RU2233582C1 - Milk cooling apparatus - Google Patents

Abstract

FIELD: agricultural engineering.

SUBSTANCE: apparatus provides for supplying of freshly drawn milk directly from vacuum pipeline of milking unit through widened portion, wherein mechanical cleaning filters are mounted for preliminary cleaning of milk. Heat exchanger is joined with widened part for reducing number of vacuum joints and, accordingly, for preventing air admission into milk contour. Heat exchanger is made in the form of set of parallel rectangular heat-exchanging fins welded to one another through layers providing gaps therebetween so as to form alternating parallel channels for milk and water contours, to provide for eliminating possibility of cooling water admission into milk contour of heat exchanger. Milk contour channels inlets and outlets are arranged at end sides of heat-exchanging fins. Water contour channels inlets and outlets are arranged at ends of diagonal lines of their sides. Employment of said gap-forming layers manufactured from the same material as heat-exchanging fins allows stable sizes to be provided and milk and water contour channels to be hermetically sealed. Said layers simultaneously serve as solder for welding of heat-exchanging fins in inert gas medium. Such features provide for unified construction of heat-exchanger, because in the given case limitations as to transverse sizes of heat-exchanger channels are practically eliminated. Apparatus provides for fast flow cooling of milk in dairy farms on the basis of energy saving technology.

EFFECT: unified and simplified construction, enhanced reliability in operation owing to eliminating of air and water admission into milk contour and stabilized sizes of gaps between heat-exchanging fins.

6 dwg

Description

The invention relates to refrigeration equipment and is intended for instantaneous cooling of milk on dairy farms and farms using energy-saving technology.

A known device for cooling milk according to patent No. 1794235 F 25 D 3/00, A 01 J 9/04, 1991, SU. The device contains a cold accumulator, a milk dispenser, a heat exchanger, a coolant supply line and a refrigeration unit, the evaporator of which is located in the battery reservoir. The battery is charged between the periods of milk cooling and is carried out by freezing ice on a tubular evaporator when filling the battery tank with water or by finely dispersing water through nozzles mounted above the evaporator. In the operating mode, milk is fed into the dispenser and cooled during continuous film draining along the outer surface of the heat exchanger, made in the form of a vertical panel with internal channels for the circulation of coolant. From the outlet of the heat exchanger, the “spent” coolant enters the cold accumulator, where it is cooled by absorbing the heat of fusion during film flow around the ice outgrowths on the evaporator. After this, the coolant is again fed into the heat exchanger and the cycle repeats.

The disadvantages of this device include the difficulty in maintenance, as well as its large mass and dimensions. At the same time, despite the presence of a cold accumulator, its performance is quite low. For example, to cool 1,500 kg of milk, you need to freeze about 640 kg of ice. With the cooling capacity indicated in the description of the refrigeration unit equal to 1.65 kW, it takes 36 hours to freeze this amount of ice. Thus, with a threefold milking mode, each farm should be equipped with at least five continuously operating plants. In the case of using one installation, the cooling capacity of its unit should be increased by about an order of magnitude and be about 15 kW.

A device is known for cooling milk by as No. 1346923 F 25 D 3/00, 7/00, 1986, SU. The device comprises a heat exchanger connected to the circulation circuit of the cooling water and the cooling circuit of milk, a chiller with an evaporator located in a bath in communication with the cooling water circuit, in which a control element is provided. The evaporator of the refrigerating machine is made in the form of vertical pipes interconnected into a battery, the lower part of which is located below the expected level of cooling water and has the ability to move vertically. A fan installed in the side wall of the bath is designed to blow outside the upper part of the evaporator tubes. Milk is fed by means of a supercharger to a heat exchanger, where it is cooled by water supplied by a supercharger from a bath. In the warm season, the cooling of the circulating water is carried out using a refrigeration machine. In this case, the bath and the evaporator act as an ice maker, the accumulation of which increases the cooling efficiency during the transition periods of the device. In the cold season, cooling is carried out with the chiller turned off by using the cold outside air, which is pumped by the fan. In this case, heat transfer from water to air is provided due to the thermosiphon effect that occurs in the pipes of the evaporator.

The disadvantage of this device is that this technology is applicable only in the cold season, which coincides with a period of sharp decrease in the amount of milk produced. In the warm period of the year, cooling is carried out using a powerful refrigeration machine, the disadvantages of which have already been noted earlier. This is a difficulty in maintenance, large dimensions and high power consumption.

Moreover, the accumulation of cold in the form of ice freezing does not reduce the required energy costs, since they are determined only by the mass of the cooled milk, its final temperature and the efficiency of the refrigeration machine, which is practically independent of its cooling capacity. In a real situation, energy costs will be significantly higher due to the inevitable influx of heat to the cold accumulator from the environment.

A device for cooling milk is known according to the patent 2160986, A 01 J 9/04, F 25 D 3/00, RU.

