RU2388217C1 - Milk pasteurising-refrigerating plant - Google Patents

Abstract

FIELD: agriculture.

SUBSTANCE: invention relates to agriculture and is intended for collection of milk. Milk pasteurising-refrigerating plant comprises heat insulated rectangular reservoir with slot evaporator inbuilt into bottom, motor reducer with mixer on upper cover, compressor-capacitor device with the first magnetic starter and solenoid valve connected by pipelines of injection and suction to inlet and outlet of slot evaporator, and also sensor of reservoir temperature connected to the first magnetic starter, and sensor of reservoir temperature connected by its outlet to solenoid valve and the first magnetic starter. In lower part of plant reservoir there are half-flat disk thermal electric heaters installed with pressing plates and the second magnetic starter. On reservoir bottom there is a submersible coil-cooler with electromagnetic valve and pipelines of discharge and drain, which via electromagnetic valve and pipelines of discharge and drain is accordingly connected to water supply system and sewage system, and the same time outlet of temperature sensor is also connected to the second magnetic starter and electromagnetic valve.

EFFECT: milk pasteurising-refrigerating plant may be used in conditions of restricted water and energy consumption with simultaneous increase of efficiency factor and has simplified design.

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Description

The invention is intended for the daily collection of 1000 ... 2000 liters of milk from individual farms (IFH), its subsequent pasteurization, cooling and shipment to dairies, or packaging for a retail network. It is installed in village milk collection points, it is mainly used in combination with packaging machines to sell packages of pasteurized milk through a retail chain, which allows you to double and triple the IFC's proceeds from dairy and livestock farming.

Known milk refrigeration units according to patent RU No. 2337534 C2, intended for the collection, cooling and storage of milk before shipment to dairies. They contain a thermally insulated rectangular (square) tank with a slotted evaporator built into the bottom, a geared motor with a stirrer on the top cover (traverse), a condensing unit connected by discharge and suction pipelines with an inlet (injector) and an outlet (collector) of the slotted evaporator . Liquid freon is injected into the injector, evaporated is sucked from the collector, which cools the milk. There is also the possibility of milk cooling due to the tubular submersible coil-evaporator (FDI) with the submersible injector and collector according to the patent RU No. 2238642 dated 08.09.2003. A feature of the FDI is ⌀1.5 mm throttle openings made in the injector for uniform symmetrical flow distribution boiling liquid chladone (cold stream) over all “snakes”. This eliminates the possibility of the effective use of such a FDI for other refrigerants, such as cold water.

Their common drawback is the need for daily shipment of chilled whole milk to dairies, dictating limited purchase prices for subsequent processing.

According to sanitary standards, chilled whole milk with a temperature of 4 ° C should be stored for no more than a day, which also limits sales. In addition, milk processing at dairies begins with pasteurization (heating milk to + 70 ° C, destroying lactic acid bacteria and increasing the sanitary storage time up to 10 days). The cooling process requires energy, and the heating process also requires energy, which ultimately doubles energy consumption.

On the other hand, thermally insulated pasteurization baths of 1000 L of milk G2-OPB-1000 are known, described on the website www.deltamol.ru. They contain a gear motor with a stirrer, a sealed annular cavity around a vertical cylindrical bath with milk, into which hot steam of 95 ° C with a flow rate of 150 kg is fed for an hour and a half, and then ice water + 2 ° C with a flow rate of 5 m ³ / h. Flows are regulated by complex electro-pneumohydroautomatics. Such energy and cold supply is available only at large and medium-sized dairies and cannot be used in the conditions of the Russian countryside. OGU-2.5 domestic universal plate pasteurization and cooling units with a capacity of 2500 l / h, described on the site www.protex.ru, and German installations for full pasteurization of milk with a capacity of 5000 l / h, described on the site www.trubatec.org, are also known. They heat the milk with hot steam through the plate heat exchangers, and then cool the pasteurized milk with ice water through the same multi-section plate heat exchangers. The exposure time of the milk flow during heating to 78 ° C is 25 s, then cooling to 4 ° C. The plants contain a complex integrated control system, hydropneumatics, a lot of milk pumps, flow meters, additional heat exchangers, electromagnetic pneumatic and hydraulic valves, programmable industrial controllers.

