KR102544881B1 - vacuum chiller - Google Patents

Abstract

The internal pressure of the cooling tank 2 is reduced to the first target pressure value by the pressure reducing means 3, and after reaching the first target pressure value, the internal pressure of the cooling tank 2 is reduced to the first target pressure value for the first time. A first cooling control unit 501 that maintains the pressure at a target pressure value, and a product temperature determination unit 502 that determines whether or not the temperature detected by the product temperature sensor 21 has reached the target temperature after cooling by the first cooling control unit 501 ), and when it is determined that the target temperature has not been reached by the product temperature determination unit 502, a temperature obtained by subtracting the first temperature from the set temperature is newly set, and the set pressure value newly set by the pressure reducing means 3 and a second cooling maintenance controller 5033 for maintaining the internal pressure of the cooling tank 2 at the set pressure value for a second time after the pressure inside the cooling tank 2 reaches the set pressure value. A vacuum cooling device (1) having a second cooling control section 503 that does.

Description

vacuum chiller

The present invention relates to a vacuum cooling device for cooling foodstuffs, food, and the like. This application claims priority based on Japanese Patent Application No. 2016-044244 for which it applied to Japan on March 8, 2016, and uses the content here.

As disclosed in Patent Literature 1, there is known a vacuum cooling device in which the inside of a processing tank containing an object to be cooled is depressurized to vaporize moisture in the object to be cooled, and the object to be cooled is cooled by the heat of vaporization. In such a vacuum cooling apparatus, a product temperature sensor is attached to the object to be cooled, and vacuum cooling is performed to a target temperature range based on the temperature of the object to be cooled by the product temperature sensor.

Patent Literature 2 discloses a vacuum cooling device and a vacuum cooling method capable of stably cooling by reducing the temperature difference after cooling even when other food materials are simultaneously cooled. Specifically, by providing a supercooling prevention device for preventing supercooling of food material, the pressure in the treatment tank is reduced to a preset set pressure during vacuum cooling, and after the pressure in the treatment tank reaches the set pressure, the inside of the treatment tank is reduced. Maintain the set pressure. By doing so, the planting material that tends to be cooled is cooled to a temperature close to the saturation temperature corresponding to the set pressure, and does not fall below the saturation temperature. On the other hand, the plant material that is difficult to cool is cooled over time so as to approach the saturation temperature in the treatment tank. In this way, by controlling the maximum degree of vacuum in the treatment tank so as not to lower the pressure in the treatment tank to the pressure that can be reached by the pressure reducing means, excessive cooling of the object to be cooled and insufficient cooling of the object to be cooled are eliminated, It means to stably cool the food.

Japanese Unexamined Patent Publication No. 9-296975 Japanese Unexamined Patent Publication No. 2006-266649

When cooling hard-to-cool plant material to a target temperature using the vacuum cooling device having a supercooling prevention function described in Patent Document 2, for example, a temperature slightly lower than the target temperature is set as the first target temperature, and the treatment tank After the pressure inside the treatment tank is reduced to the saturation pressure value (first target pressure value) corresponding to the first target temperature and the pressure inside the treatment tank reaches the first target pressure value, the pressure inside the treatment tank is reduced to the first target pressure value. keep as By doing so, it is possible to wait for the temperature of hard-to-cool planting material to decrease to the target temperature.

However, depending on the type of food material, the temperature of the product may rise without falling to the target temperature on the way.

An object of the present invention is to provide a vacuum cooling device capable of reaching the target temperature by gradually lowering the target pressure step by step when the actual planting temperature is monitored for a certain period of time and the planting temperature does not decrease.

The present invention comprises a cooling tank accommodating an object to be cooled, a temperature sensor for detecting the temperature of the object to be cooled, a decompression means for depressurizing the inner space of the cooling tank, and a control unit, wherein the control unit operates on the decompression means. a first pressure reducing controller for reducing the pressure inside the cooling tank to a first target pressure value set based on a preset target temperature, and when the pressure inside the cooling tank reaches the first target pressure value After, a first cooling control unit including a first cooling maintenance control unit maintaining the pressure value inside the cooling tank at the first target pressure value for a first time, and after cooling by the first cooling control unit, the product temperature sensor a product temperature judging unit that determines whether or not the detected temperature of the product temperature has reached the target temperature; and a first temperature set in advance from the target temperature as a set temperature when it is determined by the product temperature judging unit that the product temperature has not reached the target temperature. A second cooling parameter setting unit that sets a pressure value that is a pressure conversion value of the set temperature as a set pressure value while setting a temperature obtained by subtracting A second pressure reducing controller for reducing the pressure to a set pressure value, and after the pressure value inside the cooling tank reaches the set pressure value, for a second preset time, to maintain the pressure value inside the cooling tank at the set pressure value It is related with the vacuum cooling apparatus provided with the 2nd cooling control part provided with the 2nd cooling maintenance control part.

