JP2020034199A - Vacuum cooling device - Google Patents

Abstract

To provide a vacuum cooling device which can supply cold water of a desired temperature to a decompression system toward the end of a cooling step, and which can improve the cooling speed and can reduce cavitation.SOLUTION: A vacuum cooling device includes: a processing tank 2 in which a food F is stored; a water-seal type vacuum pump 11 for sucking and exhausting gas in the processing tank 2 to the outside; a heat exchanger 9 provided in an exhaust passage 8 from the processing tank 2 to the vacuum pump 11, and for cooling an exhaust fluid by cooling water; and storage parts 6, 7 capable of cooling storage water by a chiller 5. As the storage part, the vacuum cooling device includes the first storage part 6 and the second storage part 7, and from which storage part the water should be supplied to the heat exchanger 9 and/or the vacuum pump 11 is switchable. It is preferable that, toward the end of a cooling step, the storage water in the first storage part 6 is circulated between itself and the heat exchanger 9 while being cooled by the chiller 5, and the cold water in the second storage part 7 is not circulated between itself and the heat exchanger 9 but is used as seal water of the vacuum pump 11.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vacuum cooling device that cools food by reducing the pressure in a processing tank.

  Conventionally, as disclosed in Patent Document 1 below, as a means for reducing the pressure in a cooling tank (4), a vacuum provided with a heat exchanger (6) for vapor condensation and a water ring vacuum pump (7). Cooling devices are known. In this device, room-temperature water and cold water can be switched as the water flow of the heat exchanger (6) and the sealing of the vacuum pump (7). Specifically, room temperature water from a room temperature water supply line (24) and cold water from a cold water tank (38) cooled by a chiller (25) are supplied to the heat exchanger (6) and the vacuum pump (7). And can be supplied. Then, the water after passing through the heat exchanger (6) is drained from the drain line (31) or returned to the cold water tank (38).

  In this apparatus, first, as a standby step, water in a cold water tank (38) is circulated and cooled with a chiller (25) (FIG. 2 of Patent Document 1). Then, as a cooling initial step, the vacuum pump (7) is operated while supplying normal-temperature water as sealing water in a state where the flow of water through the heat exchanger (6) is stopped, and the pressure in the cooling tank (4) is reduced. (FIG. 3 of Patent Document 1). Thereafter, as the middle stage of cooling, the passage of water through the heat exchanger (6) is started (FIG. 4 of Patent Document 1), and as the latter stage of cooling, the passage of water through the heat exchanger (6) and the vacuum pump (7). Is switched from room temperature water to cold water, and the pressure in the cooling tank (4) is further reduced (FIG. 5 of Patent Document 1). When passing cold water through the heat exchanger (6), the cold water that has passed through the heat exchanger (6) is returned to the cold water tank (38).

JP-A-2004-170060 (Paragraph 0046-0053, FIG. 1-5)

  In the related art, at the end of the cooling process (late cooling process), cold water is supplied to the heat exchanger and the vacuum pump, but the heated water after passing through the heat exchanger is returned to the cold water tank. Further, since the cold water supplied from the cold water tank to the vacuum pump is disposable, the cold water tank can be replenished with normal temperature water accordingly.

  For this reason, the water temperature in the cold water tank can rise. For this reason, depending on the cooling condition of the chiller, the cold water temperature may reach a desired temperature at the end of the cooling process in a situation where the lowest cold water temperature is required. As a result, there is a possibility that the cooling rate becomes slow or cavitation occurs in the vacuum pump.

  Therefore, an object of the present invention is to provide a vacuum cooling device that can supply cold water at a desired temperature to a decompression system at the end of a cooling process, and can improve a cooling speed and reduce cavitation.

  The present invention has been made to solve the above-mentioned problem, and the invention according to claim 1 has a processing tank in which food is stored, and a water-sealing type that sucks and discharges gas in the processing tank to the outside. A vacuum pump, a heat exchanger that is provided in an exhaust path from the processing tank to the vacuum pump, and cools an exhaust fluid with cooling water, stores water supplied to the heat exchanger and the vacuum pump, and stores the stored water. A storage unit that can be cooled by a chiller, and as the storage unit, a first storage unit and a second storage unit, and which storage unit supplies water to the heat exchanger and / or the vacuum pump. A vacuum cooling device characterized by being able to be switched.

