Goal of the work. Study of the structure and operation of the OPF-1 pasteurization-cooling unit, partial disassembly and assembly, adjustment, preparation of the unit for operation, execution of operations Maintenance and assessment of technical condition.

Equipment, tools and visual aids. Pasteurization and cooling unit OPF-1, set of plumbing tools, posters, teaching aids, instructional and technological map.

1. Study the design and operation of the OPF-1 pasteurization-cooling unit and its main assembly units.

2. Partially disassemble and reassemble the installation and prepare it for operation.

3. Put the installation into operation and, after stopping, perform maintenance operations, assessing its technical condition.

4. Draw up and submit a report on the work done.

Methodological instructions for work. The automated plate pasteurization-cooling installation OPF-1 is designed for centrifugal cleaning, pasteurization, holding and cooling of milk in a closed flow.

The OPF-1 unit is supplied in two modifications: OPF-1-20 – for pasteurization of uncontaminated milk at a temperature of 74...78 °C with a holding time of 20 s; OPF-1-300 – for pasteurization of milk from sick cows at a temperature of 90...94 °C with a holding time of 300 s.

Installation of OPF-1(Fig. 62) consists of a plate heat exchanger 1, a centrifugal milk purifier 2, a tubular holder 7, a milk pump 4 and a pump for hot water 8, surge tank 5, electro-hydraulic bypass valve 11 and bypass valve 3, piping and automation systems.

The plate heat exchanger is equipped with stainless steel plates, which are divided into five sections (Fig. 62): I– pasteurization, II And III– regeneration, IV– cooling with cold (artesian) water, V– cooling with ice water or brine.

The sections are separated from one another by special intermediate plates. Engraved on each slab serial numbers, the same numbers are indicated on the layout plate diagram. The plates are attached to the rack using plates and pressing devices. The degree of compression of thermal sections is determined by a plate with a scale installed on the upper and lower struts. The zero division is set along the axis of the vertical spacer bolt, which corresponds to the minimum compression of the device, ensuring tightness. In the pasteurization section, heat exchange occurs between hot water and milk streams, separated by thin stainless steel plates. Between the plates, water and milk alternate in countercurrent. Milk and water pumps create the pressure necessary for movement. Fittings for inlet and outlet of milk, cold and hot water are screwed into the plates.

Centrifugal milk purifier 2 is designed to remove mechanical impurities from milk. Milk is also purified from epithelial particles and accumulations of microorganisms.

The electrohydraulic bypass valve 11 serves to automatically switch the milk flow to reheating when the milk pasteurization temperature decreases. It consists of a valve with a hydraulic chamber and an electro-hydraulic relay.

The surge tank 5 serves to receive milk and uniformly fill the pump 4, which supplies milk to the first recovery section. In addition, it is used to prepare a cleaning solution for circulation washing.

Rice. 62. Technology system pasteurization and cooling unit OPF-1-300:

1 – plate apparatus, 2 – centrifugal milk purifier, 3 – bypass valve, 4 – milk pump, 5 – equalization tank, 6 – control panel, 7 – hold-up, 8 – hot water pump, 9 – boiler, 10 – injector, 11 – electrohydraulic valve that regulates the steam supply

Boiler 9 in the coolant heating system of a pasteurized installation serves to collect water, equalize its temperature and remove excess water. It consists of a cylindrical tank with a spherical lid and perforated discs mounted on an overflow pipe. At the bottom of the tank for supplying and discharging coolant there are two pipes with flanges at the ends. Injector 10 is designed to mix steam with hot water circulating between the boiler and the pasteurization unit section. It consists of a housing, inside of which there is a mixer with cylindrical nozzles and a threaded fitting with a flange for connecting the injector to the pipeline.

The amount of steam entering the mixer is adjusted automatically depending on the milk pasteurization temperature. The steam supply to the injector is controlled by an electrohydraulic valve.

The units operate automatically or manually.

Technological process in an automated plate pasteurization-cooling unit (Fig. 62) proceeds in the following order. Milk that requires processing flows by gravity into equalization tank 5, from where it is supplied by milk pump 4 to the second regeneration section, where it is heated to 36–38 °C by a counter flow of hot milk (from the soaker), which flows along the other side of the heat exchange plates, and is then sent into a centrifugal milk purifier 2. Here, under the influence of centrifugal forces, milk is purified not only from mechanical particles, but also from mucus, clots, epithelium and blood cells that appear in milk during udder disease. From the purifier, milk is supplied to the first regeneration section, where it is additionally heated by a counter flow of hot milk and sent to the pasteurization section for final heating to the temperature required by the processing technology (OPF-1-20 - up to 76 ° C and OPF-1-300 - up to 92 °C). From the pasteurization section, the milk goes to a bypass valve, which automatically switches the flow, and it goes to the surge tank to be reheated if it is not heated to the required temperature. Milk heated to a given temperature enters holder 7, where it remains for 300 s and returns to the first and second regeneration sections. In the sections it is pre-cooled by a counter flow of cold milk coming from the surge tank, and then fed into the fourth and fifth sections for final cooling.