They have increased productivity, power in terms of steam and ice water consumption, large weight and size characteristics and high price, which is available to large dairy farms, but makes their use directly in villages unacceptable.

Also known are pasteurization dairy workshops KOLAKS-1001, per 1000 liters per day, described on the site www.colaxm.ru, containing a bath of prolonged pasteurization for 500 liters of milk with an annular tight cavity around the internal reservoir for supplying steam or hot water, as well as electric heater 120 l with a power of 25 kW for the production of heating. In addition, the workshop contains a plate cooler with a water consumption of 3 m ³ per shift at a temperature of not more than 6 ° C for cooling. The warm-up (pasteurization) time of 500 liters of milk is about 4 hours.

The disadvantage of the KOLAKS-1001 equipment is the indirect heating of the tank for prolonged pasteurization of milk with water and steam created by an additional electric heating tank, as well as the inevitable loss of electricity during the transfer of heat from the tank to the tank. In fact, the process uses three heat transfer tanks: a long pasteurization tank, a water tank and a plate cooler, which complicates electro-pneumatic automation, reduces efficiency, and increases overall dimensions and cost.

In addition, a decrease in the temperature of cooling water (not more than 6 ° C), due to the need to cool the outlet temperature of pasteurized milk, involves an external refrigerator or artesian water, which imposes additional problems when installed in unequipped places. The consumption of cold (ice) water will also be increased (three times) when the milk is gradually brought to the required temperature + 4 ° C, taking into account 3 m ³ per 1000 l of product due to a decrease in the heat pressure (temperature difference) between the milk and cooling water at the end of the process. The closest known in technical essence to the alleged invention (prototype) is a milk refrigeration unit (MCU) according to patent RU No. 2337534 C2.

It contains a thermally insulated rectangular tank with a slotted evaporator built into the bottom, a geared motor with a stirrer on the top cover, a condensing unit with a solenoid valve and a magnetic starter connected by discharge and suction pipelines with a slot evaporator inlet and outlet, and a suction pressure sensor associated with a magnetic starter, and a tank temperature sensor connected by its output to a solenoid valve and a magnetic starter. MCU is designed for two-milk cooling of fresh milk for a period of not more than three hours on dairy farms from a temperature of + 34 ° C to a temperature of + 4 ° C. It is not able to warm milk for pasteurization, and also to cool hot milk in case of external heating to 70 ° C. It is known that the partial pressure of R22 freon at a temperature of + 70 ° C increases to 3.5 MPa. This can “break” the slit evaporator and overload the compressor, until it breaks.

The aim of the invention is the implementation of a milk pasteurization-refrigeration unit of low productivity (up to 1,500 liters per shift) in rural conditions of limited water and energy consumption while increasing efficiency, simplifying the design and reducing cost.

For this purpose, in a milk pasteurization and refrigeration unit containing a thermally insulated rectangular tank with a slit evaporator integrated in the bottom, a gear motor with an agitator on the top cover, a condensing unit with a first magnetic starter and a solenoid valve, connected by discharge pipelines and suction with input and output of a slotted evaporator, as well as a suction pressure sensor connected to the first magnetic actuator, and a tank temperature sensor connected to the solenoid by its output According to the invention, disk thermoelectric heaters (TENs) of the lower part of the tank with pressure plates and a second magnetic starter, as well as an immersion coil-cooler located at the bottom of the tank, with an electromagnetic valve and pressure and discharge pipelines are introduced, moreover, disk TENs pressed by the working plane directly to the side walls of the tank with the corresponding pressure plates, and the immersion coil-cooler through the solenoid valve and piping a drain and a drain are connected respectively to the water supply and sewerage, while the output of the temperature sensor is also connected to a second magnetic starter and an electromagnetic valve.

The invention is illustrated by drawings: in Fig. 1, an assembly drawing of a general view of a reservoir of a milk pasteurization-refrigeration unit (MPCU) is shown, in Fig. 2 is a combined electro-hydraulic circuit.