In addition, the product temperature determination unit determines whether or not the temperature detected by the product temperature sensor has reached the target temperature at the end of the control by the second cooling maintenance control unit, and the second cooling parameter setting unit determines the target temperature by the product temperature determination unit. When it is determined that the temperature has not been reached, the set temperature is further substituted with a value obtained by subtracting the first temperature, and the set pressure value is substituted with a pressure value that is a pressure converted value of the set temperature. It is desirable to do

Further, it is preferable that the control unit stops cooling when it is determined by the product temperature judging unit that the target temperature has been reached.

In addition, even when it is determined that the target temperature has not been reached by the product temperature determining unit after cooling by the second cooling control unit, the control unit starts the vacuum cooling operation inside the cooling tank and then sets a preset maximum cooling temperature. When time elapses, it is preferable to stop cooling.

Further, a storage unit for sequentially storing temperatures detected by the product temperature sensor after cooling by the second cooling control unit is provided, wherein the control unit stores the temperature detected by the product temperature sensor after cooling by the second cooling control unit in the storage unit. When it is higher than the previously detected temperature of the product temperature sensor stored in , it is preferable to stop operation by giving an alarm to an abnormality.

In addition, the control unit, after cooling by the second cooling control unit, even if the detected temperature of the product temperature sensor is lower than the detected temperature of the product temperature sensor last time stored in the storage unit, if the detected temperature difference is equal to or less than a predetermined value, It is preferable to stop cooling.

Preferably, the first target pressure value is a pressure conversion value of a temperature obtained by subtracting a preset lower limit temperature difference from the target temperature.

Preferably, the first temperature is preset for each sequence number in which the second cooling control unit is executed, and the second time is preset for each sequence number in which the second cooling maintenance control unit is executed.

According to the present invention, the planting temperature can reach the target temperature regardless of the type of planting material.

1 is a diagram schematically showing a vacuum cooling device according to the present embodiment.
Fig. 2 is a functional block diagram showing the functional configuration of a control device included in the vacuum cooling device according to the present embodiment.
3 is a diagram showing an example of a cooling operation of the control device included in the vacuum cooling device according to the present embodiment.

EMBODIMENT OF THE INVENTION Hereinafter, a preferable embodiment of the vacuum cooling apparatus of this invention is described, referring drawings. 1 is a diagram showing one embodiment of a vacuum cooling device according to the present invention.

As shown in FIG. 1 , the vacuum cooling device 1 includes a cooling tank 2, a decompression means 3, a pressure recovery means 4, and a control device 5.

The cooling tank 2 accommodates the object to be cooled 23 . The cooling tank 2 is equipped with an opening/closing door (not shown in the figure) for letting the cooled object 23 in and out, and the cooling tank 2 can be hermetically sealed by closing this opening/closing door. In this embodiment, planting material is accommodated in the cooling tank 2 as the object to be cooled 23 .

The cooling tank 2 is provided with a product temperature sensor 21 that detects the temperature of food material, which is an object to be cooled, accommodated in the cooling tank 2 . This product temperature sensor 21 measures the temperature of the location by being inserted into the food material accommodated in the cooling tank 2, for example.

The cooling tank 2 is equipped with a pressure sensor 22 for detecting the pressure in the cooling tank 2 .

The decompression means 3 has a vacuum unit 31, and this vacuum unit 31 is connected to the cooling bath 2 via a decompression line 33.

The vacuum unit 31 is constituted by, for example, a water ring vacuum pump.

It is preferable to install a heat exchanger 32 in the pressure reducing line 33. Furthermore, you may provide a steam ejector (not shown in drawing) on the upstream side of the heat exchanger 32 of the pressure reduction line 33.

The heat exchanger 32 cools and condenses the planting vapor in the pressure reducing line 33 and the vapor of the vapor ejector (when a vapor ejector is installed). By preliminarily cooling and condensing the planting vapor in the pressure reducing line 33 and the vapor of the vapor ejector, the temperature of the fluid in the cooling tank 2 is lowered and the volume of the discharged fluid is reduced. By doing so, the load on the vacuum unit 31 can be reduced and the pressure inside the cooling tank 2 can be reduced effectively.