  According to the first aspect of the present invention, the water supply to the heat exchanger and / or the vacuum pump is switched between the first storage unit and the second storage unit, from which of the storage units the cold water is used. Can be. If the switching is performed in the middle of the cooling step (preferably at the end of the cooling step), relatively low-temperature cold water can be supplied even in a state where the cooling step has been advanced, and the cooling rate can be improved and cavitation can be reduced.

  In the invention according to claim 2, the stored water in the first storage unit can be circulated between the heat exchanger and the water supply to the vacuum pump, and stored in the second storage unit. 2. The vacuum cooling device according to claim 1, wherein the water cannot be circulated between the heat exchanger and the water, and the water can be supplied to the vacuum pump. 3.

  According to the second aspect of the present invention, the stored water (cold water) in the first storage unit can be circulated with the heat exchanger, so that the temperature can be increased. The cold water) is not allowed to circulate with the heat exchanger, so that the temperature is prevented from rising. In the middle of the cooling step (preferably at the end), if the water sealed by the vacuum pump is switched to the stored water in the second storage section, relatively low-temperature cold water can be supplied even in the state where the cooling step has been advanced, and the cooling rate can be reduced. Improvement and reduction of cavitation can be achieved.

  The first aspect of the present invention is a first cooling step of depressurizing the inside of the processing tank while supplying room-temperature water to the vacuum pump, and the cooling water in the first storage unit while cooling the stored water in the first storage unit with a chiller. A second cooling step of circulating between the exchanger and supplying to the vacuum pump to reduce the pressure in the processing tank, and the stored water in the first storage unit is cooled by a chiller while the heat exchanger. And a third cooling step of supplying the stored water in the second storage section to the vacuum pump to further reduce the pressure in the treatment tank, and sequentially performing the steps. A vacuum cooling device according to claim 1 or claim 2.

  According to the third aspect of the present invention, the first cooling step, the second cooling step, and the third cooling step are sequentially performed to cool the food. In the situation where the lowest chilled water temperature is required at the end of the cooling step, the sealing of the vacuum pump is switched to the stored water in the second storage section as the third cooling step. Since the stored water in the second storage unit is not circulated to the heat exchanger (hence, the temperature is not raised) and is relatively low in temperature, supplying the low-temperature cold water to the vacuum pump reduces the cooling rate. And cavitation can be reduced.

  Further, in the invention according to claim 4, in each of the storage units, water supply is controlled to maintain the stored water at a set water level, but in the third cooling step, water is not supplied to the second storage unit. The vacuum cooling device according to claim 3, wherein:

  According to the fourth aspect of the present invention, since the water is not supplied to the second storage part in the third cooling step, the temperature of the stored water in the second storage part is prevented from rising. Thereby, the temperature of the water supply to the vacuum pump in the third cooling step is stabilized at a low temperature, and the cooling rate can be improved and cavitation can be reduced.

  ADVANTAGE OF THE INVENTION According to the vacuum cooling device of this invention, the cold water of a desired temperature can be supplied to a decompression system at the end of a cooling process, and the improvement of a cooling rate and reduction of cavitation can be aimed at.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic which shows the vacuum cooling device of one Example of this invention, and shows the flow of water in a standby process while showing a part in cross section. FIG. 2 is a diagram illustrating a pressure reducing unit of the vacuum cooling device of FIG. 1 and a water supply / drainage system to the unit, and illustrates a flow of water in a first cooling step. It is a figure which shows the decompression means of the vacuum cooling device of FIG. 1, and the water supply / drainage system to it, and has shown the flow of the water in a 2nd cooling process. FIG. 2 is a diagram illustrating a pressure reducing unit of the vacuum cooling device in FIG. 1 and a water supply / drainage system to the pressure reducing unit, and illustrates a flow of water in a third cooling step.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic diagram showing a vacuum cooling device 1 according to one embodiment of the present invention, and shows a part of the cross section and shows a flow of water in a standby step described later.

  The vacuum cooling device 1 according to the present embodiment includes a processing tank 2 in which a food F to be cooled is stored, a decompression unit 3 that suctions and discharges gas in the processing tank 2 to the outside, and depressurizes the processing tank 2. A decompression means 4 for introducing outside air into the decompressed processing tank 2 to repressurize the processing tank 2, and a storage unit 6 for storing water used in the decompression means 3 and cooling the stored water by a chiller 5. And control means (not shown) for controlling the means 3, 4 and the chiller 5 for vacuum cooling the food F in the processing tank 2.

