Milk cleaning and filtering processes are designed to eliminate contaminants and natural unwanted impurities from its composition. There are different ways to solve such tasks that are characterized by a technological organization, efficiency, performance and performance. Equipment for cleaning milk, which is equipped with production lines is also varied.
Total cleaning technology
All processing operations are carried out in special conditions corresponding to technical and sanitary and hygienic requirements. The basis for the regulations applied to the organization of the work of food enterprises are taken. In dairy farms, both separate technological processes for treating raw materials and complex preparation of the product can be carried out.
Basic cleaning methods are being implemented today on dairy separators and centrifuge with pasteurizers. At least this equipment allows you to remove the mucus of milk plasma, mechanical impurities and dirt particles. Thin thin filtration also gives the effect of disinfection with the destruction of harmful bacteria. Methods of cleaning milk through thermal and biological impact are developing. In such processing systems, the physicochemical properties of milk occurs, the content of surfactants (proteins, phospholipids, fat balls and acids) is optimized and the surface tension is reduced.
Delivery of raw milk for production
Moving milk between the departments on the farm or its delivery by transport to the processing plant is carried out in special containers or tanks with refrigerators. According to the requirements, the inner surfaces of the containers and tanks must be carried out from stainless steel or aluminum. The outer surfaces are separated by the heat insulating material. During the movement, it is important to maintain the optimal temperature regime of raw milk. So, the average temperature is 4-6 ° C. In this state, the raw materials may be contained no more than 10 hours. If longer transportation is planned, a special milk cooler is initially involved - equipment in the form of a tank, which immediately after milking reduces the temperature of the liquid product from 35 to 4 ° C. At the same time, pathogenic elements of the composition are removed and useful qualities are saved.
Cooling modes
Properties milk, and in particular, its bacteriological characteristics, a considerable extent will depend on the temperature of its further storage. If you leave the product in a non-liberated form, then after 10 hours of content, its acidity will increase almost 3 times, and with this, the number of unwanted bacteria will increase sharply. For optimal storage in terms of a favorable microflora, long-term content in production requires maintenance of a mode of 12 ° C. Strong cooling is also not recommended because it is destructive and for useful microorganisms. Again, a milk cooler with control sensors and an automatic temperature control system comes to the rescue, which takes into account several physicochemical properties of milk. Such equipment may contain from 100 to 1000 l at the same time depending on the model and the needs of production. The choice of specific cooling tactics will depend on the time of the content, but a small duration at different stages of purification and processing of milk are usually required to maintain 4-6 ºС.
Basic mechanical processing
Also, this process can be called centrifugal separation - this is one of the basic purification procedures, which involves the separation of milk on the fraction of different density. For example, a separation of low-fat and high-liquid milk (cream) can be carried out. Technically, the process is organized at the separator facilities with a rotating drum. The installation operator during its operation monitors the following parameters of mechanical cleaning of milk:
- Drum rotation speed.
- The speed of separation of fat balls.
- The density of fat and plasma.
- Viscosity.
As the size of the density of milk plasma and fat balls increases, the pace of separation and the sewage of the creamy mass is accelerated. In turn, an increase in viscosity helps to reduce the velocity of the separation of fat factions. The process of centrifugal purification of milk, an indirect effect has a temperature and acidity can change the protein mass of milk by increasing its colloidal state. As a result, the process of loss of flakes will begin against the background of an increase in viscosity and the difficulty of separation. As for the temperature influence, its increase reduces the level of viscosity and slows down the process of transition of fatty thick mass into a liquid state. Therefore, before separation, it is recommended to heat the milk to 35-45 ° C. Increased temperature regime provides a more efficient degreasing process.
Milk cleaning separators
The separation of dairy fractions and cleaning discussed above are performed on special separators. As a rule, these are electrical machines having a built-in engine, a collector, a bowl for loading milk and a centrifuge. On medium farms, there were widespread devices with a capacity of up to 50-70 l / h. At the same time, the drum rotation frequency can reach 12,000 rpm. Modern dairy production equipment has automated control and protection. Control and control is implemented through a combination of sensors and a controller with an operator working panel. By setting the necessary program, the user launches the separation process with robotic control in accordance with the mortgaged milk processing algorithms. Protective systems are mainly represented by devices that prevent electrical and thermal overloads.
Filtering milk
Also one of the initial processes for the preparation of dairy raw materials to biological and chemical cleaning. The main task at this stage is to bring the contamination during milking or storage by filtration. The filters themselves may have a different device. Thus, closed membranes are eliminated by liquid from large mechanical impurities. Typically, such filters are installed on the lines of production milk and milking systems. The quality and degree of cleaning depth will depend on the characteristics of the material used. The most effective milk cleaning filter made from nonwoven matter. Sometimes in one circulating circuit or in several filtering devices for delaying particles of different fractions.
Bactericidal Phase Cleaning
This is the time period, in the process of which microorganisms that fell into milk do not multiply, but die. In this phase, the crude product is characterized by the presence of natural bactericidal properties provided by antibacterial substances. These include leukocytes, normal antibodies, lysozymes, etc. This ability of milk will depend on the physiological state of livestock from which it was obtained. The duration of the bactericidal purification of milk is determined by the outer microflora and the storage temperature, but usually does not exceed 2-3 hours. In the future, it will be important not so much cleaning as such as technological processes to maintain the life of antibacterial substances. Primary cooling, and filtering, as well as enzymes that are struggling with toxins causing milk defects can be attributed to the main measures of this kind.
Milk cleaning technology by thermal exposure
For disinfection of dairy raw materials, thermal processing is used. In the process of its implementation, not only the destruction of microorganisms with the products of their livelihoods occurs, but also creates favorable conditions for maintaining and maintaining the beneficial properties of milk. It should be noted that in itself the temperature effect in any form destroys the primary physico-chemical structure of raw materials. The degree of change will depend on the duration and temperature mode of processing. In dairy farms, this operation is performed by special heaters of tubular, capacitive and lamellar types. Multifunctional thermal processing equipment also includes a bath design for pasteurization.
Conclusion
The efficiency of preparing dairy raw materials for further processing is largely determined by its initial state. Not every raw material is in principle suitable for use in the food industry. There are special standards and requirements that determine the suitability of the product to the workpiece. After the control inspection of physico-chemical and biological indicators, milk cleaning on the previously appointed scheme begins. These are also separate chemical treatment operations with filtering, and deep comprehensive separation with improved bacterial microflora products. A specific set of cleaning technological operations will depend on the tasks of the billet of the dairy product on the farm or production line.
