account the energy losses in the pump, the relative value of which is estimated by the efficiency of the pump ηΗ

Efficiency. Efficiency factor ηΗ and characterizes the perfection of the design and the economical operation of the pump. The quantity ηΗ reflects the power loss in the pump itself and is expressed by the product

where ηο6 is the delivery coefficient, or the volumetric efficiency, which is the ratio of the actual volumetric flow Q to the theoretical Q T and takes into account the loss of productivity when liquid leaks through the clearances and glands of the pump, the release of air from the pumped liquid (from suction during suction). It expresses the ratio of the useful power of the pump to the sum of the useful power and the power lost with leaks; ηΓ is the hydraulic efficiency, which expresses the ratio of the actual pump head to the theoretical one (takes into account the head loss when greed moves through the pump). In accordance with GOST 17398-72, the hydraulic efficiency expresses the ratio of the useful power of the pump to the sum of the useful power and the power spent to overcome the hydraulic resistance in the pump; ηmech - mechanical efficiency, characterizing the loss of power due to mechanical friction and the pump (in bearings, oil seals).

The value, ηΗ depends on the design and degree of wear of the pump, and on average is 0.3 ... 0.65 for centrifugal pumps and 0.8 ... 0.9 for piston pumps.

The power consumed by the motor N dv is greater than the power on the pump shaft by the amount of mechanical losses in transmission from the electric motor to the pump (ηper) and in the electric motor itself (ηdv)

The total efficiency of the pumping unit η is equal to the ratio of the useful power Ν π to the rated motor power NДВ and characterizes the total power losses

The installed power of the engine is usually taken more than the power N DV, taking into account the possible overloads arising in the

1.1. Transportation of milk to dairy factories, acceptance and storage

the moment of starting the pump to overcome the energy of the resting fluid mass

where β is the power factor.

The power reserve factor β, depending on the value of the rated motor power NДВ, is given below:

Brief characteristics of the pumps. Centrifugal pumps.Centrifugal pumps are widely used in the dairy industry to transport low-viscosity liquid dairy products (milk, skim milk, buttermilk, whey, etc.) with temperatures no higher than 90 ° C. They are used in technological schemes, lines for feeding and pushing liquid dairy products through heat exchangers, filters, separators for feeding milk filling lines, filling machines, in lines and installations for circulatory CIP cleaning of pipelines, tanks, plate-type plants, etc. Pumps with delivery of 10 and 25 m 3 / h is used for emptying automobile tanks and for supplying milk to processing shops. Pumps with a delivery of 50 m 3 / h is used for unloadingrailway tanks. Valuablethe pumps are simple in their design, easily disassembled for washing, ensure uniform milk supply and create a head up to 30 m.

The flow of centrifugal pumps can be easily adjusted by changing the resistance on the discharge pipeline using a tap or valve. In centrifugal milk pumps of the latest designs, the working bodies are directly connected to the shafts of high-speed electric motors, which leads to their compactness, low weight and relatively low cost.

Centrifugal non-self-priming pumps operate under flood, for which they are installed below the container from which the liquid is pumped.

The characteristic of a centrifugal pump is a curve that expresses the relationship between volumetric flow and head, power and efficiency.

The characteristic of the pump allows you to determine the volumetric flow, power and efficiency of the pump at various pressures. With unchanged

Rice. 1.4. Feature of centrifugal pump

1.1.3. Pumping milk and dairy products

the frequency of rotation of the impeller, the volumetric flow changes with a change in head, with an increase in the required head, the volumetric flow decreases, and vice versa. In the absence of pressure, the volumetric flow rate of the pump is the highest, and at a certain high head, the volumetric flow rate drops to zero. The optimal value of the volumetric flow rate and pressure is taken at the highest value of efficiency, it is the passport characteristic of the pump, that is, it is indicated in the passport or removed in production conditions.

The characteristic of the center

run pump is shown in fig. 1.4. Here, the optimal values ​​at the highest efficiency correspond to a volumetric flow of 12 m3 / h at a head of 16 m (the maximum head of the pump is no more than 22 m). As seen from the characteristics, a centrifugal pump can operate in different modes with a wide adjustment of the volumetric flow by changing the head. This is a great advantage of centrifugal pumps.

Each pump must have its own characteristic, it changes with a change in the speed or diameter of the impeller. The characteristic indicated in the passport of the plant, in most cases, corresponds to the operation of the pump on water with a temperature of 20 ° C at atmospheric pressure.

