JP4958888B2 - Vacuum thawing device - Google Patents

Description

  The present invention relates to a vacuum thawing apparatus for thawing an object to be thawed by the latent heat of water vapor.

As a thawing device for thawing an object to be thawed such as frozen food, a vacuum thawing device using latent heat of water vapor has been proposed. For example, as disclosed in Patent Document 1, this vacuum thawing apparatus has a thawing chamber that contains an object to be thawed and water is stored in an inner bottom portion thereof. A heater is installed. When thawing the object to be thawed, the thawing chamber is evacuated by a vacuum pump to form a vacuum, and water stored in the inner bottom portion is heated by a heater to form steam. The water vapor collects on the surface of the frozen food or the like and is condensed by the food. At that time, the latent heat of the water vapor is applied to the material to be thawed, so that the material to be thawed is thawed.
Japanese Patent Laid-Open No. 5-15358

  By the way, in the above vacuum thawing apparatus, the air entering the thawing chamber is exhausted, and an exhaust operation by a vacuum pump is performed in order to keep the water vapor pressure in the chamber at a set pressure. There is a problem that energy efficiency is poor because it is exhausted to the outside together with air without being used for thawing. Then, this invention makes it a subject to provide the vacuum thawing apparatus which can improve energy efficiency.

  A vacuum thawing device according to a first aspect of the present invention is made to solve the above-described problem, and is a vacuum thawing device for thawing a material to be thawed by the latent heat of water vapor, and a vacuum in which the material to be thawed is housed. A defroster, a water storage container disposed in the vacuum defroster and containing water, a heating means for heating the water in the water reservoir into water vapor, a vacuum pump for exhausting the vacuum defroster, and A heat transfer tube extending through the water storage container, a first end connected to the discharge side of the vacuum pump, a second end connected to the first end of the heat transfer tube, and the heat transfer tube. High pressure holding means for holding the inside of the heat pipe and the circulation pipe at a high pressure.

  According to the vacuum thawing device according to the first aspect of the invention, the water vapor discharged from the vacuum thawing chamber by the vacuum pump is not discharged to the outside of the vacuum thawing chamber, but is sent into the heat transfer tube via the circulation pipe. Yes. The water vapor sent into the heat transfer tube is compressed by the vacuum pump and is held at a high pressure by the high-pressure holding means, so that the saturated vapor temperature is higher than the saturated vapor temperature in the vacuum thawing chamber. . Since the heat transfer tube is arranged in the water storage container, the water vapor in the heat transfer tube can exchange heat with the water in the water storage container to heat the water in the water storage container. As a result, water vapor that has not been used for thawing the object to be thawed can be used as an auxiliary heating source for evaporating water in the water storage container, and energy efficiency can be improved.

  A vacuum thawing device according to a second aspect of the present invention is made to solve the above-described problem, and is a vacuum thawing device for thawing a material to be thawed by the latent heat of water vapor, and a vacuum that houses the material to be thawed inside. A defroster, a water storage container disposed in the vacuum defroster and containing water, a heating means for heating the water in the water reservoir into water vapor, a vacuum pump for exhausting the vacuum defroster, and A heat transfer tube disposed below the object to be thawed in the vacuum thawing chamber, a first end connected to the discharge side of the vacuum pump, and a second end connected to the first end of the heat transfer tube A circulation pipe to be connected; and high-pressure holding means for holding the heat transfer pipe and the inside of the circulation pipe at a high pressure.

  According to the vacuum thawing device of the second invention, the water vapor discharged from the vacuum thawing chamber by the vacuum pump is not discharged to the outside of the vacuum thawing chamber, but is sent into the heat transfer tube through the circulation pipe. Yes. The water vapor sent into the heat transfer tube is compressed by the vacuum pump and is held at a high pressure by the high-pressure holding means, so that the saturated vapor temperature is higher than the saturated vapor temperature in the vacuum thawing chamber. . Since the heat transfer tube is disposed below the object to be thawed, the water vapor in the heat transfer tube can exchange heat with water dripped from the object to be thawed to heat the water in the water storage container. As a result, water vapor that has not been used for thawing the material to be thawed can be used as an auxiliary heating source for generating water vapor in the vacuum thawing chamber, and energy efficiency can be improved.