Milk cleaning - It is the removal of various mechanical inclusions and impurities. Depending on the milking equipment used, apply:
Filters in the form of gauze, folded in three-five layers, flannels - two or three layers, gauze with wool layers, brass, kapron and lavsan mesh;
Separators-cleaners (centrifugal milk cleaning).
The following requirements are presented to materials for filters:
High hygroscopicity and ability to delay impurities of small sizes;
Preservation in a contaminated state of high moisture repair;
A relatively easy separation of accumulated pollution when washing filters;
Minimum and stable hydraulic resistance;
High mechanical strength and resistance to the abrasion of the filter threads with multiple bends and tension;
Low cost material for filter.
Bandwidth of the filter, kg / h:
where F-total filter area, m 2; V is the rate of milk flow through the filter, m / h; P is the density of milk, kg / m 3.
Total filter area, m 2:
where F 0.- section of the sequence of one filter hole, m 2; p- The number of holes.
The rate of milk flow through the filter, m / h,
where μ is the coefficient of the expiration of milk (C \u003d 0.8); G - Sustainment of gravity, m / s 2; h - product pillar height over filter, m.
The area of \u200b\u200bthe filter fabric required to filter milk, m 2,
where M -the amount of milk to be filtered, l; Q is the amount of milk passing through 1 m 2 of the filter tissue, L / m 2.
When cleaning milk using a separator-cleaner determine the time of continuous operation, h,
,
(32)
where V G. p - the volume of mud space of the drum, l; R -the percentage of sediment of separator mucus from the total volume of milk transmitted (P \u003d.0,03...0,06 %); L.- Performance of the cleaner, l / h.
Capacity of mud space of the drum separator-cleaner, L,
, (33)
where R Maxand R min- maximum and minimal radii of mud space, cm; N -baraban Plate Package Height, see
When cleaning milk, mechanical and partially bacteriological impurities are removed, which improves its quality, the prerequisites for longer storage are created.
Depending on the execution, milk filters are divided into: open and closed. In open milk, it passes through the filter partition under the influence of hydrostatic pressure, because they have low performance and quickly contaminated. In closed filters, milk passes through the tissue under pressure.
Opened Twecks are used when making portable buckets. Filters - TSEDIKS are installed on the necks of flask, dairy tanks and other tanks.
Fig. 68. Cylindrical filters with multiple (s) and disposable elements (b) use:
1,7 -Pretty gaskets; 2 - body; 3 - filter element; 4 - Ring; 5 - Nut; 6 - adapter; 8 -Karkas; 9 - traffic jam; 10 - Milk Locker.
Modern milking units are equipped with cylindrical dairy filters (Fig. 68), installed in series in the lines of the milk pipeline.
In practice, milk filters are used, the working elements of which are: cotton wheels, march, flange, paper, metal mesh, synthetic fabrics (lavsan, and the like).
Comparatively with cotton filter elements, synthetic materials have a more stable filtering rate, higher bacteriological purity and strength, easily clean and sterilized. However, even the use of the most advanced filter materials does not provide complete cleaning of milk from mechanical, and even more than bacterial inclusions. In addition, the filter surface is rapidly contaminated by a layer of impurities, which entails an increase in the amount of bacteria in milk, passing through such a contaminated layer. In the case of long use of the filter, the remains of organic impurities decompose and dramatically increase the microbial flora.
Recently, dispose of disposable paper filters. They are easier to use and provide better milk cleaning.
A significantly more advanced method of filtering and cleaning milk is centrifugal cleaning. In this case, the milk is cleared not only from mechanical inclusions, as well as from mucus, epithelium and blood clots, which appear in milk with udder disease. In contrast to filtering at centrifugal cleaning, milk does not blur the contaminants that are deposited in the mud space of the cleaner.
For farm dairy, as well as milk processing enterprises, industry produces centrifugal separators-cleaners of different sizes in terms of performance. They differ in large bandwidth, reliability in operation, provide high quality of milk cleaning.
Modern milk processing equipment will become the basis of profitable business. Separate aggregates will help expand the possibilities of a dairy farm. Using simple manufacturer's recipes, you can establish the release of delicious dairy products with increased value added. On the other hand, a small dairy will bring good profits when using the procurement of basic raw materials in various farms.
Business development options
The own business of milk processing can be started with small volumes. Cottage cheese, sour cream, cheeses can be manufactured using low-cost equipment from cow's milk. Further investments will help with time to expand the range of products.
The arrangement of the production workshop at a small dairy farm will increase the profitability of an individual economy. Under these conditions, it will be advantageous to recycle its own products, as it will expand the markets of sales and increase the prices of ready-made milk products.
One of the options for purchasing a business is to purchase the finished dairy production "turnkey". This will require large material investments. The advantage will often be an adjustable production line, a ready-made sales system, procurement of raw materials. Often the proposed dairy equipment will be part of an effective livestock farm. Despite the visible advantages of such a well-established business, its acquisition may be associated with certain hidden problems.
Aggregates for the production line for processing and bottling of milk
There are many complexes that are effectively working on various dairyheads. They differ depending on production capacity. Equipment for milk bottling is often the necessary part of larger formations. The number of individual aggregates of such lines depends on the scale of production. Especially profitable can be the use of used devices.
Different technological tasks can solve equipment for the dairy industry, which consists of the following individual modules:
- milk tanks are used when stored, start-up, long pasteurization;
- separators separate fractions of solid products, with their help they get cream and purified milk;
- homogenizers are finely crushed, purified milk mass, making it homogeneous for the manufacture of frozen products;
- pasteurizer of milk for the destruction of pathogenic microorganisms;
- heat exchanger milk equipment, cooling products using accumulated ice, freon;
- emulsifiers converting liquid and powdered substances in the emulsion;
- sanitary and hygienic installations work using detergents for dairy equipment, in particular, special soap. (This allows you to carefully clean all the aggregates, maintain them in a normal sanitary condition).
High-quality stainless steel food containers provide long-term storage of products, do not react with raw materials.
They are used for pasteurization and cooling milk, its thermal processing, transportation, storage, normalization of cream, oil and cheese. They differ in durability, they can be connected to pumps, homogenizer, separator, packaging devices. The cost of individual aggregates begins from 52,000 rubles.