The MPHU contains a rectangular thermally insulated tank 1 with dimensions of 130 × 200 × 85 cm with a slotted evaporator 2 integrated in the bottom, a geared motor 3 with an agitator 4 on the top cover 5. The compressor-condenser unit (KKA) 6 includes a compressor 7, a condenser 8 air cooling, liquid refrigerant receiver 9, filter drier 10, solenoid valve 11, thermostatic valve 12. Discharge pipes 13 and suction 14 connect KKA 6 respectively to the inlet and outlet of the slit evaporator 2. A sensor d is installed in the suction pipe 14 phenomena 15. KKA 6 is connected to a three-phase 380 V 50 Hz network through the first magnetic actuator 16. At the bottom of the tank 1, a temperature sensor 17 is fixed, the output of which is connected to a solenoid valve 11 and a magnetic actuator 16. A pressure sensor 15 is connected to the input of the first magnetic actuator 16. In the lower part of the tank 1, half-plane disc thermoelectric heaters (TENs) 18 with a power of 1 kW (at 220 V) in the amount of 24 pcs. Are mounted in the amount of 24 pcs., Connected to a common second magnetic starter 19. The TENs 18 are evenly distributed along the side walls and pressed against the working surface bone with heat-conducting paste to the side walls of the tank 1 with the corresponding plates 20, nuts 21 and asbestos 4 mm gaskets 22. The outer diameter of the disk heating elements is 150 mm, the temperature sensor 17 is placed on the side wall of the tank 1 between a pair of disk heating elements 18. On the bottom of the tank 1 is placed an immersion cooler coil 23 with a solenoid valve 24 and pressure piping 25 and drain 26, respectively connected to the water supply and sewage. The immersion coil-cooler 23 is made of stainless steel ⌀14 × 1 pipe, consists of six “snakes” of 8 m each, directly welded (without throttling holes) into the pressure pipelines 25 and drain 26 made from ⌀30 × 1 pipes, 5. Due to the equal linear resistance of the “snakes”, a division of the water flow into six equal flows and uniform cooling of the volume of milk is created. The output of the temperature sensor 17 is connected with a salt-water valve 11, an electromagnetic valve 24, as well as a first magnetic actuator 16 and a second magnetic actuator 19.

To reduce convection losses from air circulation, as well as to seal the upper cover 5 along the contour of the shell of the tank 1, an elastic cuff 27 with latches is installed (not shown in FIG. 1 and 2).

To increase the resource of disk heating elements 18, they are connected through a second magnetic starter 19 in pairs, in series, with a triangle to a three-phase 380 V network (Fig. 2), so that for each heating element 18 there is 190 V with an allocated power of 0.747 kW. Such a connection allows to reduce the power at each heater 18 and the temperature of nichrome spirals, thereby increasing the resource, effectively using the entire contact area of the sides of the tank 1 with milk, at the same time, balancing the load on the three-phase network and obtaining the total thermal contact power of the spirals with milk, N = 0.747 × 24 = 17.4 kW - 5.8 kW from each phase.

The MPHU installed in the village works as follows.

When assembling the first 450 L from the IFC, the milk level in the tank is 200 mm, which covers the heating elements 18, the mixer 4 and the immersion coil-cooler 23. This allows you to turn on the MPHU. The second magnetic starter 19 connects the mains voltage of 380 V × 3ph, 50 Hz to the heating elements 18, which begin to warm the milk with a total capacity of 17.4 kW. The entire heat flow from the half-plane disk heating elements 18 is reflected by heat-insulated asbestos gaskets 22 and is directed from the heated working plane of the heating elements 18 through the wall of the tank 1 into the milk due to the tight thermal contact and good heat dissipation provided by the heat-conducting paste, pressure plates 20 and nuts 21. Gear motor 3 with stirrer 4 mixes milk. The mixer 4 in combination with the high thermal conductivity of 2 mm stainless steel of the tank 1 ensures uniform heating of all layers and homogenization of milk, as well as minimal overheating of the contact plane of the heating elements 18, reliable heat removal and the necessary resource of their work. Moreover, on the walls of the tank 1, local boiling of milk is excluded. In the process of heating the initial volume of milk in the tank 1 MPHU continues its acceptance from the IFC, weighing and reloading the tank 1. The total heating time of 1000 ... 1500 l of milk from the initial temperature of 17 ... 20 ° C to 70 ° C is 2.5 ... 4 hours. The total power of the heating elements 18 is limited to 18 kW for rural conditions. However, this capacity, taking into account high efficiency, is quite enough for the process of prolonged pasteurization of milk for the mentioned time. Moreover, the acceptance of 1000 ... 1500 l of milk from cans, its weighing and loading into the tank 1 takes several hours.