  The vacuum thawing apparatus according to the first and second inventions can take various configurations, for example, the heating means can be an electric heater.

  The high-pressure holding means can be configured by a valve installed at the second end of the heat transfer tube, or can be configured by narrowing the second end of the heat transfer tube.

  The first and second discharge pipes are connected to the discharge side of the vacuum pump, the first discharge pipe is connected to the circulation pipe via the first on-off valve, and the second discharge pipe is connected to the second discharge pipe. It is preferable to connect to an exhaust vacuum pump that exhausts to the outside of the vacuum thawing chamber through an on-off valve.

  In addition, an air separation means is installed between the vacuum pump and the first and second discharge pipes, and by this air separation means, water vapor is sent to the first discharge pipe and air is sent to the second discharge pipe. It can also be sent out.

  Moreover, it is preferable to further comprise a control means for controlling heating by the electric heater so that the pressure in the vacuum thawing chamber becomes constant.

  The vacuum pump is a water ring vacuum pump, and further includes a refrigerator that cools the water that is a working medium of the water ring vacuum pump, and the water in the water storage container is heated by the condensed exhaust heat of the refrigerator. It can also be.

  ADVANTAGE OF THE INVENTION According to this invention, the vacuum thawing apparatus which can improve energy efficiency can be provided.

  Hereinafter, embodiments of a vacuum thawing apparatus according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic view of a vacuum thawing apparatus.

  As shown in FIG. 1, a vacuum thawing apparatus 1 includes a vacuum thawing chamber 2 that houses an object to be thawed F (frozen food or the like), and a steam supply unit 3 that supplies steam into the vacuum thawing chamber 2. A circulation unit 4 for exhausting water vapor in the vacuum thawing cabinet 2 and circulating it in the vacuum thawing cabinet 2 and an exhaust unit 5 for exhausting air in the vacuum thawing cabinet 2 to the outside are provided.

  The vacuum thawing box 2 has a rectangular parallelepiped shape, and a shelf 21 on which the object to be thawed F is placed in three stages in the vertical direction. Further, the vacuum thawing box 2 is provided with a door (not shown) so that the article to be thawed F can be taken in and out. The material of the vacuum thawing box 2 is not particularly limited, but is preferably made of stainless steel. Moreover, it is preferable that the shelf 21 installed in the vacuum thawing chamber 2 is formed with a plurality of through holes so that water vapor or water can freely pass therethrough. For example, the shelf 21 may be formed by punch metal or the like. can do.

  The steam supply unit 3 is for supplying water vapor into the vacuum thawing chamber 2, and is installed at the bottom of the vacuum thawing chamber 2, and a water storage container 31 in which water is stored, and water in the water storage container 31. An electric heater 32 that generates water vapor by heating, and a heat transfer tube 33 that extends in a meandering manner above and above the water surface in the water storage container 31 are provided. The water storage container 31 is installed below the object to be thawed F, and is formed in a rectangular parallelepiped shape whose upper surface is open. Since the water storage container 31 is installed below the object to be thawed F, the water generated by the contact between the water vapor and the object to be thawed F falls and returns into the water storage container 31.

  The electric heater 32 is installed so as to extend in the water storage container 31, and is configured so that the amount of water in the water storage container 31 can be adjusted by controlling the capacity by a variable resistance or performing intermittent operation. ing. The heat transfer tube 33 is installed below the object to be thawed F, and a part of the heat transfer tube 33 extends above the water surface in the water storage container 31. A second end portion of the heat transfer tube 33 is opened downward in the vacuum thawing chamber 2, and the first end portion is connected to a circulation pipe 44 described later. Further, a throttle for keeping the pressure in the heat transfer tube 33 at a high pressure is formed on the second end side of the heat transfer tube 33.