Varieties of separators and their purpose
The purification of dairy raw materials from various impurities, the removal of bacteria is an essential operation at the first stages of its processing. Also, for the production of sour cream, the necessary task will be the separation of milk on cream and its degreased part, which is later normalized by fatters. Those and other tasks solve separators. Depending on the specialization, these devices are divided into cleaners and cream separators. On dairyheads such equipment will be indispensable. In addition, it is the main and necessary for milk processing at home.
Separators are closed, semi-closed and open. The high degree of sterilization is achieved by minimal contact with the environment, so closed models are best suitable for these purposes.
Also, the aggregates differ in the degree of automation. Models with manual cleaning drum cost cheaper. The most common devices with the upper milk introduction were obtained.
They are made of stainless steel, and seals are made of polymeric materials and food rubber.
Installation for the production of condensed milk
Small home farms due to the low purchasing value of milk are often faced with the problem of its implementation. The sale of a recycled natural product will help solve such problems. The arrangement of a mini-shop, which contains equipment for the production of milk powder, will be a particularly profitable solution for solving the problem.
In addition, milk equipment will be useful for the production of various types of cheese, cottage cheese, oil, ice cream, condensed milk. At the same time, it is advantageous to focus on efforts on condensed milk, because costs will be the same as during the pasteurization of milk.
Recipes of condensed milk are quite simple, and the installation of USM-4 will provide an excellent result in the form of 11 kg of delicious products in four hours, during which one cycle lasts. This apparatus has a capacity of 30 l, the weight is 45 kg, and the power consumption is 3.5 kW / hour.
Such an installation is easy to serve one person. In addition, it takes a minimum of space.
Cleansing, pasteurization and packaging
Strict observance of production technology ensures the quality of the finished product and the efficiency of the milk processing line.
First of all, the integrity and quality of dairy raw materials is checked, and then it falls inside the receiving capacity through special filters using pumps and further into the normalization system. The separation process occurs here, as a result of which the primary cleansing of raw materials passes, separation of it on the fraction.
The next step is the use of pasteurization methods and cooling. It uses equipment for the pasteurization of milk.
The further fermentation procedure automatically leads to the production of sour cream.
Finished products are packaged on a filling line, without which equipment for milk production will not fully fulfill its purpose.
This line refers to the packaging part. With it, there is a filling of dairy products in plastic, glass bottles with automatic caps of covers. After that, the label is pasted. Finished products can also be packaged in packages. Such a line runs from the network of 220 V and has a capacity of up to 20 packages per minute.
Inside the workshop it is necessary to establish equipment for the storage of milk, which consists of containers of various purposes. Such aggregates are necessary for both home and large-scale production.
Profitability of the Milk Processing Workshop
One of the optimal ways of opening a business is to purchase a modular plant. Separate modules make up a warehouse, laboratory, consumer parts that are interconnected in accordance with the technological scheme. At the same time, the equipment for the primary processing of milk is initially used, and in the following stages, pasteurized, condensed, conventional milk, ripped, kefir, cottage cheese, sour cream, yogurt are made of this raw material.
Such lines are offered ready and with their help you can immediately process up to 2000 liters of dairy raw materials at the same time.
And you wonder what equipment will be the most useful for milk processing? If the information presented in this article seems useful, then put "huskies", share with your friends on the Internet.
Primary milk treatment is carried out to preserve its sanitary and hygienic, food and technological properties.
Operations of primary processing of milk include cleaning it from mechanical impurities, cooling and pasteurization. Primary milk treatment should be carried out simultaneously with milking.
For the mechanization of primary processing of milk, our industry produces a variety of machines and equipment: coolers, coolers cleaners, refrigeration units, pasteurizers, etc.
Cleaning milk from mechanical impurities is performed using filters or centrifugal cleaners.
Filters (cotton mugs, mesh, gauze, flannel and lavsanov) are delayed mechanical impurities. The best degree is achieved with the combined use of a metal mesh with a tissue partition.
Centrifugal cleanerswhich are used on large farms and complexes give a higher degree of milk cleaning.
Cooling milk Can be carried out in several ways. The choice of method depends on many factors, including from the type of cooler, the amount of cooled milk, the presence of cold water, the availability of electricity economy to produce artificial cold, etc.
Various irrigation coolers received the greatest distribution. The milk comes on their surface or under the pressure and flows on them a thin layer towards the refrigerant in parallel along the other side. In this case, the heat from milk through the thin wall of the apparatus is transmitted to the coolant, which can be cold water not higher than 10 ° C, ice water, cooled in frigaters or on refrigeration systems up to 0 + 4 ° C, or brine, cooled on refrigeration plants and having Minus temperature.
Packet irrigation coolers are also effective (for example, OU-1000A) and plate (OOT-M and OOOU-M), which are universal units, as they are equipped with milk cleaners.
Cooling and storage of milk are tank-coolers, tank thermoses (TOV-1, TO-2 and Tom-2a).
Pasteurization of milk - Thermal treatment up to 63-90 ° C in order to disinfect. In this case, without a noticeable change in taste, smell and consistency of milk, brucellious, tuberculosis and other pathogens of microorganisms die.
In the milk-commodity farms, steam pasteurizers with displacement drums of bilateral heating, as well as lamellar pasteurizers, were most common.
Automated tubular and lamellar pasteurization plants are the most perfect devices for milk pasteurization. These include universal lamellar pasteurization-cooling plants Oph-3M and OP2-U5, as well as the installation of OPF-1-20 and OPF-1-300.
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Practical lesson number 2
Equipment for mechanical processing of milk and dairy products
2.1. Equipment for separation and concentration of milk by membrane methods
The membrane methods of processing milk include ultrafiltration, reverse osmosis and electrodialysis.
The essence of all membrane methods is the separation and concentration of dairy raw materials during filtration through special membranes under the action of pressure (ultrafiltration and reverse osmosis) or electric field (electrodialysis).
Ultrafiltration is used to release proteins from milk and whey; In reverse osmosis, concentration of dairy raw materials occurs, since only water passes through the membranes; Electrodialysis is subjected to milk serum in order to demineralization.
