JP4640701B2 - Vacuum cooling device - Google Patents

Description

  The present invention relates to a vacuum cooling device for cooling foods, foods and the like.

As disclosed in the following Patent Document 1, a vacuum cooling device that depressurizes the inside of a cooling tank in which an object to be cooled is stored, vaporizes moisture in the object to be cooled, and cools the object to be cooled with the heat of vaporization. Are known.
JP-A-9-296975

  In the vacuum cooling device as in Patent Document 1, when the capacity of the cooling tank increases with the increase in capacity of the device, it takes time to eliminate air at the beginning of the vacuum cooling operation, resulting in a longer vacuum cooling operation time. There was a problem. Since the time of air exhaustion is determined by the exhaust capacity of the vacuum pump, it is conceivable to increase the capacity of the vacuum pump in order to reduce the time of air exhaust, but it is not easy to increase the capacity of the vacuum pump. Must use multiple vacuum pumps. As a result, an increase in power consumption, an increase in size of the device, and an increase in cost are caused.

  The problem to be solved by the present invention is to reduce the air exclusion time without increasing the capacity of a decompressor such as a vacuum pump and without being subject to the laws and regulations relating to the pressure vessel.

Up to now, it has been uncommon to consider supplying high-temperature steam in a vacuum cooling operation of a vacuum cooling device for cooling purposes. However, the inventors of this application have overcome this common sense in the development process for solving the problem and have solved the problem.
That is, the invention described in claim 1 is a vacuum cooling device comprising a cooling tank and a pressure reducing means for the cooling tank including a first pressure reducer, a heat exchanger, and a second pressure reducer, to the cooling tank. A steam supply means, a pressure detection means in the cooling tank, and a control means, and the control means outputs a signal from the pressure detection means without operating the first pressure reducer at the initial stage of the vacuum cooling operation. Input , operate the second pressure reducer and the heat exchanger so that the pressure in the cooling tank does not become positive, and when the pressure P2 is lower than the set pressure P1, the steam supply valve is opened and cooled. When the steam is supplied to the tank and the set pressure P1 is reached, the steam supply valve is closed and the inside of the cooling tank is controlled between P1 and P2 to eliminate air .

According to a second aspect of the present invention, in the first aspect , the first pressure reducer is a steam ejector.

According to a third aspect of the present invention, in the first or second aspect, the second pressure reducer is a vacuum pump.

According to the first to third aspects of the invention, the air removal time can be shortened without increasing the capacity of the decompression means that performs air removal using steam, and the inside of the cooling tank is positive. Since it does not become a pressure, it can be set as the cooling tank of a structure which does not receive the application of a conventional pressure vessel. Also, since not operated the first pressure reducer, not increased pressure loss due to the operation of the first decompressor, an air clearance by said second pressure reducer can be performed in a short time.

  According to the present invention, it is possible to shorten the air exclusion time without increasing the capacity of the decompression unit and without receiving the application of laws and regulations relating to the pressure vessel.

  An embodiment of the present invention will be described. This embodiment is a vacuum cooling device including a cooling tank and a pressure reducing means for the cooling tank, the steam supplying means to the cooling tank, the pressure detecting means in the cooling tank, the initial stage of the vacuum cooling operation, A signal from the pressure detecting means is input to control the steam supply means and the pressure reducing means so that the steam supply means supplies steam into the cooling tank so that the pressure in the cooling tank does not become positive. Control means for removing air in the cooling tank by exhausting from the cooling tank by the decompression means.

  According to this embodiment, in the initial stage of the vacuum cooling operation, the steam supply means and the decompression means are operated, and the air in the cooling tank is eliminated by exhausting while steaming. As a result, the time required for air removal can be shortened compared to the case where no steam is supplied. Further, the pressure in the cooling tank does not become a positive pressure by the control of the control means, and thus is excluded from the target of the pressure vessel.

  Next, elements in this embodiment will be described. Ingredients for vacuum cooling are boiled foods. The cooling tank is an area for vacuum-cooling the food material, means a sealable room or container, and can also be referred to as a region or a space. Moreover, since the inside of this cooling tank does not become a positive pressure and does not receive application of a pressure vessel, it has a simple structure in terms of strength.

