JP4253844B2 - Vacuum cooling method and apparatus - Google Patents

Description

  The present invention relates to a vacuum cooling method and a vacuum cooling device for vacuum-cooling an object to be cooled in a cooling chamber.

  A technique for vacuum cooling the vacuum chamber by vacuum suction using a vacuum suction means is widely known and put into practical use in Patent Document 1 and Patent Document 2.

JP-A-11-137227 Japanese Patent Laid-Open No. 11-118287

In such a conventional vacuum cooling apparatus, it is required to perform vacuum cooling in a short time.
In order to realize the cooling for a short time, the capacity of the vacuum suction means may be strengthened, but there is a problem that the apparatus becomes larger and the initial cost and running cost increase.

  The problem to be solved by the present invention is to enable vacuum cooling in a short time without enhancing the capacity of the vacuum suction means.

  The present invention has been made to solve the above-mentioned problems, and the invention according to claim 1 is a vacuum cooling method in which a cooling chamber is vacuum-sucked by a vacuum suction means to cool an object to be cooled in a cooling chamber. A preliminary step of setting the negative pressure chamber to a low pressure and a cooling step of vacuum suction of the cooling chamber by the vacuum suction means and the negative pressure chamber are performed after the preliminary step.

  According to a second aspect of the present invention, in the first aspect, the cooling step includes a first cooling step in which the cooling chamber communicates with the vacuum suction means and the negative pressure storage chamber, and the accumulation of the negative pressure after the first cooling step. And a second cooling step of blocking the pressure chamber from the cooling chamber and the vacuum suction means.

  According to a third aspect of the present invention, there is provided a cooling chamber that accommodates an object to be cooled, a vacuum suction unit that vacuum-sucks the cooling chamber, and a control unit that operates the vacuum suction unit to vacuum-cool the object to be cooled. The vacuum cooling device comprises a storage negative pressure chamber that is connected to the cooling chamber and the vacuum suction means so as to be freely cut off, and the control means communicates the negative pressure chamber with the vacuum suction means. And a cooling step in which the cooling chamber is vacuum-sucked by the vacuum suction means and the negative pressure storage chamber after the preliminary step.

  According to a fourth aspect of the present invention, in the third aspect, the cooling step includes a first cooling step in which the cooling chamber is connected to the vacuum suction means and the negative pressure storage chamber, and the negative accumulation after the first cooling step. And a second cooling step of blocking the pressure chamber from the cooling chamber and the vacuum suction means.

  Further, the invention according to claim 4 is the invention as claimed in claim 4, further comprising a heat exchanger for condensation between the cooling chamber and the vacuum suction means, wherein the negative pressure chamber is in the first cooling step. It is characterized in that it communicates with the cooling chamber via a heat exchanger.

  According to the present invention, the negative pressure chamber is set to a low pressure before entering the vacuum cooling step, and the cooling chamber is vacuum-cooled by the negative pressure chamber and the vacuum suction means. The cooling time can be shortened compared to vacuum suction.

  Next, an embodiment of the present invention will be described. The present invention is applied to a vacuum cooling method and apparatus for vacuum cooling, and can be applied to various types and types as long as the object to be cooled is vacuum-cooled by vacuum suction of a cooling chamber by a vacuum suction means. .

  A vacuum cooling device according to an embodiment of the present invention includes a cooling chamber that accommodates an object to be cooled, a vacuum suction unit that vacuum-sucks the cooling chamber, and a control that operates the vacuum suction unit to vacuum-cool the object to be cooled. A vacuum accumulator that is connected to the cooling chamber and the vacuum suction means so as to be cut off, and the control means connects the negative pressure chamber to the vacuum suction means. A preliminary step of communicating and lowering the pressure and a cooling step of vacuum suction of the cooling chamber by the vacuum suction means and the negative pressure storage chamber are performed after the preliminary step.

  In this embodiment, before entering the cooling step, the negative pressure chamber is communicated with the vacuum suction means so that the negative pressure chamber is kept at a low pressure. Thereafter, the cooling chamber communicates with the vacuum suction means and the negative pressure storage chamber, and the cooling chamber is vacuum sucked by both. Therefore, the cooling chamber can be evacuated in a short time compared with the case where the vacuum suction is performed by the vacuum suction means alone, and as a result, the cooling time can be shortened.

