Patent ID: 8347826
Filing Date: 2013-01-08
Classification: F24H

Abstract:
1. A heat exchanger comprising: a water tube that comprises a helical tube body, the helical tube body includes a plurality of hollow tubular loops arranged in a vertical direction and connected to each other; and a casing that surrounds periphery of the helical tube body, a combustion gas is configured to be introduced into the casing from a supply port and to be discharged from a discharge port; wherein each of the loops is in a generally ellipse shape in a plan view or in a generally rectangular shape in a plan view, includes a pair of two straight tube portions extending in a width direction of the casing and includes a pair of two bent tube portions connected to respective ends of the straight tube portions, each of the bent tube portions being generally circular, or a part of the bent tube portion being linear; wherein the pair of the bent tube portions are formed as inclined tube portions inclining with respect to the horizontal surface and the pair of the straight tube portions are formed as horizontal non-inclined pipe portions; wherein the heat exchanger comprises at least two helical tube bodies that are arranged generally concentrically with at least an inner helical tube body and an outer helical tube body disposed horizontally apart from and surrounding the inner helical tube body to form a generally-uniform horizontally-extending gap between the inner helical tube body and the outer helical tube body, the straight tube portions are arranged in a front and back directions of the casing, and the bent tube portions are arranged in the width direction of the casing.