JP2016090200A - Vacuum cooling apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform a positive discharging of residual liquid and keep a clean state without leaving impurities even if liquid containing impurities enters into a vacuum pump of a vacuum cooling apparatus.SOLUTION: A vacuum cooling apparatus comprises a cooling tank 2 storing items to be cooled, a vacuum pump 1 for sucking gas in the cooling tank, a surrounding air feeding pipe 3 connected to a vacuum pipe 9 and having a vacuum pump drying valve 4 in the midway part of it, a vacuum valve 6 of the vacuum pipe for shutting off at the cooling tank and the vacuum pump, and water supply means for supplying cleaning water to the vacuum pump rather than the vacuum valve. In the case that vacuum pump drying control is carried out under a state that the vacuum valve is closed and the vacuum pump is being operated, the vacuum pump drying control is performed in an order of cleaning step of supplying cleaning water by the water supply means, a residual liquid pushing out step of repeating opening or closing of the vacuum pump drying valve by several times, and a drying step of holding a state in which the vacuum pump drying valve is opened.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vacuum cooling device that cools an object to be cooled in a cooling tank by reducing the pressure in the cooling tank using a dry vacuum pump.

  There is a vacuum cooling device that accommodates an object to be cooled such as food cooked in a cooling tank and cools the object to be cooled by decompressing the inside of the cooling tank. When the inside of the cooling tank containing the object to be cooled is decompressed and the saturation temperature in the cooling tank falls below the temperature of the object to be cooled, the water in the object to be cooled evaporates. At that time, since the heat of vaporization is taken from the object to be cooled, the temperature of the object to be cooled decreases. In vacuum cooling, since cooling is performed from the inside of the object to be cooled, cooling can be performed uniformly in a short time.

As the vacuum generator, an ejector device and a vacuum pump are used, and if it is a dry type vacuum pump, the supply of steam and the circulation of water are not necessary, so the structure of the device should be simple. it can.

In the vacuum generator of the vacuum cooling device, the vapor evaporated from the object to be cooled is also sucked. In this case, since the volume of the moisture that has become a gas is significantly larger than that of the liquid, the amount of gas that must be discharged by the vacuum generator increases, which takes time to depressurize the cooling tank. It will be. Therefore, in the vacuum cooling device, a heat exchanger is provided in the middle of the vacuum pipe that sends the gas in the cooling tank to the vacuum generator, and the gas component sucked by the vacuum generator is cooled in the middle of the vacuum pipe. When the gas is cooled by the heat exchanger, the vapor condenses into a liquid, so that moisture can be separated from the suction gas. By doing in this way, since the volume of the gas discharged | emitted by a vacuum generator becomes small, the efficiency of pressure reduction can be improved.

When the vacuum generator is a dry-type vacuum pump, the separated water is stored in the drain tank as drain and is not sent to the vacuum pump. However, part of the water is sent to the vacuum pump, and the water liquefied in the vacuum pump may remain. If this residual liquid remains in the vacuum pump, it is unsanitary, and therefore, in the invention described in Japanese Patent Application Laid-Open No. 2014-66384, the drying operation of the vacuum pump is performed every time the cooling operation is performed.

However, the residual liquid generated here is a result of evaporation of moisture in the object to be cooled. When the residual liquid containing impurities reaches the vacuum pump, the impurities are contained in the vacuum pump only by drying the vacuum pump. In other cases, the inside of the vacuum pump cannot be kept hygienic. Further, in the dry type vacuum pump, when the vacuum pump is filled with the cleaning water by supplying the cleaning water into the vacuum pump, the vacuum pump may be fixed when the vacuum pump is operated in that state.

JP 2014-66384 A

  The problem to be solved by the present invention is a vacuum cooling device that cools an object to be cooled by depressurizing the inside of a cooling tank by a dry-type vacuum pump and evaporating water from the object to be cooled. It is an object of the present invention to provide a sanitary vacuum cooling device capable of reliably discharging residual liquid without leaving impurities even when residual liquid containing impurities enters the pump.