The device comprises a flow-through heat exchanger connected to the milk circuit and the cooling water circulation circuit so that the inlet of the milk circuit of the heat exchanger is connected directly to the vacuum line of the milking unit through the expander, and the outlet of the milk circuit is connected to the heat-insulated storage tank through the milk flow stabilizer, the expander and flow stabilizer milk are interconnected by a vacuum bypass and installed so that the difference between the levels of the free surface m Lok expander in flow regulator and satisfies the relation

where l is the length of the channels of the heat exchanger, m,

the input of the water circulation circuit of the heat exchanger is connected through a pump to a well located in the immediate vicinity of the farm, and the output of the water circulation circuit is connected to the storage of heated drinking water.

The heat exchanger, depending on performance, is available in two versions.

In the first version, a heat exchanger with a capacity of up to 400 liters of fresh milk per hour consists of two blocks, each of which has its own independent water circuit, the blocks being interconnected using two adjustable floating loops and, when in operation, are pulled together through vacuum seals with locks, and the surfaces the heat transfer of each block is made in the form of rigid meanders separating between themselves two systems of parallel interpenetrating channels located on both sides of monolithic plates, while the channels with side surfaces contiguous blocks to form a single composite legkorazborny milk circuit, and the channels on the outer sides of contiguous panels, flat lids sealed to form two parallel circuit intended for the circulation of cooling water.

In the second version, a heat exchanger with a capacity of more than 400 liters of fresh milk per hour consists of a parallel set of heat exchange surfaces forming alternating easy-to-assembled milk and water circuits, the heat exchange surfaces being made in the form of rigid meanders separating two systems of parallel interpenetrating channels located on both sides of the monolithic plates, while the heat exchange surfaces are installed between the movable and fixed flat covers and in In this condition they are pulled through the vacuum seals with a power screw.

The disadvantages of the device are: the lack of preliminary filtration of milk from mechanical impurities, which worsens the conditions of heat transfer due to inevitable deposits on the working surface of the heat exchanger.

The implementation of the expander and the heat exchanger in the form of independent structural elements provides for the presence of an additional milk line with a large number of vacuum connections, which makes it difficult to clean the system after each milking cycle. In addition, the existing methods for connecting vacuum pipelines in the dairy industry do not provide the required tightness; therefore, the inevitable leakage of air into the milk circuit in areas of the already formed flow leads to a disruption in its continuity and, accordingly, to a deterioration of heat transfer conditions in the heat exchanger channels.

In addition, the design of heat exchangers proposed in the device depends on their performance, which complicates the unification of the device as a whole. In addition, the need to ensure high coaxiality of the composite channels in the circuits from the side of the contacting blocks and heat transfer surfaces leads to an increase in the complexity of their manufacture.

Moreover, the presence of rubber vacuum seals between the heat exchanger plates of the milk and water circuits necessitates using only clean drinking water as a coolant [SanPiN 2.3.4.551-96 “Production of milk and milk products”], since it is possible that it will seep into the milk circuit of the heat exchanger . This, in turn, limits the possibility of using such devices in combination with low quality water.

In terms of the set of essential features, this device is the closest to the claimed one and can be adopted as a prototype.

To reduce the amount of deposits, improve cleaning conditions, unify the design of the heat exchanger, as well as to prevent the ingress of cooling water into the milk circuit of the heat exchanger, the proposed device for cooling milk containing a flow heat exchanger, the milk circuit input of which is connected through the expander directly to the vacuum line of the milking unit, and the milk outlet the heat exchanger circuit is connected to a heat-insulated storage tank through a milk flow stabilizer, characterized in that milk purification filters are installed in the expander, and the expander is combined with a heat exchanger, while the heat exchanger consists of a parallel set of rectangular heat exchanger plates welded together through gaping gaskets so that they form alternating parallel channels of the milk and water circuits, the inputs and outputs of the channels the milk circuit are located on the end faces of the heat exchanger plates, and the inputs and outputs of the channels of the water circuit are located at the ends of the diagonals of their sides.

The figures show:

Figure 1 - schematic diagram of a device for cooling milk;

Figure 2 is a front view of a heat exchanger;

Figure 3 is a rear view of the heat exchanger;

Figure 4 is a sectional view of a heat exchanger;

Figure 5 - the extender of figure 4;

FIG. 6 is a view A of FIG. 4.

The figures depict:

1 - vacuum line of the milk line of the milking unit;

2 - expander;

3 - heat exchanger;

4 - milk flow stabilizer;

5 - bypass vacuum wire;

6 - filters for cleaning milk;

7 - heat transfer plates;

8 - gap-laying gaskets;

9 - channels of the milk circuit;

10 - channels of the water circuit;

11 - fitting of the output manifold of the water circuit;

12 - fitting of the input manifold of the water circuit;

13 - input and output collectors of the water circuit;

14 - square plates;

15 - the case of the expander;

16 - output collector of the milk circuit;

17 - input fitting of the milk circuit;

18 - output fitting for connecting to the vacuum line of the milking unit;

19 - outlet fitting of the milk circuit;

20 - covers;

21 - vacuum seal;

22 - locks;

23 - power screws;

24 - stiffeners;

25 - casing of a heat exchanger;

26 is the base.