  The processing tank 2 is a hollow container that can withstand reduced pressure in the internal space, and can be opened and closed by a door. The processing tank 2 is typically formed in a substantially rectangular box shape, and an opening at the front can be opened and closed by a door. The food F can be taken in and out of the processing tank 2 by opening the door, and the opening of the processing tank 2 can be closed airtight by closing the door. The door may be provided on both the front and back of the processing tank 2.

  The decompression unit 3 is a unit that sucks and discharges a gas (air or steam) in the processing tank 2 to the outside to reduce the pressure in the processing tank 2. In this embodiment, the pressure reducing means 3 includes a heat exchanger 9, a check valve 10, and a vacuum pump 11 in order in an exhaust path 8 from inside the processing tank 2.

  The heat exchanger 9 exchanges heat without mixing the exhaust fluid from the processing tank 2 and the cooling water. In the heat exchanger 9, the exhaust fluid can be cooled by the cooling water to condense the vapor in the exhaust fluid.

  The vacuum pump 11 is of a water-sealing type, and is operated while being supplied with water called water sealing, as is well known. Although the details will be described later, the heat exchanger 9 and the vacuum pump 11 can be supplied by switching between normal temperature water and cold water. Note that cold water refers to water cooled by the chiller 5, and room-temperature water refers to water that is not cooled.

  The pressure recovery means 4 is means for introducing outside air into the depressurized processing tank 2 to recover the pressure inside the processing tank 2. In the present embodiment, the pressure recovery means 4 includes an air filter 13 and a vacuum release valve 14 in order in an air supply path 12 into the processing tank 2. When the vacuum release valve 14 is opened in a state where the pressure in the processing tank 2 is reduced, outside air is introduced into the processing tank 2 via the air filter 13, and the pressure in the processing tank 2 can be restored. The vacuum release valve 14 is preferably composed of a valve whose opening can be adjusted.

  The chiller 5 includes a refrigerator (not shown) and cools water from the storage units 6 and 7. As is well known, a refrigerator includes a compressor, a condenser, an expansion valve, and an evaporator, and executes a refrigeration cycle of compression, condensation, expansion, and evaporation of a refrigerant. Then, in the evaporator, heat exchange is performed without mixing the refrigerant and water, and the water from the storage units 6 and 7 is cooled.

  The storage unit includes a first storage unit 6 and a second storage unit 7. In the present embodiment, the inside of the cold water tank 15 is partitioned by a partition plate 16 and divided into a first storage section 6 and a second storage section 7. By providing the storage sections 6 and 7 integrally in one cold water tank 15, a compact configuration is achieved. In addition, the area in contact with the outside air can be reduced, and heat insulation can be easily performed. However, two chilled water tanks 15 may be prepared, and one chilled water tank 15 may be used as the first storage unit 6 and the other chilled water tank 15 may be used as the second storage unit 7.

  In the present embodiment, the second storage unit 7 has a smaller capacity than the first storage unit 6. The capacity (water storage amount) of the second storage unit 7 is set to be equal to or slightly larger than the amount of water used (water sealing amount) in the third cooling step described later. For example, in the present embodiment, the capacity of the first storage section 6 is 400 L, and the capacity of the second storage section 7 is 20 to 60 L (5 to 15% of the capacity of the first storage section 6, more preferably 5 to 10 L). %).

  Water can be supplied to the first storage section 6 via the first water supply passage 17. In the present embodiment, normal temperature water is supplied to the first storage unit 6 from the first water supply channel 17 as appropriate by the ball tap 18, and the stored water in the first storage unit 6 is maintained at the set water level.

  Water can be supplied to the second storage section 7 via the second water supply passage 19. In the present embodiment, normal temperature water is appropriately supplied to the second storage section 7 from the second water supply channel 19 by the ball tap 20, and the stored water in the second storage section 7 is maintained at the set water level. However, the second water supply channel 19 is provided with a water supply shutoff valve 21, and the open / close of the water supply shutoff valve 21 switches whether water can be supplied to the second storage unit 7 through the second water supply channel 19. In a state in which the rehydration cutoff valve 21 is opened, the stored water in the second storage section 7 is maintained at the set water level by the ball tap 20, but in a state in which the rehydration cutoff valve 21 is closed, the second water through the second refill channel 19 is provided. Water supply to the two storage units 7 is prevented.

