JP2013245860A - Vacuum cooling apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent trouble occurring in a vacuum generation device and to improve cooling capability by sufficiently separating moisture by condensing steam from suction air while minimizing an increase in a footprint, and thereby reducing the amount of moisture sent to the vacuum generation device 1.SOLUTION: A vacuum cooling apparatus includes a cooling tank 2 housing a body to be cooled and a vacuum generation device 1 sucking air in the cooling tank, and cools the body to be cooled by vacuumizing the cooling tank. The vacuum cooling apparatus further includes a plurality of heat exchangers 5 installed between the cooling tank 2 and vacuum generation device 1. In order that air sucked from the cooling tank 2 is cooled by upstream-side heat exchangers A, B and then cooled by a downstream-side heat exchanger C, the heat exchangers are connected in series, the upstream-side heat exchangers A, B are connected together so that the sucked air flows in parallel, and the downstream-side heat exchanger C is connected so that the sucked air flows in a single stream.

Description

The present invention relates to a vacuum cooling device that depressurizes a cooling tank with a vacuum generator and cools an object to be cooled in the cooling tank by heat of vaporization.

As described in JP-A-2005-134085, there is a vacuum cooling device as a device for cooling food. The vacuum cooling device contains the food to be cooled in the cooling tank, and the cooling tank is evacuated by a vacuum generator comprising a water ejector, a vacuum pump, etc., and the water content in the food is reduced by lowering the saturated vapor temperature. It vaporizes and cools food. In the case of vacuum cooling, since it can be rapidly cooled from the inside of the food, it can be cooled in a short time.

In a vacuum cooling device that lowers the temperature of an object to be cooled by evaporating moisture in the object to be cooled, the moisture generated by vaporization and vapor is sucked together with air by the vacuum generator. However, since the volume of water becomes significantly large when it becomes steam, if the vacuum generator sucks it in the state of steam, the load on the vacuum generator increases. Therefore, in the vacuum cooling device, a heat exchanger is provided in the middle of the vacuum pipe portion connecting the cooling tank and the vacuum generator, and the volume is reduced by cooling and condensing the steam. By providing a plurality of heat exchangers and cooling them in multiple stages, more heat can be taken from the air, and the volume of the air can be reduced by condensing the steam. If the volume of air that must be discharged is reduced, the vacuum generator can discharge a large amount of air in the cooling tank earlier, and thus the cooling capacity can be increased.

When the vacuum generator is a dry roots type vacuum pump, in the vacuum pump, the two three-leaf rotors rotating in opposite directions inside the casing rotate with a slight gap between the casing inner wall and the rotor. It has a structure that performs an exhaust operation. Therefore, if a large amount of steam (water) flows into the vacuum pump, the oil seal that separates the gear chamber and the exhaust chamber with the rotor may be damaged. Furthermore, if the operation is stopped for a long time while moisture remains in the pump, the rotor and the casing may stick to each other and cannot be started at the start of the next operation.

For this reason, it is necessary to drain and separate the vapor contained in the sucked air at the primary side of the dry roots vacuum pump, and the vacuum pipe section is provided with a large-capacity heat exchanger. Was removed. However, when a large heat exchanger is provided, there is a problem that the installation area of the apparatus becomes large.

JP 2005-134085 A

The problem to be solved by the present invention is to reduce the amount of moisture sent to the vacuum generator by sufficiently separating the moisture by condensing the vapor from the suction air while minimizing the increase in the installation area. An object of the present invention is to provide a vacuum cooling device capable of preventing problems in the vacuum generator and improving the cooling capacity.

The invention according to claim 1 has a cooling tank for storing an object to be cooled and a vacuum generator for sucking air in the cooling tank, and cooling the object to be cooled by evacuating the inside of the cooling tank. In the device, a plurality of heat exchangers are installed between the cooling tank and the vacuum generator, and the air sucked from the cooling tank is cooled by the upstream heat exchanger and then cooled by the downstream heat exchanger. The upstream heat exchanger connects the heat exchanger so that the sucked air flows in parallel, and the sucked air flows in a single row in the downstream heat exchanger. In this way, the heat exchangers are connected.

