JPH05113279A - Method and apparatus for removing freezing of heat exchanger for supercooled water - Google Patents

Abstract

PURPOSE:To immediately restart manufacture of supercooled water by detecting a flowing state of water to be cooled in an inner tube, and rapidly heating the tube to removing freezing of the tube when the tube is frozen. CONSTITUTION:A flowing state of water to be cooled in an inner tube 8 is detected. A flow of brine in an outer tube 7 is stopped when the flow of the water to be cooled is stopped due to freezing, and the tube 8 is simultaneously heated. Thus, when the freezing in the tube 8 is removed and the flow of the water to be cooled is detected, heating of the tube 8 is stopped by a delay for a predetermined time, and the flow of the brine in the tube 7 is restarted simultaneously upon stopping of the heating.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a freezing releasing method and device for a supercooled water heat exchanger for cooling or supercooling water or the like below freezing.

[0002]

2. Description of the Related Art As a conventional apparatus for producing supercooled water, a spiral or spiral water pipe is immersed in a tank of brine (cooling medium), and the brine is stirred by a stirrer to cool the raw water in the water pipe. By passing raw water through the inner tube of the straight tube and the straight tube, and by passing brine through the outer tube, heat is exchanged.
A method of cooling raw water is known.

By the way, in the heat exchanger of these conventional supercooled water producing apparatuses, when the raw water in the water pipe is frozen due to various factors, in the former case, the water pipe is taken out from the brine tank and is heated by a heater. Unfreeze the water pipe.
In the latter case, after the brine of the outer pipe is discharged, the freezing inside the inner pipe is indirectly released by a heater from the outside of the outer pipe, or hot water is flowed into the outer pipe instead of the brine. You have to release the freeze.

However, in each of the above-mentioned freeze releasing means, a complicated work must be carried out for taking out the water pipe from the brine tank, discharging the brine, installing a heater, etc. When heating indirectly, the heating efficiency is poor, and there are many inconveniences such as it takes a long time to release the freeze. Furthermore, when the supercooled water is produced again after the freezing in the inner pipe is released, it takes time to prepare and start the supercooled water, so that efficient and continuous production of the supercooled water is impossible.

[0005]

SUMMARY OF THE INVENTION In view of the above problems, the present invention detects the flow state of water to be cooled in the inner pipe, and when the inner pipe is frozen, the inner pipe is quickly heated to It is an object of the present invention to provide a freezing release method and an apparatus therefor, which can release the freezing and immediately restart the production of supercooled water.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and in the method of releasing the freeze, the water to be cooled is circulated in the inner pipe forming the double pipe. A method of defreezing a heat exchanger in which brine is circulated in an outer pipe forming a double pipe and the inner pipe is cooled from the outer periphery, and a circulation state of water to be cooled in the inner pipe is detected. Then, when the flow of the brine in the outer pipe is stopped when the flow is stopped by freezing, the inner pipe is heated at the same time, and when the freezing in the inner pipe is eliminated and the flow of water to be cooled is detected, The heating of the inner pipe is stopped after a lapse of a set time, and at the same time, the flow of brine in the outer pipe is restarted.
Further, in the freeze releasing device, the water to be cooled is circulated in the inner pipe forming the double pipe and the brine is circulated in the outer pipe forming the double pipe to cool the inner pipe from the outer periphery. And a brine tank, the outer pipe and the brine tank are connected via a brine supply path and a brine return path, and the inner tube and the cold storage water tank are connected to the cold water supply path and the cold water return path. A brine circulation pump for supplying brine in the brine tank to the outer pipe is provided in the brine supply passage, and cooled water in the cold water storage tank is supplied to the inner pipe in the cold water supply passage. While providing a cold water supply pump to provide a freeze detection sensor to detect the presence or absence of freezing from the circulation state of the water to be cooled in the inner pipe, a heater for defreezing to heat the inner pipe when it is frozen, It In which characterized in that a controller for controlling the brine circulation pump and the unfrozen heater based on a detection signal of the freeze detection sensor.

