Heat pipe

Abstract

To provide a heat pipe which improves the amount of heat transport, can transport a large amount of heat highly efficiently without electricity, and can be easily enlarged in terms of its structure. [Solution] A loop-shaped heat pipe 1 has a liquid phase section 4 whose interior is kept at negative pressure and in which liquid working fluid is stored at the lower part, and has a first pipe section 2 extending in the vertical direction, a second pipe section 3 extending in the vertical direction with its upper and lower ends respectively communicating with the upper and lower ends of the first pipe section 2, an evaporator 5 which evaporates the working fluid in the liquid phase section 4 at the lower part of the first pipe section 2, a condenser 6 which is interposed above the liquid level of the liquid phase section 4 of the second pipe section 3 and condenses vapor V of the working fluid evaporated by the evaporator 5, a liquid collection section 7 which collects the working fluid condensed and liquefied in the condenser 6 and drops it into the liquid phase section 4 of the second pipe section 3, and a bypass pipe 8 whose one end opens between the condenser 6 and the liquid collection section 7 and whose other end opens into the second pipe section 3 between the liquid collection section 7 and the liquid phase section 4.

Description

[Technical field]

[0001] The present invention relates to a heat pipe for transporting thermal energy from a low-temperature heat source such as hot water. [Background technology]

[0002] Conventionally, various heat sources such as boiler steam are used in various processes in factory production facilities, but most of the residual heat is not utilized and is discharged as warm wastewater, etc. In addition, the heat absorbed by the circulating water used to cool the equipment is released into the atmosphere by cooling towers, etc., and is therefore not utilized.

[0003] Theoretically, it is possible to use heat pipes to recover low-temperature exhaust heat; for example, a heat pipe using a wick has been proposed (Patent Document 1, etc.); however, heat pipes using a wick are restricted in that the return flow of the working fluid is achieved by the capillary action of the wick, and therefore cannot transport large amounts of thermal energy.

[0004] For this reason, a two-phase circulation loop heat pipe (Patent Document 2, etc.) is known that circulates a two-phase mixed fluid of gas and liquid without using a wick. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2022-139889 A [Patent Document 2] JP 2008-170117 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in conventional two-phase circulation loop heat pipes that do not use a wick, heat transport is achieved by using the sensible heat of the working fluid circulated by air bubbles, and the heat transport capacity is poor compared to cases where the latent heat of evaporation of the working fluid is used. As a result, a large amount of working fluid acting as a heat transfer medium is required to transport a large amount of heat.

[0007] SUMMARY OF THE PRESENT EMBODIMENTS Accordingly, a primary object of the present invention is to provide a heat pipe that is capable of transporting a large amount of heat with a small amount of working fluid compared to conventional heat pipes. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, the present invention provides a loop-shaped heat pipe having a liquid phase section whose interior is kept at negative pressure and in which liquid working fluid is stored in a lower part, the heat pipe comprising: a first pipe section extending in a vertical direction; a second pipe section extending in a vertical direction and having upper and lower ends respectively communicating with upper and lower ends of the first pipe section; an evaporator for evaporating the working fluid in the liquid phase section at the lower part of the first pipe section; a condenser interposed above a liquid level of the liquid phase section of the second pipe section and condensing vapor of the working fluid evaporated by the evaporator; a liquid collection section for collecting the working fluid condensed and liquefied in the condenser and dropping it into the liquid phase section of the second pipe section; and a bypass pipe having one end opening to the second pipe section between the condenser and the liquid collection section and the other end opening to the second pipe section between the liquid collection section and the liquid phase section.

[0009] It is preferable that the apparatus further comprises an overflow pipe that causes the liquid working fluid collected in the liquid collection section to overflow at a predetermined liquid level in the liquid collection section and flow between the liquid collection section and the liquid phase section. Effect of the Invention

[0010] According to the present invention, the working fluid in the liquid phase is heated in the evaporator, vaporizes, rises as vapor, and diffuses from the first tube to the condenser in the second tube, condenses in the condenser, and falls to the liquid phase 4, and the falling energy circulates the working fluid. That is, unlike the conventional two-phase circulation heat pipe, which circulates sensible heat by bubbles, the working fluid heated in the evaporator is transported as latent heat, which is larger than the sensible heat. The driving force for circulation is the falling energy from the condenser to the liquid phase, and since vapor (latent heat) is used for heat transport, it is possible to transport a large amount of heat efficiently without electricity, compared to conventional heat pipes in which the condensed liquid generated in the heat dissipation part is returned to the heat receiving part by the capillary phenomenon of the wick, and two-phase circulation heat pipes that use the sensible heat of the working fluid for heat transport. [Brief description of the drawings]