According to a second aspect of the present invention, in the vacuum cooling apparatus, each heat exchanger has a horizontally long outer shell, and the center axis of each heat exchanger is inclined at one end with respect to the horizontal direction. Is installed so that it is lower than the other end, and the heat exchanger is installed such that a plurality of heat exchangers are stacked in the vertical direction, and the lower side of each heat exchanger is installed. A drain pipe for draining is connected to the lower wall surface.

The invention described in claim 3 is characterized in that, in the vacuum cooling apparatus, the pipe connecting the heat exchangers is connected so as to be perpendicular to the central axis of the heat exchanger.

By implementing the present invention, it is possible to reduce the amount of moisture reaching the vacuum generator while minimizing the increase in the installation area and manufacturing cost of the apparatus, preventing problems with the vacuum generator and cooling. Ability can be improved.

Configuration schematic diagram of a vacuum cooling apparatus implementing the present invention Explanatory drawing of the connection structure of the heat exchanger part of the vacuum generator implementing the present invention Flow explanatory drawing of the heat exchanger part of the vacuum generator which is implementing this invention

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram of a configuration of a vacuum cooling apparatus embodying the present invention, FIG. 2 is an explanatory diagram of a connection structure of a heat exchanger part of a vacuum generating apparatus embodying the present invention, and FIG. It is a flow explanatory view of the heat exchanger part of the vacuum generator which is.

The vacuum cooling device includes a cooling tank 2 that accommodates an object to be cooled, a vacuum generator 1 that sucks air from the cooling tank 2, a vacuum pipe section 9 that connects the cooling tank 2 and the vacuum generator 1, and the like. The cooling tank 2 is a substantially rectangular parallelepiped container having a door on its side surface, and allows an object to be cooled to be accommodated and sealed. As the vacuum generator 1, an ejector that sucks air using water or steam, or a vacuum pump that sucks air by rotation of a rotor is used. Here, it is assumed that a dry-type vacuum pump that can simplify the apparatus configuration is used.

Since the vacuum cooling device is for depressurizing the inside of the cooling tank to evaporate moisture in the object to be cooled and cool the object to be cooled, the sucked air contains steam. As it is, a large amount of steam is sent to the vacuum generator 1, so the steam is removed by the vacuum piping section 9 on the way.
Separation of the steam from the suction air is performed by condensing the steam by cooling the suction air. Therefore, a plurality of heat exchangers 5 are provided in the middle of the vacuum pipe section 9. The heat exchanger 5 is supplied with cooling water that is manufactured by the chiller 4 and stored in the cooling water tank 3, and heat is exchanged between the air sucked from the cooling tank 2 and the cooling water. In this way, the suction air is cooled.

The heat exchanger 5 includes a horizontally long cylindrical container and a heat exchange section provided in the container. Heat exchange is performed by flowing suction air on one surface of the heat exchange section and cooling water on the other surface. I do. There are a plurality of heat exchangers that are stacked in the vertical direction, and the heat exchanger 5 is named heat exchanger A, heat exchanger B, and heat exchanger C in order from the top. A drain tank 8 for accumulating the drain generated in the heat exchanger 5 is installed below the stacked heat exchangers 5, and a drain pipe 7 is connected between the heat exchanger 5 and the drain tank 8 for heat exchange. The drain of the vessel 5 flows down to the drain tank 8 through the drain pipe 7.

The plurality of installed heat exchangers are installed in parallel between the respective heat exchangers, but in each heat exchanger, the center axis in the longitudinal direction is installed with a slight inclination with respect to the horizontal. Therefore, the position of one end of each heat exchanger is higher than the other end. The cooling tank pipe 6 that connects the cooling tank 2 and the heat exchanger A is connected to the upper wall surface on the side where the installation height of the heat exchanger A is high, and the cooling tank pipe 6 and the heat exchanger A are connected. And, on the lower wall surface on the side where the installation height of the heat exchanger A is high, the parallel pipe 10 connected to the upper wall surface on the side where the installation position in the heat exchanger B is high is installed, The inside of the heat exchanger B is connected by a parallel pipe 10.