  The stored water in each of the storage units 6 and 7 can be cooled by the chiller 5. For that purpose, the first water supply channel 22 from the first storage unit 6 and the second water supply channel 23 from the second storage unit 7 are merged and connected to the chiller 5 as a chiller inlet channel 24. The first water passage 22 is provided with a flow control valve 25 (or a pressure loss element such as an orifice), while the second water passage 23 is provided with a water valve 26. Further, a water supply pump 27 is provided in the chiller inlet passage 24. When the water supply pump 27 is operated, the water from the chiller inlet channel 24 is passed through the chiller 5 (more specifically, the evaporator of the refrigerator) to be cooled, and is discharged to the chiller outlet channel 28 as cold water.

  By operating the water supply pump 27 with the flow control valve 25 and the water supply valve 26 opened, the stored water in each of the storage parts 6, 7 can be circulated between the chiller 5 and cooled. The opening degree (or the size of the orifice) of the flow control valve 25 is set in advance so that the stored water in each of the storage sections 6 and 7 is uniformly cooled. Therefore, even when the flow rate control valve 25 is provided in the first water supply passage 22, the flow rate control valve 25 is normally maintained at the predetermined opening degree after the opening degree is once adjusted. However, the installation of the flow control valve 25 (and the orifice or the like) can be omitted in some cases.

  A chiller outlet path 28 from the chiller 5 is branched into a chilled water supply path 29 and a chilled water return path 30. Whether the cold water from the chiller outlet passage 28 is sent to the cold water supply passage 29 or the cold water return passage 30 can be switched. In the present embodiment, a first switching valve (three-way valve) 31 is provided at a branch portion between the chilled water supply passage 29 and the chilled water return passage 30, and the first switching valve 31 allows the chilled water from the chiller 5 to be supplied to the chilled water supply passage 29. Or the cold water return path 30 is switched. The cold water return path 30 is branched into a first return path 32 to the first storage section 6 and a second return path 33 to the second storage section 7. A return valve 34 is provided in the second return passage 33. If the return valve 34 is closed, return of water to the second storage section 7 via the cold water return path 30 can be prevented.

  In the present embodiment, the water supply to the heat exchanger 9 and the vacuum pump 11 can be switched between normal temperature water and cold water. Therefore, the normal temperature water supply channel 35 through which the normal temperature water passes and the cold water supply channel 29 through which the cold water passes merge into the first water supply channel 36. The room temperature water supply passage 35 is provided with a room temperature water supply valve 37 and a check valve 38. In the first water supply channel 36, a heat exchange water supply channel 39 to the heat exchanger 9 is provided in a branched manner. Further, the water in the first water supply channel 36 can be supplied to the vacuum pump 11 via the sealed water supply channel 40.

  However, the water in the first water supply path 36 and the water from the second storage section 7 via the second water supply path 41 can be switched and supplied to the vacuum pump 11. In the present embodiment, a second switching valve (three-way valve) 42 is provided at the junction of the first water supply path 36 and the second water supply path 41, and the second switching valve 42 allows the first water supply path 36 to be separated from the first water supply path 36. Water (room temperature water or water stored in the first storage unit 6) to the vacuum pump 11, or water (water stored in the second storage unit 7) from the second water supply passage 41 to the vacuum pump 11 Is switched.

  The heat exchanger 9 is supplied with water through a heat exchange water supply channel 39 and discharged through a heat exchange drainage channel 43. The heat exchange drainage channel 43 from the heat exchanger 9 is connected to the chilled water return channel 30 via a chilled water return valve 44. Therefore, by opening the cold water return valve 44, the water used in the heat exchanger 9 can be returned to the cold water tank 15. At this time, if the water return valve 34 is closed, the water used in the heat exchanger 9 can be returned to the first storage unit 6 without returning to the second storage unit 7.

  The processing tank 2 is provided with a pressure sensor 45 for detecting the pressure in the processing tank 2 and a product temperature sensor 46 for detecting the temperature of the food F stored in the processing tank 2. The chiller outlet path 28 is provided with a chilled water temperature sensor 47 for detecting the temperature of the chilled water. However, the chilled water temperature sensor 47 may be provided in the chiller inlet passage 24 instead of the chiller outlet passage 28 in some cases.