The invention according to claim 1 is connected to the cooling tank for accommodating the object to be cooled, the cooling tank and the vacuum pipe connected to the cooling tank, and connected to the vacuum pipe. A vacuum pump with a vacuum pump drying valve and an outside air intake pipe at the other end, a vacuum that shuts off the cooling tank side and the vacuum pump side of the vacuum pipe closer to the cooling tank side than the outside air introduction pipe connection part of the vacuum pipe Water supply means for supplying cleaning water to the vacuum pump side of the valve and the vacuum valve is provided, and the vacuum pump is closed and the vacuum pump is operated while the vacuum pump is operated. In addition, in the vacuum pump drying control, from the cleaning step of supplying cleaning water by the water supply means, the residual liquid extrusion step of repeatedly opening and closing the vacuum pump drying valve, the vacuum pump drying valve opening time of the residual liquid extrusion step Long, and carrying out drying step of holding the opened vacuum pump drying valve, in this order.

The invention according to claim 2 is that in the vacuum cooling device, the water supply in the cleaning step is performed by alternately repeating a short time supply and a supply stop longer than the supply time a plurality of times. Features. According to a third aspect of the present invention, in the vacuum cooling device, when a cooling operation request signal for depressurizing the inside of the cooling tank is output during the vacuum pump drying control, until the end of the residual liquid extrusion step, The vacuum pump drying control is prioritized, and the cooling operation is performed after the residual liquid extrusion process is completed.

When performing the vacuum pump drying control, if the cleaning process of supplying cleaning water into the vacuum pump is performed before the residual liquid extrusion process, the cleaning water is vaporized in the vacuum pipe that is decompressed, and the generated steam is The residual water in the inside is pushed out, and the steam flushes out impurities in the vacuum pump.
Also, when supplying cleaning water in the cleaning process, if the supply amount of cleaning water becomes excessive and the inside of the vacuum pump is filled with cleaning water, the vacuum pump cannot operate normally. Water is no longer discharged. When the cleaning water is supplied by repeating a short time supply and a supply stop that is longer than the supply time alternately several times, the next cleaning water is supplied after discharging the supplied cleaning water, It is possible to prevent cleaning water from accumulating in the vacuum pump. Therefore, the vacuum pump can be cleaned without hindering the operation of the vacuum pump.

By carrying out the present invention, it becomes possible to discharge the residual liquid more reliably and maintain a clean state without leaving impurities in the vacuum pump.

1 is a schematic configuration diagram of a vacuum cooling device according to an embodiment of the present invention Time chart in one embodiment of the present invention Time chart in another embodiment of the present invention The image figure of the residual liquid shape in the vacuum pump in the Example of this invention

  An embodiment of the present invention will be described with reference to the drawings. The vacuum cooling device includes a cooling tank 2 that accommodates an object to be cooled, a vacuum pump 1 that sucks air in the cooling tank 2, a vacuum pipe 9 that connects the cooling tank 2 and the vacuum pump 1, and the like. The cooling tank 2 is a substantially rectangular parallelepiped container having a door on its side surface, and allows an object to be cooled to be accommodated and sealed. An operation control device 7 for controlling the operation of the vacuum cooling device is provided. The operation control device 7 is connected to the vacuum pump 1, and the operation control device 7 operates the vacuum pump 1 and the like.

  The vacuum cooling device evaporates moisture in the object to be cooled by reducing the pressure in the cooling tank and cools the object to be cooled by heat of vaporization, so the gas sucked from the cooling tank contains steam. It is out. Since the volume of the liquid is greatly increased when the liquid becomes a vapor, if the liquid is left as it is, a large volume of the vapor is sent to the vacuum pump 1, and the exhaust efficiency of the vacuum pump 1 is deteriorated. In addition, when liquefied moisture enters the vacuum pump, the vacuum pump performance may be reduced or the vacuum pump may be damaged. Therefore, the moisture is separated from the suction air in the middle of the vacuum pipe 9. By providing a heat exchanger 11 in the middle of the vacuum pipe 9 and supplying cooling water to the heat exchanger 11, by exchanging heat between the gas sucked from the cooling tank 2 and the cooling water, Cool the suction gas. When the suction gas is cooled by the heat exchanger, the vapor contained in the gas is condensed, so that the volume of the suction gas can be significantly reduced. The condensed water separated by the heat exchanger is stored in a drain tank (not shown) installed below the heat exchanger, and is discharged after the cooling operation is completed.