Further, a drain pipe 7 for sending the drain generated by the heat exchanger to the drain tank 8 is connected near the end portion on the side where the installation height of each heat exchanger is low. The drain pipe 7 is installed so as to connect the inside of each heat exchanger, and the drain generated in each heat exchanger flows down into the lower heat exchanger through the drain pipe 7, and the lower heat exchanger that has flowed down. After merging with the generated drain, it flows down to the lower heat exchanger and finally enters the drain tank 8. Then, a vacuum generator pipe 11 that connects the vacuum generator 1 and the heat exchanger C is connected to the upper wall surface on the side where the installation height of the heat exchanger C is high. The vacuum generator 1 is connected to the vacuum generator pipe 11. Through the heat exchanger C.

When air is sucked by the vacuum generator 1, the vacuum generator 1 sucks air in the cooling tank 2 through the vacuum pipe portion 9. The air in the cooling tank 2 enters the heat exchanger through the cooling tank pipe 6, passes through the heat exchanger 5, and then flows to the vacuum generator 1 through the vacuum generator pipe 11. In the heat exchanger 5 portion, the heat exchanger A and the heat exchanger B and the heat exchanger B and the heat exchanger C are connected by the drain pipe 7, so that the heat exchanger 5 enters the heat exchanger 5 from the cooling tank 2. The air flows to the downstream heat exchanger through the drain pipe 7 connected to the lower end of the heat exchanger. The air reaching the lowermost heat exchanger C flows to the vacuum generator 1 through the vacuum generator pipe 11 connected to the upper end of the heat exchanger C.

Moreover, since the heat exchanger A and the heat exchanger B are connected by the parallel pipe 10, the air that has entered the heat exchanger A crosses the heat exchanger A and is connected to the heat exchanger B. It flows toward the drain pipe 7 and also flows toward the parallel pipe 10 that is cut through the heat exchanger A and connected to the heat exchanger B. Since the air that has entered the heat exchanger B through the parallel pipe 10 flows toward the drain pipe 7 that connects the heat exchanger B and the heat exchanger C, the air flows across the heat exchanger B. Therefore, the air from the cooling tank 2 that has passed through the cooling tank pipe 6 flows through both the heat exchanger A and the heat exchanger B in parallel.

The air that has reached the end of the heat exchanger A enters the heat exchanger B through the drain pipe 7 connecting the heat exchanger A and the heat exchanger B. Since the outlet of the heat exchanger B is only the drain pipe 7 connecting the heat exchanger B and the heat exchanger C, the air flowing in parallel through the heat exchanger A and the heat exchanger B joins in the heat exchanger B. Then, it flows to the heat exchanger C. In the heat exchanger C, since air flows to the vacuum generator 1 through the vacuum generator pipe 11, the air that has entered the heat exchanger C from the heat exchanger B aims at the vacuum generator pipe 11. To cross.

The air flow in the heat exchanger 5 is caused to flow in parallel in the heat exchanger A and the heat exchanger B, and merged in the heat exchanger C for the following reason. In the heat exchanger 5, the air flow path area is reduced in order to perform efficient heat exchange. The upstream heat exchanger that has just been sucked from the cooling bath 2 and flows air before cooling has a large volume because it contains a large amount of steam. Therefore, the resistance of the air flow is increased in the upstream heat exchanger. However, in the downstream heat exchanger in which air after condensing a certain amount of steam by cooling in the upstream heat exchanger flows, the volume is small because the amount of steam is small. Therefore, the heat exchange efficiency is low in the downstream heat exchanger. The upstream side allows the two heat exchangers to flow in parallel, and the downstream side allows the air to flow into one heat exchanger, thereby efficiently cooling the air without increasing the air flow resistance.

