JP2014159931A - Vacuum cooling apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To discharge drain from a drain tank on the way of vacuum cooling operation of a vacuum cooling apparatus.SOLUTION: A vacuum cooling apparatus includes: a treatment tank 2 for storing an object to be cooled; a vacuum generation device 1 connected to the treatment tank 2 by a vacuum piping 9 to suck gas in the treatment tank; a heat exchanger 4 for cooling the gas sucked from the treatment tank 2 by the vacuum generation device 1 on the way; and a drain tank 6 for storing drain generated in the heat exchanger. The vacuum cooling apparatus further includes: a drain tank shield valve 5 for shielding between the heat exchanger 4 and the drain tank 6; and a vacuum piping shield valve 12 for shielding between the treatment tank 2 and the heat exchanger 4, and is configured so that when discharging drain during vacuum cooling operation, the drain tank shield valve 5 is closed to discharge the drain, and after discharging the drain, the treatment tank 2 is separated from a vacuum path by closing the vacuum piping shield valve 12, pressure in the drain tank is reduced by opening the drain tank shield valve 5 and the vacuum piping shield valve 12 is opened after reducing pressure in the drain tank.

Description

  The present invention relates to a vacuum cooling apparatus that evacuates a processing tank and cools the object to be cooled using heat of vaporization generated when water is evaporated from the object to be cooled in the processing tank.

  There is a vacuum cooling device that accommodates an object to be cooled such as food cooked in a processing tank and cools the object to be cooled by evacuating the inside of the processing tank. When the inside of the treatment tank containing the object to be cooled is depressurized and the boiling point in the treatment tank is lowered below the temperature of the object to be cooled, moisture in the object to be cooled evaporates, and at that time, from the object to be cooled Since the heat of vaporization is taken away, the object to be cooled can be cooled in a short time. As a vacuum generator used for a vacuum cooling device, there is an ejector using water or steam or a water seal type or dry type vacuum pump. When the gas in the treatment tank is sucked by the vacuum generator, the vapor generated from the object to be cooled is sucked simultaneously with the gas. However, since the volume of water greatly increases when water is changed to gas, if the vapor is sucked into the vacuum generator as it is, the amount of gas that must be discharged by the vacuum generator increases. In that case, the time required for decompression in the treatment tank becomes longer, and thus the cooling process time becomes longer.

  Therefore, as described in Japanese Patent Application Laid-Open No. 2012-102956, a heat exchanger for cooling the gas sucked by the vacuum generator is provided in the middle of the vacuum pipe for sending the gas in the processing tank to the vacuum generator. The gas is cooled in the middle of the vacuum pipe. When the gas is cooled by the heat exchanger, the volume of the gas is reduced, and particularly when the vapor is returned to the liquid by cooling the vapor, the volume is significantly reduced. Therefore, the volume of the gas that the vacuum generator must suck is reduced. It becomes small and can improve the efficiency of vacuum cooling. In the invention described in Japanese Patent Laid-Open No. 2012-102956, the condensed water generated by cooling the steam is accumulated in a drain tank installed below the heat exchanger. During the vacuum cooling operation, the drain tank also has a negative pressure, and the drain cannot be discharged from the drain tank in the negative pressure state. Therefore, the drain is stored until the end of the vacuum cooling operation, and the drain is discharged after the vacuum cooling operation is finished and the inside of the treatment tank is returned to the atmospheric pressure.

The amount of drain generation in vacuum cooling increases with the amount of the object to be cooled. For this reason, when the amount of the object to be cooled is increased, the amount of drain generated in one vacuum cooling operation may be larger than the capacity of the drain tank. If the drain amount exceeds the drain tank capacity during the vacuum cooling operation and it is necessary to discharge the drain, it is necessary to return the inside of the drain tank to atmospheric pressure. The air is taken into the tank and the pressure in the drain tank is returned to discharge the drain. However, if the pressure in the treatment tank is returned to atmospheric pressure during the vacuum cooling operation, the time required for decompression must be reduced to the high vacuum state again when the vacuum cooling is resumed. Therefore, the vacuum cooling time is significantly increased.