  Next, each component of this embodiment will be described. The object to be cooled is preferably a warm food. The cooling chamber may be of any type, type and size as long as it forms a space for accommodating the object to be cooled and can take in and out the object to be cooled. Moreover, this cooling chamber can be called a division, a container, etc.

  The vacuum suction means is preferably a combination of an ejector, a heat exchanger, and a vacuum pump as in Patent Document 2, but is not limited to this. For example, as in Patent Document 1, It can be a combination of an exchanger and a vacuum pump. As the ejector, a steam ejector, a water ejector, or the like can be used. The vacuum suction means is connected to the cooling chamber by a vacuum suction line, and a first valve for connecting and blocking the cooling chamber and the vacuum suction means is provided in the middle of the vacuum suction line.

  The negative pressure chamber has a function of holding the low pressure after a predetermined low pressure and vacuuming the cooling chamber in cooperation with the vacuum suction means. This negative pressure storage chamber can also be referred to as a buffer tank, a low pressure chamber, a pressure storage chamber, or a pressure adjustment chamber.

  The storage negative pressure chamber is communicated with the vacuum suction means, and the interior thereof is vacuum-sucked to be in a low pressure state (for example, about 10 hpa), and is in a low pressure state, and then communicated with the cooling chamber. And a state in which the gas in the cooling chamber is sucked is selectively connected. Preferably, the storage negative pressure chamber is provided so as to be able to communicate with and shut off the vacuum suction means and the cooling chamber. “Communication / interruption is possible” means that the negative pressure chamber can be selected to be in communication with the vacuum suction means or in a cutoff state, and can be selected in communication with the cooling chamber. The connection form of the negative pressure chamber is preferably a first form connected by a branch line having a second valve that branches from the vacuum suction line and controls contact and separation. However, the negative pressure chamber may be a second configuration provided on the downstream side of the first valve in the vacuum suction line.

  According to the first aspect, when the vacuum suction capacity of the negative pressure chamber decreases, the negative pressure chamber can be separated from the vacuum suction line, and the vacuum suction means vacuums the negative pressure chamber. Since only the cooling chamber can be vacuumed without suction, the cooling time can be shortened.

  Further, the control means includes a preliminary step of setting the negative pressure chamber in a low pressure by communicating with the vacuum suction means according to a pre-stored control procedure, and the vacuum suction means and the negative pressure chamber after the preliminary step. A cooling step of vacuum-sucking the cooling chamber. Preferably, the cooling step includes a first cooling step in which the cooling chamber communicates with the vacuum suction means and the negative pressure storage chamber, and the negative pressure chamber is connected to the cooling chamber and the vacuum suction after the first cooling step. And a second cooling step that shuts off the means.

  The timing of switching from the first cooling step to the second cooling step is preferably after the time when the pressure in the cooling chamber and the pressure in the negative pressure chamber are substantially balanced in the first cooling step. This timing is empirically obtained by experiment, and can be set after a set time from the start of the first cooling step, or a pressure sensor for detecting the pressure in the cooling chamber is provided so that the detected pressure becomes a set value. It can also be a point in time. By adjusting this timing according to the difference in cooling load, cooling can be performed in an optimum (shortest) state.

  The present invention is not limited to the above-described embodiment. In the above-described embodiment, a heat exchanger for condensation is provided between the cooling chamber and the vacuum suction means. The storage negative pressure chamber can be configured to communicate with the cooling chamber via the heat exchanger.

  According to this embodiment, since the amount of gas sucked by the negative pressure chamber can be increased, the cooling time can be shortened as compared with a case where the heat exchanger is not provided. By providing this heat exchanger in the vacuum suction line, the vacuum suction capability of the vacuum suction means can also be improved.

  Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory view showing a schematic configuration of an embodiment of the vacuum cooling apparatus of the present invention, and FIG. 2 is a view for explaining a pressure change in the cooling chamber according to the embodiment.