When the suction air is cooled, the vapor in the air condenses into a drain, and the drain falls to the bottom of the heat exchanger. Since the heat exchanger 5 is inclined and installed, the drain that has reached the bottom of the heat exchanger flows toward the lower side of the heat exchanger, and goes to the drain pipe 7 provided at the lower end of the heat exchanger. . The drain generated in the heat exchanger A enters the heat exchanger B through the drain pipe 7 connecting the heat exchanger A and the heat exchanger B, and joins the drain generated in the heat exchanger B. The drain merged in the heat exchanger B enters the heat exchanger C through the drain pipe 7 connecting the heat exchanger B and the heat exchanger C, and merges with the drain generated in the heat exchanger C. The drain merged in the heat exchanger C is accumulated in the drain tank 8 through the drain pipe 7 connecting the heat exchanger C and the drain tank 8.

By condensing and separating the steam in the heat exchanger 5, the amount of moisture entering the vacuum generator 1 can be reduced. Further, when the vapor condenses, the volume is greatly reduced, so that the amount of air can be reduced. By reducing the amount of air sucked by the vacuum generator 1, it is possible to increase the pressure reduction speed in the cooling tank 2, to reduce the pressure to a higher degree of vacuum, shorten the time required for vacuum cooling, and finally The cooling temperature can be further lowered.

In each heat exchanger, the central axis is installed with a slight inclination with respect to the horizontal direction in order to facilitate drainage. However, the drain pipe 7 and the parallel pipe 10 have a central axis that is vertical. Even if it is slightly inclined with respect to the vertical direction, there is no significant difference in drain discharge or the like. However, when the heat exchanger 5 is connected to the drain pipe 7 and the parallel pipe 10 by welding at the time of manufacture, it is easier to manufacture the heat exchanger 5 and the drain pipe 7 etc. if they intersect at right angles. There are advantages. When the drain pipe 7 or the like is connected to the heat exchanger 5 so as to be perpendicular to the floor surface, the individual heat exchangers 5 are inclined, so that the joint surfaces with the heat exchangers 5 are inclined. It is necessary and time-consuming. Since the drain pipe 7 and the like do not have to be perpendicular to the floor surface, the drain pipe 7 and the like are slightly inclined from the vertical to the floor surface, but the heat exchanger 5 and the drain pipe 7 and the like are at right angles. If it crosses, since manufacture becomes easy, manufacturing cost can be reduced.

The present invention is not limited to the embodiments described above, and many modifications can be made by those having ordinary knowledge in the art within the technical idea of the present invention.

DESCRIPTION OF SYMBOLS 1 Vacuum generator 2 Cooling tank 3 Cooling water tank 4 Chiller 5 Heat exchanger 6 Cooling tank piping 7 Drain piping
8 Drain tank 9 Vacuum piping 10 Parallel piping 11 Vacuum generator piping

Claims (3)

In a vacuum cooling apparatus having a cooling tank for storing an object to be cooled and a vacuum generator for sucking air in the cooling tank and cooling the object to be cooled by evacuating the cooling tank, the cooling tank and the vacuum generator A plurality of heat exchangers are installed in between, and the air sucked from the cooling tank is connected in series so that the air is cooled by the upstream heat exchanger and then cooled by the downstream heat exchanger. The upstream heat exchanger connects the heat exchanger so that the sucked air flows in parallel, and the downstream heat exchanger connects the heat exchanger so that the sucked air flows in a single row. A vacuum cooling device characterized by comprising: 2. The vacuum cooling device according to claim 1, wherein each heat exchanger has a horizontally long outer shell, and the center axis of each heat exchanger is inclined with respect to the horizontal direction so that one end is the other end. The heat exchanger is installed such that a plurality of heat exchangers are stacked in the vertical direction, and drainage is removed from the lower wall on the lower side of each heat exchanger. A vacuum cooling device characterized by connecting a drain pipe for use. 3. The vacuum cooling device according to claim 2, wherein the pipe connecting the heat exchangers is connected so as to be perpendicular to the central axis of the heat exchanger.

Images