JP7035541B2 - Vacuum defroster - Google Patents

Description

The present invention relates to a vacuum defrosting device for thawing an object to be thawed with low pressure steam.

Conventionally, as disclosed in Patent Document 1 below, a vacuum thawing device for thawing an object to be thawed with low-pressure steam is known. Explaining based on the drawings of the document, the vacuum thawing device includes a processing tank (thawing chamber 2) in which an object to be defrosted is housed, a depressurizing means (4) for sucking and exhausting the inside of the processing tank to reduce the pressure, and a boiler (riboira). It is provided with a steaming means (3) for supplying the steam from 11) into the processing tank and a depressurizing means (5) for introducing outside air into the processing tank under reduced pressure to repressurize. Then, the vacuum defrosting device executes a defrosting process of supplying steam to the decompressed processing tank to thaw the object to be thawed after the air removing step of removing air from the processing tank.

Japanese Unexamined Patent Publication No. 2005-237633

In the prior art, the steaming means is provided with a steaming valve in the steaming path from the boiler to the inside of the processing tank, and the steam from the boiler is supplied into the processing tank by opening the steaming valve. In this case, the pressure will be different before and after the steam supply valve (in other words, the boiler and the processing tank). Therefore, there are the following problems.

That is, after depressurizing the inside of the treatment tank, when the steam supply valve is opened and steam is blown into the treatment tank, the steam is discharged from the steam supply passage as a pressure pipe into the treatment tank under reduced pressure. Therefore, in the vicinity of the blow port, the blown steam becomes superheated steam (superheated steam), and there is a possibility that a temperature region far exceeding the thawing temperature may be generated. Even if it is temporary, such a situation may cause an increase in the temperature inside the tank and the occurrence of temperature unevenness, and it is desired to eliminate it.

Therefore, an object to be solved by the present invention is to provide a vacuum defrosting device capable of preventing the steam from being overheated in the treatment tank and heating the object to be thawed evenly at a desired temperature.

The present invention has been made to solve the above problems, and the invention according to claim 1 is the treatment tank in which the object to be thawed is housed and the gas in the treatment tank is sucked and discharged to the outside. A depressurizing means for depressurizing the inside of the treatment tank and a depressurizing means provided in communication with the inside of the treatment tank, connected to the decompression means via the treatment tank, and heating the stored water to supply steam into the treatment tank. It is a vacuum defrosting apparatus including a possible steam generating tank, and controlling depressurization by the depressurizing means and steam generation in the steam generating tank based on the pressure in the steam generating tank .

According to the first aspect of the present invention, the inside of the steam generation tank is provided so as to communicate with the inside of the treatment tank. In this case, when the inside of the treatment tank is depressurized by the depressurizing means, the inside of the steam generation tank is also depressurized to the same pressure. In the steam generation tank, saturated steam is generated according to the pressure in the treatment tank, so even if the steam is supplied into the treatment tank, there is no risk of overheating in the treatment tank, and the product to be thawed evenly at the desired temperature. Can be heated.
According to the first aspect of the present invention, the pressure in the treatment tank and the steam generation tank, and thus the temperature, can be adjusted as desired to heat the thawed material evenly at the desired temperature.

The invention according to claim 2 is the vacuum defrosting apparatus according to claim 1, wherein the steam generating tank is characterized in that steam is generated by blowing steam into the stored water.

According to the second aspect of the present invention, steam can be blown into the stored water of the steam generation tank to heat it. When steam is blown into the stored water in the steam generation tank while the steam generation tank is also depressurized as the pressure in the treatment tank is reduced, the blown steam transfers heat to the stored water and becomes saturated steam. , The stored water boils under reduced pressure at a temperature corresponding to the pressure of the steam generation tank (decompression in the treatment tank) to generate saturated steam. This makes it possible to prevent the steam from overheating and evenly heat the object to be thawed at a desired temperature.

The invention according to claim 3 is the vacuum defrosting apparatus according to claim 1, wherein the steam generating tank is characterized in that steam is generated by heating stored water with a heater.

According to the third aspect of the present invention, the stored water in the steam generation tank can be heated by a heater. When the stored water in the steam generation tank is heated while the steam generation tank is also depressurized as the pressure in the treatment tank is reduced, saturated steam boiled under reduced pressure at the target temperature according to the pressure is supplied to the treatment tank. be able to. This makes it possible to prevent the steam from overheating and evenly heat the object to be thawed at a desired temperature.

According to the vacuum thawing apparatus of the present invention, it is possible to prevent the steam from being overheated in the treatment tank and to heat the object to be thawed evenly at a desired temperature.

