JPH0732375U - Corrugated pipe for heat exchanger - Google Patents

Abstract

(57) [Summary] [Purpose] To correct the variation in heat transfer coefficient in the longitudinal direction of corrugated pipes for heat exchangers. In a heat exchanger corrugated tube 1 for flowing a heat transport medium in a certain direction, a corrugated pitch p is formed so as to become larger toward an upstream side of a heat transport medium 2. Therefore, on the downstream side, the temperature difference between the inside and outside due to heat dissipation or heat absorption becomes small, but the effect of increasing the surface area due to corrugations and the turbulent flow state of the heat medium are promoted compared to the upstream side.
The decrease in heat transfer coefficient due to the small temperature difference is compensated, and as a result, the heat transfer coefficient as a whole of the corrugated tube 1 is made uniform.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a corrugated tube used for flowing a heat transport medium in a heat exchanger.

[0002]

[Prior art]

 For example, corrugated pipes are used as radiators in hot water circulation type snow melting systems. As is well known, a corrugated pipe is a pipe whose peripheral wall portion is curved in a wavy shape, has excellent flexibility, and has an advantage that it has a large surface area because the peripheral wall portion is formed in a wavy shape. It is often used in the heat exchangers described above.

[0003]

[Problems to be solved by the device]

 For example, the amount of heat exchanged between hot water and the outside air or snow on the outer surface of the pipe when hot water for melting snow is passed through this type of radiator, that is, the amount of heat transfer from the hot water to the outside is the state in which hot water flows. It also greatly differs depending on the temperature difference between inside and outside or the heat transfer area. For example, when hot water heated to a certain temperature is flowed through the corrugated pipe from a certain direction, the amount of heat transfer from the hot water to the outside of the corrugated pipe increases on the upstream side where the temperature is high due to the large temperature difference between the inside and outside. On the contrary, on the downstream side, the temperature of the hot water is lowered and the temperature difference between the inside and the outside is reduced, so that the heat transfer amount is reduced.

Therefore, in the radiator in the hot water type snow melting system, there is an inconvenience that the amount of snow melting is large on the upstream side and the amount of snow melting is small on the downstream side. However, there is a problem in that it requires a complicated configuration or control, such as elaborately devising the circulation route of the above, or arranging two hot water pipes in which the hot water flow directions are opposite to each other in parallel.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a corrugated tube for a heat exchanger, which can make the heat transfer coefficient as uniform as possible in the axial direction. It is a thing.

[0006]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention is characterized in that, in a heat exchanger corrugated tube for flowing a heat transport medium in a fixed direction, the corrugated pitch is formed to be as large as the upstream side of the heat transport medium. It is what

[0007]

[Action]

 Also in the heat exchanger corrugated tube according to the present invention, the heat transport medium such as hot water or refrigerant flows in a fixed direction. In the corrugated pipe in this device, the corrugated pitch is large on the upstream side of the heat transport medium, so that the heat exchange area on the upstream side is smaller than that on the downstream side, and a turbulent state is less likely to occur. Therefore, the heat transfer coefficient on the upstream side is suppressed to be lower than that on the downstream side, which reduces the heat transfer coefficient on the upstream side, which reduces the amount of heat exchange between the heat medium and the outside on the upstream side. On the downstream side, where the temperature difference between the heat transport medium and the outside is small, the heat transfer coefficient increases due to the increase in surface area due to the smaller corrugated pitch and the promotion of turbulent flow conditions. It suppresses the decrease in heat exchange amount due to the decrease in heat. As a result, the heat exchange amount as a whole in the longitudinal direction of the corrugated pipe is made more uniform.

[0008]

【Example】

 Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing a corrugated pipe 1 according to the present invention. The corrugated pipe 1 is made of metal such as stainless steel or a shell, and is attached to a predetermined heat exchanger (not shown). It is installed and used to flow the heat transport medium 2 such as hot water from the left side to the right side in the figure. As shown in the figure, a portion of the corrugated pipe 1 having a predetermined length on the upstream side is formed as a substantially straight pipe without a corrugated pipe, and a subsequent corrugated pipe having a large pitch p is formed. The pitch p of the corrugations is set to be gradually smaller on the downstream side of the heat transport medium 2 in the right direction of FIG. 1, and is smallest on the most downstream side of FIG.

The corrugated pipe 1 shown in FIG. 1 is used, for example, as a heat radiator for snow melting using warm water as a heat transport medium 2. When warm water flows from the upstream side during snow accumulation, the temperature of the warm water and the external snow The difference is greatest on the upstream side. On the upstream side of the corrugated pipe 1, however, the hot water changes from upstream to a slight turbulent state due to the large pitch p of the corrugated pipe, but the extent is low, and the large corrugated pitch p has the effect of increasing the surface area. Due to the small amount of heat, the heat transfer coefficient between the hot water and the external snow is set below a predetermined value.

The hot water flowing in the corrugated pipe 1 radiates heat as it flows downstream, whereby the temperature gradually decreases, and the temperature difference between the inside and outside gradually decreases. On the other hand, on the downstream side of the corrugated pipe 1, the surface area is enlarged due to the small pitch p of the corrugated pipe, and the turbulent flow of hot water is increased. As a result, on the downstream side, the heat transfer coefficient from the hot water to the external snow becomes larger than on the upstream side, which compensates for the decrease in the heat transfer coefficient due to the decrease in the temperature difference between the inside and outside.

That is, on the upstream side, the temperature difference is large, but the surface area and turbulent flow state are smaller than on the downstream side. On the other hand, on the downstream side, the surface area and turbulent flow state are increased although the temperature difference is small. Therefore, the heat transfer coefficient of the corrugated tube 1 as a whole becomes equal or almost equal between the upstream side and the downstream side. Therefore, the amount of heat received by the snow outside the corrugated tube 1 is almost uniform over the entire axial direction of the corrugated tube 1, and there is no difference in the amount of snow melting in the axial direction of the corrugated tube 1.

Note that the present invention is not limited to the above-mentioned embodiment, and the heat transport medium may not be hot water, and when it is used for a heat exchanger for cooling, a refrigerant is used. May flow as a heat transport medium inside the corrugated tube. The outer diameter of the corrugated tube does not have to be the same on the upstream side and the downstream side, and the diameter may be increased on the downstream side to reduce the flow velocity of the heat transport medium.

[0013]

[Effect of device]

 As is clear from the above description, according to the present invention, the pitch of the corrugated is increased on the upstream side and decreased on the downstream side, so that the heat transfer coefficient as a whole can be made uniform, and the heat flowing in the inside can be made uniform. It is possible to correct the variation in the amount of heat radiation or the amount of heat absorption due to the temperature change of the transport medium between the upstream side and the downstream side.

[Brief description of drawings]

FIG. 1 is a sectional view schematically showing an embodiment of the present invention.

[Explanation of symbols]

 1 ... Corrugated tube, 2 ... Heat transport medium, p ... Pitch.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Creator Shinji Ishii 151, 1007 Izumisawa, Chitose-shi, Hokkaido 151 Fujikura, Hokkaido

Claims (1)

[Scope of utility model registration request] 1. A corrugated tube for a heat exchanger in which a heat transport medium flows in a fixed direction, wherein a pitch of the corrugated is formed so as to become larger toward an upstream side of the heat transport medium.