RU2206982C2 - Cooling system for rotating vacuum pumps of milking units - Google Patents

Abstract

FIELD: animal farming. SUBSTANCE: vacuum pump has water jacket positioned between stator sleeve and pump casing. Water jacket is connected to expansion vessel through two pipelines. Reduction in stator and blade temperature improves lubrication of frictional surfaces and decreases wear of blade and stator surfaces. EFFECT: increased efficiency and prolonged service life of rotating vacuum pump. 2 cl, 1 dwg _

Description

 The invention relates to agriculture, in particular to the cooling of rotary vacuum pumps of milking plants.

 A known method of cooling rotary vane vacuum pumps of milking machines by supplying emulsion lubricant to the pump cavity [1].

 The disadvantage of this method is that a significant part of the oil, coming in contact with the rubbing surface of the stator, is carried away with the forced air. Oil sprayed in the air oxidizes, the danger of an outbreak increases, the environment is polluted, there is no heat recovery from the pump casing.

 Known spool rotary pumps designed for pumping large volumes of air / gas / at low vacuum pressure using flowing water cooling [2].

 The disadvantage of these pumps is the lack of a closed water circulation system in the cooling system. The water jacket does not cover the entire heated surface of the case. Pumps have a functional focus on room ventilation and are not suitable for the implementation of the machine milking process of agricultural animals due to low vacuum pressure.

 Known water heating with natural circulation, characteristic of buildings with an individual boiler room / coil, embedded in the hearth, wood-burning stove, gas, electric and other water heaters /.

The water heated in the boiler rises along the main riser and then through the supply pipe enters the heating device. Having given him part of his heat, chilled water is returned to the boiler through the return pipe. The circulation in the heating system occurs continuously due to the difference in densities of hot and chilled water. If we neglect the heat transfer of pipelines and assume that the water heated in the boiler is cooled only in the heating device, then the value of the circulation pressure / Pa / can be determined by the formula
P _a = 9.81 (ρ ₀ -ρ _r ) h,
where h is the vertical distance between the mid-heights of the boiler and the heating device, (ρ ₀ -ρ _r ) is the density difference between chilled and hot water, kg / m ³ . Since the volume of water increases during heating, in order to prevent the increase in pressure and possible accidents, the heating system at the highest point is equipped with an expansion tank designed to remove air and recharge the system and compensate for water leaks. When the scheme of apartment heating combined with hot water supply, the capacity of the expansion tank is increased, since it simultaneously serves as a hot water battery [3].

 The presented information explains the operability of heaters with natural circulation, acting due to the difference in densities of hot and chilled water in heating systems, and can serve as an analogue of the proposed technical solution.

 A known system of water cooling of internal combustion engines (ICE) of tractors and cars. Here, water (antifreeze) by means of a centrifugal water pump is forcibly circulated along the contour of the water jacket of the engine block, removing heat from its heated parts. A centrifugal pump is connected to a radiator by hoses. Water moves inside the radiator tubes, and their outer part is blown by the flow of air created by the fan. Heat dissipates into the environment [4].

 As applied to the operation of rotary vacuum pumps, such a cooling scheme is not economically feasible. Additionally, the cost of electric energy for the drive of a centrifugal pump and fan increases, there is no possibility of using heat from heating the vacuum pump housing for useful purposes.

 Known rotary compressor, comprising a housing with suction and discharge nozzles and valves, a separation plate and an eccentric rotor interacting with it, mounted on the drive shaft, a cooling jacket with an elastic tank, hydraulically connected to the heat exchanger [5].

 The disadvantage of this compressor is that the water jacket placed in the housing of the rotary compressor does not cover the entire heated surface. The introduction of an elastic tank into the casing, which, when interacting with the eccentric rotor, is a peristaltic pump, creates a forced rather than natural / thermosiphon / closed circulation of the coolant through the heat exchanger. Those. additional energy is expended on the rotor drive. The placement of elastic containers in the grooves of the stator of a rotary vacuum pump is not advisable. The friction of the blades on them will lead to rapid wear and tear of the surface of the elastic containers, uneven wear of the blades. The invention relates to compressor engineering and cannot be used as presented for cooling rotary vacuum pumps designed for machine milking of agricultural products animals.

 The well-known unified vacuum installations UVU-60/45, equipped with vacuum rotary pumps / hereinafter referred to as pumps / performed by ATC 10.000A, UVA 12.000A, ATC 10.000A-01, UVA 12.000A-01 - prototype. Pumps are designed to create and maintain a vacuum gauge when milking cows. Pumps have been introduced into the package of all types of milking machines, including: AD-100A, DAS-2B / with milk collection in buckets /; ADM-100, ADM-200 / milking in the milk line /; milking installations like "tandem", "herringbone", "roundabout", UDS-3A. Before the introduction of the air traffic control and UVA pumps, the RVN 60/45 pumps, which had air cooling from a fan, were included in the vacuum installation UVU-60/45. Pumps of air traffic control, air-safety control have no forced cooling system [6, 7].