In the absence of performance under operating conditions, the power consumption and efficiency can be determined by calculation.

Gear pumps. Gear pumps by the type of the working chamber and its communication with the inlet and outlet refer to positive displacement rotary pumps. The liquid medium in them moves as a result of a periodic change in the volume of the chamber it occupies, alternately communicating with the inlet and outlet of the pump. The fluid pressure in gear pumps, in contrast to centrifugal pumps, is created not under the action of centrifugal force, but due to the displacement of pores.

1.1. Transportation of milk to dairy factories, acceptance and storage

tions of liquid. Gear pumps allow you to get a higher head, and they have less impact on the product than centrifugal pumps, do not impart kinetic energy to the liquid and work quietly without impacts.

The maximum allowable discharge pressure is determined by the strength of the working bodies of the gear pump, as well as the power of the electric motor. To prevent possible damage to the pump in the event of a sudden increase in the discharge pressure (for example, when a pipeline is blocked), gear pumps are equipped with safety valves that are installed directly in the pump or on the pipelines. The safety valve ensures full bypass of the pumped liquid from the discharge cavity to the suction cavity when the pressure exceeds the permissible value. In this case, the pump flow is reduced to zero.

The volumetric flow of a gear pump is determined by the size of its working bodies and their number of revolutions per minute and depends to a certain extent on the discharge pressure and the viscosity of the pumped liquid, the values ​​of which change the value of the internal volumetric losses.

In fig. 1.5 shows the characteristics of the pump, i.e. the dependence of the pump flow Q at a constant number of revolutions η and constant viscosity ν on the head (pressure) p.

Rice. 1.5. Characteristics of a gear (rotary) pump:

1 - possible position of the curve without liquid bypass; 2- operation of the pump with liquid bypass through the safety valve: A - start of opening of the safety valve; B - full bypass of liquid from the discharge part to the suction part; q - leakage in the working parts, qκ - leakage through the safety valve

The amount of leakage q is determined by the size of the clearance in the working organs of the pump, the viscosity of the liquid and the discharge pressure. The presence of suspended air, vapors, or other gases in the liquid can significantly reduce pump flow. The volumetric efficiency is not indicated on the characteristic. It can be roughly defined as a relation

1.1.3. Pumping milk and dairy products

the increase in the supply Q at the discharge pressure ρ to the supply Q 0 at the discharge pressure equal to zero, i.e., η0 = Q / Q 0.

A change in viscosity from v0 to ν1 at a constant number of revolutions and pressure will entail a change in the flow rate and power on the pump shaft. In this case, the feed can be determined approximately by the formula

where Q1 is the pump flow at a changed viscosity of the liquid and the discharge pressure p, l / s; Q is the pump flow at the viscosity of the liquid and the discharge pressure p, l / s; η0 - volumetric efficiency at viscosity ν0 and pressure p.

Power with a change in viscosity can be determined by the formula

where N1 is the pump power at a changed viscosity ν of the liquid and pressure p, kW; N

Pump power, at viscosity ν0 and discharge pressure, kW; η0, η - volumetric efficiency at fluid viscosity ν1 and ν0 and discharge pressure p.

The main technical parameters of gear pumps depend to a large extent on the accuracy of pump manufacturing. With wear and an increase in end clearances, fluid leakage increases and flow, head and efficiency decrease. If the gear pump is made with precision, then its head can be large and it can lift the liquid to any required height, depending on the installed power.

Gear pumps are increasingly used in the dairy industry, as compared to rotary lobe pumps of other types, they have some advantages - design simplicity, compactness, and reliability. They are used for pumping milk and viscous dairy products - cream, condensed milk with sugar, kefir, etc.

Rotary lobe pumps. Rotary lobe pumps are gear pumps with working bodies in the form of rotors that provide only geometric closure of the working chamber. The rotors do not carry the power load.

By the type of the working chamber and its communication with the inlet and outlet, rotary lobe pumps are classified as positive displacement rotary pumps.

Λ1. Transportation of milk to dairy factories, acceptance and storage

Rotary lobe pumps have the same features as gear pumps.

The volumetric flow of rotary lobe pumps is determined by the size and design of the working bodies, the frequency of their rotation and depends on the volumetric losses and the viscosity of the product. The power consumed by rotary pumps depends on the volumetric flow rate, pump pressure and efficiency. The overall efficiency ranges from 0.3 to 0.6.