  A vacuum valve 6 is provided downstream of the heat exchanger 11 in the vacuum pipe 9, and the outside air introduction pipe 3 is connected to the downstream side of the vacuum valve 6. The outside air introduction pipe 3 is provided with a vacuum pump drying valve 4 for sending outside air to the vacuum pump 1 during the drying operation of the vacuum pump. The vacuum pump drying valve 4 is opened when performing vacuum pump drying control, and is normally closed. The vacuum valve 6 and the vacuum pump drying valve 4 are also connected to the operation control device 7, and the operation of the vacuum valve 6 and the vacuum pump drying valve 4 is controlled by the operation control device 7.

A water supply means 10 and a vacuum pipe pressure detection means 5 are provided downstream of the vacuum valve installation portion of the vacuum pipe 9. The water supply means 10 supplies cleaning water at the time of vacuum pump drying control, and supplies cleaning water at the time of the first cleaning process at the time of vacuum pump drying control. The pressure is detected by the tank pressure detection means 8 provided in the cooling tank 2 and the vacuum pipe pressure detection means 5 provided on the downstream side of the vacuum valve 6. The detected pressure value is output to the operation control device 7, and the operation control device 7 also controls the operation of the water supply means 10.

  The cooling operation is performed by accommodating an object to be cooled in the cooling tank 2, sealing the cooling tank 2, and operating the vacuum pump 1 with the vacuum valve 6 open. When the cooling tank 2 is sealed and the vacuum pump 1 is operated, the gas in the cooling tank is discharged, and the pressure in the cooling tank decreases. If the saturation temperature in the cooling tank is made lower than the temperature of the object to be cooled by lowering the pressure in the cooling tank 2, the evaporation of water occurs from the object to be cooled, and the heat of vaporization from the surroundings when the water evaporates. Take away. Therefore, the temperature of the object to be cooled decreases as the tank pressure decreases.

  The vapor contained in the gas sucked by the vacuum pump is condensed by cooling with the heat exchanger 11 installed in the middle of the vacuum pipe 9 to reduce the volume, and the condensed water is sucked as a drain. Separated from air. However, since it is impossible to separate all the water, some water enters the vacuum pump 1 through the vacuum pipe 9.

  Therefore, the vacuum pump drying control is performed every time the cooling operation is completed, and the next cooling operation is performed in a state where the residual liquid in the vacuum pump is discharged. In the vacuum pump drying control, a cleaning process, a residual liquid extrusion process, a drying process, and a confirmation process are sequentially performed. The vacuum pump drying control process will be described with reference to FIGS. FIG. 2 shows an example in which the cooling operation request signal is not output during the execution of the vacuum pump drying control, and FIG. 3 is an example in the case where the cooling operation request signal is output during the execution of the vacuum pump drying control. In the embodiment of FIG. 2, the vacuum pump drying control process can be performed to the end, and in the embodiment of FIG. 3, the vacuum pump drying control process is terminated halfway.

First, the vacuum pump drying control process will be described with reference to FIG. In FIG. 2, the process starts from the previous process (process A) of the vacuum pump drying control, and the vacuum pump drying control starts when the closing limit of the vacuum valve 6 is detected. The first process of vacuum pump drying control is a cleaning process (process B). At this time, the vacuum pump 1 is activated and the vacuum valve is closed. In the cleaning process, since the vacuum valve 6 and the vacuum pump drying valve 4 are closed, the gas sucked by the operation of the vacuum pump 1 becomes a vacuum pipe portion downstream of the vacuum valve 6. Since the amount of gas in this portion is small, the degree of vacuum immediately rises in the vacuum pump 1 portion. In the cleaning process, cleaning water is supplied through the water supply means 10 with the vacuum pump drying valve 4 closed.