  The steam supply means has a function of supplying steam generated in a boiler into the cooling tank, and a first steam supply line for supplying steam from the boiler to the cooling tank and the first steam supply line And a first steam supply valve provided. The boiler is preferably a reboiler that generates pure steam by heating pure water or soft water. Moreover, when the said decompression means uses a steam ejector as the component, the steam supply means can use steam from a boiler as a steam supply source to this steam ejector, and it is necessary to provide a separate steam supply source. Disappear.

  Preferably, the decompression means is provided with a steam ejector as a first decompressor, a heat exchanger as a condenser and a vacuum pump as a second decompressor in this order from the upstream side in the decompression line, and the heat exchange A check valve for preventing flow in the direction of the cooling tank is provided between the pressure reducer and the second pressure reducer. The first pressure reducer is preferably a steam ejector, but is not limited thereto, and the second pressure reducer is preferably a vacuum pump, but is not limited thereto. For example, a water ejector having a pressure reducing function other than the vacuum pump can be used. Furthermore, the decompression means can be constituted by a water ejector.

The steam ejector includes a second steam supply line and a second steam supply valve provided in the second steam supply line. The steam ejector is operated by opening the second steam supply valve and is operated by closing. Is stopped. The heat exchanger includes a water supply line and a water supply valve provided in the water supply line. The heat exchanger operates (condenses) by opening the water supply valve, and stops operating by closing. The vacuum pump is activated when the power supply is turned on and stopped when the power supply is turned off. When this vacuum pump is a water seal type, the supply stop of the seal water is controlled in conjunction with the supply of power.

  The connection position of the steam supply line to the cooling tank is preferably the top or top of the cooling tank, with the connecting position of the decompression line to the cooling tank being the lower or bottom part of the cooling tank. As a result, the steam supplied by the steam supply means at the time of air exclusion enters from the top or top of the cooling tank and is exhausted from the bottom or bottom of the cooling tank. The air in the cooling tank can be exhausted efficiently.

  A return pressure means is connected to the cooling tank. This return pressure means has a function of allowing the inside of the cooling tank to communicate with the atmosphere after the vacuum cooling operation and returning the pressure to atmospheric pressure, and a function of adjusting the cooling rate by adjusting the opening during the vacuum cooling operation. Can be given. The return pressure means includes a return pressure line connected to the cooling tank, and a filter and a return pressure valve provided in the return pressure line.

  The pressure detector is a pressure sensor that detects a pressure in the cooling tank, and includes a sensor that detects a wet bulb temperature in the cooling tank and converts it into a pressure.

  The control means is configured to store a processing procedure (program) of the vacuum cooling operation and execute it. The vacuum cooling operation includes a cooling step of closing the pressure-reducing valve and operating the pressure-reducing means to depressurize the inside of the cooling tank to cool the object to be cooled, and stopping the operation of the pressure-reducing means after the cooling step. A return pressure step of opening the return pressure valve and performing a return pressure to return the inside of the cooling tank to atmospheric pressure.

  The feature of this embodiment is that, at the initial stage of the cooling step, the first steam supply valve is opened, the pressure reducing means is operated, and an air exhausting step is performed to control the inside of the cooling tank so as not to become a positive pressure. It is in the point of inclusion. In this air evacuation step, from the pressure detection means for detecting the pressure in the cooling tank so that the inside of the cooling tank does not become positive pressure (non-positive pressure), that is, lower than the set pressure below atmospheric pressure. A signal is input to control the steam supplying means and the pressure reducing means. This control is referred to as non-positive pressure air exclusion control. As a method of this non-positive pressure air exclusion control, preferably, the decompression means is controlled at a constant decompression speed, and steaming by the steaming means is controlled (for example, the first steaming valve is turned on and off). Or by changing the valve opening), the method 2 for controlling the pressure reducing means with the first steam supply valve opened, and both the pressure reducing means and the steam supplying means. It is possible to employ the control method 3 or the like. In short, control unique to the vacuum cooling device is performed such that the cooling chamber is not set to a positive pressure (below the set pressure).

  The steam temperature in the air exclusion process varies depending on the set pressure value. When the set pressure is increased, the temperature of the steam is increased. For example, if the set pressure is such that the steam temperature is 80 ° C. or higher, the cooling tank can be sterilized. In this way, by setting the set pressure to a pressure that is equal to or lower than atmospheric pressure and capable of sterilization, not only air exclusion but also sterilization in the cooling tank and sterilization of the decompression line can be performed simultaneously. Can do. In the prior art as disclosed in Japanese Patent Laid-Open No. 11-152, the sterilization of the cooling tank with steam was possible only when the vacuum cooling operation was stopped. However, according to this embodiment, the sterilization is performed for each vacuum cooling operation. It can be performed.