  The control means is a controller (not shown) for controlling the means 3, 4 and the chiller 5 based on the detection signals of the sensors 45 to 47 and the elapsed time. Specifically, the chiller 5, the vacuum pump 11, the water supply pump 27, the water supply shutoff valve 21, the water supply valve 26, the first switching valve 31, the return valve 34, the normal temperature water supply valve 37, the second switching valve 42, and the cold water return In addition to the valve 44 and the vacuum release valve 14, a pressure sensor 45, a product temperature sensor 46, a cold water temperature sensor 47, and the like are connected to the controller. Then, the controller performs vacuum cooling of the food F in the processing tank 2 according to a predetermined procedure (program). Hereinafter, an example of an operation method of the vacuum cooling device 1 will be described.

  The vacuum cooling device 1 according to the present embodiment sequentially executes a standby process, a first cooling process, a second cooling process, a third cooling process, and a vacuum release process. Hereinafter, each step will be described in order with reference to FIGS. 2 to 4 show a water supply / drainage system for the pressure reducing means 3 in addition to FIG. 1 described above. FIG. 1 shows a flow of water in a standby step, and FIG. 2 shows a flow of water in a first cooling step. FIG. 3 shows the flow of water in the second cooling step, and FIG. 4 shows the flow of water in the third cooling step. In each of the drawings, a black valve indicates a closed state, and a white valve indicates an open state.

  Before the start of operation, the vacuum release valve 14 is opened, the first switching valve 31 connects the chiller outlet path 28 and the cold water return path 30, and the second switching valve 42 connects the first water supply path 36 and the closed water supply path 40. The other valves 21, 26, 34, 37, and 44 are closed, and the chiller 5 and the pumps 11 and 27 are stopped.

  When the power is turned on, the vacuum cooling device 1 starts a standby process, and thereafter sequentially executes a first cooling process, a second cooling process, a third cooling process, and a vacuum release process. Note that the food F is typically stored in the processing tank 2 after the standby step, but may be performed before or during the standby step depending on the case before the first cooling step.

<< Standby process (Fig.1) >>
In the standby step, the stored water in each of the storage units 6 and 7 is circulated between the storage unit 6 and the chiller 5 to cool the storage water to the set temperature. Specifically, as shown in FIG. 1, in a state where the chiller outlet path 28 and the cold water return path 30 are communicated by the first switching valve 31, and in a state where the water supply valve 26 and the water return valve 34 are opened. Then, the water pump 27 is operated. Note that, as described above, the flow control valve 25 is adjusted to a predetermined opening degree in advance, and is not controlled in the present embodiment. In addition, the water supply shutoff valve 21 is opened in advance, and in the standby process, water is stored and maintained in each of the storage units 6 and 7 to the set water level.

  The stored water in each of the storage units 6 and 7 is sent to the chiller 5 via each of the water supply channels 22 and 23 and the chiller inlet channel 24 to be cooled, and the chiller outlet channel 28, the cold water return channel 30 and each of the return channels 32 are provided. , 33, and is returned to each storage section 6, 7. At this time, the chiller 5 is controlled such that the temperature detected by the cold water temperature sensor 47 is maintained at a set temperature (for example, 7 ° C.). Here, the compressor is controlled by an inverter, but may be controlled on / off in some cases. By adjusting the merging ratio from each of the storage units 6 and 7 to the water pump 27 with the flow control valve 25, and from the cold water return path 30 to each of the water return paths 32 and 33 (accordingly, each of the storage sections 6 and 7). By adjusting the distribution ratio to the storage sections in the same manner, the stored water in each of the storage sections 6 and 7 can be uniformly cooled.

  When the temperature detected by the chilled water temperature sensor 47 becomes equal to or lower than the set temperature, or when a predetermined start button is pressed (that is, the start of cooling is instructed), the process proceeds to the next step. Thereafter, the water pump 27 continues to operate at least until the end of the third cooling step. During that time, the chiller 5 also basically continues to operate, but as described above, the inverter is controlled (the inverter is controlled so as to maintain the outlet water temperature at the set temperature), so the output is based on the water temperature passed through the chiller 5. Adjusted automatically. The cooling by circulating the stored water in each storage unit 6, 7 through the chiller 5 (not passing through the heat exchanger 9) is continued until the end of the first cooling step. Is maintained at a set temperature (actually, the temperature in each of the storage sections 6, 7 may be somewhat excessive (eg, 5 to 6 ° C.)).

