Heat exchanger

Abstract

The outer surface of a core pipe 31 is pressed so as to form projections 313 on the inner surface of the core pipe 31, and a winding pipe 32 is helically wound around the outer circumference of the core pipe 31. Subsequently, the core pipe 31 and the winding pipe 32 are bent together, and brazing is performed. As a result, the outer surface of the winding pipe 32 is in contact with the outer surface of the core pipe 31 without any gap therebetween at a bending center portion (D), and the outer surface of the winding pipe (32) is bonded to the outer surface of the core pipe (31) by a brazing material (33) at the bending center portion (D) of the bent part C-C.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a heat exchanger. More specifically, the present invention relates to a heat exchanger that includes a core pipe having projections that are formed on an inner surface thereof by pressing the outer surface of the core pipe, and a winding pipe that is wound around the outer surface of the core pipe.BACKGROUND OF THE INVENTION[0002]Some heat exchangers used for air conditioners, water heaters, and the like are provided with a core pipe that forms a passage of a first fluid, a winding pipe that is wound around the outer surface of the core pipe and forms a passage of a second fluid, and a heat exchanger that exchanges heat between the first fluid and the second fluid. For example, a double pipe heat exchanger is used as a heat exchanger for a water heater such as a heat pump water heater. Such a heat exchanger is formed by two pipes: a core pipe through which water flows and a winding pipe through which the refrigerant flows....

AI Technical Summary

Benefits of technology

[0003]However, when a heat exchanger is formed by spirally winding a winding pipe around the outer circumference of a jig, pulling out the jig so as to form a winding pipe body, and inserting a core pipe into the winding pipe body, there is a possibility that a poor contact may be formed between the core pipe and the winding pipe, consequently reducing the heat transfer performance. In particular, when a core pipe having projections that are formed on the inner surface thereof by pressing the outer surface of the core pipe is used as a core pipe of a heat exchanger, since a cross-section at a bent part of such a core pipe has an irregular shape because of the projections, there is a risk that a poor contact may be formed between the core pipe and the winding pipe, consequently reducing the heat transfer performance.

[0004]Therefore, an object of the present invention is to overcome the above problem and to improve the heat transfer performance of a heat exchanger that includes a core pipe having projections that are formed on the inner surface thereof by pressing the outer surface of the core pipe, and a winding pipe that is wound around the outer surface of the core pipe. The present invention also aims to provide a method for manufacturing a heat exchanger that has a good heat transfer performance.

Problems solved by technology

However, when a heat exchanger is formed by spirally winding a winding pipe around the outer circumference of a jig, pulling out the jig so as to form a winding pipe body, and inserting a core pipe into the winding pipe body, there is a possibility that a poor contact may be formed between the core pipe and the winding pipe, consequently reducing the heat transfer performance.

In particular, when a core pipe having projections that are formed on the inner surface thereof by pressing the outer surface of the core pipe is used as a core pipe of a heat exchanger, since a cross-section at a bent part of such a core pipe has an irregular shape because of the projections, there is a risk that a poor contact may be formed between the core pipe and the winding pipe, consequently reducing the heat transfer performance.

On the other hand, when the winding pipe is wound around the core pipe and then the core pipe is spirally wound into an oval shape, since a cross-section at the bent part of the core pipe has an irregular shape because of the projections, there is a risk that a poor contact may be formed between the core pipe and the winding pipe, consequently reducing the heat transfer performance.

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