CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Japan application serial no. 2017-223712, filed on Nov. 21, 2017. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.

BACKGROUND

Technical Field

The disclosure relates to a heat exchanger and a hot water apparatus, more particularly, to a heat exchanger and a hot water apparatus having a shell pipe portion for cooling a shell plate.

Description of Related Art

In a conventional heat exchanger, since a temperature of a shell plate rises due to combustion gas supplied from a burner, it is necessary to cool the shell plate. For this reason, a heat exchanger having a shell pipe portion for cooling the shell plate has been proposed.

A heat exchanger having a shell pipe portion is described, for example, in Japanese Laid-open No. 2017-116203 (Patent Document 1). In the heat exchanger described in this publication, a combustion casing is configured by four side plates surrounding fins and a heat absorbing pipe. Further, a separate shell pipe portion is provided on each of the four side plates of the combustion casing.

Since the heat exchanger described in the above-described publication has four side plates and a shell pipe portion separately provided on each of the four side plates, the number of components is high. For this reason, assembling of the heat exchanger is complicated.

SUMMARY

A heat exchanger of an embodiment of the disclosure includes a heat exchanging portion, a shell plate, and a shell pipe portion. The shell plate surrounds the heat exchanging portion. The shell pipe portion is for cooling the shell plate. The shell plate includes a front surface portion and a main body portion. The main body portion is installed on the front surface portion and is formed by bending one sheet of plate into a U shape. The shell pipe portion is bent into a U shape along an inner surface of the main body portion and is installed on the inner surface.