Upon reaching 70 ° C in the entire milk volume, lactic acid bacteria were destroyed, pasteurization was completed, and the temperature sensor 17 exited through the second magnetic starter 19 to deenergize the heating elements 18, at the same time using a solenoid valve 24, turned on the flow of tap water of the order of 10 ... 15 l / min with a temperature 12 ... 15 ° C, flowing through the pressure pipe 25, the immersion coil-cooler 23 and the drain pipe 26. The mixer 4 continues to rotate, providing cooling of the milk and heating of the water at the outlet of the pipe 25 during heat exchange. The first 200 liters of warm water + 60 ° C from the pipeline 25 for 10 ... 20 minutes are stored in order to save in an additional tank (not shown in figure 1 and figure 2). Warm water is subsequently used to flush the tank 1 in a circulation mode from a powerful pump and for other domestic needs, and a subsequent stream of warm water is diverted to the sewer. There is a water supply system in the villages of Tatarstan, and a submersible well pump is used in the villages of Chuvashia. Depending on the pressure in the water supply system, after 1 ... 1.5 hours after turning on the solenoid valve 24, the milk reaches a temperature of 34 ° C, the output of the temperature sensor 17 turns on the solenoid valve 11 and at the same time the first magnetic starter 16, which includes CCA 6. The liquid refrigerant from the receiver 9, passing through the filter drier 10, the solenoid valve 11, thermostatic valve 12 and the discharge pipe 13, enters the inlet of the slit evaporator 2. Contacting through the tank 1 with warm milk in the slit evaporator 2, the refrigerant boils, cooling the milk, about razuyuschiysya steam is sucked through a conduit 14 to the compressor 7, where it is compressed and fed to condenser 8 air cooling. When cooled by air flow, the HFC vapor condenses into the liquid phase and enters the receiver 9. The milk is double-accelerated by cooling from 34 ° C to 22 ° C in 20 ... 30 minutes with a stream of tap water through an immersion coil-cooler 23 and a flow of evaporating refrigerant through a slotted evaporator 2. When milk is cooled to 22 ° C, further cooling with running tap water becomes impractical due to a decrease in thermal pressure (difference) between the temperature of the water in the coil 22 and the temperature of the milk in the tank 1. Therefore, the sensor temperature 17 de-energizes the solenoid valve 24 and shuts off the water supply. The total water consumption is 1500 ... 2000 l. Further cooling of the milk occurs through a slit evaporator 2 with the KKA 6 running and the mixer 4. The thermostatic valve 12 as the milk cools automatically reduces the throttling section for the passage of liquid refrigerant, while maintaining optimal overheating of the saturated vapor in the pipe 14 at a level of 6 ... 10 ° C. When milk is cooled to 4 ° C, the temperature sensor 17 de-energizes the solenoid valve 11, which shuts off the flow of freon when the compressor is running 7. The liquid freon from the slot evaporator 2 at a temperature of + 4 ° C completely evaporates and condenses into the receiver 9. The pressure in the suction pipe 14 10 ... 20 from the operation of compressor 7 decreases to 0.5 at - the pressure of the sensor 15, which through the first magnetic starter 16 turns off the control unit 6. Such completion of the cooling cycle is necessary to protect against overloads by the pressure of the slit evaporator 2 at washing the tank 1 with hot water, as well as during pasteurization heating of milk. Only such completion of the cooling cycle guarantees complete evaporation and the absence of liquid freon in the slit evaporator 2, therefore, low pressure in it and in the suction pipe 14 when flushing with hot water or heating with heating elements 18.