Rotary lobe pumps are widely used in the dairy industry for pumping dairy products of increased viscosity - condensed milk with and without sugar, cream, curd curd, ice cream mixtures, etc. dairy products into technological processing devices in a strictly defined amount, which can be regulated (for example, for feeding high-fat cream to butter makers).

The liquid head in rotary pumps, in contrast to centrifugal pumps, is created due to the displacement of portions of liquid. Rotary pumps, in contrast to piston pumps, do not have suction and pressure valves and do not need air caps due to a much higher uniformity of supply than piston pumps. Unlike centrifugal pumps, rotary pumps give a higher head, have less mechanical impact on the product and work without impacts.

Screw pumps. Screw pumps are volumetric, the liquid medium in them moves along the axis of rotation of the working bodies as a result of periodic changes in the volume of the chamber occupied by it, alternately communicating with the inlet and outlet of the pump.

Screw pumps create pressures, have very little mixing of the pumped liquid, uniform flow and provide good suction.

Screw pumps are used in various industries for pumping clean and contaminated liquids, neutral and chemically active, fluid and low-flow.

The most widespread are single-screw pumps. They provide flow rates from 0.6 to 60 m3 / h and pressures up to 2.5 MPa (25 kg / cm2). Progressing Cavity Pumps are easy to manufacture and operate compared to other positive displacement pumps.

For the supply of non-flowing media containing liquid, special screw pumps with a feed auger are used, which are supplied

1.1.3. Pumping milk and dairy products

The product flows into the suction cavity of the pump. With the help of such devices, curd masses, creams, pastes, etc. can be supplied. Single screw pumps have been used in the dairy industry since 1974.

Piston and plunger pumps. Piston and plunger for pumps are defined as reciprocating pumps with working bodies made in the form of pistons or plungers. Piston and plunger pumps are used to pump viscous products that cannot be pumped by centrifugal pumps, as well as when it is necessary to create high pressure, for example, when feeding condensed milk into the nozzles of spray dryers (pressure up to 15 MPa) or into the homogenizing heads of homogenizers (pressure up to 30 MPa).

Plunger pumps are used as dosing pumps for volumetric pressure dosing of various liquids. Several dosing pumps, united by a common drive shaft, form a dosing unit, which is used for the simultaneous dosing of several different liquid components or one liquid into several channels of technological processes, where the main requirement is to regulate and maintain the ratio of feeds of individual components.

Piston and plunger pumps are available in single and double-acting, single- and two-stage, single- and multi-piston pumps. The metering pumps are single-plunger horizontal single-action.

The principle of operation of a piston (or plunger) pump of simple action is as follows: when piston 3 (Fig. 1.6) (or rod 6) moves to one side (or rod 6), a vacuum is created in cylinder 1, suction valve 5 opens, and liquid flows from the suction pipeline into cylinder 1 until the piston reaches the end position. After that, the piston begins to move in the opposite direction and builds up pressure in the liquid, the suction valve closes, and the discharge valve2 opens under the pressure of the liquid, and the liquid is pushed into the discharge pipe. A single-acting pump uses one side of the piston.

Double-acting pumps (Fig. 1.6, c) use two piston sides. The closed cylinders 7 in these pumps are equipped with two pairs of valves. When the piston moves in one direction in one

Λ 1. Transporting milk to dairies, receiving and storing

Rice. 1.6. Diagram of piston and plunger pumps:

a - simple action; 6 - rocky; c - double action; g - three-cylinder (plunger); 1 - cylinder; 2 - discharge valve; 3 - piston; 4 - crank mechanism; 5 - suction valve; 6 - stem; 7 - closed cylinder

the chamber is pushed out of the liquid, in the other - suction. With the same dimensions and the same piston stroke, their capacity is approximately double that of single-acting pumps, and they deliver fluid more evenly. The pumps of a different type - rotary piston - are not equipped with valves, and the suction and discharge valves are closed by a piston of a special shape that makes a reciprocating movement.

Piston and plunger pumps are equipped with a mechanism for converting the rotational motion of an electric motor into a reciprocating motion of pistons (rods) with a relatively quiet stroke.

The disadvantages of piston (plunger) pumps are the complexity of the design, uneven fluid supply, the presence of valves that complicate disassembly and assembly during flushing and disinfection.