The steam ejector suctions and discharges the fluid in the cooling tank 2 by ejecting steam. The pressure on the suction side of the vacuum unit 31 can be increased by the steam ejector, and the pressure inside the cooling tank 2 can be reduced effectively.

The pressure restoration means 4 is a means for introducing outside air into the depressurized cooling tank 2 to release the vacuum state and restore pressure. Specifically, outside air is introduced through the filter 41 and can be supplied into the cooling tank 2 through the pressure recovery line 42 .

The pressure recovery line 42 is provided with a pressure recovery operation valve 43 that switches the presence or absence of communication between the outside air and the inside of the cooling tank 2 . Therefore, after reducing the pressure in the cooling tank 2 by the pressure reducing means 3 in the state where the pressure recovery operation valve 43 is closed, the pressure reduction by the pressure reduction means 3 is stopped and the pressure recovery operation valve 43 is opened. By doing so, the vacuum state in the cooling tank 2 can be released and returned to atmospheric pressure.

Like a proportional control valve, the pressure recovery operation valve 43 is configured such that its opening can be adjusted arbitrarily. Accordingly, when the pressure in the cooling tank 2 is reduced by the pressure reducing means 3, the pressure in the cooling tank 2 can be arbitrarily adjusted by adjusting the opening of the pressure recovery operation valve 43.

More specifically, the pressure in the cooling tank 2 is easily adjusted by performing a pressure reduction operation by the pressure reduction means 3 while adjusting the opening of the pressure recovery operation valve 43 based on the output of the pressure sensor 22. can do

The control device 5 controls the depressurization means 3 and the pressure recovery means 4 and the like. In this embodiment, the vacuum unit 31, the pressure recovery operation valve 43, the product temperature sensor 21, and the pressure sensor 22 are connected to the control device 5, and various controls are performed by the control device 5. It becomes possible.

Specifically, the control device 5 adjusts the opening degree of the pressure recovery operation valve 43 based on the detection signal from the pressure sensor 22 to adjust the reduced pressure level in the cooling tank 2 by the vacuum unit 31 do.

When reducing the pressure in the cooling tank 2, the control device 5 stops the pressure reducing means 3 and the pressure restoring means 4 in a state where the pressure inside the cooling tank 2 is maintained at the set pressure, so that the temperature after cooling is increased. Stable and uniform vacuum cooling can be performed.

At the end of the vacuum cooling process, the control device 5 opens the pressure recovery operation valve 43 to restore the pressure in the cooling tank 2 to atmospheric pressure. And based on the detection signal from the pressure sensor 22, completion of pressure restoration in the cooling tank 2 by the pressure recovery operation valve 43 is confirmed.

2 is a functional block diagram showing the functional configuration of the control device 5. As shown in FIG. As shown in FIG. 2 , the control device 5 includes a control unit 50 and a storage unit 51 .

The control unit 50 connects the product temperature sensor 21, the pressure sensor 22, the vacuum unit 31, the pressure recovery valve 43 and the like to perform control related to the cooling of the plant material.

Here, in the present embodiment, the control unit 50 includes a first cooling control unit that reduces the pressure inside the cooling tank to a first target pressure value, and when the product temperature is not lowered to the target temperature by the first cooling control unit, cooling Regardless of the type of planting material, by configuring the tank to include a second cooling control unit that reduces the pressure inside the tank to a set pressure value set lower than the first target pressure value, it is possible to suitably reach the target temperature.

More specifically, as shown in FIG. 2 , the control unit 50 includes a first cooling control unit 501 including a first pressure reduction control unit 5011 and a first cooling maintenance control unit 5012, and a product temperature determination unit 502 And, a second cooling control unit 503 including a second cooling parameter setting unit 5031, a second decompression control unit 5032, and a second cooling maintenance control unit 5033, a cooling interruption unit 504, and cooling A stop 505 is provided.

The first cooling control unit 501 reduces the pressure value inside the cooling tank 2 by the first pressure reduction control unit 5011 to a first target pressure value set based on a preset target temperature, and then performs the first cooling By the maintenance control part 5012, the pressure value inside the cooling tank 2 is maintained at a 1st target pressure value for the 1st time set in advance as a cooling storage holding time.

