JPH049997B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat exchanger applicable to an air conditioner heat exchanger, an air-cooled heat exchanger, and other air-cooled heat exchangers.

To explain the conventional example (Part 1), in a small heat exchanger such as a heat exchanger for an air conditioner, a plurality of heat transfer tubes 01 of the same length are installed in parallel and vertically as shown in Fig. 1. Connect adjacent heat exchanger tubes 01 with a U-shaped connecting tube 06, or connect the ends of the heat exchanger tubes 01 with a U-shaped connecting tube 06.
It is constructed by folding it into a letter shape. Headers 02 are installed at both ends of the heat exchanger tubes 01, and a large number of fins 03 are installed between adjacent heat exchanger tubes 01. The fluid inside the tube flows in the direction of arrow 05 and flows into the heat transfer tube 0.
1, and the extratubular fluid flows in the direction of arrow 04, perpendicular to the heat transfer tube 01.

In FIG. 1, inside the heat exchanger tube 01, the tube fluid flows along the heat exchanger tube 01, and a downward flow section 07 and an upward flow section 08 are generated as shown by broken line arrows. The fluid outside the tube flows in the direction of arrow 04, perpendicular to the heat exchanger tube 01, and exchanges heat via the fins 03 and the heat exchanger tube 01,
The fluid inside the tube is heated and vaporized, and the fluid outside the tube is cooled.

Figure 2 shows the heat transfer characteristics and pressure loss of the fluid in the pipe using the flow rate of the fluid in the pipe as a variable. When the fluid in the pipe is heated and evaporated, the heat transfer H ' is lower than the heat transfer H of the upward flow, and the pressure loss P' of the downward flow is larger than the pressure loss P of the upward flow, which requires more heat transfer tubes and more power, resulting in higher costs. .

The conventional example (part 2) will be explained with reference to Fig. 3.
A plurality of heat exchanger tubes 011 having the same length are arranged in parallel in the vertical direction, and headers 01 are installed at the upper and lower ends of each tube.
Before and after 2, there is a distribution header 014 and a collection header 01.
6 is installed. Fins 013 are provided between adjacent heat exchanger tubes 011.

The fluid in the tube flows in the direction of arrow 015, is distributed from distribution header 014 to each header 012, flows upward 018 along each heat transfer tube 011, evaporates, vaporizes, and is collected in collection header 016. The fluid outside the tube flows in a direction perpendicular to the heat transfer tube 011 as indicated by an arrow 019, and heat is exchanged with the fluid inside the tube via the fins 013 and the heat transfer tube 011.

This device uses only upward flow, which allows for large heat transfer and small pressure loss, but it has the drawbacks of a complicated structure and high cost.

The purpose of the present invention is to improve heat transfer characteristics in a heat exchanger in which the fluid in the pipes repeatedly rises and falls by reducing the downward part that is disadvantageous to heat transfer performance and by increasing the rising part, thereby achieving a low cost and compact design. Our purpose is to provide heat exchangers.

The invention will be explained by the embodiment shown in FIG. 4 of the accompanying drawings. A plurality of heat exchanger tubes 1 are installed in parallel and vertically, and a U-shaped connecting tube 6 is installed between adjacent heat exchanger tubes 1.
or by bending the ends of the heat transfer tubes into a U-shape.

Headers 2 are installed at both ends of the heat exchanger tubes 1, and fins 3 are installed between adjacent heat exchanger tubes. The fluid inside the tube enters in the direction of arrow 5 and flows along the heat transfer tube, and the fluid outside the tube flows in the direction of arrow 4, perpendicular to the heat transfer tube. The length of the ascending portion 1A of the heat exchanger tube 1 is longer than the length of the descending portion 1B.

The fluid inside the tube exchanges heat with the fluid outside the tube more in the ascending section 1A than in the descending section 1B of the heat transfer tube 1, and is evaporated.

The present invention has the above-mentioned configuration, and since the rising portion 1A is longer than the descending portion 1B, heat exchange increases and evaporation increases, resulting in better heat transfer characteristics than the conventional example (part 1). , the length or number of heat exchanger tubes 1 can be reduced, and a cheaper heat exchanger can be obtained compared to the conventional example (part 2).

[Brief explanation of drawings]

Fig. 1 is a perspective view of the conventional example, Fig. 2 is a graph showing the relationship between the flow rate of the fluid in the pipe, the amount of heat transfer, and the pressure loss.
FIG. 3 is a perspective view showing another conventional example, and FIG. 4 is a perspective view showing an embodiment of the heat exchanger of the present invention. 1... Heat exchanger tube, 1A... Rising part, 1B... Descending part, 2... Header, 3... Fin, 6... Connecting pipe, 7... Downflow, 8... Upflow.

Claims (1)

[Claims] 1 The heat exchanger tube is formed in a meandering shape, the straight part of which is arranged in the vertical direction, and fins are provided on the outer periphery of the heat exchanger tube, and the fluid inside the tube that repeatedly rises and descends inside the heat exchanger tube is used as the fluid outside the tube. 1. A heat exchanger that performs evaporation by exchanging heat with a heat exchanger, characterized in that the length of the rising portion of the heat transfer tube is longer than the length of the descending portion.