The units use chilled water natural ice or using refrigeration unit up to 2–4 °C, as well as artesian or tap water the same temperature. Cooling water flow 1800...2000 l/h. The temperature of the chilled milk is recorded on the control panel, and the pasteurization temperature is recorded on a chart tape, which is a document confirming compliance with the technological regime of the processing process.

The installation operates at low steam pressure (about 0.4 MPa) and is combined with a KV-300M steam boiler. Due to the high degree of heat recovery and full automation, steam consumption is negligible.

Maintenance(monthly and periodic). Upon completion of work, they pass through the installation clean water in the circulation flow for 5...7 minutes. Then a one percent alkali solution is added to tank 4 and washed at 70 °C for 10...12 minutes, turning off the supply of coolants. After draining the solution, the installation is washed again with clean water. If necessary, repeat rinsing with a solution of nitric acid (0.5%) also for 10...12 minutes and then rinse the system with clean water.

The use of washing powders “A” and nitric acid solution increases the operating life to 80...100 hours without disassembling the installation for detailed washing. After ten days of operation, the soaker and pasteurizer are disassembled in accordance with the instructions for inspection and removal of milk stone.

Technical specifications OPF-1

Work report.

1. Draw a basic technological diagram of the operation of the pasteurization and cooling unit OPF-1.

2. Provide the basic technical data of the installation.

Control questions and tasks.

1. What are the main assembly units of the OPF-1 pasteurization and cooling unit?

2. What technological scheme does the installation use?

3. Name the main maintenance operations of the installation.

Milk and dairy products are pasteurized in special containers, tubular pasteurization units, as well as plate pasteurization and cooling units.

The first include long-term pasteurization baths and universal baths.

A tubular pasteurization plant (Fig. 4.4) consists of a tubular apparatus, two centrifugal pumps, a return valve, condensate drains and a control panel with monitoring and control devices technological process.

The main element of the installation is a two-cylinder heat exchanger, consisting of an upper and lower cylinder, connected to each other by pipelines. Tube grids are welded into the ends of the cylinders, in which 24 pipes with a diameter of 30 mm are flared. Short channels are milled into the stainless steel tube sheets, connecting the ends of the tubes in series. As a result, a continuous coil with a total length of about 30 m is formed. The ends of the cylinders are closed with lids with rubber seals to ensure the tightness of the device and isolate short channels from each other.

Rice. 4.4.

1 - centrifugal pumps for milk; 2 - condensate drains; 3, 4 - pipes for condensate drainage; 5, 6, 7, 8 - milk pipelines; 9 - return

valve; 10 - steam control valve; 11 - safety valves; 12 - steam line; 13 - pressure gauges for steam; 14 - pipe for exiting pasteurized milk; 15 - pressure gauge for milk; 26 - control panel;

17 - upper cylinder; 18 - lower cylinder; 19 - frame

Steam is supplied to the inter-tube space of each cylinder. Exhaust steam in the form of condensate is removed using thermodynamic condensate traps. The heated milk moves in the intra-tube space, passing successively the lower and upper cylinders. At the inlet there is a valve that regulates the supply of steam, and at the milk outlet from the machine there is a return valve, with the help of which under-pasteurized milk is automatically sent for re-pasteurization. The return valve is connected through a temperature regulator to a temperature sensor, also located at the milk outlet from the machine. The installation is equipped with pressure gauges to monitor the pressure of steam and milk.

Processed product from storage capacity the first centrifugal pump is supplied to the lower cylinder of the heat exchanger, where it is heated by steam to 50...60 ° C and passes into the second cylinder. Here it is pasteurized at 80...90°C.

The second pump is designed to supply milk from the first cylinder to the second. In tubular pasteurization plants, the speed of movement of different products is not the same. In an installation for pasteurizing cream, the speed of its movement in the pipes of the heat exchanger is 1.2 m/s. During the heat exchange process, the cream is fed into the pasteurizer cylinders by one centrifugal pump. The speed of milk movement by two pumps is higher than by one, and is 2.4 m/s.

The advantages of tubular pasteurization plants compared to plate ones include a significantly smaller number and size of sealing gaskets, while the disadvantages are large dimensions and high metal consumption; In addition, when cleaning and washing these installations, it is required free space from the ends of the cylinders of the heat exchanger.

Tubular installations are effective when further milk processing is carried out at a temperature slightly different from the pasteurization temperature.

Pasteurization and cooling units used for heat treatment of milk, cream and ice cream mixtures. The design of each of these installations has its own characteristics, which are reflected in the description of equipment for the production of various dairy products.