Specifically, the first pressure reduction control unit 5011 sets the saturation pressure value corresponding to the first target temperature obtained by dividing the difference in the lower cooling limit temperature set in advance from the target temperature as the first target pressure value, and uses the pressure reducing means 3 to cool the tank. The pressure inside (2) is reduced to the first target pressure value.

As the cooling lower limit temperature difference, it is preferable to set a temperature difference corresponding to a reduced pressure width that does not cause an inappropriate cooling phenomenon such as supercooling of the object to be cooled 23 in reduced pressure cooling. In addition, the optimal cooling lower limit temperature difference varies depending on the object to be cooled 23, and is generally preferably set to 3°C or less.

The first cooling maintenance controller 5012 determines the pressure value inside the cooling tank 2 at a first time (for example, 15 minutes) after the pressure inside the cooling tank 2 reaches the first target pressure value. is maintained at the first target pressure value.

More specifically, the first cooling maintenance control unit 5012 adjusts the opening degree of the pressure recovery operation valve 43 based on the output of the pressure sensor 22 and performs a pressure reduction operation by the pressure reducing means 3 to cool the tank. The pressure inside (2) is maintained at the first target pressure value for the first time.

After cooling by the 1st cooling control part 501, the product temperature determination part 502 determines whether the temperature detected by the product temperature sensor 21 (temperature of the object to be cooled 23) reached target temperature.

In addition, the product temperature determination unit 502 determines whether or not the temperature detected by the product temperature sensor 21 (the temperature of the object to be cooled 23) has reached the target temperature at the end of the control by the second cooling maintenance control unit 5033. .

The second cooling control unit 503 determines that the temperature detected by the product temperature sensor 21 has not reached the target temperature after cooling by the first cooling control unit 501 and after cooling by the second cooling control unit 503. In this case, the set pressure value is further lowered and vacuum cooling is performed for a predetermined time.

Here, the second cooling control unit 503 performs cooling by the second cooling control unit 503 immediately after cooling by the first cooling control unit 501 after the first second cooling and the first second cooling. The cooling by the second cooling controller 503 performed after the second second cooling and the nth second cooling is referred to as the (n+1)th second cooling. In this way, the number identifying the number of cooling by the second cooling maintenance control unit 5033 this time after the first cooling by the second cooling control unit 503 is referred to as the second cooling sequence number. Hereinafter, the n-th second cooling is also referred to as second cooling (n).

In this way, when the second cooling control unit 503 determines that the temperature detected by the product temperature sensor 21 has not yet reached the target temperature after cooling by the first cooling control unit 501 or the second cooling control unit 503 , After the set pressure value is set low by the second cooling parameter setting unit 5031 and the pressure value inside the cooling tank 2 is reduced to the set pressure value by the second decompression control unit 5032, the second The pressure value inside the cooling tank 2 is maintained at the set pressure value for the second time by the cooling maintenance control unit 5033 . The second cooling control unit 503 repeatedly performs the above-described processing until the temperature detected by the product temperature sensor 21 reaches the target temperature. By doing so, the planting temperature can reach the target temperature regardless of the type of planting material.

More specifically, the second cooling parameter setting unit 5031, the second pressure reduction control unit 5032, and the second cooling maintenance control unit 5033 each process as follows.

The second cooling parameter setting unit 5031 determines that the temperature detected by the product temperature sensor 21 has not reached the target temperature by the product temperature determination unit 502 at the end of the control by the first cooling maintenance control unit 5012. In this case, the temperature obtained by subtracting the first temperature set in advance (for example, 1° C.) from the target temperature is stored in the storage unit 51 as the set temperature. At the same time, the second cooling parameter setting unit 5031 stores a pressure value that is a pressure conversion value of the set temperature in the storage unit 51 as a set pressure value.

In addition, the second cooling parameter setting unit 5031 determines that the temperature detected by the product temperature sensor 21 has not reached the target temperature by the product temperature determination unit 502 at the end of cooling by the second cooling maintenance control unit 5033. In this case, the value obtained by subtracting the first temperature from the previously set set temperature is newly stored in the storage unit 51 as the set temperature. At the same time, the second cooling parameter setting unit 5031 stores a pressure value that is a pressure conversion value of a newly set set temperature in the storage unit 51 as a set pressure value.

Here, if the first temperature is set to a large value such as 5° C., a cooling control different from the overcooling prevention function may occur, so the first temperature is preferably set to a value equal to or less than the aforementioned lower limit temperature difference for cooling. .