The disadvantage of the design of the pumps RVN -60/45 and ATC, UVA is the increase during their operation, the temperature of the stator housing and side covers to 120 ^o C and above. Air cooling from the fan / pumps RVN-60/45 / is not effective. There is a jamming of the rotor, carbonization of the plates, reduced service life, technical and operational reliability. The heat generated by the pumps is not used for useful work and is dissipated in the environment.

 The objective of the invention is to optimize the temperature regime of rotary vacuum pumps of milking units with an increase in their motor resources and the use of heat generated from the friction of the blades on the stator to heat water and then use it to rinse the milk pipe and dairy equipment.

 This task is achieved by the fact that between the stator sleeve over the entire external heated surface and the pump casing there is a water jacket hydraulically connected via pipelines to an expansion tank located above the pump casing and providing a natural / thermosiphon / circulation movement of the coolant.

 The drawing shows a cooling scheme of rotary vacuum pumps of milking units.

 The proposed device includes a rotor 1, blades 2, a stator sleeve 3, a housing 4, an air cylinder 5, a rarefaction regulator 6, a muffler 7, an expansion tank 8, a pipeline 9, a pipeline 10, a tap for water 11, a hot water supply valve 12, a water jacket 13, frame 14, thermal insulation 15, drain plug 16.

 The cooling of a rotary vacuum pump is as follows. When milking units are operating, air from the milking machines / is not shown on the diagram / enters the air cylinder 5 through the rarefaction regulator 6 into the air chamber between the rotor 1 and the stator 3. When the rotor 1 rotates, the air is pumped into the environment through the silencer 2 through the muffler 7. As a result of friction of the blades 2 about the stator 3, it is heated. The resulting heat is transferred to the water filling the water jacket 13, located between the stator sleeve 3 and the housing 4. Heated water through the pipe 10 from the upper part of the housing 4 rises into the expansion tank 8. Cold water from the expansion tank 8 through the pipeline 9 is supplied to the lower part of the housing 4 Thus, thermosiphon water circulation is carried out with its heating in the expansion tank 8. To prevent heat transfer to the environment, it is equipped with a frame 14 filled with thermal insulation 15.

After milking and stopping the rotary vacuum pump, the water heated in the expansion tank 8 is supplied with the help of a hot water supply valve 12 to wash milking machines and dairy equipment. Subsequent filling of expansion tank 8 with water is carried out by a tap water valve 11. As expansion tank 8, which simultaneously functions as a hot water accumulator, a VET-200 capacitive water heater with a tank capacity of 200 l and an electric heater with a capacity of 6 kW, VET-400 - 400 l can be used and 10.5 kW, VEP-600 - 600 l and 10.5 kW and others. Water heaters are included in the package of milking units. For example, the VET-200 capacitive water heater-thermos is included in the package of the ADI-100 milking unit with one rotary vacuum pump. During the operation of the vacuum pump / milking process /, lasting 2-3 hours, the electric heater is turned off. It is known that the efficiency of rotary vacuum pumps is 0.65-0.75. Therefore, with a power of 4 kW on their drive, 1.4-1.0 kW is expended on heating the pump casing 4 as a result of friction of the blades 2 against the stator sleeve 3. In this case, the water temperature in the water heater / accumulator / VET-200 without taking into account the heat transfer of pipelines 9, 10 and housing 4 will increase by 20-30 ^o C. Water heating in the tank 8 / VET-200 / occurs with closed valves 11, 12.

After the milking process is completed / the electric motor of the rotary vacuum pump is turned off / the electric motor is turned on, the temperature of the water in the tank 8 is brought to 90 ^o C, with the subsequent inclusion of the electric heater / not shown on the diagram /. After that, by opening the tap 12, hot water is supplied to the consumer. To prevent freezing of water in the water jacket 13 in the intervals between milking and at low ambient temperature, water from the pipelines 9, 10 and the water jacket 13 is drained using the drain plug 16. Depending on the location of the pipe 9 relative to the housing 4, the drain plug 16 may be located on the pipeline 9. Water from the tank 8 / VET-200 / does not drain due to the closing of the taps on the pipelines 9, 10. It should be noted that the water of the water jacket 13 and pipelines 9, 10 is drained only at lower room temperatures, g The vacuum unit is located. According to design and construction standards, the air temperature in cowsheds with a tethered content is taken to be 5-12 ^o С, and in milking parlors - 15 ^o С.