When storing chilled milk due to the thermal insulation of the tank 1, the temperature + 4 ° C rises very slowly, the mixer 4 rotates and ensures homogenization. If the temperature reaches + 5 ° C, the temperature sensor 17 again opens the solenoid valve 11 and turns on the first magnetic starter 16 of the CAC 6. Slotted evaporator 2 again cools the milk to + 4 ° C, keeping it until shipment.

After shipment or packaging of milk, the tank 1 and the immersion coil-cooler 23 are washed in the circulation mode with hot water + 60 ° C, stored in a 200 l storage tank at the initial stage of cooling. Flushing is carried out in the circulation mode of a high-pressure electric pump with the lid open. Thus, MPHU for a shift allows you to take 1000 ... 1500 l of whole milk from the population, heat it to 70 ° C, pasteurize it, then cool to + 4 ° C and save it for shipment to dairies, or pack it in retail packages sales. The shelf life of pasteurized milk compared with chilled in the prototype increases 10 times.

Due to the direct heating of milk with the help of heating elements 18 compared with indirect (through hot water or steam), the analogues achieve an efficiency close to 100%. Thanks to this, it is possible to reduce the power consumption to the level of 18 kW and make it possible to install MPHU in any Russian village. The design of MPHU in comparison with analogues is much simpler and the cost, respectively, is cheaper. The multifunctional temperature sensor 17 protects the heating elements 18 from burnout if the operator mistakenly activates heating the empty tank 1, since it is close to a pair of heating elements 18 that heat the sensor 17 through the stainless steel sheet of the tank 1 to 70 ° C due to the thermal conductivity of the metal, which is timely de-energizes the second magnetic starter 19.

An automation system controlled by a temperature sensor 17 is also much simpler. Less cooling water flow required. The obvious energetic advantages of MPHU as compared to analogues are also that the process of milk processing, adopted by the population with a temperature of 17 ... 20 ° С, begins with heating, and not with cooling to 4 ° С and subsequent heating to 70 ° С at the dairy . Due to the large cross-sections of the pipes of the cooler coil, it is convenient to maintain it, which consists in annually flushing with a stream of weakly concentrated acid to remove calcium deposits, in contrast to the quarterly assembly-disassembly-cleaning of narrow plate heat exchangers. Replacing the heating elements with the lining removed is also simple and convenient.

Thus, MPHU provides a daily output of 1000 ... 1500 liters of high-quality pasteurized whole milk, can be installed in any Russian village. This will make it possible to increase the terms for milk sales by an order of magnitude, to double and triple the peasants' revenue (in combination with the simplest plastic packaging) from dairy farming, thereby reversing the negative trends in the annual reduction in the individual milking herd of cattle.

Since December 2008, MPHU has been introduced into the production of NPP Avtomat LLC (Kovrov).

Bibliographic data

1. Patent RU No. 2337534 dated 12/26/2005. Milk refrigeration unit.

2. Patent RU No. 2238642 from 09/08/2003. Installation of milk cooling.

3. Bath pasteurization milk G2-OPB-100, website: www.deltamol.ru.

4. Universal plate pasteurization and cooling unit OGU-2.5, website: www.protex.ru.

5. Complete milk pasteurization unit 5000 l / h, website: www.trubatec.org.

6. Pasteurization dairy workshop KOLAKS-1001, website: www.colaxm.ru.

Claims (1)

A milk pasteurization and refrigeration unit containing a thermally insulated rectangular tank with a slit evaporator integrated in the bottom, a geared motor with an agitator on the top cover, a condensing unit with a first magnetic starter and a solenoid valve connected by discharge and suction pipelines with an input and the outlet of the slit evaporator, as well as the suction pressure sensor associated with the first magnetic actuator, and the tank temperature sensor, connected by its output to the solenoid valve and the first magnetic starter, characterized in that it introduced half-plane disk thermoelectric heaters (TENs) of the lower part of the tank with pressure plates and a second magnetic starter, as well as an immersion coil-cooler located at the bottom of the tank, with an electromagnetic valve and pressure and discharge pipelines, and the disk heating elements are pressed by the working plane to the side walls of the tank with the corresponding plates, and the immersion coil-cooler is connected through the solenoid valve and the pressure and discharge pipelines respectively etstvenno with running water and sewage, the temperature sensor output is also connected to the second magnetic actuator and a solenoid valve.

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