JP 2012-102956 A

  The problem to be solved by the present invention is that, in the vacuum cooling device, even when it is necessary to discharge the drain from the drain tank during the vacuum cooling operation, the time required for the vacuum cooling is greatly increased. An object of the present invention is to provide a vacuum cooling device capable of discharging drain while preventing the drainage.

  The invention according to claim 1 is a treatment tank for storing an object to be cooled, a vacuum generator connected to the treatment tank by a vacuum pipe and sucking a gas in the treatment tank, and the vacuum generator sucks from the treatment tank. In a vacuum cooling device that has a heat exchanger that cools the gas in the middle, a drain tank that stores drain generated in the heat exchanger, and cools the object to be cooled by evacuating the inside of the treatment tank, Provide a drain tank shielding valve that shields between the heat exchanger and the drain tank, and a vacuum piping shielding valve that shields between the treatment tank and the heat exchanger, and drain the drain in the drain tank during the vacuum cooling operation. When it becomes necessary, the drain tank is disconnected from the vacuum path by closing the drain tank shielding valve and drained from the drain tank, and after draining, the vacuum pipe shielding valve is closed to close the treatment tank. Disconnecting from the sky path, subjected to vacuum in the drain tank by opening the drain tank shutoff valve, and characterized in that for performing the operation of opening the vacuum line shutoff valve after the drain tank vacuum.

According to a second aspect of the present invention, in the vacuum cooling apparatus, a drain valve is connected to the drain tank for introducing air into the drain tank in a negative pressure state, and the drain tank is in the middle of the vacuum cooling operation. When draining from the tank, the pressure in the drain tank is increased by opening the air supply valve with the drain tank shielding valve closed.

According to a third aspect of the present invention, in the above-described vacuum cooling device, a pressure detecting device in the tank that detects a pressure upstream of the vacuum piping shielding valve, and a vacuum that detects a pressure downstream of the vacuum piping shielding valve. Piping pressure detection device is installed and the vacuum piping shielding valve closed after draining is the pressure inside the processing tank detected by the pressure detecting device inside the vacuum pipe. It is characterized by being opened after detecting that the value is below the value.

According to a fourth aspect of the present invention, in the vacuum cooling apparatus, a drain collecting chamber, which is a space for collecting drain generated by the heat exchanger, is provided between the heat exchanger and the drain tank. And

  In the case of the present invention, even if drain discharge is required during the vacuum cooling operation, the drain can be discharged without significantly increasing the time required for the cooling operation. In addition, since the drain can be discharged during the vacuum cooling operation, it is not necessary to increase the drain tank capacity beyond the capacity required during normal operation.

Flow chart of vacuum cooling device in one embodiment of the present invention Time chart during vacuum cooling operation in one embodiment of the present invention

  An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a flow chart of the vacuum cooling device in the first embodiment of the present invention, and FIG. 2 is a time chart during the vacuum cooling operation in one embodiment of the present invention. The vacuum cooling device includes a processing tank 2, a vacuum generator 1, a heat exchanger 4, a cold water unit 3, a drain tank 6, and the like. The vacuum cooling device evaporates water from the object to be cooled (high-temperature food) accommodated in the processing tank 2 by evacuating the inside of the processing tank 2, and performs cooling by the action of heat of vaporization generated at that time. .

The processing tank 2 and the vacuum generator 1 are connected by a vacuum pipe 9 and the gas in the processing tank 2 is discharged by operating the vacuum generator 1. At this time, if the vapor generated from the object to be cooled is sucked by the vacuum generator 1 together with the gas in the treatment tank 2, the volume of the gas that the vacuum generator 1 must suck increases, and the treatment tank Since the pressure reduction in 2 takes time, the cooling time becomes longer. Therefore, the heat exchanger 4 is provided in the vacuum pipe 9, and the volume of the gas that must be sucked is reduced by cooling the gas and vapor sucked by the vacuum generator 1.