  The circulation unit 4 includes a vacuum pump 41 having a suction side connected to a pipe extending from the upper portion of the vacuum thawing chamber 2, a first discharge pipe 42 connected to the discharge side of the vacuum pump 41, and a first on-off valve 43. And a circulation pipe 44 connected to the first discharge pipe 42. The vacuum pump 41 is for evacuating the inside of the vacuum thawing box 2 to make the inside of the vacuum thawing box 2 vacuum, and compresses the water vapor in the vacuum thawing box 2 to form the first discharge pipe 42 and the first Is sent to the circulation pipe 44 through the open / close valve 43. The vacuum pump 41 is a vacuum pump for evacuating the vacuum thawing chamber 2 so as to maintain the predetermined pressure after the inside of the vacuum thawing chamber 2 is depressurized to a predetermined pressure. When the pressure is reduced from atmospheric pressure to a predetermined pressure, the inside of the vacuum thawing chamber 2 is exhausted together with an exhaust vacuum pump 53 described later. The circulation pipe 44 is connected to the first end of the heat transfer tube 33 described above so that the water vapor exhausted by the vacuum pump 41 is returned into the vacuum thawing box 2. Moreover, it is preferable that the circulation piping 44 is comprised with the material which has heat insulation, or is covered with the material which has heat insulation so that it may not heat-exchange with the air of the vacuum thaw | zipper 2 exterior.

  The exhaust unit 5 includes a second discharge pipe 51 connected to the discharge side of the vacuum pump 41 and an exhaust vacuum pump 53 connected to the second discharge pipe via a second opening / closing valve 52. Yes. The evacuation vacuum pump 53 is a pump exclusively used for evacuation used to depressurize the vacuum thawing chamber 2 from atmospheric pressure to a predetermined pressure, and stops when the vacuum thawing chamber 2 is depressurized to a predetermined pressure. It is preferable to be controlled. Although it is preferable to make the vacuum as much as possible, for example, if the saturated steam temperature is 5 to 10 ° C., the exhaust vacuum pump 53 is controlled to stop when the pressure is reduced to 0.9 to 1.2 kPa.

  Next, the operation of the vacuum thawing apparatus 1 described above will be described below.

  First, the material to be thawed F is put into the vacuum thaw chamber 2 from the door (not shown) of the vacuum thaw box 2, the thawed material F is placed on the shelf 21, the door is closed, and the first on-off valve 43 is opened. The second on-off valve 52 is opened by closing it. Then, the vacuum pump 41 and the evacuation vacuum pump 53 are activated to evacuate the air in the vacuum thawing cabinet 2 to the outside of the vacuum thawing cabinet 2, and the vacuum thawing cabinet 2 reaches a predetermined pressure set in advance. Reduce pressure. In addition, although it does not specifically limit with the predetermined pressure at this time, For example, if it shall be 5-10 degreeC of saturated steam temperature, it will be 0.9-1.2 kPa.

  When the pressure in the vacuum thawing chamber 2 is reduced to a predetermined pressure, the first on-off valve 43 is opened, the second on-off valve 52 is closed, the exhaust vacuum pump 53 is stopped, and only the vacuum pump 41 is operated. State. And water is introduce | transduced in the water storage container 31 (an introductory water system is not specifically shown), the electric heater 32 is operated, the water in the water storage container 31 is heated, and water vapor | steam is generated. At this time, the amount of heating of the electric heater 32 with respect to the water in the water storage container 31 is adjusted by controlling the capacity with a variable resistance or by intermittent operation, and the pressure in the vacuum thawing chamber 2 is about 2.3 to 4.2 kPa. (Saturated steam temperature: 20 to 30 ° C.)

  The water vapor generated from the water in the water storage container 31 collects on the surface of the object to be thawed F having a low temperature and condenses. Due to this condensation, the water vapor provides condensation latent heat to the material to be thawed F. The material to be thawed F is gradually heated from the surface by the latent heat from the water vapor, and the inside thereof is also heated by heat conduction and gradually thawed. At this time, since there is no air molecule and only the water vapor is in a vacuum state, the heat transfer of the water vapor to the material F to be thawed is performed smoothly and can be thawed efficiently. Moreover, the water vapor | steam which gave the condensation latent heat to the to-be-thawed material F turns into water, and is dripped from the to-be-thawed material F to the water storage container 31.