A device for cooling milk contains a vacuum line of the milk line 1 of the milking unit, an expander 2, made in one housing with a heat exchanger 3, a stabilizer 4 of the milk flow, a vacuum bypass 5, milk purification filters 6.

The heat exchanger 3 contains a parallel set of rectangular heat exchanger plates 7, welded together through gap-shaped gaskets 8, made of the same material as the heat exchanger plates 7, and designed to form dimensions as well as seal channels of the milk 9 and water circuits 10 and performing simultaneously with this role of solder in welding of heat transfer plates 7 in an inert gas environment. In this case, the heat exchange plates 7 and the gap-protecting gaskets 8 are arranged so that they form alternating parallel channels of the milk 9 and water 10 circuits, the inputs and outputs of the channels of the milk circuit located on the end sides of the heat exchange plates, and the inputs and outputs of the channels of the water circuit are located at the ends diagonals of their sides. Water channels are connected to the input 11 and output 12 fittings through the input and output 13 collectors. Horizontal square plates 14 are welded to the ends of the heat exchanger, onto which the housing 15 of the expander and the output collector 16 of the milk circuit are mounted. Milk purification filters 6 are installed in the case 15 of the expander, the inlet fitting 17 of the milk circuit and the outlet fitting 18 of the connection to the vacuum line are welded together forming an expander 2. The outlet fitting 19 of the milk circuit is welded to the output manifold 16 of the milk circuit. On the housing 15 of the expander and the output manifold 16 of the milk circuit, covers 20 are pulled together through vacuum seals 21 using locks 22 and power screws 23. On each side of the heat exchanger, ribs 24 are attached to which the casing 25 is attached. The heat exchanger is connected to the base 26.

Installation works as follows.

As you move along the vacuum line 1, milk enters the expander 2, in which the milk is separated from the steam-air mixture, it is cleaned with milk purification filters 6 and removed from the vacuum line without disrupting its performance.

From the outlet of the expander 2 under the action of its own hydrostatic pressure, the milk is fed in a continuous stream to the milk circuit 9 of the heat exchanger 3, in which it is cooled in countercurrent mode with cooling water circulating in the water circuit 10.

From the output of the heat exchanger 3, the cooled milk enters the stabilizer 4 of the milk flow, which ensures the independence of the speed of movement of milk in the heat exchanger.

From the output of stabilizer 4 of the stream, the chilled milk enters the heat-insulated storage tank of the milking unit, where it is stored until the end of the milking process of the cows.

Maintenance of the device for cooling milk is reduced to its cleaning after each milking cycle. Basically, this operation is performed simultaneously with flushing the milk line of the milking unit and is carried out using the same chemicals.

Additional cleaning of the heat exchanger, which consists in the removal of extraneous solid contaminants, is performed by opening its milk circuit.

To open the milk circuit of the heat exchanger, it is enough to unscrew the upper and lower power screws 23, open the locks 22 and take the covers 20 to the side.

After that, the milk channels are subjected to mechanical cleaning using a flexible metal flat plate 1-2 cm longer than the length and 5 mm narrower than the width of the heat exchanger channels.

The device is assembled in the reverse order.

Regarding the proposed device for cooling milk, the following can be noted.

The installation of milk purification filters in the expander improves the heat transfer conditions in connection with the reduction of deposits on the working surface of the heat exchanger plates. In addition, it facilitates cleaning of heat transfer surfaces after each milking cycle.

The combination of the expander with the heat exchanger reduces the number of vacuum connections and, therefore, eliminates the possibility of air leakage into the milk circuit of the heat exchanger. Ultimately, this helps to improve the conditions of heat transfer, since further movement of milk is carried out without violating the continuity of the flow.

The implementation of the heat exchanger from a parallel set of rectangular heat exchanger plates, welded together through gaps to form alternating parallel channels of the milk and water circuits, with the inputs and outputs of the channels of the milk circuit located on the ends of the heat exchanger plates, and the inputs and outputs of the channels of the water circuit located at the ends of the diagonals of their sides, eliminates the possibility of cooling water entering the milk circuit, which, in turn, allows the use of Call such devices in combination with low quality water.

In addition, the use of gap-protecting gaskets made of the same material as the heat exchanger plates for dimensioning and sealing the channels of the milk and water circuits, which simultaneously play the role of solder in welding heat exchanger plates in an inert gas environment, helps to unify the design of the heat exchanger, since in this case, the fundamental restrictions on the transverse dimensions of the heat exchanger channels are almost completely removed.

Claims (1)

A device for cooling milk containing a flow-through heat exchanger, the input of the milk circuit of which is connected through an expander directly to the vacuum line of the milking unit, and the output of the milk circuit of the heat exchanger is connected to a heat-insulated storage tank through a milk flow stabilizer, characterized in that milk purification filters are installed in the expander, and the expander is combined with a heat exchanger, while the heat exchanger consists of a parallel set of rectangular heat exchanger plates welded between each other through gaping gaskets so that they form alternating parallel channels of the milk and water circuits, the inputs and outputs of the channels of the milk circuit located on the end faces of the heat exchanger plates, and the inputs and outputs of the channels of the water circuit are located at the ends of the diagonals of their lateral sides.

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