JPS5864488A - Heat exchanger - Google Patents

Abstract

PURPOSE:To improve the heat transfer efficiency and to reduce the weight and the size of the titled heat exchanger by a method wherein in the heat exchanger for heating supply water, a hole for receiving a pipe forming a first passage and another hole for receiving another pipe forming a second passage are molded integrally in a light and high heat conductive heat transfer section and the second passage pipe is inserted into the second hole in close contact with the inner wall of the hole. CONSTITUTION:The first passage 16 attached with fins 21 and the heat tranfer section 19 are formed integral with each other by extrusion-molding a light and good heat conductive material such as aluminum. In this case, the hole 20 for receiving the pipe 18 forming the second passage 17 is formed in the heat transfer section 19. Next, the pipe 18 is inserted into the hole 20 in such a manner that the pipe 18 is held in close contact with the inner wall of the hole 20 by expanding the pipe by the application of oil pressure inside the pipe. As a consequence, the resistance against heat transfer contact can be reduced and the weight and size of the heat exchanger can be minimized.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat exchanger for heating water supply used in water heaters, and an object of the present invention is to obtain a small, lightweight, and low-cost heat exchanger with excellent heat transfer performance.

Figure 1 shows a hot water supply system, where 1 is a hot water storage tank, 2 is a water supply pipe, 3 is a hot water supply pipe, 4 is a hot water tap, 6 is a heat insulating layer provided on the outer surface of the hot water storage tank, and 6 is a hot water storage tank 1. A forced convection type heat exchanger for heating the feed water provided externally, 7.7' a water circulation path connecting the hot water storage tank 1 and the heat exchanger 6 for heating the feed water, 8 a pump for water circulation, 9 a heating water feed, This is a heat insulating layer provided on the outer surface of the heat exchanger 6. 10 is a compressor, 11 is a pressure reducing device, 12 is a heat exchanger for collecting heat, and the compressor 10. The heat exchanger 6 for heating the feed water, the pressure reducing device 11, and the heat exchanger 12 for collecting heat are connected to one eyelid pipe 13°1.
3' and 13" to form a sealed circuit, and the refrigerant (
For example, an appropriate amount of R-22) is enclosed. In the water heater having the above configuration, the water supply heating operation is performed by operating the compressor 10 to circulate the refrigerant in the direction of the broken line arrow in the figure.
The high-pressure, high-temperature gas refrigerant discharged from the feed water heating heat exchanger 6 radiates heat to the water circulating in the direction of the solid line arrow in the figure by operating the pump 8 to heat the water, and the refrigerant condensed by the heat radiation becomes high-pressure liquid refrigerant. The refrigerant is then depressurized by the pressure reducing device 11 and enters the heat collecting heat exchanger 12, where it absorbs heat from the outside and evaporates sequentially to form a gas refrigerant which is sucked into the compressor 10, forming a cycle.

3. Figures 4 and 6 show a conventional heat exchanger 6' for heating feed water, in which an outer tube 14 and an inner tube 16 of different diameters are arranged concentrically to form a first passage 16' and a second passage through which fluid passes. It is a double back type heat exchanger with passages 17' formed therein.

In this heat exchanger, one method for improving the heat transfer characteristics between two fluids is to provide fins on the inner and outer surfaces of the inner tube 15. By the way, in the heat exchanger for heating water supply, the first. Since the inner tube 16 comes into contact with water no matter which of the second passages the water passes through, it is necessary to use a steel tube with excellent corrosion resistance, and a steel tube with internal and external fins has the disadvantage of being high in cost and heavy in weight. Furthermore, since the outer tube 14 is provided outside the inner tube 16 to form the first passage 16', the outer tube dimension h' becomes large, which not only increases the weight but also increases the overall height H' of the heat exchanger. However, the problem was that it did not take up much space to install and was not compatible with the miniaturization of water heaters.

The present invention solves the above-mentioned drawbacks of the conventional art by integrally forming the first passage and the heat conduction part using a lightweight and highly thermally conductive material, and arranging the tube serving as the second passage in close contact with the heat conduction part. It is something that will be resolved.

An embodiment of the present invention will be described below with reference to FIGS. 2 and 3. Reference numeral 16 denotes a first passage formed by extrusion molding of a lightweight and highly thermally conductive material such as aluminum (An), and numeral 17 denotes a second passage arranged parallel to the first passage 16, which is formed by a tube 18. has been done. Reference numeral 19 denotes a heat conduction portion formed integrally with the first passage 16, and a hole 20 is provided to surround the tube 18 to maintain the first passage 16 and the second passage 17 at a constant interval. A fin 21 is provided to protrude into the first passage 16, and is formed integrally with the heat conduction section 19.

The above first passage 16, heat conduction part 19, and fin 2g'' are A
fl, can be easily manufactured by extrusion molding, and can be easily manufactured by extrusion molding.
Since the heat conduction part 19 is provided with a hole 20 for accommodating the heat conduction part 19, it is possible to insert the pipe 18 into the extruded material and expand it using hydraulic pressure or the like to bring it into close contact with the heat conduction part 19, thereby reducing the heat transfer contact resistance. Since the passage 16, the heat conduction part 19°9 fins 21 are integrally molded, the heat transfer performance is excellent.

A refrigerant (e.g. R-
22) and into the second passage 1T, and if the pipe 18 is made of a steel pipe, there will be no problem in terms of corrosion resistance, and the amount of copper used can be greatly reduced, making it possible to reduce weight and cost. Furthermore, since the first passage 16 and the second passage 17 are arranged in parallel, the cross-sectional shape is flattened, and the height h is smaller than that of a conventional double-back heat exchanger, so the total height H of the heat exchanger can be reduced. , the installation space for equipment becomes smaller.

In the above embodiments, the inner surface of the tube forming the second passage is smooth, but there is no problem if a tube with inner grooves is used, and the heat transfer characteristics can be further improved.

As is clear from the above description, the feed water heating heat exchanger of the present invention has low thermal resistance and excellent heat transfer characteristics because the first passage and the heat conduction part are integrally formed. Furthermore, since the first passage and the second passage are arranged in parallel, the cross-sectional height can be reduced, and the overall height of the heat exchanger can also be reduced, resulting in effects such as saving installation space.

[Brief explanation of the drawing]

Fig. 1 is a system diagram of a water heater, Fig. 2 is an external perspective view of the heat exchanger for heating water supply of the present invention, and Fig. 3 is A-A in Fig. 2.
4 is an external perspective view of a conventional heat exchanger for heating feed water, and FIG. 5 is a sectional view taken along line BB in FIG. 4. 1... Hot water storage tank, 6,6'... Heat exchanger for heating water supply, 8... Pump, 1o... Compressor,
12... Heat exchanger for heat collection, 16.16'...-
...first passage, 17, 17'...second passage,
18...Pipe, 19...Heat conduction part, 21...
·fin. − Name of agent Patent attorney Toshio Nakao and 1 other person 2nd
figure#! Figure 3 II II t'l tl Figure 4 Figure 5

Claims (3)

[Claims] (1) The first passage and the heat conduction part are integrally molded from a lightweight and highly thermally conductive material, and the tube forming the second passage is placed in parallel with the first passage and in close contact with the heat conduction part. Placed heat exchanger. (2) The heat exchanger according to claim 1, wherein the fins protruding into the first passage are integrally molded with the heat conducting portion. (3) The first passage and the heat conduction part are integrally molded from aluminum material, and the tube is formed from copper material, and the refrigerant is passed through the first passage and water is passed through the second passage. A heat exchanger according to scope 1.