In a state where the vacuum pump drying valve 4 is closed and the amount of suction gas flowing through the vacuum pump 1 portion is small, the flow rate of the suction gas flowing through the vacuum pump decreases. For this reason, when the cleaning water is supplied in this state, the cleaning water is vaporized, and the evaporated cleaning water is mixed with the residual liquid in the vacuum pump 1 to push out the residual liquid while diluting the residual liquid. The supply of cleaning water at this time is performed by repeatedly opening and closing the water supply electromagnetic valve provided in the water supply means several times, and the time for opening the water supply electromagnetic valve is very short, and the amount of water supplied at one time is small. Keep it. The time for closing the water supply electromagnetic valve is longer than the time for opening, and during that time, the cleaning water is discharged from the vacuum pump. When the water supply solenoid valve is closed, the water supply is stopped. If the operation of the vacuum pump 1 is continued in this state, the liquid in the vacuum pump is discharged from the vacuum pump. Therefore, even if the amount of liquid in the vacuum pump temporarily increases due to the supply of cleaning water, it decreases during the subsequent stoppage of water supply. The water supply time and the water supply stop time are set to 0.5 seconds and 5 seconds, respectively, and the water supply stop time is set to be sufficiently longer than the water supply time so that the water is supplied while discharging the cleaning water.

The next step is a residual liquid extrusion step (step C). At this time, the vacuum pump 1 continues to operate, the vacuum valve 6 remains closed, and the water supply means 10 stops supplying cleaning water. . In this state, the vacuum pump drying valve 4 is opened and closed. The vacuum pump drying valve 4 repeats opening for 2 seconds and closing for 1 second five times. Since the inside of the vacuum pump 1 is depressurized at this time, when the vacuum pump drying valve 4 is opened, the outside air vigorously enters the vacuum pump 1 and the amount of gas flowing in the vacuum pump 1 increases instantaneously. At that time, the effect of pushing the residual liquid by the gas flow in the vacuum pump 1 is enhanced. Since the vacuum pump drying valve 4 repeats opening for 2 seconds and closing for 1 second, the gas flow rate in the vacuum pump 1 changes intermittently.

  If the vacuum pump drying valve 4 is kept open, the outside air taken in the vacuum pump 1 flows, so that the gas flow is fast but the flow rate is constant. In this case, an action of pushing out the residual liquid by the gas flow occurs in the vacuum pump, but when the flow rate is constant, the action of discharging the residual liquid is not so great. Here, when the vacuum pump drying valve 4 is closed, the introduction of outside air is interrupted, so that the flow rate of the gas flowing through the vacuum pump once decreases. Thereafter, when the vacuum pump drying valve 4 is opened and the introduction of the outside air is resumed, the amount of gas flowing into the vacuum pump 1 increases rapidly and the action of pushing the residual liquid increases. By repeating this, the effect of discharging the residual liquid in the vacuum pump is enhanced.

  The description of FIG. 4 is an image of residual liquid and air flow in the vacuum pump, and is when the amount of air flowing in the vacuum pump is increased or decreased by opening and closing the vacuum pump drying valve. In FIG. 4, the vacuum pump drying valve is opened so that a large amount of air is flowing, the vacuum pump drying valve 4 is closed and the air flow in the vacuum pump is reduced, and the vacuum pump drying is performed. A state in which the air flow is rapidly increased by opening the valve 4 and a state in which the air flow pushes the residual liquid are shown. When the vacuum pump drying valve 4 is opened and closed, the residual liquid is greatly pushed out each time, so that the time for discharging the residual liquid from the vacuum pump can be shortened.

When the residual liquid extrusion process (process C) is completed, a drying process (process D) is performed. The drying process is a process of drying the inside of the vacuum pump 1 after the residual liquid is extruded in the residual liquid extrusion process. Since the rough discharge of the residual liquid can be performed by the residual liquid extrusion process, the surface inside the vacuum pump 1 can be obtained by keeping the vacuum pump drying valve 4 open and letting gas flow through the vacuum pump 1 at a high flow rate. Dry. The drying process takes longer than the residual liquid extrusion process.