In addition, when the process of this second cooling parameter setting unit 5031 corresponds to the n (n≥1)-th second cooling control unit 503, it is referred to as the n-th second cooling parameter setting process. Then, the n-th set temperature and the n-th set pressure value set by the n-th second cooling parameter setting process are simply described as set temperature n and set pressure value n, respectively.

The second pressure reduction control unit 5032 reduces the pressure by the pressure reduction means 3 to the set pressure value set in the storage unit 51 . If the processing of the second pressure reduction control unit 5032 this time corresponds to the n-th second cooling control unit 503, it is referred to as the n-th second pressure reduction control unit process.

The second cooling maintenance control unit 5033 cools in advance after the pressure inside the cooling tank 2 reaches the set pressure value set in the storage unit 51 by the pressure reduction control by the second pressure reduction control unit 5032. The pressure inside the cooling tank 2 is maintained at the set pressure value for a second time (for example, 2 minutes) set as the holding time. If the process of the second cooling control unit 5033 this time corresponds to the n-th second cooling control unit 503, it is referred to as the n-th second cooling control unit process.

After the end of the control, the second cooling control unit 5033 sets the temperature detected by the food temperature sensor 21 to a second cooling sequence number (n(n≥1) for identifying cooling by the second cooling control unit 503 this time. )) and stored in the storage unit 51. The detection temperature of the product temperature sensor 21 after completion of the n-th second cooling maintenance controller process is referred to as the n-th detection, and is simply described as the detected temperature (n).

In addition, the first temperature is not a uniform value and is preset for each sequence number (n) in which the second cooling control unit 503 is executed, and the sequence number (n) in which the second cooling maintenance control unit 5033 is executed also for the second time n) may be set in advance. By doing so, for example, the first temperature and the second time can be configured so as to gradually decrease and converge as n increases, for example.

The cooling interruption unit 504, after cooling by the second cooling control unit 503, when the detection temperature of the product temperature sensor 21 is higher than the detection temperature of the previous product temperature sensor 21 stored in the storage unit 51, Alerts abnormalities and stops operation.

That is, in the cooling interruption unit 504, the detected temperature n of the product temperature sensor 21 after cooling by the second cooling control unit 503 this time (n-th) is the same as the previous (n-1-th). When it is higher than the detected temperature (n-1) of the product temperature sensor 21 after cooling by the second cooling control unit 503, it is determined that a cooling abnormality has occurred, an abnormality is alarmed, and operation is stopped.

The cooling stop unit 505 starts the vacuum cooling operation in the cooling tank 2 even when it is determined by the product temperature determination unit 502 that the target temperature has not been reached after cooling by the second cooling control unit 503. Then, when the preset maximum cooling time has elapsed, cooling is stopped.

Specifically, when the maximum cooling time elapses after starting the vacuum cooling operation in the cooling tank 2, the cooling stop unit 505 opens the pressure recovery operation valve 43 to lower the inside of the cooling tank 2 to atmospheric pressure. pressurize And based on the detection signal from the pressure sensor 22, completion of pressure restoration in the cooling tank 2 by the pressure recovery operation valve 43 is confirmed.

In addition, the cooling stop unit 505 determines the last (th) time the detected temperature n of the product temperature sensor 21 was stored in the storage unit 51 after cooling by the second (nth) cooling control unit 503 this time (nth). Even if it is lower than the detected temperature (n-1) of the n-1st) product temperature sensor 21, if the detected temperature difference is equal to or less than a predetermined value, cooling is stopped.

By doing so, the cooling stop unit 505 can prevent waste by stopping the cooling when it is assumed that the cooling effect is small even if the processing by the second cooling control unit 503 is repeated.

As described above, the controller 50 is configured.

The storage unit 51 stores the aforementioned lower limit temperature difference for cooling, the first time, the first temperature, the second time, the maximum cooling time, the first target temperature, the first target pressure value, and the like.

In addition, the storage unit 51 stores the set temperature n and the set pressure value n set by the nth (n≥1) second cooling parameter setting process described above.

In addition, the storage unit 51 stores the detected temperature n detected after the cooling process by the above-described nth (n≥1) second cooling control unit 503 .