Pasteurization and cooling plants used in the production of drinking milk usually include a surge tank, centrifugal pumps for milk and hot water, a plate apparatus, a milk separator, a stand, a check valve, a water heating system and a control cabinet. Depending on the performance, such installations may have a different number of sections in the plate apparatus, and also differ in the method of heating the coolant. The technological diagram of an automated plate pasteurization-cooling unit with a capacity of 1000 l/h is shown in Fig. 4.5.

The centrifugal pump is designed to take milk from the surge tank and supply it to the plate apparatus. To prevent air from suction into the pump, a certain milk level (at least 300 mm) is maintained in the surge tank using a float mechanism. Failure to comply with this condition leads to foaming, which reduces the effectiveness of pasteurization.

The ends of the upper and lower horizontal rods are fixed in the main front (Fig. 4.6, a) and auxiliary rear posts of the plate apparatus. The upper one is intended for hanging heat exchange plates. Along the periphery of each plate, a large rubber gasket is placed in a special groove, hermetically sealing the channel.

The plates have holes with small o-rings. After assembling the plates in the apparatus, two isolated systems of channels are formed through which milk and coolant move.

The plate apparatus is equipped with heat exchange plates made of stainless steel, which are divided into five sections: the first and second stages of regeneration, pasteurization, cooling with artesian water and cooling with ice water. Some plate devices have one regeneration section. The sections are separated from each other by special intermediate plates, at the corners of which there are fittings for supplying and discharging liquids. Serial numbers are stamped on the plate; the same numbers are indicated on the plate layout diagram.

Rice. 4.5.

1 - plate apparatus; 2 - milk separator; 3 - milk

pump; 4 - surge tank; 5 - control panel; 6 - holder;

7 - water pump; 8 - convection tank; 9 - injector; 10 - valve regulating steam supply; 11 - electrohydraulic bypass valve;

I, II- regeneration sections; III- pasteurization section; IV- cooling section cold water; V- ice water cooling section

The plates are pressed against the rack with a plate and clamping devices. The degree of compression of thermal sections is determined from a table with a scale located on the upper and lower struts. The zero division is set along the axis of the vertical strut bolt; it corresponds to the minimum compression that ensures the tightness of the apparatus.

In high-capacity installations, sections of plate apparatus are located on both sides of the main rack (Fig. 4.6, b).

The milk separator is used to purify milk. When using a purifier with centrifugal discharge of sediment, one separator is installed, with a manual one - two.

The holding agent is one of the main elements of pasteurization-cooling units. In it, the milk is kept at pasteurization temperature for a certain time (20 or 300 s) necessary to complete the bactericidal effect of the temperature.

Rice. 4.6.

A- with one-sided sections: 7, 2,11, 12 - fittings;

• 3 - front pillar; 4 - upper corner hole; 5 - small ring rubber gasket; 6 - boundary plate; 7 - rod; 8 - pressure plate;
• 9 - rear pillar; 10 - screw; 13 - large rubber gasket;
• 14 - lower corner hole; 15 - heat exchange plate; b - with double-sided arrangement of sections: 1 - clamping device;
• 2 - pressure plates; 3 - first recovery section; 4 - fitting for removing milk from the recovery section and supplying it to the milk separator;
• 5 - second recovery section; 6 - fitting for introducing milk into the recovery section after the soaker; 7 - pasteurization section; 8 - main stand; 9 - water and brine cooling section; 10 - fitting for supplying pasteurized milk; 11 - spacer; 12 - leg; 13 - fitting for brine outlet; 14 - a fitting for releasing pasteurized milk from the pasteurization section and feeding it into the conditioner; 15 - fitting for supplying milk to the recovery section after the milk separator; 16 - fitting for releasing hot water; 17 - outlet fitting cold water; 18 - fitting for brine supply;
• 19 - fitting for supplying pasteurized milk to the water cooling section;
• 20 - dividing plates; 21 - connection for raw milk supply

The support consists of one or four cylinders, which are mounted on tubular supports. In some installations, the holder is made in the form of four sections, each of which is a spiral made of a pipe with a diameter of 60 mm.

When processing milk obtained from healthy animals, one section is involved in the work. In the case of processing milk from sick animals, it is passed sequentially through all four sections of the holding tank. Thus, the holding time of milk, other things being equal, depends on the capacity of the stand.

The return, or bypass, electro-hydraulic valve is used to automatically switch the milk flow to re-pasteurization when its temperature in the pasteurization section decreases.

Heating system intermediate coolant The pasteurization-cooling unit consists of a convection tank, hot water pump, injector, steam supply valve and pipelines.

The tank serves to collect, equalize the temperature and drain excess water.

The injector is designed to mix steam with water circulating between the convection tank and the pasteurization section of the installation. The amount of steam entering the injector is regulated by a valve depending on the set milk pasteurization temperature.

An injector - plate apparatus - convection tank is used to circulate hot water in the system. centrifugal pump 2K 20/18 or 2K 20/30.