<< First cooling process (Fig. 2) >>
In the first cooling step, while the vacuum release valve 14 is closed and the passage of water through the heat exchanger 9 is stopped, while supplying room temperature water as sealing water for the vacuum pump 11, the inside of the processing tank 2 is evacuated by the vacuum pump 11. Reduce pressure.

  Specifically, the vacuum release valve 14 is closed to seal the inside of the processing tank 2. Further, by keeping the cold water return valve 44 closed, the passage of water through the heat exchanger 9 is disabled. Further, with the second switching valve 42 connecting the first water supply path 36 and the sealed water supply path 40, the normal temperature water supply valve 37 is opened to supply room temperature water as water sealing to the vacuum pump 11. Then, the inside of the processing tank 2 is depressurized by operating the vacuum pump 11.

  Thus, the pressure in the processing tank 2 is reduced, and the food F in the processing tank 2 is cooled. When the temperature detected by the product temperature sensor 46 becomes equal to or lower than the chiller switching temperature (for example, 60 ° C.), the process proceeds to the next step. However, control may be performed based on the detected pressure of the pressure sensor 45, such as when the product temperature sensor 46 fails, in which case the detected pressure of the pressure sensor 45 is changed to the chiller switching pressure (saturation pressure (for example, 200 hPa) at the chiller switching temperature). ) When it becomes the following, it moves to the next step.

<< Second cooling process (Fig. 3) >>
In the second cooling step, while the water is passed through the heat exchanger 9, the water passing through the heat exchanger 9 and the sealing of the vacuum pump 11 are switched from normal-temperature water to cold water to further reduce the pressure inside the processing tank 2. At this time, the water after passing through the heat exchanger 9 is returned to the first storage unit 6. Further, the refilling shutoff valve 21, the water supply valve 26, and the water return valve 34 are closed, and the supply / drainage of the second storage unit 7 is not performed.

  Specifically, the normal temperature water supply valve 37 is closed, and the first switching valve 31 is switched so that the chiller outlet path 28 communicates with the cold water supply path 29. Thereby, the cold water from the first storage section 6 through the chiller 5 can be supplied to the heat exchanger 9 and the vacuum pump 11 through the chiller outlet path 28 and the cold water supply path 29. That is, the chilled water from the chilled water supply channel 29 is supplied to the heat exchanger 9 via the heat exchange water channel 39 and is also supplied to the vacuum pump 11 via the sealed water supply channel 40. Then, by opening the cold water return valve 44, the cold water that has passed through the heat exchanger 9 can be returned to the first storage section 6. As described above, in the second cooling step, the water supplement shutoff valve 21, the water supply valve 26, and the water return valve 34 are closed, and the supply / drainage of the second storage unit 7 is not performed. Remains substantially at the set temperature.

  Thus, the pressure in the processing tank 2 is further reduced, and the cooling of the food F in the processing tank 2 is advanced. When the temperature detected by the product temperature sensor 46 becomes lower than the water sealing switching temperature (for example, 30 ° C.), the process proceeds to the next step. However, similarly to the transition from the first cooling step to the second cooling step, the control may be performed based on the detected pressure of the pressure sensor 45 at the transition from the second cooling step to the third cooling step. In this case, when the pressure detected by the pressure sensor 45 becomes equal to or lower than the water sealing switching pressure (saturation pressure (for example, 42 hPa) at the water sealing switching temperature), the process proceeds to the next step.

≪Third cooling process (Fig. 4) ≫
In the third cooling step, the water sealed by the vacuum pump 11 is switched from the water in the first storage 6 to the water in the second storage 7. That is, in the second cooling step, the water from the first storage section 6 was supplied to the heat exchanger 9 and the vacuum pump 11, but in the third cooling step, the heat exchanger 9 was supplied to the heat exchanger 9 from the first storage section 6. While supplying water from the second storage unit 7 to the vacuum pump 11.

  Specifically, the second switching valve 42 is switched so that the second water supply channel 41 from the second storage unit 7 communicates with the sealed water supply channel 40 to the vacuum pump 11. Thereby, cold water in the second storage unit 7 can be supplied as the water sealing of the vacuum pump 11. In the third cooling step, the water supplement shutoff valve 21, the water supply valve 26, and the water return valve 34 are kept closed.