The control of the decompression means in the air exclusion process differs as follows depending on the configuration of the decompression means. In the case where the decompression means is composed of the heat exchanger and the vacuum pump, the heat exchanger and the vacuum pump are operated during the air exclusion process. Due to the operation of the heat exchanger, the steam introduced into the cooling tank and exhausted has a volume of about 1/000 when condensed in the heat exchanger, which assists the vacuum pumping by the vacuum pump. .

  Further, in the case where the decompression means is composed of the steam ejector, the heat exchanger, and the vacuum pump, the operation of the steam ejector is stopped during the air exclusion process, and the heat exchanger and the vacuum pump are Operate. When the steam ejector is operated, the pressure loss of the decompression line increases, but the air can be effectively removed by steaming into the cooling tank without increasing the pressure loss. And since the vacuum evacuation assisting effect is as described above by the operation of the heat exchanger, the time required for air removal can be shortened.

  Embodiment 1 of the vacuum cooling device of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a diagram illustrating a schematic configuration of the first embodiment.

  The first embodiment includes a cooling tank 1 for storing a food material to be cooled, a steam supply means 2 for supplying steam into the cooling tank 1, a decompression means 3 for reducing the pressure in the cooling tank 1, and the The main part includes a return pressure means 4 for returning the pressure in the cooling tank 1, and a control means 5 for controlling the steam supply means 2, the pressure reduction means 3, the pressure return means 4, and the like.

  The steam supply means 2 has a function of supplying steam generated in the boiler 6 into the cooling tank 1, and a first steam supply line 7 for supplying steam from the boiler 6 to the cooling tank 1 and this A first steam supply valve 8 provided in the first steam supply line 7 is provided. The boiler 6 generates steam by heating the soft water generated by the water softener 9. The water softener 9 is supplied with water from a first water supply line 11.

  The decompression unit 3 decompresses the inside of the cooling tank 1 by sucking the gas in the cooling tank 1, and a known steam ejector 13 and a heat exchanger 14 that functions as a condenser in the decompression line 12. , And a check valve 15 for blocking the flow in the direction of the cooling tank 1 and a water-sealed vacuum pump 16.

  A second water supply line 17 and a first drainage line 18 for supplying cooling water are connected to the heat exchanger 14, and the heat is supplied by opening and closing a second water supply valve (not shown) provided in the second water supply line 17. The operation of the exchanger 14 is configured to be controlled. The vacuum pump 16 is connected to a third water supply line 19 and a second drain line 21 for supplying sealed water.

  Steam supply to the steam ejector 13 is performed through a second steam supply line 22 connected to the boiler 6. The second steam supply line 22 is provided with a second steam supply valve 23, and the operation of the steam ejector 13 is controlled by controlling the second steam supply valve 23.

  The return pressure means 4 includes a return pressure line 24, a filter 25 and a return pressure valve 26.

  Here, the first connection position 27 of the decompression line to the cooling tank 1 is the lower part of the cooling tank 1, and the connection position 28 of the first steaming line 7 to the cooling tank 1 is the position of the cooling tank 1. The top.

The control means 5 inputs a signal from a pressure detector 29 that detects the pressure in the cooling tank 1, and the first steam supply valve 8, the second steam supply valve 23, the heat exchanger 14, and the vacuum The pump 16 and the return pressure valve 26 are controlled.

  The control means 5 stores the processing procedure (program) of the vacuum cooling operation in a memory (not shown) and executes this processing procedure. The processing procedure includes a cooling step of closing the pressure-reducing valve 26 and operating the pressure-reducing means 3 to depressurize the inside of the cooling tank 1 to cool an object to be cooled, and operation of the pressure-reducing means 3 after the cooling step. And a pressure-recovering step of opening the pressure-reducing valve 26 and returning the pressure in the cooling tank 1 to atmospheric pressure.