[0007]

According to the present invention, the freeze detection sensor monitors the flow state of the cooled water in the inner pipe, and when the inner pipe freezes and the flow of the cooled water stops, the freeze detection sensor detects this. The detection signal is output to the controller. The controller receiving the detection signal from the freeze detection sensor outputs a stop signal for the brine circulation pump to stop its operation, and outputs an operation signal for the freeze release heater to start its operation. Then, when the freezing inside the inner tube is canceled by the operation of the heater for freezing and the circulation of the cooled water starts, the freezing detection sensor detects this and outputs the detection signal to the controller. The controller receiving the detection signal from the freeze detection sensor outputs the operation stop signal of the freeze release heater to stop its operation after a preset time has elapsed, and also outputs the operation signal of the brine circulation pump. To start its operation and restart the production of supercooled water.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a schematic explanatory view of a supercooled water production apparatus using a heat exchanger provided with a freeze release device according to the present invention. This supercooled water production apparatus includes a refrigerator 1, a brine tank 2, a heat exchanger 6 and It is composed of a cold water storage tank 20.

The refrigerator 1 uses, for example, a system in which the liquefied refrigerant is decompressed by the expansion valve 1a and then the brine (cooling medium) is cooled by latent heat of vaporization. It is equipped with a container 1b.

The heat exchanger 6 has an outer tube 7 as shown in FIG.
A double tube structure in which the inner tube 8 is inserted into the inside of the
Brine supplied from the brine tank 2 flows between the outer pipe 7 and the inner pipe 8, and cooled water supplied from the cool water storage tank 20 flows in the inner pipe 8. Therefore, the inner pipe 8 is cooled from the outer periphery to produce supercooled water.

The brine tank 2 and the outer pipe 7 of the heat exchanger 6 are
The brine supply passage 3 and the brine return passage 4 are connected to each other, and the brine supply passage 3 is provided with a brine circulation pump 5 that supplies brine cooled in the brine tank 2 into the outer pipe 7. Therefore, the cooled brine in the brine tank 2 will be the brine circulation pump 5
Thus, the inner pipe 8 is circulated in the brine tank 2 and the outer pipe 7, and the inner pipe 8 is cooled from the outer periphery while flowing in the outer pipe 7. And
The brine circulation pump 5 is connected to the controller 1 via the communication line 18.
7 and starts and stops the brine supply operation based on the output signal from the controller 17.

The inner pipe 8 of the heat exchanger 6 and the cold storage water tank 20 are
The cold water supply passage 12 and the cold water return passage 13 are connected to each other, and the cold water supply passage 12 is provided with a cold water supply pump 21 for supplying the cooled water in the cold storage water tank 20 into the inner pipe 8. Therefore, the water to be cooled in the cold storage water tank 20 circulates in the cold storage water tank 20 and the inner pipe 8 by the cold water supply pump 21, and while flowing in the inner pipe 8, the brine flowing in the outer pipe 7 Is cooled to become supercooled water and is returned to the cold storage water tank 20. Further, the cold water supply passage 12 between the cold water supply pump 21 and the inner pipe 8 is provided with a freeze detection sensor 14 that detects the flow state of the water to be cooled in the inner pipe 8. This freezing detection sensor 14 constantly monitors the flow state of the water to be cooled in the inner pipe 8, and when the water to be cooled in the inner pipe 8 freezes due to cooling by the brine, the flow of the water to be cooled is stopped. A detection signal indicating that the inside of the inner pipe 8 is frozen is output to the controller 17 via the communication line 19, and the frozen water in the inner pipe 8 is frozen due to the heating operation of the freeze release heater 15. When it is resolved and the distribution is restarted, a detection signal indicating that the freezing in the inner pipe 8 is resolved is output to the controller 17 via the communication line 19. In this embodiment, the freeze detection sensor 14
Will be described as being provided in the cold water supply passage 12, but the configuration is not limited to this, and a configuration in which the freeze detection sensor 14 is provided in the cold water return passage 13 is also suitable depending on the implementation.

As shown in detail in FIG. 2, both ends of the outer tube 7 are sealed by a lid member 9 with the inner tube 8 installed therein, and a mounting member 10 is provided near both ends.
Respectively, and holes (reference numeral omitted) penetrating into the outer pipe 7 are formed at respective portions to which the mounting member 10 is fixed, and the brine supply path 3 is connected to one hole and the other hole is connected to the other hole. The brine return path 4 is connected.
Also, as shown in detail in FIG. 2, the inner pipe 8 is also connected at one end thereof with a cold water supply passage 12 via a connecting member 11, and at the other end thereof, illustration is omitted. However, the cold water return passage 13 is also connected via the connecting member 11.

In the present invention, when the inside of the inner tube 8 is frozen, the freeze releasing heater 15 for releasing the freeze is composed of a linear or tape-shaped electric resistance wire. As shown, the inner tube 8 is attached to the outer circumference over at least two-thirds of its total length. The freeze release heater 15 is connected to the controller 17 via the communication line 16, and starts and stops the heating operation based on the output signal from the controller 17.