The heat exchanger 4 is connected to the cold water unit 3 so that the cold water generated by the cold water unit 3 is stored in an internal tank. In the heat exchanger 4, a plurality of heat transfer tubes that pass through a tank storing cold water are installed, and the gas sucked from the treatment tank 2 is dispersed and flowed in the heat transfer tubes, thereby cooling the suction gas. I do. A drain collecting chamber 14 for collecting condensed water (drain) generated by cooling the suction gas is provided at the lower part of the heat exchanger 4. The drain is collected in the drain collecting chamber 14 and then exchanges heat. It flows down to a drain tank 6 provided below the vessel 4.

The piping connecting the heat exchanger 4 and the drain tank 6 is provided with a drain tank shielding valve 5 that shields between the heat exchanger 4 and the drain tank 6. A vacuum pipe shielding valve 12 is also provided on the upstream side of the drain tank 6 of the vacuum pipe 9. In order to detect the pressure upstream of the vacuum pipe shielding valve 12, the tank pressure detector 7 and the vacuum pipe shielding valve 12 are installed in the processing tank 2. A vacuum pipe pressure detection device 8 is provided in the vacuum pipe 9 in order to detect the downstream pressure.

The drain tank 6 stores drainage generated during the vacuum cooling operation. A drain pipe for draining and a drain valve 11 installed in the middle of the drain pipe are provided at the bottom of the drain tank 6, and the drain valve 11 is opened to drain the drain. However, when the inside of the drain tank 6 is at a negative pressure due to the operation of the vacuum cooling device, drainage from the drain tank 6 cannot be performed even if the drain valve 11 is opened. At the time of draining from the drain tank 6, The inside of the drain tank 6 needs to be equal to the atmospheric pressure. When the vacuum cooling operation is completed, the inside of the treatment tank is returned to the atmospheric pressure and the object to be cooled is taken in and out. At that time, the pressure in the drain tank 6 becomes the atmospheric pressure. If the pressure in the drain tank 6 is atmospheric pressure, the drain in the drain tank 6 can be discharged to the outside by opening the drain valve 11 of the drain pipe provided below the drain tank 6. . However, since the drain is generated during the vacuum cooling operation, it may be necessary to discharge the drain during the vacuum cooling operation. The drain tank 6 is provided with a water level detection device 13 for detecting the high water level and the low water level L, and when the drain in the drain tank 6 becomes higher than the H water level during the vacuum cooling operation. The drain is discharged even during the vacuum cooling operation.

  The vacuum cooling operation in the embodiment will be described. First, as a preparation, an object to be cooled is accommodated in the processing tank 2 and the processing tank 2 is sealed. In step A, the operation of the vacuum generator 1 is started and the vacuum cooling operation is started. At the time of the process A, the drain tank shielding valve 5 and the vacuum piping shielding valve 12 are open, and the air supply valve 10 and the drain valve 11 are closed. Since the drain of the drain tank 6 is discharged before the start of the vacuum cooling operation, the water level in the drain tank 6 at this time is lower than the L water level. Further, the pressure in the processing tank detected by the tank pressure detection device 7 and the pressure in the vacuum pipe detected by the vacuum pipe pressure detection device 8 are the same value at the start of the process A, and thereafter Due to the operation of the vacuum generator 1 and the cooling effect by the heat exchanger 4, the pressure in the processing tank is greater than the pressure in the vacuum pipe. When the vacuum cooling operation is performed, the vacuum generator 1 sucks and discharges the gas in the processing tank 2 through the vacuum pipe 9, so that the pressure in the processing tank 2 decreases. When the pressure in the treatment tank decreases, the water evaporates from the object to be cooled accommodated in the treatment tank 2, and when the water evaporates, the heat of vaporization is taken away from the surroundings. It goes down.