It is a schematic diagram of the vacuum defrosting apparatus of one Example of this invention.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic view showing a vacuum defrosting device 1 according to an embodiment of the present invention.

The vacuum defrosting device 1 of the present embodiment includes a processing tank 2 in which an object to be thawed is housed, a decompression means 3 for sucking and discharging the gas in the processing tank 2 to the outside to reduce the pressure in the processing tank 2, and a processing tank. It is provided with a steam generating tank 4 provided in communication with the inside of 2, a decompression means 5 for introducing outside air into the depressurized treatment tank 2 to repressurize the inside of the treatment tank 2, and a control means (not shown).

The processing tank 2 is a hollow container in which an object to be thawed is stored, and can be opened and closed by a door. For example, the processing tank 2 is formed in a substantially rectangular hollow box shape, and the front surface can be opened and closed by a door. The processing tank 2 is provided with a pressure release valve 6 composed of a check valve. In the unlikely event that the inside of the processing tank 2 is pressurized, the pressure release valve 6 opens by itself for processing. The pressure in the tank 2 is released to the atmospheric pressure. If desired, a steam trap or the like may be provided at the bottom of the processing tank 2.

The depressurizing means 3 sucks and discharges the gas in the processing tank 2 to the outside to reduce the pressure in the processing tank 2. In this embodiment, as the depressurizing means 3, the exhaust passage 7 from the inside of the processing tank 2 is provided with a steam ejector 8, a heat exchanger 9 for steam condensation, a check valve 10, and a water-sealed vacuum pump 11.

The steam ejector 8 is provided with a suction port 8a connected to the processing tank 2, and steam from the ejector steam supply passage 12 can be ejected from the inlet 8b to the outlet 8c by a nozzle. By ejecting steam from the inlet 8b toward the outlet 8c, the gas in the processing tank 2 is also sucked and discharged to the outlet 8c through the suction port 8a. By operating the opening and closing of the ejector steaming valve 13 provided in the ejector steaming passage 12, it is possible to switch whether or not the steam ejector 8 is activated.

The heat exchanger 9 is an indirect heat exchanger that exchanges heat without mixing the fluid in the exhaust passage 7 with the cooling water. In the heat exchanger 9, the cooling water is supplied through the heat exchange water supply channel 14, and the cooling water is discharged through the heat exchange drainage channel 15. The heat exchange water supply channel 14 is provided with a heat exchange water supply valve 16 and a check valve 17. By opening the heat exchange water valve 16, cooling water can be passed through the heat exchanger 9. By passing water through the heat exchanger 9, the steam in the exhaust passage 7 can be cooled and condensed by the cooling water in the heat exchanger 9. The heat exchange water supply valve 16 is provided in the heat exchange water supply channel 14, but may be provided in the heat exchange drainage channel 15 as the case may be.

The vacuum pump 11 is a water-sealed type, and as is well known, the vacuum pump 11 is operated while being supplied with water called water-sealed. A water-sealing water supply valve 19 is provided in the water-sealing water supply channel 18 to the vacuum pump 11, and by opening the water-sealing water supply valve 19, the water-sealing water can be supplied to the vacuum pump 11. The opening and closing of the sealed water supply valve 19 is linked to the start and stop of the vacuum pump 11. When the vacuum pump 11 is operated with the sealed water supply valve 19 open, the vacuum pump 11 sucks fluid from the heat exchanger 9 side and discharges the fluid.

The steam generation tank 4 is a hollow container for storing water. The shape of the steam generation tank 4 is not particularly limited, but in this embodiment, it is formed in a substantially cylindrical shape. At this time, the substantially cylindrical steam generation tank 4 is arranged along the vertical direction along the axis, and the upper and lower openings are closed.

The steam generation tank 4 is provided so as to communicate with the processing tank 2 via the communication passage 20. In this embodiment, the communication passage 20 is not provided with a valve, and the inside of the steam generation tank 4 is always in communication with the inside of the processing tank 2. The communication passage 20 is preferably connected at one end to the upper part of the steam generating tank 4 and the other end to the lower side of the processing tank 2.

Water is stored in the steam generation tank 4 up to a set water level, and the stored water is heated so that steam can be supplied into the treatment tank 2. Therefore, the steam generating tank 4 is provided with a tank water supply means 21, a tank drainage means 22, and a tank steaming means 23.

The tank water supply means 21 supplies water to the steam generation tank 4 via the tank water supply channel 24. A tank water supply valve 25 is provided in the tank water supply channel 24 to the steam generation tank 4. By opening the tank water supply valve 25, water can be supplied to the steam generation tank 4.