  In the second cooling step and the third cooling step, the first storage section 6 circulates the stored water between the heat exchanger 9 and the second cooling step. Thus, room temperature water is supplied via the first water supply passage 17. Therefore, the temperature of the stored water in the first storage unit 6 becomes higher than the set temperature (the cooling target temperature in the standby step) (for example, 12 to 13 ° C.). On the other hand, the stored water in the second storage section 7 cannot be circulated with the heat exchanger 9 and is not replenished, so that the temperature rise is prevented. In other words, the water stored in the second storage unit 7 is cooled to the set temperature in the standby step and the first cooling step, and then the cooling state is substantially maintained (for example, 5 to 6 ° C.). Therefore, in a situation where the lowest chilled water temperature is required at the end of the cooling step, as a third cooling step, the sealed water of the vacuum pump 11 is switched to the stored water of the second storage section 7 so that stable low-temperature water is supplied to the vacuum pump. 11 can be supplied. By supplying this low-temperature cold water to the vacuum pump 11, it is possible to improve the cooling rate and reduce cavitation.

  Thus, the pressure in the processing tank 2 is further reduced, and the cooling of the food F in the processing tank 2 is advanced. When a predetermined termination condition is satisfied, such as when the temperature detected by the product temperature sensor 46 reaches a cooling target temperature (for example, 18 ° C.), water supply to the heat exchanger 9 and the vacuum pump 11 is stopped, and the vacuum pump 11 is stopped. To the next step. However, in preparation for the next vacuum cooling operation, the stored water in each of the storage units 6 and 7 is circulated between the storage units 6 and 7 with the chiller 5 to continue cooling to the set temperature in the same manner as in the standby process. Good.

  In each cooling step, the opening of the vacuum release valve 14 may be adjusted. In that case, the pressure in the processing tank 2 can be reduced as desired, and the food F in the processing tank 2 can be gradually cooled. .

≪Vacuum release process≫
In the vacuum release step, the pressure inside the processing tank 2 is restored to the atmospheric pressure by using the pressure restoration means 4. Specifically, the vacuum release valve 14 is opened, and the pressure inside the processing tank 2 is restored to the atmospheric pressure. At this time, the pressure inside the processing tank 2 can be gradually restored by adjusting the opening of the vacuum release valve 14. In this way, after the pressure in the processing tank 2 is restored to the atmospheric pressure, the door of the processing tank 2 is opened, and the cooled food F can be taken out of the processing tank 2.

  According to the vacuum cooling device 1 of the present embodiment, the food F can be cooled by sequentially executing the first cooling step, the second cooling step, and the third cooling step. In a situation where the lowest cold water temperature is required at the end of the cooling step, the water sealed in the vacuum pump 11 is switched to the stored water in the second storage unit 7 as the third cooling step. The stored water in the second storage unit 7 is not circulated between the heat exchanger 9 (hence, the temperature is not increased) and is not newly supplied (hence, the temperature is not increased), and is relatively low in temperature. Since the low-temperature cold water is supplied to the vacuum pump 11, the cooling rate can be improved and cavitation can be reduced.

  The vacuum cooling device 1 of the present invention is not limited to the configuration of the above-described embodiment, and can be appropriately changed. In particular, (a) the processing tank 2 in which the food F is stored, (b) a water-sealed vacuum pump 11 for sucking and discharging the gas in the processing tank 2 to the outside, and (c) a vacuum pump from the processing tank 2 A heat exchanger 9 provided in an exhaust passage 8 for cooling the exhaust fluid with cooling water; and (d) storing the water supply to the heat exchanger 9 and the vacuum pump 11, and cooling the stored water by the chiller 5. (E) as a storage unit, a first storage unit 6 and a second storage unit 7, and water in any of the storage units is supplied to the heat exchanger 9 and / or the vacuum pump 11. If the supply can be switched, other configurations can be appropriately changed.

  For example, in the above-described embodiment, when cold water is supplied as sealing water for the vacuum pump 11, the supply source of the cold water can be switched between the first storage section 6 and the second storage section 7. Alternatively or additionally, when supplying cold water as water flow through the heat exchanger 9, the supply source of the cold water may be switchable between the first storage unit 6 and the second storage unit 7.