  The vacuum cooling device 1 of the embodiment includes a cooling chamber 2, a vacuum suction unit 4 connected to the cooling chamber 1 through a vacuum suction line 3, a buffer tank 5 as a negative pressure storage chamber, and the vacuum cooling. A controller 6 that controls the unit 4 and the like is provided as a main part. The vacuum suction line 3 includes a first electromagnetic valve 7 for selecting communication and blocking between the cooling chamber 2 and the vacuum suction unit 4, and a first heat exchanger 8 for condensation.

  The cooling chamber 2 includes a door (not shown) through which an object to be cooled is taken in and out, and a return pressure line 11 having a filter 9 and a return pressure valve 10.

  The vacuum suction unit 4 has a configuration in which a steam ejector 12, a second heat exchanger 13 for condensation, and a water seal vacuum pump 14 are connected in series in this order.

  The buffer tank 5 is connected to the vacuum suction line 3 on the downstream side of the first heat exchanger 8 via a branch line 15 branched from the vacuum suction line 3. The branch line 15 is provided with a second electromagnetic valve 16 for communicating and blocking the buffer tank 5 with respect to the vacuum suction line 3.

  The controller 6 operates the vacuum suction unit 4, the first heat exchanger 8, the first electromagnetic valve 7, the second electromagnetic valve 16, the return pressure valve 10, and the like according to a previously stored control procedure. To control. Control of the operation of the first heat exchanger 8 is performed by supplying cooling water in the same manner as the second heat exchanger 13, and is deactivated by stopping supply of cooling water.

  In this control procedure, the control characteristic of the present invention, that is, a preliminary step of connecting the buffer tank 5 to the vacuum suction unit 4 to make the pressure low, and the vacuum suction unit 4 and the buffer tank 5 after the preliminary step are performed. And a cooling step of performing vacuum suction of the cooling chamber 2. In this cooling step, the cooling chamber 2 communicates with the vacuum suction unit 4 and the buffer tank 5, and after the first cooling step, the buffer tank 5 is placed in the cooling chamber 2 and the vacuum suction. A second cooling step for shutting off the unit 4.

  The operation of this embodiment according to this control procedure will be described with reference to FIG. First, when the vacuum cooling process is not performed, that is, when the vacuum suction unit 4 is not operated (before the vacuum cooling process or after the vacuum cooling process), the first electromagnetic valve 7 is closed and the first heat exchange is performed. The vacuum suction unit 4 is operated with the device 8 in the non-operating state and the second electromagnetic valve 16 in the open state. Thereby, the pressure in the buffer tank 5 gradually decreases. When the set pressure (for example, 17 hpa) is reached, the operation of the vacuum suction unit 4 is stopped and the second electromagnetic valve 16 is closed to shut off the vacuum suction line 3 and consequently the vacuum suction unit 4. State. Thus, a preliminary process for accumulating and holding the buffer tank 5 at a low pressure is performed.

  When the above preliminary process is completed, the vacuum cooling process is started. That is, in the state where the object to be cooled is accommodated in the cooling chamber 2, the first electromagnetic valve 7 is opened, the first heat exchanger 8 is activated, the second electromagnetic valve 16 is opened, and the vacuum The first cooling step is performed by operating the suction unit 4. Thereby, the cooling chamber 2 is vacuum-sucked by the vacuum suction unit 4 and the buffer tank 5 (both). The vacuum suction by the buffer tank 5 occurs when the gas in the cooling chamber 2 moves into the buffer tank 5. A change in pressure in the cooling chamber 2 due to the suction of both is shown by a curve A in FIG. In the conventional example in which the buffer tank 5 is not used, the pressure decreases as shown by the curve E. However, in this embodiment, since the pressure can be reduced as shown by the curve A, the cooling time can be shortened.

  In this first cooling step, the first heat exchanger 8 is provided and, as an operating state, by condensing the vapor sucked from the cooling chamber 2, the suction capacity of the vacuum suction unit 4 increases, The amount of gas stored in the buffer tank 5 can be increased, and the suction capacity of the buffer tank 5 can be increased. As a result, the cooling time can be shortened as compared with the case where the first heat exchanger 8 is not used.

  On the other hand, the pressure in the buffer tank 5 changes as shown by a curve G. At time t1, the pressure is substantially balanced with the pressure in the cooling chamber 2, and thereafter falls with the same change as the pressure. At time t2, the second electromagnetic valve 16 is closed, the buffer tank 5 is disconnected from the vacuum suction line 3, and the second cooling step is executed.