The tank drainage means 22 discharges water from the steam generation tank 4 via the tank drainage channel 26. A tank drain valve 27 and a check valve 28 are sequentially provided in the tank drainage channel 26 from the steam generation tank 4. By opening the tank drain valve 27, drainage can be performed from the steam generation tank 4.

In this embodiment, the tank water supply channel 24 and the tank drainage channel 26 are connected to the lower part of the steam generation tank 4. The tank water supply channel 24 on the downstream side (steam generation tank 4 side) of the tank water supply valve 25 and the tank drainage channel 26 on the upstream side (steam generation tank 4 side) of the tank drainage valve 27 are the common pipeline 29. Has been done.

The tank steaming means 23 blows steam (steam from a boiler or a reboiler) into the stored water in the steam generating tank 4 via the tank steaming passage 30 to heat the stored water. A steam supply shutoff valve 31 and a tank steam supply valve 32 are sequentially provided in the tank steam supply passage 30 to the steam generation tank 4. The steam supply shutoff valve 31 is a valve (for example, a solenoid valve) that can be switched on and off, and the tank steam supply valve 32 is preferably a valve whose opening degree can be adjusted (for example, a proportional control valve). The steam supply shutoff valve 31 is opened in conjunction with the opening of the tank steam supply valve 32. By opening the steam supply shutoff valve 31 and the tank steam supply valve 32, steam can be supplied to the stored water in the steam generation tank 4. At that time, by adjusting the opening degree of the tank steam supply valve 32, the amount of steam supplied into the steam generation tank 4 can be adjusted. In the illustrated example, a baffle plate 33 for improving the dryness of steam is provided in the upper part of the steam generation tank 4.

The depressurizing means 5 introduces outside air into the depressurized treatment tank 2 to repressurize the inside of the treatment tank 2. In this embodiment, the air filter 35 and the vacuum release valve 36 are provided in the air supply path 34 into the treatment tank 2 as the pressure reducing means 5. When the vacuum release valve 36 is opened while the inside of the treatment tank 2 is depressurized, the outside air is introduced into the treatment tank 2 via the air filter 35, and the inside of the treatment tank 2 can be recompressed. The vacuum release valve 36 is preferably composed of a valve whose opening degree can be adjusted (for example, a proportional control valve).

The steam generation tank 4 is provided with a pressure sensor 37. In this embodiment, the pressure sensor 37 is provided in the upper part of the steam generation tank 4 and detects the pressure in the gas phase portion. However, since the processing tank 2 and the steam generation tank 4 are communicated with each other by the communication passage 20, the pressure sensor 37 may be provided in the processing tank 2 instead of the steam generation tank 4. Alternatively, if the pressure in the processing tank 2 or the steam generation tank 4 can be detected, it may be provided in another place (for example, the communication passage 20).

The steam generation tank 4 is provided with a water level sensor 38 that detects the water level in the tank. As the water level sensor 38, an electrode type water level detector is used in this embodiment, but the water level sensor 38 is not limited to this, and for example, a capacitance type water level detector or the like can also be used.

The control means is a controller (not shown) that controls the means 3, 5, 21, 22, 23 based on the detection signals of the sensors 37, 38, the elapsed time, and the like. Specifically, a vacuum pump 11, an ejector steam supply valve 13, a heat exchange water supply valve 16, a sealed water supply valve 19, a tank water supply valve 25, a tank drain valve 27, a steam supply shutoff valve 31, a tank steam supply valve 32, and a vacuum. In addition to the release valve 36, the pressure sensor 37, the water level sensor 38, and the like are connected to the controller. Then, the controller attempts to thaw the object to be thawed in the processing tank 2 according to a predetermined procedure (program). Typically, after the air removal step, the operation including the thawing treatment step is performed to thaw the object to be thawed in the treatment tank 2. Hereinafter, a specific operation example will be described.

Prior to the start of operation, the object to be thawed is housed in the treatment tank 2 in advance, and the door of the treatment tank 2 is airtightly closed. At that time, the vacuum release valve 36 is opened, but the other valves are closed, and the vacuum pump 11 is stopped. When the start of operation is instructed, such as when the start button is pressed, the controller executes a thawing process after the air evacuating step.

Further, at the latest, by the start of the thawing process, water is stored in the steam generation tank 4 up to the set water level by the tank water supply means 21. After that, by controlling the tank water supply means 21 and the tank drainage means 22 based on the detection signal of the water level sensor 38 until the end of the thawing process, the stored water in the steam generation tank 4 is maintained at the set water level (set range). Will be done.

The first set pressure and the third set pressure, which will be described later, may be set to a certain pressure range or a certain predetermined pressure. When the pressure range is set, the depressurization in the treatment tank 2 and the steam supply into the treatment tank 2 are controlled so as to be within the range of the upper limit pressure and the lower limit pressure.