Since the optimal operation of vacuum pumps is possible at an initial air temperature of 5-15 ^o C, then at negative temperatures heating of the pump housing is necessary. This is because the viscosity of the oil used to lubricate the rubbing surfaces and seal the gap between the blades 2 and the stator sleeve 3, largely depends on its temperature. At low temperatures, the viscosity of the oil is high, the conditions for supplying oil from the lubricator to the rubbing vapors are worsening, “dry” friction of the blades 2 against the stator sleeve 3 is observed and is accompanied by their increased wear, the air supply from the communication system of the milking unit and milking machines decreases sharply and the value of vacuum pressure .

T. about. , the optimal feed and vacuum gauge values do not meet the conditions of machine milking technology. Starting vacuum pumps at low temperatures and operating in the "idle" mode are accompanied by a sharp decrease in their service life. Thus, the functioning of the cooling system of rotary vacuum pumps can be carried out in 3 modes:
1. The expansion tank 8 / VET-200 / is filled to the desired level and there is no discharge of heated and cold water. The taps 11, 12 are closed, and the taps on the pipelines 9, 10 are open. For 2-3 hours of pump operation, the temperature in the expansion tank rises to 20-30 ^o C above its original. In this case, the pump operates without overheating, ensuring optimal flow rates and vacuum gauges.

 2. The influx and outflow of water occurs simultaneously during the entire operation time of the milking unit, the taps 11, 12, as well as the taps on the pipelines 9, 10 are open. The pump operates without overheating at optimal flow rates and vacuum gauges. But this mode is not economical, because there is an idle discharge of water into the sewage system, heat recovery from heating the pump casing does not occur.

3. At negative air temperatures in the room where the pump is installed, it is necessary to carry out warming up before using it with the VET-200 or another heater. To do this, the tap of the supply water 12 is closed, and the water edge 11 is opened. The expansion tank 8 is filled with water to the desired level. If the water in the expansion tank 8 remained after the previous milking, then only it is added to the desired level. The taps on pipelines 9, 10 remain closed after the previous milking, and the water from them and the water jacket was drained using the drain plug 16. Freezing of water in the expansion tank 8 / VET-200 / does not occur in the intervals between milking, because the frame 14 is equipped with thermal insulation 15. After filling the expansion tank 8 with water, the tap of the tap water 11 closes, the electric heater mounted in the VET-200 is turned on. After heating the water to a temperature of 30-40 ^o С, the heater is turned off, the taps on the pipelines 9, 10 open. After pouring warm water through the drain plug 16, it indicates that the stator sleeve 3 and pump housing 4 are warmed up, the hole is blocked by the drain plug 16, the pump is turned on to ensure optimal flow rates and vacuum gauges.

After the milking process is completed, the water heater / VET-200 / is turned on, the valves on the pipelines 9, 10 are closed and, using the drain plug 16 of them and a water jacket 13, water is drained. This ensures the heating of the vacuum pump, its operation during milking with heat recovery from heating of the stator sleeve 3 and the housing 4. The procedure for using water heated to 90 ^o C for technological purposes is similar to the first mode. After the washing process of the dairy equipment is completed, the hot water supply valve 12 closes, and the expansion tank 8 can be filled with water to the required level, after which the tap of water 11 closes.

 The advantage of the proposed cooling scheme for vacuum pumps of milking machines is the use of heat generated from the friction of the blades 2 on the stator 3, for heating the water used for technological purposes. Saving electric energy for heating water in the VET-200 water heater using the proposed technical solution will be 16-23%.

Sources of information
1. V. M. Khameev. Thermodynamic processes and parametric characteristics of vacuum pumps. "Science", Novosibirsk, 1986, p.75.

 2. J. Yarwood. High vacuum technique. Theory, practice, industrial applications and material properties. M.-L., 1960, p. 15.

 3. A. A. Zakharov. The use of heat in agriculture. M .: Kolos, 1974, pp. 91-118.

 4. A.V. Nikolaenko. Theory, design and calculation of automotive engines. - M .: Kolos, 1984. - p. 287-296.

 5. A.S. USSR 1110935, F 04 C 18/356. Bull. 32 from 08.30.84.

 6. The pump is vacuum. Passport ATC 10.000A. Substation Kurganselmash, 1998. - 31 p. - prototype.

 7. S.V. Melnikov. Technological equipment of livestock farms and complexes. L., "Agropromizdat", 1985, - p. 486-496.

Claims (2)

 1. The cooling system of rotary vacuum pumps of milking machines, characterized in that the pump is equipped with a water jacket between its stator sleeve and the housing and an expansion tank, which is thermally insulated, is located above the pump, communicates with the water jacket through two piping equipped with taps and has an additional pipeline for water supply to the milk line of the milking unit.  2. The system according to claim 1, characterized in that a drain hole is made in the vacuum pump housing.