  In the first embodiment, at the initial stage of the cooling step, the first steam supply valve 8 is opened and the pressure reducing means 3 is operated, so that the inside of the cooling tank 1 does not become a positive pressure, specifically, An air evacuation process is performed to control the inside of the cooling tank 1 so as not to exceed the set pressure P1 (for example, atmospheric pressure-50 hpa). In this air evacuation step, a signal from the pressure detector 29 is input to control the steam supply means 2 and the pressure reducing means 3 so that the pressure in the cooling tank 1 is equal to or lower than the set pressure. Perform positive pressure air exclusion control.

  The operation of the embodiment having the above configuration will be described. Referring to FIG. 1, the object to be cooled is accommodated in the cooling tank 1 and the cooling tank 1 is sealed. Then, in the state where the return pressure valve 26 is closed, the pressure reducing means 3 is operated to start the vacuum cooling operation.

  In the initial stage of the vacuum cooling operation, first, the non-positive pressure air exclusion control is performed. That is, when the heat exchanger 14 and the vacuum pump 16 are operated and the pressure in the cooling tank 1 becomes a pressure P2 lower than the set pressure P1, the first steam supply valve 8 is opened and the set pressure is set. When P1 is reached, the first steam supply valve 8 is closed, and the pressure in the cooling tank 1 is controlled between P1 and P2. During this control, the operation of the steam ejector 13 is stopped.

  Then, the steam from the first steam supply line 7 is supplied from the top of the cooling tank 1 to the cooling tank 1, while the gas in the cooling tank 1 is exhausted from the lower part of the cooling tank 1. That is, the air in the cooling tank 1 is discharged while being pushed downward by the steam. In addition, since the steam supplied into the cooling tank 1 is condensed in the heat exchanger 14, the exhaust capacity of the vacuum pump 16 can be increased, and the operation of the steam ejector 13 is stopped. Therefore, pressure loss can be reduced and the exhaust capability of the vacuum pump 16 can be increased. As a result, the time required for air removal in the cooling tank 1 can be shortened to about half compared with the conventional case.

  In this air exhausting step, the pressure in the cooling tank 1 is controlled to be equal to or lower than the set pressure P1, so that it does not become a positive pressure and the cooling tank 1 does not need to be a pressure vessel.

  When this air exclusion process is completed, the first steam supply valve 8 is closed, and the cooling process of the object to be cooled is performed as in the conventional case. In this cooling process, a vacuum cooling process is performed in which the object to be cooled by moisture vapor is cooled from the object to be cooled in the cooling tank 1. In this vacuum cooling operation, the pressure detected by the pressure detector 29 is controlled to have a predetermined pressure pattern. When this vacuum cooling step is completed, the operation of the pressure reducing means 3 is stopped, and the pressure-reducing step of opening the pressure-reducing valve 26 and returning the pressure inside the cooling tank 1 is performed. The control method in the cooling process after the air exclusion process can be variously changed.

Next, a second embodiment of the present invention will be described with reference to FIG. In the second embodiment, the same components as those of the first embodiment are denoted by the same reference numerals and the description thereof is omitted. Hereinafter, configurations different from those of the first embodiment will be described. The difference from the first embodiment is the configuration of the decompression means 3, and in the second embodiment, the steam ejector 13 is omitted. Accordingly, only the steam ejector is not controlled, and the other operations are performed in the same manner as the control in the first embodiment, and the air exhausting process in the initial stage of the vacuum cooling operation is performed in the same manner.

It is a figure explaining schematic structure of Example 1 of this invention. It is a figure explaining schematic structure of Example 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cooling tank 2 Steaming means 3 Pressure reducing means 5 Control means

Claims (3)

A vacuum cooling device comprising a cooling tank, and a pressure reducing means for the cooling tank including a first pressure reducer, a heat exchanger, and a second pressure reducer, and a steam supply means to the cooling tank, comprising a pressure detecting means, and control means, the vacuum cooling operation early, not operate the first pressure reducer, if the input signal from the pressure detecting means, pressure in said cooling tank The second pressure reducer and the heat exchanger are operated so that the pressure does not become positive, and when the pressure P2 is lower than the set pressure P1, the steam supply valve is opened and steam is supplied to the cooling tank. A vacuum cooling device characterized by closing the steam valve and controlling the inside of the cooling tank between P1 and P2 to exclude air . The vacuum cooling apparatus according to claim 1, wherein the first pressure reducer is a steam ejector. The vacuum cooling device according to claim 1, wherein the second pressure reducer is a vacuum pump.

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