  The water vapor that is not used for thawing the material to be thawed F described above is discharged from the vacuum thawing chamber 2 by the vacuum pump 41, and is sent to the heat transfer tube 33 through the first discharge pipe 42 and the circulation pipe 44. Since the water vapor sent to the heat transfer tube 33 is compressed by the vacuum pump 41, the pressure in the heat transfer tube 33 is higher than the pressure in the vacuum thawing chamber 2, for example, 4.2 to 7.4 kPa ( Saturated steam temperature: 30 to 40 ° C.). Since the saturated steam temperature in the heat transfer tube 33 is higher than the saturated steam temperature in the vacuum thawing chamber 2 in this way, the water vapor in the heat transfer tube 33 and the water in the water storage container 31 exchange heat, and the heat transfer tube 33 As the water vapor is condensed, the water in the water storage container 31 is heated to generate water vapor. The water vapor in the heat transfer tube 33 is condensed to become water and returns to the water storage container 31. Further, since the heat transfer tube 33 also extends below the object to be thawed F, the water dripped from the object to be thawed F comes into contact with the heat transfer tube 33 and is heated by exchanging heat with the water vapor in the heat transfer tube 33.

  As described above, according to the present embodiment, the water vapor discharged by the vacuum pump 41 to the outside of the vacuum thawing chamber 2 without being used for thawing the material to be thawed F is stored in the water storage container 31 through the heat transfer pipe 33. Since it uses as a heat source for heating the water dripped from the to-be-thawed substance F, energy efficiency can be improved as the vacuum thawing apparatus 1 whole.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to these, A various change is possible unless it deviates from the meaning of this invention. For example, in the above embodiment, an electric heater is used as a heating means for heating the water in the water storage container 31 to form water vapor, but other heating means using induction heating such as IH or the like are used outside. The water in the water storage container 3 can also be evaporated using a heating means for circulating hot water heated by a heat pump.

  Further, in the above embodiment, the inside of the heat transfer tube 33 is held at a high pressure by forming the throttle 331 on the second end side of the heat transfer tube 33, but means for holding the inside of the heat transfer tube 33 at a high pressure is particularly However, the present invention is not limited to this. For example, by providing a valve on the second end side of the heat transfer tube 33, the inside of the heat transfer tube 33 can be held at a high pressure.

  Moreover, although the heat exchanger tube 33 in the said embodiment has taken the structure that internal water vapor | steam flows from the bottom to the top in the vacuum thawing warehouse 2, it can also be made the structure which flows from the top to the bottom. .

  In the above embodiment, the vacuum pump 41 and the exhaust vacuum pump 53 are used, but the exhaust vacuum pump 53 can be omitted and only the vacuum pump 41 can be used.

  In the above embodiment, when air enters the vacuum thawing chamber 2, the air in the vacuum thawing chamber 2 is activated by temporarily opening the second on-off valve 52 and starting the exhaust vacuum pump 53. Can be exhausted. Further, in this method, the water vapor in the vacuum thawing chamber 2 is also discharged together. However, as shown in FIG. 2, air separation means is provided between the vacuum pump 41 and the first and second discharge pipes 42 and 51. By installing 6, only the air in the vacuum thawing box 2 is discharged from the exhaust part 5, and the water vapor can be returned from the circulation part 4 to the vacuum thawing box 2. When the air separating means 6 is installed in this way, the exhaust vacuum pump 53 is turned on when the air amount in the air separating means 6 is equal to or higher than the upper limit set value, and is turned off when it is equal to or lower than the lower limit set value. Exhaust air operation may be introduced. The air separation means is not limited to the illustrated position.

  The vacuum pump 41 of the above embodiment can employ various pumps such as a blower type pump, a water ring type pump, and a roots type pump according to the degree of pressure increase. When a water ring type pump is adopted, it is necessary to cool water that is a working medium of the vacuum pump 41. For this reason, as shown in FIG. 3, a small refrigerator 7 is installed, and the cold water generated here is supplied to the vacuum pump 41 and at the same time, a water cooling device 8 that radiates the exhaust heat from the small refrigerator 7 (for example, The amount of heat released from a cooling tower, a water-air heat exchanger, etc.) can be reduced to dissipate heat to the water in the water storage container 31.

  Moreover, about the control method of the vacuum pump 41 and the electric heater 32 in the said embodiment, the vacuum pump 41 is made into a fixed exhaust operation (for example, constant rotation speed), and the pressure in the vacuum thawing chamber 2 is set beforehand. The electric heater 32 side may be controlled so that the pressure becomes (a pressure set to a constant value, or a pressure set to change with time).

