JPH0665761U - Heat exchanger for supercooled water production equipment - Google Patents

Abstract

(57) [Abstract] [Purpose] To reliably prevent freezing in the heat exchanger, ensure stable operation over a long period of time, and improve thermal efficiency. A heat exchanger 3 having a double-pipe structure, which includes an outer pipe 6 and an inner pipe 7 inserted in the outer pipe 6,
The inner pipe 7 is constituted by a corrugated flexible pipe, and water to be cooled is circulated in the outer pipe 6, and the inner pipe 7
A structure in which a coolant is circulated therein to cool the water to be cooled in the outer pipe 6 from the inside, and further, the entire double pipe structure composed of both pipes 6 and 7 is formed in a spiral shape.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a heat exchanger in a supercooled water production system for cooling water to below freezing or supercooling.

[0002]

[Prior art]

 Conventionally, as a heat exchanger of a supercooled water manufacturing device, raw water is passed through an inner pipe of a straight or spiral double pipe or an inner pipe of a shell-and-tube heat exchanger, and a refrigerant such as brine is used as an outer pipe. A method is known in which raw water is cooled by performing heat exchange through.

By the way, in a conventional heat exchanger, as shown in FIG. 3, a circular tube is used as the inner tube 21, and this is inserted into an outer tube 22 which is also a circular tube, and in this state, a spiral shape is formed. What is formed is used. However, in this heat exchanger, since both the inner pipe 21 and the outer pipe 22 are straight pipes, the flow of water and the refrigerant is good, and therefore the heat efficiency is low.

Further, in the conventional linear heat exchanger, an inner tube having a large number of fins on the outer surface is used as the inner tube. However, in this heat exchanger, attaching a large number of fins to the outer surface of the inner tube requires a lot of time and effort to attach the fins, and also increases the cost. In addition to this, since the fins block the flow of the refrigerant, there is a problem that it easily freezes.

[0005]

[Problems to be solved by the device]

 In view of the above problems, the present invention aims to reliably prevent freezing in the heat exchanger, ensure stable operation over a long period of time, and improve the thermal efficiency.

[0006]

[Means for Solving the Problems]

 The present invention has been made in order to solve the above-mentioned problems, and is a heat exchanger having a double pipe structure including an outer pipe and an inner pipe inserted in the outer pipe. Is constituted by a corrugated flexible tube, and while the water to be cooled is circulated in the outer tube, a refrigerant is circulated in the inner tube to cool the water to be cooled in the outer tube from the inside. Further, it is characterized in that the entire double-tube structure composed of both tubes is formed in a spiral shape.

[0007]

[Action]

 According to this invention, since the inner tube is formed in a corrugated shape, the heat transfer surface area is increased and the heat exchange rate is improved. Since the entire double-tube structure consisting of the corrugated inner tube and the outer tube is formed in a spiral shape, the water to be cooled flowing through the outer tube is mixed well and the temperature in the cross section is uniform. It will be close and there will be no freeze.

[0008]

【Example】

 Hereinafter, a specific embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic explanatory view of a supercooled water production apparatus including a heat exchanger according to the present invention.

In FIG. 1, the supercooled water producing apparatus 1 is basically composed of a refrigerator 2, a heat exchanger 3 and a cold storage water tank 4.

The refrigerator 2 condenses and liquefies a refrigerant such as CFC gas under high pressure, and circulates the liquefied refrigerant directly into the heat exchanger 3. The refrigerator 2 includes an expansion valve 5 for decompressing the refrigerant. There is. That is, the liquefied refrigerant is decompressed by the expansion valve 5, is circulated in the heat exchanger 3, and the water to be cooled is directly cooled by the latent heat of vaporization of the refrigerant during this circulation process.

The heat exchanger 3 has a double pipe structure composed of an outer pipe 6 and an inner pipe 7 inserted inside the outer pipe 6, and the entire double pipe structure is formed in a spiral shape. It is configured as a The cooled water supplied from the cold storage water tank 4 flows between the outer pipe 6 and the inner pipe 7, and the refrigerant supplied from the refrigerator 2 flows in the inner pipe 7. . Therefore, the cooling water in the outer pipe 6 is cooled from the inside to produce supercooled water.

The inner pipe 7 of the heat exchanger 3 and the refrigerator 2 are connected via a refrigerant supply passage 8 and a refrigerant return passage 9 connected to the expansion valve 5. Therefore, according to this configuration, the liquefied refrigerant circulates in the inner pipe 7 and the refrigerator 2 through the refrigerant supply passage 8 and the refrigerant return passage 9, and is circulated in the inner pipe 7 while being circulated. The water to be cooled in the pipe 6 is cooled from the inside.