[Movement Description]

Next, the cooling operation of this embodiment will be described with reference to FIG. 3 . 3 is a diagram showing an example of a cooling operation of the vacuum cooling device 1 of the present embodiment. The horizontal axis represents time (t), the vertical axis (left) represents pressure (P), and the vertical axis (right) represents temperature (T). Here, the temperature (T) is the saturation temperature corresponding to the pressure (P), and the pressure (P) means the saturation pressure corresponding to the temperature (T).

3, the cooling parameters of the vacuum cooling device 1 are set to 17°C for the target temperature, 19 hPa saturation pressure corresponding to the target temperature, 2°C for the lower cooling limit temperature difference, and 15°C for the first target temperature (17°C-2 °C), the first target pressure value corresponding to the first target temperature is 17 hPa, the cooling holding time (first hour) in the first cooling maintenance controller 5012 is 15 minutes, the first temperature is 1 ° C, the second cooling The cooling storage holding time (second time) in the maintenance control unit 5033 is set to 2 minutes, and the maximum cooling time is set to 40 minutes.

In addition, it is assumed that the temperature of the object to be cooled 23 before cooling is 100°C (saturation pressure conversion value 1013 hPa), and the cooling is performed to a target temperature of 17°C.

First, the cooling tank 2 accommodates the food material, which is the object to be cooled 23, and inserts the product temperature sensor 21 into the food material. Then, the opening/closing door for operation of the cooling tank 2 is closed. At this time, the controller stops the vacuum unit 31 while making the pressure recovery operation valve 43 a closed state.

Next, at time t ₀ , the first pressure reduction control unit 5011 operates the vacuum unit 31 . By the operation of the vacuum unit 31, the air in the cooling tank 2 is evacuated through the pressure reducing line 33. Since the saturation temperature decreases as the pressure in the cooling tank 2 decreases, the moisture of the plant material in the cooling tank 2 evaporates actively, and this vapor is sucked in by the pressure reducing line 33 together with the air. And the planting material is cooled by the latent heat of vaporization according to the evaporation of the moisture in the planting material.

At the time t ₁ , when the pressure in the cooling tank 2 reaches the first target pressure value of 17 hPa (corresponding to a saturation temperature of 15° C.), the first cooling maintenance controller 5012 sets the first time (15 minutes) During this elapsed time (t ₂ ), the pressure in the cooling tank 2 is maintained at 17 hPa (corresponding to a saturation temperature of 15°C) by operating the vacuum unit 31 while adjusting the opening of the pressure recovery control valve. .

On the other hand, the detection temperature of the product temperature sensor 21 shows more than 25°C at the time t ₁ , and has not reached the target temperature of 17°C. And it turns out that 25 degreeC is shown in the time ( _t2 ) after the 1st time (15 minutes) elapsed, and target temperature 17 degreeC has not been reached.

Therefore, the second cooling parameter setting unit 5031 sets the set temperature (1) to 14 ° C obtained by subtracting the first temperature (1 ° C) from the first target temperature of 15 ° C, and sets the set pressure (1) to the set temperature. The saturation pressure corresponding to 14°C in (1) is set to 16 hPa.

After the pressure in the cooling tank 2 is lowered to the set pressure 1 at the time t ₃ by the second pressure reduction control unit 5032, the second cooling maintenance control unit 5033 controls the second time (2) therefrom. minutes) until the elapsed time (t ₄ ), the pressure in the cooling bath 2 is reduced to 16 hPa (corresponding to a saturation temperature of 14° C.) by operating the vacuum unit 31 while adjusting the opening of the pressure recovery control valve. keep

On the other hand, the detected temperature of the product temperature sensor 21 shows 20°C at the time t ₄ , and it is understood that the target temperature of 17°C has not been reached.

Therefore, the second cooling parameter setting unit 5031 sets the set temperature (2) to 13 ° C obtained by subtracting the first temperature (1 ° C) from the set temperature (1) of 14 ° C, and sets the set pressure (2). Set the saturation pressure of 15 hPa corresponding to the set temperature (2) of 13 ° C.

After the pressure in the cooling tank 2 is lowered to the set pressure 2 at the time t ₅ by the second pressure reduction control unit 5032, the second cooling maintenance control unit 5033 controls the second time (2) therefrom. minutes) until the elapsed time (t ₆ ), the pressure in the cooling bath 2 is reduced to 15 hPa (corresponding to a saturation temperature of 13° C.) by operating the vacuum unit 31 while adjusting the opening degree of the pressure recovery control valve. keep

On the other hand, the detection temperature of the product temperature sensor 21 shows 17°C at the time t ₆ , and it is understood that the target temperature of 17°C has been reached.