The executive body of installations for filtering and inverse osmosis is a semi-permeable membrane based on cellulose acetate and porous polymeric materials. For ultrafiltration, membranes with pore sizes are used. Such membranes detain the molecules with the size of large than the sizes of pores, and minor molecules are passed. The ultrafiltration process is carried out under a pressure of 0.1 ... 0.5 MPa. For reverse osmosis use semi-permeable membranes with a pore size of less than 50 nm, the process leads at a pressure of 1 ... 10 MPa.
The membrane apparatus is a device consisting of a housing, membrane, a drainage node, fasteners, structural elements for the input of the original solution and the output of the concentrate and the filtrate, stirring, etc. For membrane separation, four types of devices are used: flat, tubular, rolled and hollow fibers. In fig. 2.1 shows the main types of membrane devices.
Industrial membrane devices are packages, blocks, complexes of membrane elements: cells, sections, modules. The membrane apparatus is typically part of a periodic or continuous membrane installation, which also includes pumps, dosing devices, containers for the starting solution, filtrate, concentrate and detergent solutions, connecting pipes and instrumentation.
The ultrafiltration unit consists of a filtering machine, a pump for feeding a product, pump for pushing the product through membrane filters, connective pipelines and control valves.
The main part of the filtering apparatus is the semi-permeable membrane - a thin porous film, the size of the portion of which is less than 0.5 μm. The film is placed on a macroporous substrate, reinforcing its mechanical strength. Typically, a porous stainless sheet steel is used as a substrate with a thickness of 0.5 ... 3 mm with pores 0.5 ... 10 μm.
Figure 2.1. Membrane devices:
a - flat-frame: 1- flange, 2 membrane, 3-drainage plate, 4- sealing plate, 5- separation plate; b - tubular: 1-sealing material (compound), 2- housing, 3- tubular membrane; - Rolled: 1- Tube for removal of the filtrate, 2-membrane, 3- channel-forming element (turbulizer), 4- Substrate - drainage, 5- adhesive compound; G - with full fibers: 1- Drainage substrate, 2- washer with hollow fiber, 3- body, 4- hollow fiber, 5- cover.
In the first stage, a concentrate containing from 3 to 15% protein and a lactose salt solution is obtained as a result of ultrafiltration. In the second stage, the lactose-saline solution is passed through a reverse osmosis membrane and a concentrated solution of lactose (10 ... 20%) and a filtrate, which represents a 1% saline solution.
The designs of ultrafiltration plants for processing dairy and food products are diverse. In the most advanced, for example, in the Sartokon-2 system, the filtered liquid is pushed by the pump through thin channels between the two filters.
Part of the fluid passes through membrane filters, and the rest enters the container with the source product to recycle again through the system. A continuous tangential flow along the filter surface leads to effective filtration, since it does not allow delayed particles or substances to settle on the surface of the filters and block them. The cleaning effect is enhanced due to the use of a special grid filters in a narrow channel that causes the turbulence of the flow.
The system "Microsart" modules are used with membrane filters from cellulose acetate or polyolefin with pores with sizes 0.1; 0.3; 0.45 μm or Ultrasart modules with ultrafilters from cellulose triacetate or polysulfone with nominal selectivity for molecular weight, 10,000 and 5000.
The performance of the Sartokon-2 system depends on the number of modules installed in it, the surface area of \u200b\u200bwhich may vary in the range of 0.7 ... 4.9 m2 at ultrafiltration and 0.7, .. 4.2 m2 for microfiltration.
2.2. Equipment for separating heterogeneous systems
The essence of the process of separation (separation) of milk, as well as any heterogeneous system, is precipitated by the dispersed phase in the field of action of gravitational and centrifugal forces.
During separation, the milk is divided into two fractions of different density: high-screen (cream) and low-aluminous (skimmed milk).
Separators-dairy separators, separators-cream separators, separators for obtaining high-liquid cream and universal with interchangeable drums differ.
According to the method of supplying milk and removal of separation products, the devices are open, semi-closed and closed.
In open separators with a capacity of up to 0.3 kg / s milk feed, the decomposition of cream and skimmed milk occur in contact with air. In this case, milk foam is formed, worsening the operating conditions of separators. In semi-closed separators with a capacity of 0.5 ... 1 kg / s milk is supplied in an open manner, and the removal of products is closed under pressure. In closed (hermetic) separators with a capacity of over 1 kg / s milk feed and the separation of separation products occur without access under pressure from pipes.
According to the method of removing mechanical impurities and protein bunch, separators can be with manual discharge of the sediment (stopping the separator, disassembly and cleaning of the drum), with periodic unloading through the windows in the drum housing (self-discharged) and with continuous discharge over nozzles through the periphery of the drum housing ( Curd).
Depending on the type of drive, separators can be with manual and electric drive. The transmission of rotation from the electric motor to the drum in the separators of the second group is carried out using a screw pair or belt transmission. The drums of small productivity separators are installed directly on the motor shaft.
One of the main technological parameters characterizing the operation of separators is the temperature of the separable or product cleaned.
Milk sent to separation or purification must have a temperature of 40 ... 45 ° C. High-temperature separation is carried out at a temperature of 60 ... 85 ° C, during the separation of cold milk, the product has a temperature of 4 ... 10˚С.
The main nodes of the separator of any type (Fig. 2.2) are a box consisting of a housing and a bowl, a drum, a receiving-pin device and a drive mechanism, which includes a vertical shaft (spindle) and a horizontal shaft with a gear wheel.
In the case of the bed, the drive mechanism is placed on the vertical shaft of which the drum is installed. The face bowl is closed by a lid that serves to accommodate the receiving-output device. Self-revoking and nozzle separators have a sediment receiver or a condensed fraction (for example, a curd bunch). The flange electric motor is located on the side of the bed, and its shaft is connected to the drive mechanism through an accelerated centrifugal friction clutch.
Depending on the technological purpose of the drums of separators differ in constructive design (Fig. 2.3).
Figure 2.2. Separator - half-closed type milk cleaner with manual discharge:
1- Bed housing, 2- brake, 3- receiving - output device, 4- Cover of the separator, 5- Bowl of the bed, 6-stopper drum, 7- drum, 8-vertical shaft (spindle), 9-toothed wheel of the horizontal shaft.