λ 1.3. Pumping milk and dairy products

The uneven fluid supply by the piston pump is due to the fact that the piston speed is not the same throughout the stroke. For the first half of the stroke, the feed increases, for the second, it decreases. On return stroke, the single-acting pump does not deliver any liquid at all. An important indicator of the operation of a piston (plunger) pump is the degree of flow irregularity, which is characterized by the ratio of the maximum flow in the middle of the stroke to the average flow in one double stroke of the piston.

To soften the shocks and equalize the feed, several cylinders are used in one block, working alternately, in this case the cranks are set at an angle to one another (Fig. 1.6, d). Air caps are used for the same purpose. When installed on the discharge pipeline, an excess of liquid enters them, during the period of the greatest liquid into the discharge branch side and equalizes the pump flow. When air caps are installed on the suction pipe, the pore speed is ensured and the air in the cap is compressed. On the return stroke of the piston, the compressed air pushes out a more even flow of fluid as it is sucked into the pump, and abrupt jolts are eliminated. The flow rate of the plunger pump depends on the number of strokes per hour and its dimensions. For piston and plunger pumps, the capacity can be determined by the formula

Q = (60π / 4) D2 Snηο = 47.1D2 Snηο,

where Q is the pump flow rate, m3 / h; D is the piston diameter, m; S is the piston stroke, m; η is the number of double piston strokes (or the number of crank revolutions) per minute; η0 - volumetric efficiency, approximately equal to 0.7 ... 0.9.

Volumetric efficiency depends on the design of the pump, the viscosity and temperature of the pumped liquid, the condition of the pump and is determined by the leakage through the piston leaks. As the pump wears out, the volumetric efficiency decreases, as the viscosity increases, it increases, and as the temperature of the liquid rises, it decreases, since in this case the liquid evaporates more easily and a vapor cushion forms, which makes it difficult to fill the cylinder. For hot milk η0 is 0.7, for cold milk and cream - 0.8 ... 0.9. The flow rate of a double-acting pump is determined by the formula

Q = (60π / 4) (2D2 -d2) Sη ο,

where d is the rod diameter, m.

/. 1. Transportation of milk to dairy factories, acceptance and storage

The power consumed to operate the pump is determined by the formula

N = QpΗ / (3600ηM),

where Q is the flow rate, m3 / h; p p is the pump pressure, Pa; ηΜ - mechanical efficiency of the pump, equal to 0.8 ... 0.9.

The delivery of the piston pump is regulated by changing the number of strokes and the size of the piston stroke.

Vane pumps. Vane pumps by the type of the working chamber and its communication with the inlet and outlet refers to a volumetric rotary-reciprocating vane pump, the working bodies of which include gates made in the form of plates. Plast-type pumps are used for pumping thick, low-flowing products containing moisture.

The main working body of the pump (Fig. 1.7) is a rotating rotor, in the grooves of which the plates are inserted. The rotor is eccentrically located in the pump housing. When the rotor rotates, the plates, under the action of centrifugal force, come out of the slots, are pressed against the walls of the housing 6 and slide along them. In this case, between the plastic

Rice. 1.7. Vane (vane) pump:

/ - top cover; 2- shaft; 3- nut with handle; 4- discharge pipe; 5 - bottom cover; 6 - body; 7 - sleeve; 8 - plate; 9 - rotor

1.1.3. Pumping milk and dairy products

slimes form working chambers filled with product. During the rotation of the rotor, due to the eccentricity of the latter, the plates freely enter and exit the grooves. The largest outlet of the plates from the grooves corresponds to the suction nozzle, at this time the product enters the pump. With further rotation of the rotor, the plates move the product, gradually enter the grooves, the working chambers between them decrease, and the product is pushed out into the discharge nozzle 4.

In these pumps, considerable friction of the plates against the walls of the casing is observed, and liquid friction of the product against the stationary walls of the casing and gate. During operation, with insufficient precision manufacturing, jamming of the plates may occur. To avoid the formation of scoring, the plates are made of stainless steel with heat treatment to the highest possible hardness with careful surface finishing. In cases where the centrifugal force is insufficient (at very low rpm) to exit the plates, springs are installed in the grooves that push the plates out as the rotor rotates.