In a pasteurization-cooling unit with electrically heated intermediate coolant (B6-OP2-F1), instead of a convection tank with an injector, electric water heater- capacity cylindrical with a capacity of about 40 liters, on the lid of which there are electric heating elements. To replenish and maintain a constant water level, a surge tank is mounted on the tank body. Excess water from the water heater is removed using an overflow pipe. The water level in the tank is controlled by a special meter, which turns off the heating elements when the level drops below normal.

The operation of a pasteurization-cooling unit in the production of drinking milk is as follows. Milk from the container (see Fig. 4.5) is directed by gravity or under pressure into the surge tank, from where it is pumped into the first regeneration section of the plate apparatus. Heated to 37...40°C, it enters the milk purifier to remove mechanical impurities and is sent for further heating to the second regeneration section and pasteurization section, where it is heated to 90°C.

From the pasteurization section, milk is directed through an electro-hydraulic bypass valve to the holder, stays there for 300 s, and then enters the regeneration sections to transfer heat to the counter flow of milk entering the apparatus. After this, it enters sequentially into the cooling sections with water and brine, where it is cooled to 8°C, and leaves the installation.

The milk is cooled with artesian water and ice water or brine, which comes from the refrigeration unit. Cooling milk to a temperature not higher than 8°C is possible only with a normal rate of supply of water and brine in the cooling section. The entire pasteurization process is controlled automatically.

The required pasteurization temperature is maintained by an electronic bridge. The adjustment is smooth. Milk pasteurization temperature is recorded on a chart tape control device. Sound and light alarm turns on when the pasteurization temperature drops below 90°C.

Along with indirect heating of the product, when milk is processed with hot water heated by steam or electric heaters, c. Some pasteurizers use infrared heaters as a source of direct heating of the product. In small-capacity pasteurizers, milk is supplied for processing infrared emitter thin layer.

IN pasteurization in the cooling unit UOM-IK-1(Fig. 4.7) in addition to the infrared electric heating sections, there is a hold- er and a plate heat exchanger.

Rice. 4.7.

• -milk, ---cold water, ---ice water,
• - x - supply of tap water, ---- water discharge during washing
• 1 - infrared electric heating section; 2 - withstander;
• 3, 15 - thermometers; 4 - viewing area; 5,6 - three-way valves;
• 7 - cooling section with ice water (brine); 8 - water cooling section; 9 - regeneration section; 10 - pressure gauge; 11 - plate heat exchanger; 12, 13 - valves; 14 - bypass valve; 16 - resistance thermometer; 17 - tap; 18 - surge tank; 19 - pump; 20 - washing pipeline; 21 - milk storage container

The infrared heating section consists of tubes quartz glass U-shaped with anodized aluminum reflectors. The section has 16 tubes (10 main, 4 regulating the heating mode and 2 additional), on which a nichrome spiral is wound. The tubes are connected to the network in parallel.

The holder consists of two stainless steel pipes connected in series.

The plate heat exchanger has a regeneration section and two cooling sections.

The milk enters the equalization tank and from it is sequentially supplied by a pump to the regeneration, infrared heating and holding sections. After aging, pasteurized milk passes through a regeneration section, transferring heat to cold milk, and successively passes through cooling sections with water and brine.

Plate pasteurization-cooling units have certain advantages compared to other types of thermal devices:

• small working volume of the apparatus, which allows automation devices to more accurately monitor the progress of the technological process (in a plate installation, the working volume for the product and coolant is 3 times less than in a tubular installation of the same productivity);
• ability to work quite efficiently with minimal thermal pressure;
• minimal heat inflows and losses of heat and cold ( thermal insulation usually not required);
• significant savings (80...90%) of heat in the regeneration sections ( specific consumption steam in plate devices is 2...3 times less than in tubular ones, and 4...5 times less than in capacitive heat exchangers);
• small installation area (a plate installation occupies approximately 4 times less floor surface than a tubular installation of similar performance);
• the ability to change the number of plates in each section, which allows you to adapt the heat exchanger to a specific technological process;
• possibility of in-place circulation washing of equipment.

The highest technological indicators among domestic thermal devices, there are modular automated pasteurization and cooling units with electric heating “Potok Therm 500/1000/3000”.

The peculiarity of these installations is a high heat recovery coefficient (0.9), a hot water preparation system with electric heating and a four-section plate heat exchanger (two regeneration sections, a pasteurization section and a cooling section). In the heat exchanger, the rubber gaskets are made of a proprietary material and are connected to the plates with special clamps, i.e. without the help of glue. Main technical characteristics of installations of this type are given in table. 4.1.