Open-type disappearance-cream separator drum with manual discharge (Fig. 2.4) consists of a base, sealing ring, a plate holder, a package of plates, a separation plate, housing and a tie nut. The base of the drum has a complex shape and represents the bottom with the central tube. There are three rectangular channels in the tube for the passage of milk to the plate. The top of the tube has a thread for fastening a tie nut. On the rim of the base, a cutout is made under the fixer of the case, and on the conical part of the base - the protrusion for fixing the plate holder with a package of plates. In the center of the founding there is an oblong ledge, providing a reliable gearing the drum with a vertical shaft of the separator.
A package of 48 ... 56 plates is used to form an intermediate space in which milk is separated on cream and skimmed milk.
The clearance of the intermediate space is created by three spikes 0.4 mm high, located on the outside of each plate The last plate has spikes on both sides, which allows for the clearance not only with a neighboring plate, but also with the base of the drum. In each plate of three holes; When assembling a plate in the package, vertical channels are formed through which milk is distributed in an intermediate space.
Figure 2.3. Technological schemes of drums of separators of various types:
a - Drum separator - separator (cream separator), b - drum separator - clarifier (dairy cleaner), in - drum of a nozzle separator (cottage cheese), M - separator drum with periodic discharge: 1- Tarbed inserts, 2- precipitate (separator mucus) , 3- severe fraction (skimmed milk), 4- light fraction (cream), 5-clarified liquid (pure milk), 6-curled serum, 7- receiver of cottage cheese, 8-curled bunch, 9-nozzle, 10- pressure disc Cream, 11- pressure disc. Degreased milk, 12- unloading windows, 13- Rolling bottom (piston), 14- Piston motion control valve, 15- receiver of precipitate.
Three ribs are performed on the upper surface of the separation plate, providing the necessary gap between the inner surface of the drum housing and the separation plate. In the upper cylindrical part of the separation plate there is a hole for draining cream.
The hull of the drum has a conical shape with some extension at the base, which forms mud space. At the bottom of the housing from the outside there is a retainer, which is included in the assembly to the bottom of the base of the drum. In the top of the cervix cervix there are two slotted output channels for removal of low-fat milk, a hole for the release of cream and an adjusting screw, which is a thread bushing.
The quantitative ratio between cream and low-fat milk in separators may vary in very wide limits - from 1: 3 to 1:12. At the same time, the required ratio is achieved using adjusting devices, the principle of which is based on either on changing the rate of cream or skim milk by changing the pressure, or on the change in the section of the outlet.
Fig.2.4. The separator drum is an open-type cream-separator with manual discharge: 1-tie nut, 2- housing of the drum, 3-separation plate, 4-packet of plates, 5-plate holder, 6-sealing ring, 7- base of the drum.
With the first method, the adjusting screw with the opening of the constant section is written inside. The rate of cream expiration is reduced, as the centrifugal force as the screw approaches the axis of rotation is reduced, and the pressure decreases with it. The cream will come out less, but they will be more viscous and contain more fat.
The second method of regulating the fat content of the cream is implemented in semi-closed cream separators. A distinctive feature of the drum of the separator of this type is the design of the separation plate, at the top of which two pressure cameras are placed. In one camera there is a pressure disk of the selection device of the separator. In the chamber located in the neck of the drum cover, the pressure disk of the defatted milk is placed. In such separators, the ratio of the amount of cream and skimmed milk is regulated by valves (chokes) installed on the nozzles of the receiving-output device.
A more complex device has drums of separators with periodic unloading separator mucus (precipitate). Based on the drum (Fig. 2.5) there is a moving bottom (piston). Seal between the base, as well as the drum cover and the piston provide sealing rings. At the junction level between the piston and the drum cover, windows are placed to unload the sediment. In the upper position of the piston, the windows are closed, when it drops, the precipitate is unloaded through the windows to the receiver.
Fig. 2.5. Drum separator - a cream separator with periodic discharge:
1- base of the drum, 2- Rolling bottom (piston), 3, 5-sealing rings, 4- window for unloading sediment, 6-test ring, 7-drum cover, 8- unloading valve, 9- fat, 10- switchgear ring buffer water.
The principle of operation of the drum separator-cream separator with periodic discharge of the sediment is based on the creation of a certain pressure drop between milk in the drum and a liquid (buffer water) under the moving bottom (piston). Unloading is controlled using the hydraulic system in manual and automatic modes. The main elements of the system are hydroezel and control panel.
The composition of the hydraulic circulation (Fig. 2.6) includes a filter, a gearbox for regulating water pressure in the drum unloading system (buffer water), pressure gauges, an electromagnetic valve for supplying irrigation water to the sediment receiver, manual valves for managing the separator work manually, as well as a three-way crane for Putting water cavity under the rolling bottom (piston) drum in a closed position.
The control panel includes three time relays, the off button on the remote control and manual unloading, signal lamps and fuses. The time relay is used to install the interval between unloading (30min), as well as the operation of two other relays. One of them is necessary to control the operation of the electromagnetic feed water supply valve, the second-to regulate the discharge time (0.2 ... 0,5c) of the separator drum.
The hydraulic separator unloading control system affects the moving bottom (piston) of the drum using two unloading valves located in the drum housing at an angle of 180 °. The valves are connected drilled in the body base with cavity under the piston and the buffer water supply device under the render of the drum. They opened into the space between the vertical wall of the drum and the seed casing. Receiving and output devices of separators are designed to enter milk into the separator and removal of separation products. Open-type separators (Fig. 2.7), the receiving-output device is a cup-shaped container powered by the separator.
Fig. 2.6. Self-discharge separator hydraulic dispenser connection scheme:
1-filter, 2, 6-hand control valves, 3- electromagnetic irrigation water supply valve, 4- three-way faucet modes of operation, 5- electromagnetic buffer water supply valve, 7, 9- pressure gauges, 8-pressure reducer, RV - time relay .
The capacity consists of a receiving float chamber and two camshafts with cream horn and low-fat milk. The receiving float chamber provides a uniform flow of milk coming from storage tank. The float chamber has a tube with a calibrated hole in the center, its diameter provides the nominal separator performance at a certain level of milk, which is supported by the float. With an insufficient level of milk, the float is lowered and opens the access of milk from the tank to the chamber. When the nominal float is exceeded, the drain hole of the milk container is closed, and the level in the chamber decreases.
The elements of the cup-shaped capacity of the open type separator are made of sheet metal (usually tinned or stainless steel sheet), separators of small productivity-polymeric materials.