Brine circulation pump 5, freeze detection sensor 1
4 and heater 15 for defrosting and communication line 1 respectively
The controller 17 connected via 8, 19, 16 controls the operation of the brine circulation pump 5 and the freeze release heater 15 based on the detection signal from the freeze detection sensor 14.

As described above, the cold water storage tank 20 is connected to the inner pipe 8 of the heat exchanger 6 via the cold water supply passage 12 and the cold water return passage 13, and is cooled by brine while flowing through the inner pipe 8. The cooled water that has become supercooled water is the cold water return path 1
Inflow from 3. Part of the supercooled water that has flowed into the cold storage water tank 20 is frozen, and the frozen water can be stored in the frozen state. Then, in the cold water storage tank 20, a hot water supply valve 22 for supplying hot water into the cold water storage tank 20 for defrosting, and an extraction valve 2 for taking out the obtained cooling water.
3 and 3 are provided.

In the structure of the supercooled water producing apparatus described in the above embodiment, the brine (cooling medium) cooled to a predetermined temperature (about -10 ° C) in the brine tank 2 is used.
Is driven by the brine circulation pump 5, and is indicated by an arrow A in FIG.
As shown by, it is introduced into the outer pipe 7 of the heat exchanger 6 via the brine supply passage 3. The brine introduced into the outer pipe 7 cools the inner pipe 8 from the outer periphery while circulating in the outer pipe 7, and cools the water to be cooled in the inner pipe 8. Then, the brine that has finished flowing through the outer pipe 7 is returned to the brine tank 2 through the brine return passage 4 as shown by an arrow B in FIG. 1.

With respect to the circulation of the brine, the water to be cooled in the cold storage water tank 20 is driven by the cold water supply pump 21 to be transferred to the inside of the heat exchanger 6 via the cold water supply passage 12 as shown by an arrow C in FIG. It is introduced into the tube 8. That is, the water to be cooled flowing through the inner pipe 8 is introduced so as to flow in the direction opposite to the flow direction of the brine. The water to be cooled introduced into the inner pipe 8 is cooled by the brine flowing in the opposite direction while flowing through the inner pipe 8 to become supercooled water. Then, the supercooled water in the inner pipe 8 is cooled by the cold water return passage 1 as shown by an arrow D in FIG.
3 flows into the cold storage water tank 20 and a part thereof is frozen in the cold storage water tank 20. At this time, since the water to be cooled flows through the inner pipe 8 and the brine flows between the outer pipe 7 and the inner pipe 8, the heat transfer coefficient is improved.

As described above, the water to be cooled that has passed through the inner pipe 8 becomes supercooled water having a temperature below the freezing point (about -4 ° C.) when it is returned to the cold storage water tank 20, and about 5% of it is Since the ice pieces are turned into ice pieces, a continuous operation can store a required amount of ice blocks and sorbets in the cold storage water tank 20.

In the supercooled water production process as described above,
When the supercooled water freezes in the inner pipe 8 of the heat exchanger 6 due to an unexpected accident and the flow of the cooled water in the inner pipe 8 stops, the freeze detection sensor 14 detects this and The detection signal is output to the controller 17. Upon receiving the detection signal from the freeze detection sensor 14, the controller 17 outputs a stop signal for the brine circulation pump 5 to stop the brine supply operation. At the same time, an operation start signal of the freeze release heater 15 is output to start the heating operation. When the heating operation of the freeze release heater 15 is started, the heat is transferred to the inner tube 8
And heats the ice frozen in the inner pipe 8 to melt the ice. At this time, part of the heat also heats the brine at the same time. In the embodiment shown in FIG. 1, the brine thus warmed rises along the outer circumference of the inner pipe 8 and also heats the upper portion of the inner pipe 8. That is, the inner pipe 8 is heated by the freeze release heater 15 as well as by the brine, so that the frost on the inner pipe 8 is melted in a short time.