Basic technical data of plate pasteurization and cooling units for milk

Table 4.1

Index
Productivity, l/h
Temperature of milk at the entrance to the machine, °C:
heating (pasteurization)
cooling
Regeneration coefficient, not less
Milk holding time at pasteurization temperature, s
Temperature coolant, °C
Coolant ratio
Supply line pressure, kPa, not less
Installed power, kW
Power consumed by the installation in pasteurization mode, kW
dimensions, mm	2150 x 900 x x 1845	2150 x 900 x x 1845	2715 x 1225 x x 2215
Occupied area, m 2
Installation weight, kg

In addition to automated ones, modular semi-automatic pasteurization and cooling units “Potok Therm 3000/5000/10000” are also produced, in which the product is heated to a pasteurization temperature with steam pressure of 300 kPa. The steam consumption in these installations is 60, 100 and 173 kg/h, respectively.

Along with pasteurizers, which use infrared rays as a source of direct heating of milk, milk pasteurization units have been developed and are becoming increasingly widespread, the operation of which is based on the use of ultraviolet radiation. The use of such installations can significantly reduce the metal and energy intensity of the technological process of milk pasteurization, improve its quality and reduce losses, while preserving the useful components of the product (proteins, fats, vitamins).

The operating principle of pasteurizers of this type is the non-contact effect of ultraviolet radiation on a specially formed thin-layer milk flow.

Thus, pasteurizers of the UFO type have five standard sizes (Table 4.2), differing in size or size and shape.

Table 4.2

Basic technical data of UFO type pasteurizers

All pasteurizers of this type are designed in the same way: a housing in which the milk distributor, upper and lower irradiation devices with pasteurization plates and a power supply are located. The milk distributor consists of a sprinkler valve to which milk is supplied through a pipeline. Irradiating devices are special gas discharge lamps and reflectors. The design of the upper and lower irradiating devices is the same.

The pasteurizer works as follows. Milk through the holes of the sprinkler valve is fed in a thin layer onto the upper pasteurization plate and, flowing down it, passes through an intense flow ultraviolet rays, emitted by the irradiating device. Through the holes of the upper irrigating collector, the milk flows to the lower pasteurization plate, where it is re-processed by the lower irradiation device. Pasteurized milk flows from the lower pasteurization plate into the collection tank, and from it into the receiving container.

The power supply unit of the pasteurizer contains ballasts that ensure the operation of the upper and lower irradiation devices. In pasteurizers with a capacity of 1000 l/h or more, the ballasts are located in a separate cabinet.

For periodic washing of pasteurizers with soda solution and water, all their working parts that come into contact with milk are easily removable.

Pasteurizers of the UFO type are non-pressure devices and when using a milk pump to supply milk, the latter must be equipped shut-off valve, providing a pressure of 0.1...5 m of water column.

One of the promising areas for improving pasteurization plants is the use of rotary heaters in them, special design which allows, due to the molecular friction of the particles of the processed product, to heat the latter to a given temperature. The temperature of the heat treatment of the product depends on the time it is in the rotary heater and can be adjusted within a wide range. At the same time, the product is homogenized.

High-temperature milk pasteurizer with rotary heater PMR-0.2 VT(Fig. 4.8) with a capacity of 500, 1000 and 1800 l/h is designed for pasteurization, aging, filtration and cooling of milk. It can be used in conjunction with a milking machine or independently. If necessary, the pasteurizer is set to milk sterilization mode.

Rice. 4.8.

• 1 - control panel; 2 - resistance thermometer; 3 - automatic return valve; 4 - milk entry; 5 - receiving tank; 6 - milk pump; 7 - filter; 8 - plate heat exchanger; 9 - milk yield;
• 10 - holder; 11 - walk-through valve; 12 - rotary heater

The specific energy costs compared to the costs of operating other installations in this device are reduced by 2.5...3 times, and the area occupied by it does not exceed 1.5 m 2.

Milk from the storage tank enters the receiving tank and is supplied by a milk pump to the filter and then to the plate heat exchanger. In the regeneration section of the apparatus, the milk is heated by heat transferred from the product coming from the conditioner and fed into a rotary heater. The milk processing temperature in the heater is measured with a resistance thermometer and displayed using a digital indicator on the control panel.

If the specified pasteurization regime is violated, the milk is sent for re-processing using an automatic return valve. Milk heated to the required temperature is supplied to the holder, where it remains for 15...20 s, and then sequentially moves through the regeneration and cooling sections of the plate heat exchanger.

The pasteurizer is equipped electronically controlled, which allows you to continuously monitor its operating parameters.

The main technical data of the PMR-0.2 VT pasteurizer of various modifications are given in table. 4.3.

Table 4.3

Basic technical data of pasteurizers with a rotary heater

Index	PMR-0.2VT	PMR-0.2-1VT	PMR-0.2-2VT
Performance,
Milk temperature, °C:
arriving for processing
pasteurization
Duration of milk exposure at pasteurization temperature, s
Temperature of chilled milk (at a coolant temperature of 1...3°C and at a supply intensity of at least 1.5 m 3 /h), °C
Installation warm-up duration, min
Filter type	Non-woven or mesh
Installed power, kW
Overall dimensions of the installation, mm	1100 X 750 x x 1500	1100 X 1000 x x 1500	1200 X 1100 x x 1500
Installation weight, kg

Pasteurization and cooling plant is used to pasteurize and cool dairy products. In other words, this installation is necessary for all enterprises that work with this category of goods. In addition, this installation is equipped with an automatic temperature control and regulation system, which makes its use even more convenient.