The flow rate of a rotary vane pump with an eccentric position of the rotor with an accuracy sufficient for practice (in m3 / h) can be determined by the formula

Q = 3600 n [π (D + d) eb - 2b with Z] φ 0 η 0

where n is the rotation frequency, s-1; D is the diameter of the casing brace, m; d is the rotor diameter, m; e is the eccentricity of the rotor installation, m; b is the length of the plates or the rotor, m; c is the thickness of the plates, m; Z is the number of plates; φ0 is the coefficient that takes into account the decrease in the volume of the interblade space as a result of mixing of the suction zone from the maximum suction gap (φ0 = 0.95); η0 - volumetric efficiency, depending on the quality of the pump, pressure, viscosity of the pumped product and the way it is fed into the suction cavity (for well-made pumps η0 = 0.8 ... 0.95).

The power consumed by the pump (in kW) is determined by the formula

N = ρQp / (102η MEX)

where ηMEX is the mechanical efficiency (for a viscous mass, it should be taken equal to 0.3 ... 0.6 at a pressure of up to 0.2 MPa (2 kgf / cm2).

The vane pump has been modified in the curd conveying plant. Curd is a non-flowing product; for its supply to the suction cavity of the pump, a hopper with a feeder screw is used in the installation.

1.1. Transportation of milk to dairy factories, acceptance and storage

Diaphragm pumps. In the dairy industry, for pumping highly viscous products of delicate consistency and milk under vacuum, diaphragm or diaphragm pumps with good self-priming properties are used.

The main working body of diaphragm pumps are diaphragms made of rubber, rubberized fabric or special plastic polymeric materials with low bending stiffness. The pressure generated by the diaphragm pumps is due to the strength of the diaphragm and does not exceed 0.25 MPa. The operation of diaphragm pumps does not cause large mechanical influences on the product, which allows maintaining the consistency of delicate products during pumping.

Diaphragm pumps in most cases are equipped with a device for regulating the stroke of the stem with a diaphragm and allow you to change the flow from zero to maximum. Therefore, they are used as metering pumps.

Diaphragm pumps are divided into double and single chamber pumps, i.e. with one or two rods.

Rubber or gummed balls are used as valves. Diaphragm pumps, like piston pumps, are characterized by unevenness and pulsation of the flow. Double chamber pumps have less unevenness.

The main characteristics of a diaphragm pump are flow rate, head, vacuum suction head, number of double strokes, power consumption, and efficiency.

The flow rate of the diaphragm pump (in l / h) can be calculated theoretically as the volume described by the diaphragm during the pumping process per unit of time, according to the formula

QT = 60Wni / 1000,

where W is the volume described by the diaphragm, cm3; n is the number of double strokes per minute; i is the number of working chambers.

The actual flow will be less due to valve leakage and other reasons.

QД = QТ η0

where η0 is the volumetric efficiency, taking into account all the losses in total.

For an approximate calculation when working on water, we can take η0 = 0.85.

1.1.3. Pumping milk and dairy products

The volumetric efficiency decreases with increasing pressure and depends on the properties of the fluid and the number of double strokes.

The head of diaphragm pumps is determined by the specific data of the pumping unit and is limited by the strength of the diaphragm.

The vacuum lift of diaphragm pumps depends on the temperature and properties of the pumped product, on the number of double strokes, and on the correct execution of the suction line. It does not exceed 5 m water for viscous dairy products. Art.

The total head of the pump is equal to the sum of the delivery heads and the vacuum head.

Hose pumps. Positive displacement hose pumps are used for pumping low-viscosity and semi-viscous products. In practice, single and multi-hose pumps are used. Multi-lang pumps allow the simultaneous supply of product to several channels in equal quantities. Hose pumps are used when performing various kinds of experimental work. They are distinguished by the simplicity of the device - there are no valves and gland seals.

The working body of the pump (Fig. 1.8) is a hose 2 made of elastic material installed on a special profile casing 1.

Rice. 1.8. Hose pump diagram:

1 - profile body; 2 - hose; 3 - roller holder; 4 - roller

1.1. Transportation of milk to dairy factories, acceptance and storage

rial (for example, rubber). The hose is periodically compressed by the roll-in roller 4. The product, which is filled with the hose, is squeezed out of the hose by this roll during the roll-in process. Three rollers in holders are installed for reliable and continuous product delivery through the hose and to prevent the return of the displaced product. When the first roller comes off the hose, the second squeezes the hose and cuts off a certain portion of the product in the hose. Three doses of liquid are displaced in one revolution of the holder shaft. The ends of the hose are fixed in the body or in special clamps to which the pipelines are connected. To avoid rapid wear, the hose and the profile surface of the body are lubricated with a silicone compound or continuously wetted with water.