  Further, in the above embodiment, a steam ejector may be further provided as the pressure reducing means 3. In that case, a steam ejector, a heat exchanger 9 and a vacuum pump 11 are sequentially provided in an exhaust path 8 from inside the processing tank 2. Then, when a predetermined operating condition is satisfied in the middle of the second cooling step or at the start or in the middle of the third cooling step, the steam ejector may be operated.

  In the first cooling step, water was not passed through the heat exchanger 9. However, in some cases, normal temperature water may be passed through the heat exchanger 9 if predetermined water passing conditions are satisfied. In this case, the heat exchange drainage channel 43 is provided with a branch to the outside to be branched, and the room temperature water after passing through the heat exchanger 9 is drained to the outside through the waste channel (that is, the first storage). (It is not returned to the part 6).

  In the above-described embodiment, the first storage unit 6 and the second storage unit 7 are provided. However, in some cases, more (that is, three or more storage units in total) may be provided. Also in that case, in the standby step or the first cooling step, the stored water in each storage section is cooled, and in the subsequent step, the cold water in each of the second or more storage sections is sequentially supplied as water to the decompression means 3. What is necessary is just to use it. At that time, similarly to the above-described embodiment, the used cold water is not returned to each of the second or more storage units, new water is not supplied, the cooling state is maintained as much as possible, and only the use of the cold water is used. Good to be done.

  Further, the vacuum cooling device 1 only needs to have at least a vacuum cooling function, and may have a function of heating the food F in the treatment tank 2 in some cases. That is, after the food F in the treatment tank 2 is heated, the food F may be vacuum cooled in the same manner as in the above embodiment.

DESCRIPTION OF SYMBOLS 1 Vacuum cooling device 2 Processing tank 3 Decompression means 4 Decompression means 5 Chiller 6 First storage part 7 Second storage part 8 Exhaust path 9 Heat exchanger 10 Check valve 11 Vacuum pump 12 Air supply path 13 Air filter 14 Vacuum release Valve 15 Cold water tank 16 Partition plate 17 First water supply path 18 Ball tap 19 Second water supply path 20 Ball tap 21 Water supply cutoff valve 22 First water supply path 23 Second water supply path 24 Chiller inlet path 25 Flow control valve 26 Water supply valve 27 Water supply pump 28 Chiller outlet path 29 Chilled water supply path 30 Chilled water return path 31 First switching valve 32 First return path 33 Second return path 34 Return valve 35 Room temperature water supply path 36 First water path 37 Room temperature water supply valve 38 Check valve 39 Heat exchange water channel 40 Sealed water channel 41 Second water channel 42 Second switching valve 43 Heat exchange drain channel 44 Cold water return valve 45 Pressure sensor 46 Material temperature sensor 47 Water temperature sensor

Claims (4)

A processing tank in which food is stored,
A water-sealed vacuum pump that sucks and discharges the gas in this processing tank to the outside,
A heat exchanger provided in an exhaust path from the processing tank to the vacuum pump, and cooling an exhaust fluid with cooling water;
Storing a water supply to the heat exchanger and the vacuum pump, and a storage unit capable of cooling the stored water by a chiller,
The storage section includes a first storage section and a second storage section, and it is possible to switch between which storage section water is supplied to the heat exchanger and / or the vacuum pump. Vacuum cooling device. The stored water in the first storage unit is circulated between the heat exchanger and the water pump is supplied to the vacuum pump,
2. The vacuum cooling device according to claim 1, wherein the stored water in the second storage unit is not allowed to circulate with the heat exchanger and can be supplied to the vacuum pump. 3. While supplying room temperature water to the vacuum pump, a first cooling step of reducing the pressure in the processing tank,
A second cooling step of storing water in the first storage unit, circulating between the heat exchanger while cooling with a chiller and supplying the vacuum pump, and depressurizing the inside of the processing tank,
The stored water in the first storage unit is circulated between the heat exchanger while cooling with a chiller, and the stored water in the second storage unit is supplied to the vacuum pump to circulate the processing tank. The vacuum cooling device according to claim 1, wherein the third cooling step of further reducing the pressure is sequentially performed. In each of the storage sections, water supply is controlled so as to maintain stored water at a set water level, but in the third cooling step, water is not supplied to the second storage section. The vacuum according to claim 3, wherein Cooling system.

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