  By this second cooling step, the pressure in the cooling chamber 2 is lowered as shown by a curve B in FIG. 2, and the pressure in the buffer tank 5 is kept almost constant as shown by a straight line D. When this second cooling step is not performed, the pressure in the cooling chamber 2 changes as shown by curve F. However, by performing the second cooling step, the pressure can be reduced as shown by curve B, and cooling Time can be shortened.

  According to this embodiment, conventionally, the pressure in the cooling chamber 2 could be lowered only as shown by the curve E in FIG. 2, whereas it is lowered as shown by the curves A and B. The time required for vacuum cooling can be shortened. Moreover, since it is not necessary to make the cooling capacity of the vacuum suction unit 4 large, an increase in the size and cost of the apparatus can be suppressed. 2, time t3 indicates that steam is generated from the object to be cooled.

  The present invention is not limited to the above-described embodiment. In FIG. 1, a communication line (not shown) for directly communicating the buffer tank 5 with the cooling chamber 2 is provided separately from the vacuum suction line 3. The buffer tank 5 can be configured to perform the suction action. 1, the vacuum suction unit 4 and another vacuum suction means (not shown) may be connected to the buffer tank 5 so that the buffer tank 5 is vacuum-sucked. At this time, the buffer tank 5 is provided with return pressure means (not shown) similar to the filter 9, the return pressure valve 11, and the return pressure line 11 so that the pressure in the buffer tank 5 does not drop below a set value. It is preferable to perform PID control on the other vacuum suction means and the return pressure means. By performing this control, the object to be cooled can be controlled to a predetermined target temperature by continuously communicating the buffer tank 5 without disconnecting from the vacuum suction line 3 while being cooled in a short time. it can.

It is explanatory drawing which shows schematic structure of one Example of the vacuum cooling device of this invention. It is a pressure characteristic figure explaining operation of the example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vacuum cooling device 2 Cooling chamber 3 Vacuum suction line 4 Vacuum suction unit (vacuum suction means)
5 Buffer tank (accumulation negative pressure chamber)

Claims (5)

  In the vacuum cooling method in which the cooling chamber 2 is vacuum-sucked by the vacuum suction means 4 to vacuum-cool the object to be cooled in the cooling chamber 2, a preliminary process for setting the negative pressure chamber 5 to a low pressure, and the vacuum after the preliminary process A vacuum cooling method comprising: performing a cooling step of vacuum suction of the cooling chamber 2 by the suction means 4 and the negative pressure storage chamber 5.   A cooling step includes a first cooling step in which the cooling chamber 2 communicates with the vacuum suction means 4 and the negative pressure chamber 5, and after the first cooling step, the negative pressure chamber 5 is changed into the cooling chamber 2 and the vacuum. The vacuum cooling method according to claim 2, further comprising a second cooling step of blocking the suction means 4.   Vacuum cooling provided with a cooling chamber 2 for accommodating an object to be cooled, a vacuum suction means 4 for vacuum-sucking the inside of the cooling chamber 2, and a control means 6 for operating the vacuum suction means 4 to vacuum-cool the object to be cooled. The apparatus includes a storage negative pressure chamber 5 connected to the cooling chamber 2 and the vacuum suction means 5 so as to be freely cut off and connected to the vacuum suction means 5, and the control means 6 includes the vacuum suction means 5 in the vacuum suction means 4. A vacuum cooling apparatus characterized by performing a preliminary step of communicating with a low pressure and a cooling step of vacuum suction of the cooling chamber 2 by the vacuum suction means 4 and the negative pressure storage chamber 5 after the preliminary step.   The cooling step includes a first cooling step in which the cooling chamber 2 is connected to the vacuum suction means 4 and the negative pressure storage chamber 5, and after the first cooling step, the negative pressure chamber 5 is connected to the cooling chamber 2 and the vacuum. The vacuum cooling device according to claim 3, further comprising a second cooling step for blocking the suction means 4. A heat exchanger 8 for condensation is provided between the cooling chamber 2 and the vacuum suction means 4, and the negative pressure chamber 5 communicates with the cooling chamber 2 via the heat exchanger 8 during the first cooling step. The vacuum cooling device according to claim 4, wherein:

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