The peristaltic pump provides a pulsed volumetric flow rate, which is dependent on the speed of the shaft with roller holders and the diameter of the hose. The shaft rotation speed, as a rule, does not exceed 4 s-1 (240 rpm). The pump pressure (no more than 0.25 MPa) is limited by the strength and elastic properties of the hose (it should not have permanent deformation). The suction properties of the pump are good, the product is sucked in without filling the hose.

In the general case, the flow rate of the peristaltic pump (in l / s) can be determined by the formula

Q = WnZη 0,

where W is the dose volume of the displaced liquid, l; η is the rotation frequency of the rollers, s-1; Ζ - number of rollers (3); η0 - volumetric efficiency, on average 0.75.

Basic rules for the safe operation of pumps. TO operation and repair of pumps is allowed by a qualified mechanic and technician who knows the device, the principle of operation of the pumps and has certain experience in servicing, assembling, disassembling, adjusting and repairing, and, if necessary, checking or testing the pumps.

Compliance with the rules of safe operation during the operation of pumps excludes their premature failure, various accidents, accidents and causes of product damage. Moving mechanisms or individual parts of pumps, as well as rotating parts of the drive of the units, must have reliable guards, excluding the danger to the personnel servicing the pumps and pumping units. It is strictly forbidden to remove the guards of the running pumps. The rotational speed of the working bodies of most types

1.1.3. Pumping milk and dairy products

Since centrifugal pumps are high, minor faults can lead to accidents and rapid damage to the pump. It is impossible to work on a pump that is not in good working order (if the working parts touch the body, the lid with increased vibration and noise).

It is necessary to connect the suction and discharge pipes to the pump without distortions and lateral, axial forces on the pump. The pipes must have their own supports. Tighten the oil seal or replace lip seals only after the pump has stopped completely. It is necessary to select the right pump, taking into account the viscosity, temperature and specific characteristics of the pumped product, capacity, discharge and suction head.

Before installation and first start-up, the pump should be disassembled, inspected, rinsed and made sure that the parts are in good working order. When assembling the pump, the rubber o-rings, gaskets and seals must be correctly installed. It is possible to disassemble the pump only in a certain sequence with disconnected pipelines and the electric motor turned off. In this case, the “Do not turn on” warning sign should be installed on the start button of the electric motor. The power supply to the electric motor must be made in accordance with the rules for electric power wiring with reliable protection against damage to the wires and a convenient location of the starting protective device. The electric motor must be grounded.

When starting centrifugal pumps, first open the valve on the suction line, then the valve on the discharge line and turn on the electric motor. If there are rubber seals and mechanical seals in the pump, do not turn on the pump without liquid; if the flow of liquid stops, the pump must be turned off immediately. Violation of this rule can lead to rapid wear of the sealing device.

When rotary lobe pumps are in operation, it is strictly forbidden to completely close the valves on the discharge line. When starting up rotary pumps on the pumps, first open all the valves on the discharge line.

The high pressure plunger pump of the ONB-M type cannot be put into operation if the pressure gauge is absent or defective. Before starting the ONB-M pump, it is necessary to check the presence of oil in the oil bath and the amount of water used to cool and flush the product from the plungers. When the ONB-M pump is operating, it is necessary to monitor the heating of the rubbing parts. When pumping

1.1. Transportation of milk to dairy factories, acceptance and storage

ONB-M condensed milk in order to avoid the deposition of milk sugar every day after the end of work for 5 ... 10 minutes, it is necessary to pump water through the pump with a temperature of 50 ° C.

It is necessary to ensure that too high resistances do not arise on the discharge line of plunger and gear pumps, do not install shut-off valves, this may damage the pump, since these pumps can develop pressures up to 10 MPa or more.

Screw pumps must not be turned on even for a short time without liquid in order to avoid rapid wear of the rubber cage.

When the pumps are operating at specified modes, the total noise level should not exceed 75 dB at a distance of 1 m from the pump. When sanitizing the room, it is forbidden to direct a stream of water to the pump electric motor, as this may damage it.