In the air evacuating step, with the vacuum release valve 36 closed, the inside of the processing tank 2 is depressurized to the first set pressure (for example, 8 hPa) by the depressurizing means 3. However, instead of reducing the pressure to the first set pressure, the pressure may be reduced for the first set time. In any case, in the air exhausting step, the sealing water supply valve 19 is opened and the vacuum pump 11 is operated to reduce the pressure in the treatment tank 2. Further, during depressurization, when the set timing (typically, a predetermined pressure or less) is reached, the ejector steam supply valve 13 is opened to operate the steam ejector 8, and the heat exchange water supply valve 16 is opened to cool water to the heat exchanger 9. Through. When the pressure inside the processing tank 2 is reduced to a predetermined level, the pressure reducing means 3 is stopped and the process proceeds to the next step.

In the thawing treatment step, the stored water in the steam generation tank 4 is heated by the tank steaming means 23, and the steam generated by the heating is supplied to the treatment tank 2 to thaw the defrosted material in the treatment tank 2. Try. In this embodiment, the steam supply from the steam generation tank 4 to the processing tank 2 is performed up to the second set pressure (for example, the saturation temperature is a pressure equivalent to 18 to 20 ° C.), and the second set pressure is set. Hold time. That is, after depressurizing to the first set pressure in the air exclusion step, the pressure is restored to the second set pressure in the thawing process step with steam, and the pressure is maintained at the second set pressure for the second set time.

Specifically, the opening degree of the tank steam supply valve 32 is adjusted based on the detected pressure of the pressure sensor 37 so as to maintain the second set pressure. During this period, the decompression means 3 may be kept stopped, but in some cases, the opening degree of the tank steam supply valve 32 may be adjusted while the decompression means 3 is operated. Alternatively, steam supply up to the upper limit pressure of the second set pressure and steam condensation (standby) up to the lower limit pressure in a state where the steam supply is stopped (the tank steam supply valve 32 is closed) may be repeated. In addition, the depressurizing means 3 may be operated during the holding at the second set pressure to temporarily depressurize the inside of the processing tank 2.

After holding at the second set pressure for the second set time as the main treatment, if desired, the pressure is reduced to a third set pressure lower than the second set pressure (for example, a pressure equivalent to a saturation temperature of 8 ° C.) as a squeezing treatment. The third set time may be held. Further, after that, as a low temperature holding process, the pressure and temperature in the treatment tank 2 may be held at a predetermined pressure and temperature for a predetermined time. At that time, the pressure and temperature may be adjusted so as to gradually increase with the passage of time. Although the control target temperature is different, the squeeze treatment and the low temperature holding treatment can be carried out under the same control as the main treatment.

When the series of thawing processing steps is completed, the depressurizing means 3 is stopped, and the inside of the processing tank 2 is restored to the atmospheric pressure by the pressure reducing means 5 in a state where the steam generation in the steam generation tank 4 is stopped. As a result, the door of the processing tank 2 can be opened and the defrosted material can be taken out from the inside of the processing tank 2.

According to the vacuum thawing device 1 of the present embodiment, the inside of the steam generation tank 4 is always in communication with the inside of the treatment tank 2, so that when the inside of the treatment tank 2 is depressurized in the air exhausting step, the inside of the steam generation tank 4 is also the same. The pressure is reduced. Along with this, in the thawing treatment step, saturated steam is generated in the steam generation tank 4 according to the pressure in the treatment tank 2, so that even if the steam is supplied into the treatment tank 2, overheating occurs in the treatment tank 2. The object to be thawed can be heated evenly at a desired temperature without any possibility of occurrence. That is, the tank steaming means 23 is in a state where the inside of the treatment tank 2 and the inside of the steam generation tank 4 are under the same pressure (in other words, the inside of the steam generation tank 4 has a vacuum degree equivalent to the target temperature like the treatment tank 2). When steam is blown into the stored water in the steam generation tank 4, the blown steam transfers heat to the stored water to become saturated steam, and the stored water is the pressure of the steam generation tank 4 (decompression in the treatment tank 2). It boils under reduced pressure at a temperature corresponding to the above temperature to generate saturated steam. This makes it possible to prevent the steam from overheating and evenly heat the object to be thawed at a desired temperature.