Description of installation

Today there are tubular and plate installations. Next, the device of the second type of such devices will be described. So, a plate pasteurization-cooling unit consists of such basic elements as:

• plate heat exchanger;
• a system designed for the preparation of hot water (includes a pump, an injector and a convection type tank).

The main purpose of this system is that it heats products to the ripening temperature. There is also a pump for the products themselves. Naturally, since there is an automatic system for monitoring and adjusting parameters, there is also a control panel for this system. It is important to note that the pasteurization and cooling unit is quite compact and designed in a modular style. The only thing is the sustainer, which is a separate structural element. Regarding installation, it can be mounted in any accessible location. In the end it turns out convenient system, having everything necessary for automatic operation, which at the same time takes up little space.

Purpose of the installation

The pasteurization-cooling unit is designed to perform the following actions:

• Heating the dairy product to a temperature of 55-60 degrees Celsius (separation temperature).
• Heating to a temperature of 75-80 degrees (milk homogenization).
• Heating to the pasteurization temperature of the dairy product is 90-95 degrees.
• The equipment also holds the product at its pasteurization temperature for 300 seconds.
• The last operation is cooling the product to the ripening temperature, that is, to 20-50 degrees.

Purpose of elements

The plate pasteurization and cooling unit for milk is also capable of working with liquid products such as beer, juice, wine, drinks, alkalis and others. A plate heat exchanger is responsible for heating and cooling this product. All operations are carried out with a closed stream. It is also worth noting that due to the high thermal efficiency of such heat exchangers, they have compact dimensions. As for the efficiency, for all installations made on the basis of this model, it is more than 90%. All parts of the pasteurization and cooling unit that come into contact with food during operation are made of steel approved for use in the food industry.

The coolant in such systems is either water or brine. The heat carrier can also be water or steam. The device has which consists of plates, a frame and a pressure plate. All these parts are tightened together with fixing pins.

Installation specifications

The pasteurization and cooling unit for milk has a certain range of technical parameters, which varies depending on the model. Next, the parameters of the PBK-1 product will be described.

First and most important parameter- this is, of course, productivity. For this equipment it ranges from 1000 to 10,000 l/hour. The next parameter is the temperature of both the coolant and the coolant in the system. The difference between the output products and these media is from 2 to 4 degrees Celsius with a factor of 1/3. All models also differ in their dimensions, but not too much, and the parameter itself is not very important. The material used to make the plate is steel grade 12Х18Н10Т. The thickness of the plates is 0.6 mm. Maximum temperature for PBK-1 it is 150 degrees.

Operating principle of a pasteurization-cooling unit

IN automatic system Plate type working process is as follows.

The production facility has a milk collector, which is connected to the surge tank of the device. Products flow from the collection into this module either using a pump or by gravity. It is important here to ensure that the milk level does not fall below 300 ml, otherwise air will begin to leak into the milk pump. After this, the pump pumps the product into the first section of the heat exchanger. Here milk product heats up, as heat exchanges with hot milk coming from the pasteurization section through the holder. Here the temperature of the object rises to approximately 47-50 degrees Celsius, after which the milk is pumped through the clarifier to the second section. Here the product is reheated. Heat exchange occurs with the same pasteurized milk that underwent preliminary heat exchange in section number 1. After completing this procedure, the milk enters the pasteurization section, which is considered the third. Here the coolant is ordinary water. The heat exchange continues until the dairy product reaches 76 degrees Celsius.

Further, as described above, pasteurized milk returns through sections 1 and 2, where it gives off heat, thereby cooling to 20-25 degrees. After this, the products are pumped into a cooler, where the temperature drops to 5-8 degrees. The completely cooled milk is then transferred to storage tanks. This is where the work of the milk pasteurization and cooling unit ends.

Tubular type installation

The description above concerned a plate-type device, but there is also a second one - a tubular one. Such devices consist of a tubular apparatus, two centrifugal pumps, a return valve, condensate drainage units, as well as a control panel designed to control automatic control and operation control devices.

Description of the unit elements

The tubular pasteurization-cooling unit includes: It consists of two cylinders, upper and lower, which are connected to each other using a pipe system. Tube grids are welded into the ends of these cylinders, each of which contains 24 pipes with a diameter of 30 mm. The gratings are made of stainless steel and also have short channels. These channels connect all 24 pipes. The result is a continuous type coil with a total length of approximately 30 m. The cylinders, in turn, are closed with covers that are equipped with rubber seals. This is done not only to create a completely sealed structure, but also to separate the short channels from each other.

During the operation of the device, steam is present, which, upon entering, enters the space between the cylinders. After it has worked, it is removed from the device in the form of condensate using thermodynamic type condensate traps.