The outer pipe 6 of the heat exchanger 3 and the cold storage water tank 4 are connected via a cold water supply passage 10 and a cold water return passage 11, and the cold water supply passage 10 is connected to the cooled water in the cold storage water tank 4. A cold water supply pump 12 for supplying the water into the outer pipe 6 is provided. Therefore, the water to be cooled in the cold storage water tank 4 circulates in the cold storage water tank 4 and the outer pipe 6 by the cold water supply pump 12, and while flowing in the outer pipe 6, the refrigerant flowing in the inner pipe 7. Is cooled from the inside by the above to become supercooled water, which is returned to the cold storage water tank 4.

Now, the outer pipe 6 and the inner pipe 7, which are essential parts of the heat exchanger 3 according to the present invention, will be described in more detail. First, as shown in detail in FIG. 2, the outer tube 6 is sealed at both ends with a lid member 13 in a state where the inner tube 7 is installed, and mounting members 14 are provided near both ends. Holes (reference numeral omitted) penetrating into the outer pipe 6 are formed in the portions to which the mounting members 14 are fixed, and the cold water supply passage 10 is connected to one of the holes and the cold water to the other hole. The return path 11 is connected (illustration regarding the connection state on this side is omitted). Next, as shown in detail in FIG. 2, the inner pipe 7 is also connected to the refrigerant supply passage 8 at one end through a connecting member 15, and is not shown at the other end. However, the refrigerant return path 9 is also connected via the connecting member 15.

Further, the inner tube 7 in the present invention is constituted by a flexible tube having a corrugated shape, as shown by the uneven shape in FIG. This flexible tube is a thin-walled stainless steel tube that is bellows molded in the axial direction. Both ends are not molded, and the flexible tube is connected to the refrigerant supply passage 8 and the refrigerant return passage 9 and the outer pipe 6. The seal is designed to be easy and reliable. The flexible tube used as the inner tube 7 is a marketable product, and is usually called a corrugated tube or a Benley tube. Since it is beveled, it is easy to bend and has good workability. Is. It is also preferable to use bellows molded up to both ends depending on the implementation.

By the way, the heat exchanger 3 according to the present invention has a double pipe structure composed of the outer pipe 6 and the inner pipe 7 configured as described above. One of the features is that the entire double-tube structure is formed in a spiral shape. This point will be described in detail below.

In the present invention, the reason why the entire double-tube structure is formed in a spiral shape is based on the following findings. That is, since the water to be cooled flowing between the outer pipe 6 and the inner pipe 7 is curved in both pipes 6 and 7, the centrifugal force acting on the water to be cooled when flowing in the pipe axial direction through the curved portion. A pressure distribution occurs in the direction of the radius of curvature so that On the other hand, the fluid in the corrugated portion of the inner pipe 7 is not subjected to centrifugal force because the flow in the pipe axial direction is blocked. Therefore, a flow is generated along the corrugated fold from the higher pressure side to the lower pressure side (that is, the centripetal direction of the curved portion), and after half-circling the inner tube 7 on both sides, the corrugated fold portion It flows out and mixes with the mainstream. That is, by forming a double pipe structure having the inner pipe 7 formed of a corrugated flexible pipe in a spiral shape, the water to be cooled flowing outside the inner pipe 7 has a pipe shaft. A directional flow and a centripetal flow occur, and these flows have a favorable effect on the stirring action of the water to be cooled, and as a result, the water to be cooled is well mixed in this double pipe and the temperature in the cross section is increased. Is close to uniform. As a result, freezing of the water to be cooled can be effectively and surely prevented, and long-term stable operation becomes possible.

Next, the cold water storage tank 4 will be described. The cold water storage tank 4 is connected to the outer pipe 6 of the heat exchanger 3 via the cold water supply passage 10 and the cold water return passage 11 as described above. Therefore, the water to be cooled that has flowed from the cold storage water tank 4 into the heat exchanger 3 via the cold water supply passage 10 is cooled from the inside by the refrigerant flowing in the inner pipe 7 while flowing in the outer pipe 6. It becomes supercooled water and flows into the cold storage water tank 4 through the cold water return passage 11. Part of the supercooled water that has flowed into the cold storage water tank 4 is frozen, and the frozen water can be stored in the frozen state. The cold water storage tank 4 is provided with a raw water supply valve 16 for supplying raw water into the cold water storage tank 4 for deicing, and an extraction valve 17 for taking out the obtained cooling water.