In order to ensure that cream flowing from the holes in the drum and low-fat milk into the corresponding camshafts, the vertical shafts of open-type separators can be adjusted in height by a special screw located under the lower support of the vertical shaft of the separator. Along with the shaft, the drum is lowered or rises.
Fig. 2.7. Open-type factor-cream separator:
1- Bowl of the bed, 2- Distribution chamber of low fat milk, 3- distribution chamber of the cream, 4-receiving float chamber, 5-float, 6- bottom of the cup-shaped container, 7-tap, 8- Tube of the Float Camera, 9- screw fatty adjustment , 10- Oil Pouring Tube, 11- Pulsator Button, 12-Oblocked Oil Level Window, 13- Oil Plum Tube, 14-height Drum Adjustment screw.
In a small-capacity separator with an electric drive, this adjustment is associated with the rise or lowering of the engine along with the drum using the screw in the bottom of the separator body. Semi-closed separators have a more complex design of the receiving-output device (Fig. 2.8), which consists of one (for breasts) or two (for cream separators) of pressure disks.
The pressure disk is made in the form of two flat circles, between which there are several spiral channels for the liquid. With the help of concentrically located connections, the channel channels are connected to the tight tubes, at the ends of which are adjusting the throttle valves.
On the axis of the receiving and output device, a central tube is installed, on which milk goes into the drum. The tube can be connected directly to the milk feed pipe or with a float chamber controlling milk supply to the separator.
With the help of adjusting valves, it is possible to change the fatty cream obtained. The intensity of the cream flow is measured by a symbol descendant, which is a housing with a float in it. A rod is installed on the float, which is included in the glass graded tube. The more intense the flow of cream flow, the higher the float rises. On the position of the rod head relative to the tube scale, the flow rate per unit of time is estimated.
When working the separator, the milk incomes in the drum displaces the separation products into pressure chambers. Rounding together with these cameras, cream, skimmed or purified whole milk is captured by spiral channels of fixed disks. At the same time, the speed pressure of the rotating fluid goes into the stage static, as a result of which in the channels of the discs, the pressure of the separation products rises to 250 ... 300 kPa. With this pressure, cream and skimmed milk are moved along pipelines to heat exchanging machines from storage tank. Thus, the separator performs the functions of the pump.
Fig. 2.8. Receiving and output device of the semi-closed separator of the cream separator:
1- Power Cream disc, 2- pressure disc fat milk, 3- Output of separation products, 4- Adjustable cream valve, 5, 7- pressure gauges, 6- central milk inlet tube, 8- adjustable skimmed milk valve.
In a hermetic separator, milk on separation is served in the drum below, through the hollow vertical shaft, which the bottom end comes under the face. At the end of the shaft, the disks of the pumping device are fixed, which, rotating together with the shaft, play the role of the pressure wheel and injected milk into the drum. Milk falls under the plate holder, and then along vertical channels formed by holes in plates, is distributed over their package. Cream in such a drum is assembled in the central tube of the plate and are derived from the drum under pressure, created at the inlet of the separator with a pressure device.
Safety milk, passing between the separation plate and the cover of the drum, enters the pressure chamber of the pressure disk and is output from the separator. The hermetic separators ensure the most complete allocation of the fatty phase of milk, since in the process of their drum there are no foaming and formation of air bubbles that violate the separation of milk.
In modern separators-cream separators in skimmed milk, fat balls fall, the size of which is less than 0.1 μm, and 0.02 ... 0.05% fat remains in low-fat milk (Table 2.1).
In the manufacture of many dairy products, milk of certain fatty is used as raw materials, for example, with a fat content of 3.2 or 3.5%. This milk is called normalized, and the process of bringing milk to standard fatty - normalization. The simplest way to normalize milk is to add to it in a certain proportion of skim milk or cream and mixing them in the tank. More convenient is the method of normalizing milk in a stream, which is carried out using selection separators equipped with a device for normalization, which is installed at the separator receiving and output.
In fig. 2.9 shows one of the devices for the normalization of milk in the stream using the separator-cream separator. The cream outlet pipe is connected by a pipe with a degreasing milk drain pipeline. At the exit of the cream set choke. In the process of normalizing milk, part of the cream on the nozzle is sent to the output from the separator and, mixing with low-fat milk, forms a normalized mixture. Excess cream comes through the pipeline. With a fully open throttle, the separator works as a cream separator. The throttle handle has a cap closing the cylindrical part of the throttle housing on which the scale is applied. Using this scale, the device for normalization is installed on the specified fatness of milk on the table. The accuracy of the normalization of milk in the content of fat with such a device is ± 0.2%.
Depending on the technological purpose, most separators in their device have features.
Tab.2.1. Technical characteristics of creation separators.
Indicator | Outdoor with manual discharge | Half-closed with manual discharge |
||||
Performance, m3 / h | ||||||
Drum rotation frequency, C-1 | ||||||
Mud volume, dm3 | ||||||
Overall dimensions, mm | ||||||
Mass without electric motor, kg |
Thus, in separators for high-wheeled cream, the distances between the plates (up to 0.6 mm) are increased, as well as between the plates and the plate. The receiver of high-wheeled cream (bipores 82 ... 85%) and the nozzle for their removal have a greater bias. The supply of separable cream (30 ... 40% fat is 30%) in the separator is adjusted using a crane. Setting the separator to obtain high-liquid creams for various types of cream oil is made by changing the amount of cream and pressure at the outlet of the pachate (according to a pressure gauge using an adjusting piston)
Call "HREF \u003d" / TEXT / CATEGORY / KOLL / "REL \u003d" BOOKMARK "\u003e collector high-speed motors single-phase current with voltage 220 V.
Since the separators are equipped with asynchronous electric motors of industrial frequency 50 with a rotational frequency of no more than 50 C-1, to the drive mechanism, which ensures the rotation of the separator drum with a frequency of 80c-1, has special requirements.
The most common scheme of the separator drive mechanism is shown in Fig. 2.10. The electric motor leads to rotation the leading part of the coupling, the pads of which under the action of the centrifugal force are pressed against the inner cylindrical part of the coupling, rigidly installed on the horizontal drive of the drive. On the same shaft, a gear wheel is fixed to transmit rotation from the horizontal shaft of the separator to the vertical. The latter has a multi-turn screw cutting, which is engaged with a gear wheel.