The essence of the unit's operation

The milk that needs to be heated moves in turn through the upper and then the lower cylinder. It moves through the intra-pipe space. The unit also has a valve that regulates the steam supply. It is located immediately at the entrance of this substance. At the outlet of the device there is another valve, but of a return type. It works in automatic mode, and its main purpose is to return under-pasteurized milk for a second operation. To perform this function, the mechanism is connected to a temperature sensor through a device such as a temperature controller, which is also located at the milk outlet. Since the device contains steam and milk pressure, the unit also has several pressure gauges.

It is worth noting that processing begins from the lower cylinder, where steam is present, which heats the milk to a temperature of 50-60 degrees. The milk enters the lower part under the influence of the first centrifugal pump. A second pump is used to pump to the upper one. In the upper part, the substance is pasteurized to a temperature of 80-90 degrees Celsius.

Main advantages of the installation

This equipment has become widespread because it has a number of significant advantages that are important for this industry. Firstly, the device fully complies thermal conditions both during pasteurization and during cooling. At the same time, the specified performance is maintained. Secondly, the modular design minimizes the size of the device, which makes it compact, and therefore convenient for placement and use.

Rice. 5. 14. Process diagram of OPU-3M

1 – heat exchanger; 2 – hot water pump; 3 – boiler;

4 – injector; 5 – tubular holder; 6 – control panel;

7 – automatic return valve for under-pasteurized milk;

8 – tank; 9 – milk pump; 10 – intermediate tank;

11 – flow stabilizer; 12 – pump; 13 – pasteurization section;

14 – regeneration section; 15 – water cooling section;

16 – brine cooling section; 17 – milk purifier

Cooling and pasteurization unit OPU - 3U is designed for centrifugal cleaning, thin-layer pasteurization of milk in a closed flow and its subsequent cooling.

Each installation includes: a plate pasteurizer-cooler, an equalization tank with a float, milk pumps, a flow uniformity regulator, separators - milk purifiers, an automatic valve for removing underpasteurized milk, a boiler for heating water, a steam injector, a pump for hot water, a control panel with a timer and steam and brine pipelines with pressure and flow regulators.

The installation sections differ in different plate layouts, types and locations. The installation has five sections: pasteurization, regeneration (stages I and II), water cooling and brine cooling. The operation of a plate automated pasteurization and cooling unit is carried out as follows. Raw milk from the tank is pumped into the intermediate tank. The milk level in the tank is maintained by a float device. From the tank, milk is directed by pump 12 through flow stabilizer 11 to the regeneration section of the plate apparatus, where it is heated with pasteurized milk. Then the milk goes into alternating milk purifiers 17. The purified milk is fed under pressure into the pasteurization section of the plate apparatus, in which it is heated with hot water to a temperature of 76 ± 2 0 C and then sent to a tubular holder 5 , and then to section 14 of regeneration. When the pasteurization temperature is below the specified milk automatic valve returns to tank 10 for repeated heat treatment. At a given pasteurization temperature, milk from stand 5 sequentially passes through water and brine cooling sections 15 and 16 of the plate apparatus, cooling to 4 ± 2°C. Water for the pasteurization section is heated in the injector 4 and is supplied by water pump 2.

Technical specifications:

Capacity, l/h 3000

Temperature, 0 C:

Pasteurization 76 ± 2

Chilled milk 4 ± 2

Steam consumption, kg/h 72

Cooling consumption 9000

Operating pressure 1,5

pair, MPA

Installed power

electric motors, kW 16.5

Overall dimensions, mm:

Length 2015

Width 700

Purpose

Pasteurization and cooling of milk, juices, juice drinks, wines, wine materials, beer, kvass, and other liquid food products.

Versions:

• Automated pasteurizers for the production of drinking milk.
• Automated multifunctional pasteurizers for the production of milk for drinking purposes and the simultaneous preparation of milk for the processes of ripening and heating.
• Semi-automatic pasteurizers with manual control.

Additional option: design of the pasteurizer with the function of sanitizing the product supply and dispensing lines.

Characteristics

Options
Productivity, l/hour *
Pasteurization mode, °C	79 - 120 (set from the control panel)
Product inlet temperature, °C
Product outlet temperature, °C - for cold filling - for hot filling	4 - 6 Arbitrary (set from the control panel)
Exposure time, sec. **	20–25 (for drinking milk) 300 (milk for fermented milk products)
Coolant: Primary - secondary	Steam Hot water (hot water temperature is 3-5 °C higher than the set temperature for pasteurization of the product).
Coolant	Ice water (+ 1 - + 3 °C), glycol solutions, brines
Inlet and outlet diameters product nozzles, mm	DN 35 (DIN)	DN 50 (DIN)	DN 50 (DIN)

* The capacity of pasteurization and cooling units can be set arbitrarily by the Customer in the range of up to 25,000 l/h
** The holding time at pasteurization temperature can be set arbitrarily by the Customer.