[0011] [Figure 1] 1 is a vertical cross-sectional view showing an embodiment of a heat pipe according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] An embodiment of the heat pipe according to the present invention will be described below with reference to the drawings. Referring to Fig. 1, the heat pipe 1 is in the form of a loop having a liquid phase part in which the inside is under negative pressure and liquid working fluid is stored in the lower part, and includes a first pipe part 2 extending in the vertical direction, a second pipe part 3 extending in the vertical direction and having upper and lower ends respectively communicating with the upper and lower ends of the first pipe part 2, an evaporator 5 for evaporating the working fluid in the liquid phase part 4 in the lower part of the first pipe part 2, a condenser 6 interposed above the liquid level of the liquid phase part 4 of the second pipe part 3 for condensing the vapor of the working fluid evaporated by the evaporator 5, a liquid collecting part 7 for collecting the working fluid condensed and liquefied by the condenser 6 and dropping it into the liquid phase part 4 of the second pipe part 3, and a bypass pipe 8 having one end opening to the second pipe part 3 between the condenser 6 and the liquid collecting part 7 and the other end opening to the second pipe part 3 between the liquid collecting part 7 and the liquid phase part 4.

[0013] 1 shows an example of a loop-shaped heat pipe 1 in which the upper and lower ends of a first pipe section 2 and a second pipe section 3 are connected in communication with each other via upper and lower horizontal communication sections 9, 10. The loop shape of the heat pipe 1 is not limited to the illustrated example, and may be an ellipse or other shape. The inside of the heat pipe 1 is previously evacuated to a negative pressure and sealed, but the inside pressure can be reduced when necessary by connecting a vacuum pump.

[0014] An evaporator 11 is interposed in the first tube section 2, and a part of the working fluid of the liquid phase section 4 is filled in the evaporator 11 up to a predetermined water level. The evaporator 5 heats and evaporates the working fluid of the liquid phase section 4 in the evaporator 11. In the illustrated example, the evaporator 5 has a supply port 5a for supplying a heat medium 12H for heat exchange with the liquid working fluid in the evaporator 11, and a discharge port 5b for discharging the heat medium 12L after heat exchange. The working fluid of the liquid phase section 4 in the evaporator 11 is heated by the heat medium 12H supplied to the supply port 5a from the outside of the evaporator 5, and steam V of the working fluid is generated. The working fluid of the liquid phase section 4 is, for example, water, and the heat medium 12H supplied to the supply port 5a is, for example, warm wastewater at 50 to 60°C. The heat medium 12H may be any fluid that can heat the working fluid of the liquid phase section 4 in the evaporator 11 and boil it at a low temperature under reduced pressure. The heat medium 12L, which has lost heat through heat exchange with the working fluid and has been cooled, is discharged from the discharge port 5b of the evaporator 5.

[0015] The working fluid vapor evaporated in the evaporator 11 rises inside the first tube section 2 and diffuses from the upper connecting section 9 to the condenser 6 of the second tube section 3, where it is condensed (cooled) and separated into liquid (condensed water) and gas (uncondensed vapor).

[0016] The condenser 6 has a supply port 6a through which a refrigerant 13L for cooling the vapor of the working fluid is supplied, and a discharge port 6b through which the refrigerant 13H after cooling the vapor V of the working fluid is discharged. The refrigerant 13L may be any fluid capable of cooling the vapor V of the working fluid, and is, for example, water at 20 to 30°C. The refrigerant 13H heated by the condenser 6 is discharged from the discharge port 6b. In this manner, the heat of the heat medium 12H is transported to the refrigerant 13H by the heat pipe 1. In the illustrated example, a can body 14 is interposed in the second pipe portion 3, and the condenser 6 is disposed within the can body 14.

[0017] The working fluid condensed in the condenser 6 is collected in the liquid collecting section 7 provided at the bottom of the condenser 6. In the illustrated example, the liquid collecting section 7 is provided at the bottom of the can body 14. A space S1 is provided between the condenser 6 and the liquid collecting section 7 in the can body 14. The liquid collecting section 7 has a liquid drainage outlet 7a at its bottom. As shown in the illustrated example, the liquid drainage outlet 7a is cylindrical and extends downward from the bottom of the liquid collecting section 7, so that the vector of the falling working fluid can be matched. The amount of working fluid (liquid) flowing through the liquid drainage outlet 7a per unit time is set to be less than the amount of working fluid condensed and liquefied per unit time in the condenser 6, so that the working fluid (condensed liquid) accumulates in the liquid collecting section 7, and the working fluid accumulated in the liquid collecting section 7 is discharged from the liquid drainage outlet 7a all at once and falls into the liquid phase section 4 below the second pipe section 3. A downward flow is created in the liquid phase section 4 of the second pipe section 3 by the falling energy of the working fluid discharged from the drainage port 7 a, and the working fluid in the liquid phase section 4 is quickly moved to the first pipe section 2.