As described above, the frozen ice in the inner pipe 8 is melted by the heating operation of the defreezing heater 15, but the water melted in the inner pipe 8 is heavier than the ice, so Tends to concentrate on the bottom. Therefore, if the cold water supply pump 21 is driven even while the inner tube 8 is being heated by the freeze release heater 15, the ice in the center of the inner tube 8 will melt as the ice that comes into contact with the wall of the inner tube 8 melts. Becomes a plug shape, is pushed by the water pressure of the cold water supply pump 21, moves toward the outlet of the inner pipe 8 and is pushed out of the pipe. As a result, the ice in the inner pipe 8 is removed from the pipe. If this state is continued for a certain period of time, the ice frozen in the inner pipe 8 gradually melts and becomes water, which flows into the cold storage water tank 20 through the cold water return passage 13. In this way, when the freezing in the inner pipe 8 is eliminated and the flow of the water to be cooled starts, the freezing detection sensor 1
4 detects and outputs the detection signal to the controller 17. Controller 17 that receives a detection signal from the freeze detection sensor 14
In order to make the defrosting more complete, the heating operation for the freeze releasing heater 15 is continued for a certain period of time, and after the set time has elapsed, a stop signal for the freeze releasing heater 15 is output, and the heating operation is stopped. Stop. At the same time, an operation start signal for the brine circulation pump 5 is output to start the brine supply operation. This brine circulation pump 5
By driving the above, the production of supercooled water will be restarted.

[0022]

As described above, according to the present invention, the flow state of the water to be cooled in the inner pipe can be constantly detected, and when the inner pipe is frozen, the freezing in the inner pipe can be quickly released. Thus, the production of supercooled water can be resumed in a short time, and the supercooled water can be produced efficiently and continuously. Also, a freeze detection sensor,
It is designed to be able to automatically perform freezing release by a controller or the like, and when restarting the production of supercooled water, complicated work such as preparation for restart can be eliminated,
It is effective in promoting labor saving. Furthermore, it is possible to make the structure relatively compact and compact, and it is very effective for defrosting this type of heat exchanger.

[Brief description of drawings]

FIG. 1 is a schematic explanatory diagram of an apparatus for producing supercooled water by a heat exchanger provided with a freeze release device according to the present invention.

FIG. 2 is a partial cross-sectional view showing an enlarged part of the heat exchanger shown in FIG.

FIG. 3 is an enlarged sectional view taken along line III-III in FIG.

[Explanation of symbols]

 2 Brine Tank 3 Brine Supply Channel 4 Brine Reflux Channel 5 Brine Circulation Pump 6 Heat Exchanger 7 Outer Tube 8 Inner Tube 12 Chilled Water Supply Channel 13 Chilled Water Circulation Channel 14 Freezing Detection Sensor 15 Freezing Release Heater 17 Controller 20 Cold Water Storage Tank 21 Cold Water Supply pump

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Akio Morita 3-chome, Asahi-cho, Nishi-Biwajima-cho, Nishi-Kasugai-gun, Aichi Prefecture Air-conditioning factory, Mitsubishi Heavy Industries, Ltd. Asahi-cho 3-chome Mitsubishi Heavy Industries, Ltd. Air Conditioning Factory

Claims (2)

[Claims] 1. Cooling water is circulated in an inner pipe 8 forming a double pipe and brine is circulated in an outer pipe 7 forming a double pipe to cool the inner pipe 8 from the outer periphery. A method for defrosting a heat exchanger (6), comprising the inner tube (8)
The flow state of the water to be cooled inside is detected, and when the flow is stopped due to freezing, the flow of the brine inside the outer pipe 7 is stopped, and at the same time, the inner pipe 8 is heated. When the freezing is eliminated and the circulation of the water to be cooled is detected, the heating of the inner pipe 8 is stopped after a preset time elapses, and at the same time, the circulation of the brine in the outer pipe 7 is restarted. How to unfreeze a water heat exchanger. 2. Cooling water is circulated in the inner pipe 8 forming the double pipe, and brine is circulated in the outer pipe 7 forming the double pipe to cool the inner pipe 8 from the outer periphery. Which is a freezing release device for the heat exchanger 6
And the brine tank 2 are connected via a brine supply passage 3 and a brine return passage 4, and the inner pipe 8 and the cold storage water tank 20 are connected via a cold water supply passage 12 and a cold water return passage 13.
The brine supply passage 3 is provided with a brine circulation pump 5 for supplying the brine in the brine tank 2 into the outer pipe 7, and the cold water supply passage 12 is provided with the cooled water in the cold storage water tank 20 in the inner pipe 8. A cold water supply pump 21 for supplying the inner pipe 8 with the cold water supply pump
Heater for defrosting 1 that heats when it freezes
5, and a controller 17 for controlling the brine circulation pump 5 and the freeze releasing heater 15 based on the detection signal of the freezing detection sensor 14 is provided. Freezing release device.