The cooling stop 505 stops cooling. Specifically, the cooling stopper 505 stops the vacuum unit 31 and opens the pressure recovery operation valve 43 .

In this way, when the planting material has not reached the target temperature, it becomes possible to approach the target temperature by gradually lowering the target pressure.

[Effect Description]

As described above, the vacuum cooling device 1 of the present embodiment reduces the internal pressure of the cooling tank 2 to the first target pressure value, and after the internal pressure of the cooling tank 2 reaches the first target pressure value, , After cooling by the first cooling controller 501 for maintaining the internal pressure of the cooling tank 2 at the first target pressure value for the first time (for example, 15 minutes), and the first cooling controller 501, When the temperature detected by the product temperature sensor 21 has not reached the target temperature, a pressure conversion value of the temperature obtained by subtracting the first temperature (for example, 1°C) is newly set as the set pressure value, and the set pressure value After the internal pressure of the cooling tank 2 reaches the new set pressure value by reducing the pressure to A cooling control unit 503 is provided.

In this way, even if the food material that is difficult to be cooled does not go down to the target temperature midway through the process of the first cooling control unit 501 and the food temperature rises, the second cooling control unit 503 lowers the target pressure and cools it again to reach the target temperature. approach is possible.

Further, in the vacuum cooling device 1 of the present embodiment, when the temperature detected by the product temperature sensor 21 has not reached the target temperature at the end of the control by the second cooling control unit 503, the set temperature is further set to the first temperature. The temperature is subtracted, and the set pressure value is replaced with a pressure value that is a pressure converted value of the subtracted set temperature.

As a result, even if the food material that is difficult to be cooled does not drop to the target temperature midway through the processing of the second cooling control unit 503 and the food temperature increases, the target pressure is further lowered and the cooling by the second cooling control unit 503 is repeated. It becomes possible to get close to the temperature.

Further, in the vacuum cooling device 1 of the present embodiment, cooling is stopped when the temperature detected by the product temperature sensor 21 reaches the target temperature.

Accordingly, overcooling of the planting material can be prevented.

Furthermore, in the vacuum cooling device 1 of the present embodiment, even when the temperature detected by the product temperature sensor 21 has not reached the target temperature after cooling by the second cooling control unit 503, the vacuum in the cooling tank 2 is When the preset maximum cooling time elapses after starting the cooling operation, the cooling is stopped.

Accordingly, waste can be prevented by not repeating the process by the second cooling controller 503 more than necessary.

In addition, in the vacuum cooling device 1 of the present embodiment, after cooling by the n+1th second cooling control unit 503, the temperature detected by the product temperature sensor 21 is the same as the previous (n-th) second cooling control unit 503. When it is higher than the temperature detected by the product temperature sensor 21 after cooling by (503), an abnormality is alarmed and the operation is stopped.

Thereby, abnormality of the vacuum cooling device 1 can be detected at an early stage, and abnormal operation can be stopped at an early stage.

In addition, in the vacuum cooling device 1 of the present embodiment, the detected temperature (n+1) of the product temperature sensor 21 after cooling by the second cooling control unit 503 this time (n+1th) is the same as the previous (n+1th) Even if it is lower than the detected temperature n of the product temperature sensor 21 after cooling by the nth) second cooling control unit 503, when the detected temperature difference is equal to or less than a predetermined value, cooling is stopped.

Accordingly, when it is assumed that the cooling effect is small even if the processing by the second cooling controller 503 is repeated, the cooling stop unit 505 stops cooling, thereby preventing waste.

In addition, the 1st target pressure value in the vacuum cooling apparatus 1 of this embodiment can be made into the pressure conversion value of the temperature obtained by subtracting the preset lower limit temperature difference from the target temperature.

Thereby, it becomes possible to rapidly approach the detection temperature of the product temperature sensor 21 to a target temperature.

Moreover, the 1st temperature and the 2nd time period in the vacuum cooling apparatus 1 of this embodiment can be set in advance for each sequence number by which the 2nd cooling control part 503 is executed, respectively.

Accordingly, for example, the first temperature and the second time can be configured to gradually decrease and converge as n increases.

In addition, this embodiment is not limited to the above-mentioned embodiment, In the range which does not deviate from the meaning of this invention, it is possible to add various changes.