Fig. 2.10 Diagram of the separator drive mechanism.
1 - electric motor, 2- leading part of the centrifugal acceleration coupling, 3- led part of the coupling, 4- horizontal shaft, 5-toothed wheel, 6- elastic throat support, 7- drum, 8-vertical shaft.
The movement in the separator actuator is carried out according to the principle of a helical pair, in which the vertical shaft is a screw, and the wheel - sector. When the screw cutting of the vertical shaft is moving at high speed (up to 25 m / s), slides along the wheels to the teeth, therefore, to reduce their wear, the screw pair is made of materials with a small coefficient of friction and good wear resistance. Equally important is the accuracy of the manufacture and purity of the processing of gearing surfaces.
The screw transmission of the separator drive mechanism in the process should be mounted, for which the separator boxes have corks for fill and lubrication drain.
It is important to note that the gear pair of the separator drive transmits the rotation in two directions: from the electric motor to the drum during its acceleration and work, as well as from the drum with a large inertia, to the electric motor when the separator is turned off. It is explained by this multisope (11th) the design of the screw and a large angle of inclination of his tooth. Transfer ratio from screw pairs of separators is within 3 ... 6.
One of the most important features of the separators drive mechanism is the presence of a so-called elastic throat support, i.e., setting the upper bearing of the vertical shaft with the possibility of some freedom of movement in the horizontal plane. For this, between the upper bearing, located under the base of the drum, and its nest in the separator bed is introduced elastic element. In small separators, it can be a rubber sleeve. More productive - a group of radially located compression springs (usually six at an angle of 60 ° to each other).
The inaccuracies of the manufacture and mutual arrangement of the parts of the drum during assembly leads to some displacement of the axis of the vertical shaft rotating in the bearings relative to the axis of rotation of the drum. In this case, the centrifugal force in this case adversely affects the work of the separator. The presence of an elastic element in a throat support allows the drum under certain limits to self-balancing (the drum tilts the vertical shaft so that the center of its severity coincides with the geometric axis of rotation of the drum).
For the depreciation of the vertical oscillations of the drum, the vertical shaft of the separator relies on the spring located under the lower bearing.
In high performance separators, the vertical oscillations of the drum are perceived by a group of springs installed in the thorough support of the vertical shaft parallel to its axis. Separators with a capacity of up to 1000 l / h such springs do not have, since the mass of their drums is relatively small. At the same time, small oscillations of the vertical shaft can lead to the fastening of the lower bearing, and in order to avoid this, the bearing is performed by spherical. The frequency of rotation of the separator drum is controlled by an arrow tachometer and a special device - a pulsator. The peculiarity of his work is that, when you press the pulsator button with hand with each turn of the eccentric shaft, one push is felt. The eccentric shaft through a worm pair is connected to the gear that serves to drive the tachometer and the pulsate and installed on the horizontal shaft of the separator drive mechanism. In the instructions for the separator, the number of the journey of the minute, which must have a pulsator at the rated frequency of the drum rotation. Tachometer shows the frequency of rotation of the horizontal shaft of the separator drive, the value of which is also indicated in the instructions.
The drums of separators have large kinetic energy, and when the engine is disconnected, the separator continues to rotate for a fairly long time. In high-performance separators, the turning time to zero takes several dozen minutes. Since, after the end of the work cycle, the separators need to be disassembled, clean from the sediment and rinse (with the exception of self-discharged sink), in order to save the time of service personnel, separators are equipped with special brake devices. Such a device is two pads with overlays of friction material. Through the spring-loaded rod, they are connected to the handle and are located in the separator bowl at an angle of 180 ° to each other. In such a brake device, the pads affect the outer wall of the drum.
In some design structures, including self-discharge separators, the brake is installed in the housing of the acceleration centrifugal clutch. In this case, the brake block is pressed against the outer surface of the coupling bowl, rigidly connected with a horizontal drive shaft. Separators of average performance in the face of the bed there are lock bolts for fixing the drum when cleaning and washing. To do this, when turning, they enter the nest of the drum housing.
2.3. Equipment for homogenization of milk and dairy products
Homogenization is a fragmentation (dispersion) of fat balls by impact on milk or cream of significant external effort. During the processing, the dimensions of the fat balls and the speed of the pop-up are reduced. There is a redistribution of the hem of fat ball, a fat emulsion is stabilized, and homogenized milk does not defend.
The valve type homogenizers serve to treat milk and cream in order to prevent their separation overlap.
Gomogenizers-plasticizers of rotary type are used to change the consistency of such dairy products such as melted cheeses and butter. In the butter treated with their help, the aqueous phase is dispersed, with the result that the product is better stored.
The principle of the valve type homogenizers that have received the greatest distribution is as follows. In a homogenizer cylinder, a mechanical effect is obtained for milk at a pressure of 15 ... 20 MPa. When lifting the valve, which opens the narrow slit, the milk comes out of the cylinder. This is possible when operating pressure in the cylinder. When passing through a narrow circular slit between the saddle and the valve, the milk speed increases from zero to a value greater than 100 m / s. The pressure in the stream drops sharply, and a drop of fat that fell into such a flow is pulled out, and then as a result of the operation of the surface tension forces, it is crushed into small particles.
When the homogenizer is operating at the outlet of the valve slit, the adhesion of crushed particles and the formation of "clodes" are often observed, which reduce the effectiveness of homogenization. In order to avoid this, two-stage homogenization is used (Fig. 2.11). A pressure of 75% of the worker is created on the first stage, the operating pressure is installed on the second stage. For homogenization, the temperature of the dairy raw should be 60 ... 65 ° C. At lower temperatures, the abandonment of fat is enhanced, whey proteins can be deposited at higher.
Fig.2.11. Homogenizing head.
I is the first stage, II - the second stage, 1-seat of the valve, 2-valve, 3-rod, 4- pressure screw, 5-cup, 6- springs, 7, 8- housings.
A homogenizer with a two-stage homogenizing head (Fig. 2.12) consists of a bed, housing, a plunger block, a homogenizing head, drive and a crank-connecting mechanism.
Fig. .2.12. Homogenizer A1-OGM-5
1 - electric motor, 2-stringed drive, 3- cranked-connecting mechanism with lubrication and cooling systems, 4- block plunger with homogenizing and pressure gauge and safety valve, 5- pressure gauge, 6- Homogenizing head, 7- Klinorem.
