Method for manufacturing heat exchanger and heat exchanger obtained by same

Abstract

Provided is a method of joining a large diameter water pipe to a small diameter refrigerant pipe to manufacture a heat exchanger, such that dropping of molten solder is advantageously prevented and effective joining of the water pipe to the refrigerant pipes is achieved while reduction in the strength of base materials is effectively suppressed. In the manufacture of a heat exchanger formed by joining a small diameter refrigerant pipe to the outer peripheral surface of a large diameter water pipe, strip-like solder plate material is used for the joining material, and after the solder plate material is mounted on the outer peripheral surface of a water pipe so as to be sandwiched with the refrigerant pipe, the solder plate material is melted by heating to a temperature that does not exceed 350 DEG C, and the water pipe and refrigerant pipe are joined.

Description

technical field [0001] The present invention relates to a manufacturing method of a heat exchanger and the heat exchanger obtained by the manufacturing method, in particular to a heat exchanger for hot water supply that can be advantageously manufactured by winding and joining refrigerant pipes around water pipes. heater technology. Background technique [0002] Conventionally, there is known a heat exchanger composed of a large-diameter water pipe with a water passage in the pipe and a refrigerant pipe with a diameter smaller than that of the water pipe. As one of the heat exchangers, the heat exchanger for hot water supply is used in the following form, that is, the water pipe with a large diameter is bent and processed into a racetrack shape (Japanese: トラック shape) or a swirl shape ( Japanese: scroll き shape), and to spirally wind around the water pipe, joining one or more refrigerant pipes with smaller diameters. [0003] In addition, in order to manufacture such a heat...

AI Technical Summary

Problems solved by technology

However, in such a manufacturing method using the steps of winding thin tubes-bending-furnace brazing, the brazing temperature is as high as 800°C, so the temperatures of the core tube and the thin tube as the base material become high. , as a result, the grain size becomes large and the material softens, so there is a problem that the strength decreases and becomes a cause of leakage

In addition, brazing is performed after the bending process. Therefore, there is also a problem that the core tube is flat at the bent portion due to the lack of joint between the core tube and the thin tube, and the pressure loss on the water passage side becomes large. Such a problem: the thin tube leaves the core tube, and there is a gap between the thin tube and the core tube, which makes it difficult to join, resulting in a large thermal resistance

However, there must be a predetermined gap between the contact portion between the thin tube and the straight tube or the contact portion between the thin tube and the core tube. In this form, the linear brazing material wound together with the thin tube , The solder wire is wound on the straight tube and the core tube and positioned on one side of the thin tube, so when the above-mentioned linear brazing material and solder wire are melted by heating, the brazing material, The molten material of the solder is biased to one side of the thin tube, and sometimes it cannot be sufficiently supplied to the contact portion between the thin tube and the straight tube or the contact portion between the thin tube and the core tube, and the melt is self-sustained before bonding. The straight tube or the core tube is melted and dripped, and therefore, there are problems such as that it is difficult to effectively perform bonding between the thin tube and the straight tube or between the thin tube and the core tube. There is a gap between the tube and the straight tube or between the above thin tube and the core tube, resulting in a non-joint part

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