[0018] The bypass pipe 8 communicates the space S1 between the condenser 6 and the liquid collecting section 7 with the space S2 (the space in the second pipe section 3) between the liquid collecting section 7 and the liquid phase section 4 of the second pipe section 3. Therefore, even if the working fluid liquefied in the condenser 6 is stored in the liquid collecting section 7 and the drainage port 7a is blocked by the working fluid, the provision of the bypass pipe 8 prevents a pressure difference from occurring between the space S1 and the space S2. This prevents a height difference from occurring between the liquid level 4a of the liquid phase section 4 in the evaporator 11 interposed in the first pipe section 2 and the liquid level 4b of the liquid phase section 4 in the second pipe section 3, and does not impede the movement and circulation of the working fluid. In other words, the reduction in the working fluid in the liquid phase section 4 due to evaporation by the evaporator 5 in the evaporator 11 interposed in the first pipe section 2 is caused by the fact that the space S1 and the space S2 are maintained at an almost uniform pressure, and therefore the difference in height between the liquid level 4a of the liquid phase section 4 in the evaporator 11 and the liquid level 4b of the liquid phase section 4 in the second pipe section 3 is eliminated, so that the working fluid (condensed water) that has fallen from the liquid collection section 7 to the second pipe section 3 quickly flows back in the direction of the liquid level 4a of the evaporator 11.

[0019] The heat pipe 1 further includes an overflow pipe 15 that allows the working fluid (condensed water) collected in the liquid collection section 7 to overflow at a predetermined liquid level in the liquid collection section 7 and flow between the liquid collection section 7 and the liquid phase section 4. When the liquid level 7b in the liquid collection section 7 rises as the liquefaction of the steam V in the condenser 6 progresses, the working fluid (condensed water) in the liquid collection section 7 is discharged through the overflow pipe 15 to the liquid phase section 4 of the second pipe section 3, thereby maintaining the liquid level 7b in the liquid collection section 7 at a predetermined water level. This prevents the working fluid (condensed water) in the liquid collection section 7 from overflowing into the bypass pipe 8 and clogging the bypass pipe 8. The bypass pipe 8 may also function as the overflow pipe 15 by configuring the bypass pipe 8 so that the working fluid (condensed water) that has risen in the liquid collection section 7 also flows through it.

[0020] According to the heat pipe 1 having the above configuration, the working fluid in the liquid phase section 4 is heated in the evaporator 5 and rises as vapor V, condensed in the condenser 6, and falls to the liquid phase section 4, and the falling energy circulates the working fluid. That is, unlike the conventional two-phase circulation type heat pipe, which circulates sensible heat by bubbles, the working fluid heated in the evaporator 5 is vaporized and transported as latent heat larger than the sensible heat. Because vapor (latent heat) is used for heat transport, the amount of heat transport is easier to make larger in structure compared to conventional heat pipes that use the capillary phenomenon of the wick as a driving force, and two-phase circulation type heat pipes that use sensible heat, and a large amount of heat can be transported highly efficiently without electricity.

[0021] The present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present invention. For example, the evaporator and condenser are not limited to the illustrated example, and may have a structure capable of evaporating and condensing the working fluid in the heat pipe 1. [Explanation of symbols]

[0022] 1 Heat pipe 2 First pipe section 3 Second pipe section 4 Liquid phase 5. Evaporator 6. Condenser 7. Collection section 8 Bypass pipe 15 Overflow pipe

Claims

1. A loop-shaped heat pipe having a liquid phase part in which a liquid working fluid is stored at a lower part and an inside of the heat pipe is kept at a negative pressure, A first pipe portion extending in a vertical direction; a second pipe portion extending in a vertical direction and having upper and lower ends respectively communicating with upper and lower ends of the first pipe portion; an evaporator that evaporates the working fluid in the liquid phase portion in a lower portion of the first pipe portion; a condenser that is interposed above a liquid level of the liquid phase portion of the second pipe portion and that condenses the vapor of the working fluid evaporated by the evaporator; a liquid collecting section that collects the working fluid condensed and liquefied in the condenser and drops it to the liquid phase section of the second pipe section; a bypass pipe having one end that opens into the space between the condenser and the liquid collecting section and the other end that opens into and communicates with the second pipe section between the liquid collecting section and the liquid phase section, so as to prevent a difference in height between the liquid level of the liquid phase section in the first pipe section and the liquid level of the liquid phase section in the second pipe section from occurring, thereby not hindering the circulation of the working fluid; having The heat pipe.

2. 2. The heat pipe according to claim 1, further comprising an overflow pipe that causes the liquid working fluid collected in the liquid collecting section to overflow at a predetermined liquid level in the liquid collecting section and flow between the liquid collecting section and the liquid phase section.

Images