By the way, if water is stored in the bottom of the treatment tank 2 and the stored water is heated to thaw the thawed material without providing the steam generation tank 4, there are the following inconveniences. .. That is, if water is first stored in the treatment tank 2 in which the defrosted material is stored and the stored water is boiled under reduced pressure, if sudden boiling occurs, droplets of the stored water may adhere to the defrosted material. be. Further, in the thawing treatment step, oil and drip may be eluted from the defrosted material, but these elutions may contaminate the stored water, and there is a risk of contamination on the heater and the water storage portion and bacterial contamination. Further, if a water storage unit or a heater is provided at the bottom of the treatment tank 2, it becomes difficult to clean the inside of the treatment tank 2 and it becomes difficult to keep the inside of the treatment tank 2 hygienic.

On the other hand, according to the vacuum thawing device 1 of the above embodiment, the steam generation tank 4 is provided separately from the treatment tank 2, and the baffle plate 33 is preferably provided on the upper part of the steam generation tank 4, so that the stored water is stored. It is possible to prevent the outflow of droplets. Further, by providing the steam generation tank 4 separately from the treatment tank 2, there is no possibility that the stored water or the steam generation portion is contaminated by the oil content or drip of the object to be thawed. Moreover, since the flow of the fluid during operation is one-way from the steam generating tank 4 to the inside of the processing tank 2, contamination of the stored water and the steam generating portion is surely prevented. Further, since the steam generation tank 4 is controlled by the water level and the stored water amount is not large, the stored water can be replaced for each batch to easily carry out hygienic operation.

The vacuum thawing device 1 of the present invention is not limited to the configuration (including control) of the above embodiment, and can be appropriately changed. In particular, (a) a treatment tank 2 in which an object to be thawed is housed, (b) a decompression means 3 for sucking and discharging the gas in the treatment tank 2 to the outside to reduce the pressure in the treatment tank 2, and (c) a treatment tank. Other configurations can be appropriately changed as long as the steam generating tank 4 is provided so as to communicate with the inside of the 2 and can supply steam into the treatment tank 2 by heating the stored water.

For example, in the above embodiment, the stored water in the steam generating tank 4 is heated by directly blowing steam by the tank steaming means 23, but may be indirectly heated by the steam heater. When a steam heater is used, a steam pipe (for example, a coil) is installed in the stored water of the steam generation tank 4, and steam is supplied into the steam pipe by the tank steaming means 23 to heat the stored water. In this case as well, in the thawing process, the opening degree (or opening / closing) of the tank steaming valve 32 may be controlled based on the detected pressure of the pressure sensor 37. The condensed water of steam supplied to the steam heater is discharged to the outside through the steam trap.

Alternatively, an electric heater may be used instead of omitting the installation of the tank steaming means 23. When an electric heater is used, in the defrosting process, the capacity (or start / stop) of the electric heater may be controlled based on the detection pressure of the pressure sensor 37. When a steam heater or an electric heater is used, steam is not directly blown into the steam generation tank 4, so that the water level fluctuation is suppressed and the water quality in the steam generation tank 4 (and thus the quality of steam in the treatment tank 2) is improved. Easy to maintain as desired.

1 Vacuum defroster 2 Processing tank 3 Decompression means 4 Steam generation tank 5 Depressurization means 6 Pressurization release valve 7 Exhaust passage 8 Steam ejector (8a: suction port, 8b: inlet, 8c: outlet)
9 Heat exchanger 10 Check valve 11 Vacuum pump 12 Ejector steam supply channel 13 Ejector steam supply valve 14 Heat exchange water supply channel 15 Heat exchange drainage channel 16 Heat exchange water supply valve 17 Check valve 18 Sealed water supply channel 19 Sealed water supply valve 20 consecutive passages 21 tank water supply means 22 tank drainage means 23 tank steam supply means 24 tank water supply channel 25 tank water supply valve 26 tank drainage channel 27 tank drain valve 28 check valve 29 common pipeline 30 tank steam supply channel 31 steam supply shutoff valve 32 Tank steam supply valve 33 Baffle plate 34 Air supply passage 35 Air filter 36 Vacuum release valve 37 Pressure sensor 38 Water level sensor

Claims (3)

A processing tank that houses the material to be thawed,
A decompression means for sucking and discharging the gas in the treatment tank to the outside to reduce the pressure in the treatment tank.
It is provided with a steam generation tank that is provided in communication with the inside of the treatment tank, is connected to the decompression means via the treatment tank, and can supply steam into the treatment tank by heating the stored water.
Based on the pressure in the steam generation tank, the depressurization by the depressurizing means and the steam generation in the steam generation tank are controlled.
A vacuum defroster characterized by that. The vacuum defrosting device according to claim 1, wherein the steam generation tank generates steam by blowing steam into the stored water. The vacuum defrosting device according to claim 1, wherein the steam generation tank generates steam by heating stored water with a heater.

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