[modified example]

For example, in this embodiment, you may install a steam ejector on the side of the cooling tank 2 of the pressure reduction line 33. The steam ejector suctions and discharges the fluid in the cooling tank 2 by ejecting steam. In this case, the heat exchanger 32 reduces the temperature of the fluid in the cooling tank 2 by pre-cooling and condensing the planting vapor in the pressure reducing line 33 and the vapor of the vapor ejector, while reducing the volume of the discharged fluid Decrease. By doing so, the pressure on the suction side of the vacuum unit 31 can be increased by the steam ejector, and the pressure inside the cooling tank 2 can be effectively reduced.

1: vacuum cooling device
2: cooling bath
21: food temperature sensor
22: pressure sensor
3: decompression means
31: vacuum unit
32: heat converter
33: decompression line
4: Restoration means
41: filter
42: pressure recovery line
43: pressure recovery valve
5: control unit
50: control unit
501: first cooling control unit
5011: first decompression controller
5012: first cooling maintenance controller
502: product temperature determining unit
503: second cooling control unit
5031: second cooling parameter setting unit
5032: second decompression controller
5033: second cooling maintenance controller
504: cooling stop
505: cooling stop
51: storage unit

Claims (8)

A cooling tank accommodating the object to be cooled;
A product temperature sensor for detecting the temperature of the object to be cooled;
a decompression means for depressurizing the inner space of the cooling tank;
Equipped with a control unit,
The control unit,
A first pressure reducing control unit for reducing the pressure value inside the cooling tank to a first target pressure value set based on a preset target temperature by the pressure reducing means, and the pressure value inside the cooling tank is the first target pressure value A first cooling control unit having a first cooling maintenance control unit maintaining the pressure value inside the cooling tank at the first target pressure value for a first time after reaching ,
a product temperature judgment unit that determines whether or not the temperature detected by the product temperature sensor has reached the target temperature after cooling by the first cooling control unit;
When it is determined that the target temperature has not been reached by the product temperature determination unit, a temperature obtained by subtracting the first temperature set in advance from the target temperature is set as the set temperature, and a pressure at the set temperature is set as a set pressure value. A second cooling parameter setting unit for setting a pressure value as a converted value; a second pressure reduction control unit for reducing the pressure to a set pressure value set by the second cooling parameter setting unit by means of the pressure reducing unit; and a pressure value inside the cooling tank. A vacuum cooling device comprising a second cooling control unit including a second cooling maintenance control unit that maintains the pressure value inside the cooling tank at the set pressure value for a preset second time period after reaching the set pressure value . According to claim 1,
The product temperature determination unit determines whether or not the temperature detected by the product temperature sensor has reached the target temperature at the end of the control by the second cooling maintenance control unit;
The second cooling parameter setting unit replaces the set temperature with a value obtained by subtracting the first temperature, when it is determined by the product temperature determination unit that the target temperature has not been reached, and the set pressure value A vacuum cooling device that is further substituted with a pressure value that is a pressure conversion value of the set temperature that has been substituted. According to claim 1 or 2,
The control unit,
A vacuum cooling device that stops cooling when it is determined by the product temperature determination unit that the target temperature has been reached. According to claim 2,
The control unit,
After cooling by the second cooling control unit, even when it is determined by the product temperature determining unit that the target temperature has not been reached, when the preset maximum cooling time has elapsed since the vacuum cooling operation of the inside of the cooling tank was started. , vacuum cooling device to stop cooling. According to claim 2 or 4,
After cooling by the second cooling control unit, a storage unit for sequentially storing detected temperatures of the product temperature sensor is provided;
The control unit, after cooling by the second cooling control unit, when the detection temperature of the product temperature sensor is higher than the detection temperature of the previous product temperature sensor stored in the storage unit, alarms an abnormality and stops operation of the vacuum cooling device. . According to claim 5,
The control unit, after cooling by the second cooling control unit, even if the detection temperature of the product temperature sensor is lower than the detection temperature of the product temperature sensor last stored in the storage unit, if the detected temperature difference is equal to or less than a predetermined value, the control unit performs cooling. Stopping vacuum cooling device. The method of any one of claims 1, 2, or 4,
The first target pressure value is a pressure conversion value of a temperature obtained by subtracting a preset cooling lower limit temperature difference from the target temperature. The method of any one of claims 1, 2, or 4,
The first temperature is preset for each sequence number in which the second cooling control unit is executed,
The second time is preset for each sequence number in which the second cooling maintenance control unit is executed.

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