The gas sucked through the vacuum pipe 9 is cooled by the heat exchanger 4. Since the heat transfer tube of the heat exchanger 4 through which the suction gas flows is installed through a tank for storing cold water, the gas flowing in the heat transfer tube is cooled by the cold water outside the heat transfer tube, and the steam is condensed. The condensed water generated in the heat transfer tube portion gathers in the drain collecting chamber 14 provided below the heat exchanger 4 and flows down to the drain tank 6 provided further below the drain collecting chamber 14. When the steam is cooled to condensate, the volume is greatly reduced. When the volume of the gas is reduced, the amount of gas that must be exhausted by the vacuum generator 1 is reduced, so that the pressure in the treatment tank 2 can be reduced more quickly, and the time required for cooling can be reduced.

When the vacuum cooling operation is performed, the condensed water generated in the heat exchanger 4 accumulates in the drain tank 6, and thus the water level in the drain tank 6 rises. And operation for drain drainage is started in process B in which the water level of drain tank 6 has reached the H water level. The drainage from the drain tank 6 is performed while the vacuum cooling operation in the treatment tank 2 is continued. First, in step C, the drain tank shielding valve 5 is closed to disconnect the drain tank 6 from the vacuum pipe 9. After detecting that the drain tank shielding valve 5 is closed, the air supply valve 10 is opened in step D, and the air is introduced into the drain tank 6. In the drain tank 6 connected to the vacuum pipe 9 when the vacuum cooling operation was performed, the inside was at a negative pressure, so that when the air supply valve 10 is opened, external air enters the drain tank 6. When the drain valve 11 is opened in the process E after the introduction of the atmosphere into the drain tank 6, drainage from the drain tank 6 is performed. As the drain is discharged, the water level in the drain tank 6 is lowered, and after the water level in the drain tank is lowered to the L water level, the drain valve 11 is closed in Step F, and the air supply valve 10 is also closed in Step G.

In this state, the pressure in the drain tank 6 is significantly higher than the pressure in the treatment tank 2, so if the drain tank 6 and the vacuum pipe 9 are connected, the backflow of air and drain from the drain tank 6 to the treatment tank 2 occurs. It will occur. In order to avoid this, the vacuum pipe shielding valve 12 is closed in step H, the processing tank 2 is separated from the vacuum pipe 9, and the drain tank shielding valve 5 is opened in step I. Then, the pressure is maintained in a high vacuum state on the upstream side of the vacuum piping shielding valve 12 of the vacuum piping 9, but the downstream side of the vacuum piping shielding valve 12 is connected to the drain tank 6 in the atmospheric pressure state. Therefore, the pressure increases. Therefore, the value of the pressure in the vacuum pipe detected by the vacuum pipe pressure detection device 8 becomes higher than the value of the pressure in the processing tank detected by the pressure detector 7 in the tank. Thereafter, since the vacuum generator 1 is operated on the downstream side of the vacuum pipe 9, the pressure is reduced, and the vacuum pipe shielding valve 12 is opened in Step J where the pressure in the processing tank is equal to or higher than the pressure in the vacuum pipe. If the pressure in the drain tank 6 is lowered until the pressure in the processing tank ≧ the pressure in the vacuum pipe, the gas flow does not flow back to the processing tank 2 even when the vacuum pipe shielding valve 12 is opened. In 2, the cooling proceeds further by further vacuuming. The operation of vacuum cooling is terminated by stopping the operation of the vacuum generator 1 in step K. By doing in this way, drainage can be performed during the vacuum cooling operation. Thereafter, the treatment tank 2 is returned to atmospheric pressure, and the object to be cooled is taken out of the treatment tank 2. After the vacuum cooling operation is completed and the treatment tank 2 is returned to the atmospheric pressure, the drain tank 6 is also in the atmospheric pressure state, so the drain in the drain tank 6 is discharged at this time.

In this embodiment, since drain is discharged during the vacuum cooling operation, the drain tank 6 is disconnected from the vacuum pipe by shielding the heat exchanger 4 and the drain tank 6 so that only the drain tank 6 is brought to atmospheric pressure. So that you can bring it back. By disconnecting the drain tank 6 from the vacuum pipe 9, the drain can be discharged while the vacuum cooling operation is continued. In addition, an air supply pipe having an air intake port is connected to the drain tank 6, and an air supply valve 10 is provided in the middle of the air supply pipe. If the inside of the drain tank 6 is at a negative pressure, the drain cannot be discharged, but by introducing the outside air directly into the drain tank 6 through the air supply valve 10, the pressure in the drain tank 6 can be increased. It becomes possible to discharge.