In the configuration of the supercooled water producing apparatus 1 described in the above embodiment, the refrigerant (for example, freon) liquefied in the condenser (not shown) of the refrigerator 2 is decompressed by the expansion valve 5 to a predetermined level. The temperature is adjusted (about -4 ° C.) and introduced into the inner pipe 7 of the heat exchanger 3 via the refrigerant supply passage 8 as shown by an arrow A in FIG. The refrigerant introduced into the inner pipe 7 cools the water to be cooled flowing from the inner side of the inner pipe 7 while flowing through the inner pipe 7. Then, the refrigerant that has finished flowing through the inner pipe 7 is recirculated into the refrigerator 2 via the refrigerant recirculation passage 9 as shown by an arrow B in FIG.

With respect to the circulation of the refrigerant, the water to be cooled in the cold water storage tank 4 is heated by the driving of the cold water supply pump 12 via the cold water supply passage 10 as shown by an arrow C in FIG. It is introduced into the outer pipe 6 of the exchanger 3. The water to be cooled introduced into the outer pipe 6 flows outside the inner pipe 7 made of the corrugated flexible pipe. At this time, the water to be cooled has a flow in the axial direction of the pipe and a centripetal direction. It flows while being accompanied by a stirring action by the flow, and during this distribution, it is cooled from the inside by the refrigerant flowing in the inner pipe 7 to become supercooled water. As described above, the water to be cooled circulates in the outer pipe 6 with a stirring action, the mixing is good, and the temperature in the cross section is close to uniform, so that a part to be partially frozen occurs. Instead, it becomes supercooled water. Therefore, the situation that the inside of the outer tube 6 is frozen is automatically and beforehand prevented. Then, the supercooled water that has passed through the outer pipe 6 flows into the cold storage water tank 4 through the cold water return passage 11 as shown by an arrow D in FIG. 1, and a part thereof is frozen in the cold storage water tank 4. .

In this way, when the water to be cooled passes through the heat exchanger 3 and flows back into the cold storage water tank 4, it is supercooled water having a temperature below the freezing point (about −2 ° C.). Approximately 5% of the ice cubes are turned into ice pieces, so that by continuously operating the supercooled water production system 1, it is possible to store a required amount of ice blocks and sherbets in the cold storage water tank 4.

The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above-mentioned embodiment, and can be appropriately modified according to the implementation. For example, in the above-described embodiment, the configuration in which the refrigerant and the water to be cooled are parallel flows has been described as a specific example of the circulation directions in the heat exchanger 3, but it is also preferable to implement this as a counter flow. is there.

[0024]

[Effect of device]

 As described above, according to this invention, since the inner pipe is formed in a corrugated shape, the heat transfer surface area between the refrigerant and the water to be cooled can be significantly increased, and the thermal efficiency can be improved with a relatively simple structure. Can be improved. Further, since a desired heat transfer surface area can be secured with a simple structure, it is extremely easy to downsize the heat exchanger itself.

In addition, since the entire double pipe structure including the corrugated inner pipe and the outer pipe is formed in a spiral shape, the cooled water flowing in the outer pipe is in a circulation state with a stirring action, As a result, the water to be cooled is well mixed and the temperature in the cross section is close to uniform, and the freezing of the water to be cooled in the outer pipe can be effectively and reliably prevented, ensuring stable operation over a long period of time. Can be secured.

Furthermore, since the inner tube is formed of a corrugated flexible tube, it can be formed relatively easily and reliably even when the entire double tube structure is formed in a spiral shape. It is very effective as a heat exchanger.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view for explaining the overall configuration of a supercooled water producing apparatus including a heat exchanger according to an embodiment of the present invention, and is an explanatory view partially broken.

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

FIG. 3 is a partial cross-sectional view showing an enlarged part of a conventional spiral heat exchanger.

[Explanation of symbols]

 1 Supercooled Water Production Equipment 2 Refrigerator 3 Heat Exchanger 4 Cold Storage Water Tank 6 Outer Tube 7 Inner Tube

Claims (1)

[Scope of utility model registration request] 1. A heat exchanger 3 having a double-pipe structure, which comprises an outer pipe 6 and an inner pipe 7 inserted in the outer pipe 6, wherein the inner pipe 7 is a corrugated pipe. Composed of a flexible tube,
The water to be cooled is circulated in the outer pipe 6 and the refrigerant is circulated in the inner pipe 7 to cool the water to be cooled in the outer pipe 6 from the inside. A heat exchanger for a supercooled water production device, characterized in that the entire double pipe structure is formed in a spiral shape.