  Further, the exhaust amount of the vacuum pump 41 can be divided into several stages, and the electric heater 32 can be controlled so that the pressure in the vacuum thawing chamber 2 becomes a preset pressure in each stage.

  Moreover, in the said embodiment, although the heating source of the to-be-thawed object F is only water vapor | steam, it can also be used together with other heating sources, such as a high frequency and a microwave.

  The heat transfer tube 33 can be a finned heat transfer tube, or a plurality of heat transfer tubes 33 can be connected in parallel instead of in series. Moreover, it is preferable that the surface of the heat transfer tube 33 is subjected to a surface treatment suitable for boiling water.

  Moreover, in the said embodiment, although the heat exchanger tube 33 is extended in the water storage container 3 and the downward direction of the to-be-thawed substance F, for example, it extends only in the water storage container 3, or it extends only under the to-be-thawed substance F. It may be.

It is the schematic which shows embodiment of the vacuum thawing apparatus which concerns on this invention. It is the schematic which shows other embodiment of the vacuum thawing apparatus which concerns on this invention. It is the schematic which shows other embodiment of the vacuum thawing apparatus which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vacuum thawing apparatus 2 Vacuum thawing warehouse 31 Water storage container 32 Electric heater (heating means)
33 Heat transfer tube 331 Restriction (high pressure holding means)
41 Vacuum pump 44 Circulation piping

Claims (9)

A vacuum thawing device for thawing an object to be thawed by the latent heat of water vapor,
A vacuum thawing chamber for storing the material to be thawed,
A water storage container disposed in the vacuum thawing chamber and containing water;
Heating means for heating the water in the water storage container to steam;
A vacuum pump for evacuating the vacuum thawing chamber;
A heat transfer tube extending through the water reservoir;
A circulation pipe having a first end connected to the discharge side of the vacuum pump and a second end connected to the first end of the heat transfer tube;
High-pressure holding means for holding the heat transfer pipe and the circulation pipe at a high pressure;
A vacuum thawing apparatus. A vacuum thawing device for thawing an object to be thawed by the latent heat of water vapor,
A vacuum thawing chamber for storing the material to be thawed,
A water storage container disposed in the vacuum thawing chamber and containing water;
Heating means for heating the water in the water storage container to steam;
A vacuum pump for evacuating the vacuum thawing chamber;
A heat transfer tube disposed below the material to be thawed in the vacuum thawing chamber;
A circulation pipe having a first end connected to the discharge side of the vacuum pump and a second end connected to the first end of the heat transfer tube;
High-pressure holding means for holding the heat transfer pipe and the circulation pipe at a high pressure;
A vacuum thawing apparatus.   The vacuum thawing apparatus according to claim 1 or 2, wherein the heating means is an electric heater.   The vacuum thawing device according to any one of claims 1 to 3, wherein the high-pressure holding means is a valve installed at a second end of the heat transfer tube.   The vacuum thawing apparatus according to any one of claims 1 to 3, wherein the high-pressure holding unit is configured by narrowing a second end of the heat transfer tube. The vacuum pump is connected to the first and second discharge pipes on the discharge side,
The first discharge pipe is connected to the circulation pipe via a first on-off valve,
The vacuum thawing device according to any one of claims 1 to 5, wherein the second discharge pipe is connected to an evacuation vacuum pump that evacuates the vacuum thawing chamber through a second on-off valve. Air separation means installed between the vacuum pump and the first and second discharge pipes;
The vacuum thawing apparatus according to claim 6, wherein the air separation unit sends water vapor to the first discharge pipe and sends air to the second discharge pipe.   The vacuum thawing apparatus according to any one of claims 2 to 7, further comprising control means for controlling heating by the electric heater so that the pressure in the vacuum thawing chamber becomes constant. The vacuum pump is a water ring vacuum pump,
The vacuum thawing apparatus further includes a refrigerator that cools water that is a working medium of the water ring vacuum pump,
The vacuum thawing device according to any one of claims 1 to 8, wherein the water in the water storage container is heated by the condensed exhaust heat of the refrigerator.

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