Since the pressure in the drain tank is increased when draining, the pressure in the drain tank 6 is higher than the pressure in the processing tank 2 immediately after draining. By connecting the drain tank 6 to the vacuum pipe 9 in a state where the processing tank 2 is disconnected from the vacuum pipe 9, it is possible to prevent the gas flow from flowing backward from the vacuum pipe 9 to the processing tank 2. The pressure can be reduced. Waiting for the pressure in the vacuum pipe 9 connected to the drain tank 6 to be equal to or lower than the pressure in the treatment tank 2, the vacuum pipe shielding valve 12 is opened, so that the reverse flow from the drain tank 6 to the treatment tank 2 occurs. Can be prevented. When the drain tank shielding valve 5 is closed, the drain generated in the heat exchanger 4 is not sent to the drain tank 6, but the temporarily accumulated drain may accumulate in the drain collecting chamber 14 provided in the heat exchanger 4. it can. The drain in the drain collecting chamber 14 is sent to the drain tank 6 after the drain tank shielding valve 5 is opened.

The present invention is not limited to the embodiments described above, and many modifications can be made by those having ordinary knowledge in the art within the technical idea of the present invention.

1 Vacuum generator
2 Treatment tank 3 Cold water unit 4 Heat exchanger
5 Drain tank shielding valve 6 Drain tank 7 In-tank pressure detection device 8 Vacuum piping pressure detection device 9 Vacuum piping 10 Air supply valve 11 Drain valve 12 Vacuum piping shielding valve 13 Water level detection device 14 Drain collecting chamber

Claims (4)

  A processing tank that contains the object to be cooled, a vacuum generator connected to the processing tank by a vacuum pipe and sucking the gas in the processing tank, and a heat exchange that cools the gas sucked from the processing tank by the vacuum generator halfway In a vacuum cooling device that cools the object to be cooled by evacuating the inside of the treatment tank, and having a drain tank for storing drain generated in the heat exchanger, the space between the heat exchanger and the drain tank If there is a drain tank shielding valve to shield and a vacuum pipe shielding valve to shield between the treatment tank and the heat exchanger, it is necessary to drain the drain tank during the vacuum cooling operation. By closing the shielding valve, the drain tank is separated from the vacuum path and drained from the drain tank, and after draining, the vacuum pipe shielding valve is closed to disconnect the treatment tank from the vacuum path and draining. Subjected to vacuum in the drain tank by opening the Ntanku shutoff valve, a vacuum cooling apparatus, characterized in that performing the operation of opening the vacuum line shutoff valve after the drain tank vacuum.   2. The vacuum cooling apparatus according to claim 1, wherein an air supply valve for introducing air into the drain tank in a negative pressure state is connected to the drain tank, and drainage is discharged from the drain tank during the vacuum cooling operation. When performing, the vacuum cooling device characterized by raising the pressure in a drain tank by opening an air supply valve in the state where a drain tank shielding valve was closed.   The vacuum cooling device according to claim 1 or 2, wherein the pressure detecting device in the tank for detecting the pressure upstream of the vacuum piping shielding valve and the vacuum piping pressure detection for detecting the pressure downstream of the vacuum piping shielding valve. The vacuum piping shielding valve that is provided with a device and closed after draining is discharged so that the pressure value in the vacuum piping detected by the vacuum piping pressure detection device is less than the pressure value in the processing bath detected by the pressure detection device in the bath. A vacuum cooling device, which is opened after it has been detected. The vacuum cooling device according to any one of claims 1 to 3, wherein a drain collecting chamber which is a space for collecting drain generated by the heat exchanger is provided between the heat exchanger and the drain tank. A vacuum cooling device.

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