When the drying process is completed, the vacuum pump drying valve 4 is closed and the process proceeds to a confirmation process (process E). The confirmation process is to confirm whether or not the capacity of the vacuum pump 1 is available. The vacuum pump 1 is operated while the vacuum valve 6 and the vacuum pump drying valve 4 are closed, and it is confirmed that the pressure is decreasing, so that abnormalities such as accumulation of residual liquid occur in the vacuum pump 1. Confirm that it is not. Up to the confirmation step is the vacuum pump drying control, and during the vacuum pump drying control, the cooling operation request signal for depressurizing the inside of the cooling tank is not output, so the vacuum pump drying control is performed to the end.

The embodiment of FIG. 3 is an example in which a cooling operation request signal is output during the vacuum pump drying control. In this example, the cooling operation request signal is output in the middle of the residual liquid extrusion step (step C). The process until the cooling operation request signal is output is the same as in the case of FIG. If a cooling operation request signal is output before the residual liquid extrusion process is completed, vacuum pump drying control is performed until the residual liquid extrusion process is completed, and the vacuum pump drying control is interrupted at the end of the residual liquid extrusion process. And it transfers to cooling operation (process F). This is because the impurities that have entered the vacuum pump may remain before the residual liquid push-out process is completed, that is, in a state where the residual liquid in the vacuum pump 1 is accumulated, and the cooling operation is performed in this state. This is because the vacuum pump is dried with impurities remaining, and the vacuum pump may become unsanitary. Therefore, when the residual liquid push-out process has not been completed, the vacuum pump can be kept hygienic by giving priority to discharging the residual liquid from the vacuum pump.

Further, when the cooling operation request signal is output after the residual liquid pushing-out process is completed, the vacuum pump drying control is immediately interrupted and the cooling operation is started. If the process has progressed to the end of the residual liquid extrusion process, the discharge of impurities that have entered the vacuum pump is also completed, so that the sanitary condition in the vacuum pump does not deteriorate.

In the cooling operation, the vacuum pump 1 is opened while the vacuum pump 1 continues to operate, and the vacuum pump drying valve 4 is kept closed. When the vacuum pump 6 is opened and the vacuum pump 1 is operated, the vacuum pump 1 sucks the gas in the cooling tank 2 and can perform a cooling operation. When the cooling operation is performed, gas flows in the vacuum pump, and therefore, the drying in the vacuum pump can be performed.

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 pump
2 Cooling tank
3 Outside air introduction piping
4 Vacuum pump drying valve
5 Vacuum piping pressure detection means
6 Vacuum valve
7 Operation control device
8 Tank pressure detection means
9 Vacuum piping 10 Water supply means 11 Heat exchanger

Claims (3)

  A cooling tank that contains the object to be cooled, a vacuum pump that is connected to the cooling tank by a vacuum pipe and sucks the gas in the cooling tank, is connected to the vacuum pipe, has a vacuum pump drying valve in the middle, and the other end Includes an outside air introduction pipe having an outside air intake port, a vacuum valve that shuts off the cooling tank side and the vacuum pump side of the vacuum pipe closer to the cooling tank side than the connection part of the outside air introduction pipe of the vacuum pipe, and a vacuum pump than the vacuum valve. Water supply means for supplying cleaning water is provided on the side, the vacuum valve is closed, the vacuum pump is operated, and the vacuum pump drying control is performed. Vacuum pump drying for a longer time than the vacuum pump drying valve opening time of the cleaning process for supplying cleaning water by the supply means, the residual liquid extrusion process for repeatedly opening and closing the vacuum pump drying valve, and the residual liquid extrusion process Drying step of holding an open state, the vacuum cooling device and performs in sequence. 2. The vacuum cooling apparatus according to claim 1, wherein the water supply in the cleaning step is performed by alternately repeating a short-time supply and a supply stop longer than the supply time a plurality of times. apparatus. The vacuum cooling apparatus according to claim 1 or 2, wherein when a cooling operation request signal for depressurizing the inside of the cooling tank is output during the vacuum pump drying control, the vacuum pump drying is performed until the end of the residual liquid extrusion process. A vacuum cooling apparatus characterized by giving priority to control and performing a cooling operation after completion of the residual liquid extrusion process.

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