The bed is made of chawls and outside shelted steel steel. Inside it is installed an electric motor on the plate, which is attached to the bed articulated on two brackets.
The plunger block consists of a plunger housing, clarity seals, suction and injection valves and valve saddles. When operating a single plunger pair, the liquid comes to the homogenizing head with a pulsating flow. In order to align it in homogenizers, three cannger pumps, resulting in action
the crankshaft, whose knees are shifted by 120 ° relative to each other.
Two-stage homogenizing head, a gauge head and a safety valve, located on the opposite side of the homogenizing head, are attached to the plunger block of the bolts. The pressure gauge head has a throttling device that allows you to reduce the amplitude of the oscillations of the pressure gauge arrow during the homogenizer operation. The drive of the homogenizer includes an electric motor and belt transmission.
The crank-connecting mechanism consists of a crankshaft installed on two conical roller bearings, rods and slave pulleys. The connecting rods are connected to the slider hinged.
Industry produces homogenizers of various performance (Table 2.2).
Tab.2.2. Technical characteristics of homogenizers for milk and liquid dairy products
Indicator | |||
Performance, m3 / h | |||
Working pressure, MPa | |||
Temperature of the processed product, ºС | |||
Number of plungers | |||
Plunger stroke, mm | |||
Crankshaft rotation frequency, C-1 | |||
Number of homogenizer steps | |||
Electric motor power, kW | |||
Overall dimensions, mm | 1430 × 1110 × 1640 | 1480 × 1110 × 1640 |
|
Mass, kg. |
In the case when the homogenization needs to eliminate the access of microorganisms to the processed product, special aseptic homogenizing heads are used. In such heads into space, a hot pairs under pressure of 30 ... 60 kPa are served in the space bounded by two sealing elements. This high temperature zone serves as a barrier that prevents bacteria to enter the homogenizer cylinder.
Homogenizers-plasticizers on the principle of operation and the device differ from the valve type homogenizers. The working body in them is a rotor, which can have a different number of blades - 12, 16 or 24.
Homogenizer-plasticizer (Fig. 2.13) consists of bed, housing with screws, a receiving bunker and drive. The drive allows you to adjust the speed of rotation of the feed screws (using the variator) in the range of 0.2, .. 0.387 C-1. The frequency of rotation of the rotor with blades is not regulated and is 11.86 C-1. The principle of operation of the machine is as follows. Creamy oil is fed to the bunker, from where with the help of two screws rotating in opposite directions, it is pushed through the rotor and from the nozzle with the diaphragm goes into the bunker of the packing machine.
Fig. 2.13. Homogenizer M6 OGA for butter:
1- Wheel, 2nd, 3-housing, 4- mounting nozzle, 5- nozzle, 6-lock, 7- screw chamber, 8- bunker, 9-control panel, 10-screw.
To prevent the oil sticking oil, the working organs of the homogenizer are lubricated before starting work with a special Skrying solution. The performance of the homogenizer depends on the frequency of rotation of the supply screws and is 0.76 ... 1.52 m3 / h. Machine power drive 18.3 kW.
The Yaz-OGZ homogenizer is designed to process the molten cheese mass in the production of melted cheeses and consists of the following parts: base, housing, a set of homogenizing tool, bunker, discharge device and drive.
The base serves to mount the components of the homogenizer on it. The enclosure contains work units and sealing devices.
The homogenizing tool (Fig. 2.14) for feeding, grinding and mixing the molten cheese mass is made in the form of movable and fixed knives separated by spacer rings, as well as the loading paddle wheel and the discharge rotor. Moving knives have special grooves performed at a certain angle to the end surface, which contributes to the movement of the gridden product to the discharge device. Homogenizing tool shaft rotates with a frequency of 49 C-1.
The bunker for receiving and accumulating the cheese mass has a heat insulating shirt.
The discharge device in the form of two pipes, interconnected using the crane, serves to remove the homogenized mass into the packing dispenser.
Fig. 2.14. A set of homogenizer homogenizing tool:
1- A fixed ring, a 2-rolling ring, a 3-blade ring, 4- bunker, a movable knife, 6- housing, 7- fixed knife, 8- discharge rotor, 9 - shaft of a homogenizer.
The drive consists of an 11 kW engine designed to transmit rotation from the shaft to the moving part of the homogenizing tool.
The processing of the product on the Homogenizer of the Yaz-OGZ is as follows. The molten cheese mass is periodically or continuously fed to the homogenizer bunker. Under the action of the vacuum generated by the loading blade wheel, the product enters the homogenizing tool in which, passing consistently through moving and fixed knives, is homogenized and fed to the discharge device.
The use of a homogenizer makes it possible to abandon the technological operation of filping the cheese mass in order to remove its unspylled particles.
2.4. Equipment for preliminary dehydration of cottage cheese and casein mass
This equipment include separators for dehydration of cottage cheese clot, apparatus of separation of serum and centrifuge. Most of this equipment is described in sections devoted to the production of appropriate types of products (cheese, cottage cheese, etc.).
Centrifuges used in the dairy industry can be seated and filtering, periodic and continuous action.
The continuing centrifuge for pre-dehydration of the curd mass is currently applied relatively rarely.
The filtering centrifuge of the periodic action for dehydration of the milk sugar consists of a rotor, casing, drive and control panel. The cylindrical shape rotor is made of stainless steel. Its perforated surface is equipped with a metal grid. To increase strength, the rotor has two bandages. The rotor openings with a diameter of 5 mm are located in a checker manner in a step of 20 mm. The rotor is fixed on the shaft of the motor installed on the base with the ball support drive fastening bolts with rubber shock absorbers. The rotor and the drive are closed with steel casing. To load the rotor, the product provides a boot funnel. The lid has a blocking device.
Control questions.
1. What is the average duration of continuous operation of different types of filters? 2. Due to what increases the efficiency of ultrafiltration of dairy serum in the Sartokon-2 system? 3. In what cases is the cleaning of milk using dairy separators ineffective? 4. What factors affect the process of milk separation? 5. How do milk fat regulate in various types of cream separators? 6. In which separators, milk supply to the drum is carried out from below? 7. How is the normalization in the creation separators? 8. What factors affect the homogenization of milk? 9. With what pressure is homogenization on the first and second steps? 10. What are homogenizers come with three permanent pumps?
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