POSSIBILITY OF SYNCHRONIZING THE PERFORMANCE OF PASTEURIZERS WITH THE PERFORMANCE OF THE FILLING LINE.

Implementation of various temperature conditions product processing and the ability to connect external equipment (separator, homogenizer) ensures the versatility of the pasteurizer.

Principle of operation:

1. The initial product enters the receiving tank, in which, thanks to special device it is filled to a certain level. From the receiving tank, the product is pumped into the regeneration section(s) of a multi-section plate apparatus for preheating and then sent to the pasteurization section, where it is heated to a given temperature. Next, the heated product enters the soaker, from which it is sent sequentially to the regeneration and cooling sections. At the customer's request, recovery sections can have outputs to a separator and homogenizer.
2. The product is heated to the required temperature in the pasteurization section by hot water, which circulates in a closed steam heating circuit.
3. Cooling of milk to the required temperature is carried out in two stages according to the counterflow principle: first - in the regeneration section(s) with the original cold product and then, in the cooling section - with coolant (ice water, etc.)
4. The multifunctional pasteurizer has an additional hot water preparation circuit and additional sections plate heat exchanger to provide different temperatures of the product at the outlets, for example, for hot filling, or for the release of warm pasteurized milk for the purpose of its further fermentation and production of fermented milk products.

Automation:

The process of processing the product in the pasteurizer is fully automated. The process control system is built on the basis of programmable controllers from Omron (Japan). The accuracy of maintaining the pasteurization temperature regime is ensured by the implementation of the PID law automatic regulation temperature when controlling the steam valve.

Permission for the initial release of the product is given by the operator. Next, the control system monitors the pasteurization temperature regime, and if it is violated, the installation goes into a circulation state inner contour until the specified mode is restored.

Using the operator's touch panel allows you to perform a variety of visualization of the process in digital and graphical forms with the issuance of messages on the operator's actions and emergency situations(functions of the SKADA system). In a separate window, parameters of the pasteurization technological process are set. The pasteurizer has a function for archiving the values ​​of process parameters on a type of storage medium convenient for the customer, which makes it possible to document the entire technological process.

A high degree of automation using USB and Ethernet ports allows, at the customer’s request, to provide the ability to connect the pasteurizer to a top-level system and industrial control system of the enterprise.

SEMI-AUTOMATIC PASTEURIZERS WITH MANUAL CONTROL.

All pasteurizers of the OKL series are similar in their design.

In manually controlled pasteurizers, pumps, heating of hot water and product circuits, as well as the “circulation”, “pasteurization”, “drain” modes are switched on using switches. The temperature regime is set and controlled according to the PID law by Omron temperature controllers, which control the steam supply valves in the hot water preparation circuits.

Permission for the initial release of the product is also given by the operator, and then the control system monitors the pasteurization temperature regime, and if it is violated, the installation goes into a state of circulation through the internal circuit until the set mode is restored.

Visualization of the installation status is carried out by light indicators, and temperature conditions are indicated on temperature controllers. To archive temperature conditions, a paper or electronic recorder is used. The temperature settings are set by the operator on the temperature controllers and on the recorder, which also displays a temperature graph.

The pasteurizer also controls the product level in the receiving tank and the pressure in the product lines and in the hot water circuits.

DESIGN FEATURES (for all versions of pasteurizers):

1. The plate heat exchanger has several sections (for the basic version - 3 sections: regeneration, pasteurization and cooling) and consists of a frame with clamping devices, a set of heat exchange plates with seals, separating and pressure plates. The plate apparatus uses heat exchange plates stamped from stainless steel sheets. On both sides of each plate there are channels through which, on one side, the product moves, and on the other, the coolant or coolant moves. Tightness in assembled device is created by rubber sealing gaskets (NBR, EPDM) inserted into special grooves in the plates.
2. The holder is a pipeline system that ensures a certain holding time of the product at the pasteurization temperature.
3. The receiving tank is a cylindrical container with a level regulator, which ensures a constant level of the product.
4. The hot preparation unit is made using a soldered heat exchanger, an expansion tank and a safety group.
5. To supply hot water to the pasteurization circuit, a stainless steel centrifugal pump from Grundfos (Germany) is used.

Main advantages of heat exchangersbased on API Schmidt-Bretten plates (Germany):

• Efficient heat exchange due to a special corrugated profile of the flow part of the plate, which forms three-dimensional turbulent flows. This minimizes the likelihood of contaminants depositing on the surface of the plates.
• Double sealing of heat transfer plates in the media inlet and outlet areas, which prevents media displacement.
• Presence of a special leakage edge in the sealing area. If one of the seals depressurizes, the medium will flow out without mixing with the other.
• In addition to the function of media separation, the seals center the plate stack. The seals are fixed in the plates with special clips in only one direction, which greatly facilitates the assembly technology.

We are engaged in the manufacture of pasteurizers for milk and other products.