Hot-water heater manufacturing method and hot-water heater manufactured by the same

Abstract

Provided is a hot-water heater manufacturing method capable of obtaining stable heat exchange characteristics by applying a moderate contact surface pressure between heating-medium circulating tubes and heater members that constitute a hot-water heater, and capable of improving the reliability by enhancing the joint strength between the heating-medium circulating tubes, with a simple and easy manufacturing process.

1 . A hot-water heater manufacturing method in which a plurality of tube constituent members formed of a sheet-metal material are brazed, thus forming heating-medium circulating tubes having heater contact surfaces; the heating-medium circulating tubes are arranged in parallel and are joined such that a heating medium can circulate therebetween, thus forming a heater main body; and heater members are interposed between the heating-medium circulating tubes and are brought into close contact with the heater contact surfaces, thus heating the heating medium flowing in the heating-medium circulating tubes, the hot-water heater manufacturing method comprising:
 a heating-medium circulating tube forming step of forming the heating-medium circulating tubes by brazing the tube constituent members;   a positioning and pressing step of arranging the heating-medium circulating tubes in parallel, disposing the heater members between the heating-medium circulating tubes, and, while positioning the heating-medium circulating tubes and the heater members, pressing the heating-medium circulating tubes and the heater members in a laminating direction thereof such that the heater members are brought into close contact with the heater contact surfaces of the heating-medium circulating tubes; and   a tube joining step of joining the heating-medium circulating tubes that have been positioned in the positioning and pressing step.   
     
     
         2 . A hot-water heater manufacturing method according to  claim 1 ,
 wherein, in the positioning and pressing step, the heating-medium circulating tubes are laminated and positioned such that heating-medium circulating holes that are formed so as to penetrate the heating-medium circulating tubes in the laminating direction thereof are aligned; and   in the tube joining step, circumferential portions of the heating-medium circulating holes are joined through brazing by inserting a heating device into inner circumferences of the heating-medium circulating holes to heat inner circumferential portions of the heating-medium circulating holes.   
     
     
         3 . A hot-water heater manufacturing method according to  claim 1 ,
 wherein, in the heating-medium circulating tube forming step, the heating-medium circulating tubes are formed by brazing the tube constituent members;   joining of the heating-medium circulating tubes in the tube joining step is performed also through brazing; and   a brazing filler metal having a lower melting point than a brazing filler metal that is used in the heating-medium circulating tube forming step is used as a brazing filler metal that is used in the tube joining step.   
     
     
         4 . A hot-water heater manufacturing method according to  claim 2 , wherein a brazing filler metal is attached, in advance, to the circumferential portions of the heating-medium circulating holes, and the brazing filler metal is melted in the tube joining step, thereby joining the circumferential portions of the heating-medium circulating holes through brazing. 
     
     
         5 . A hot-water heater manufacturing method according to  claim 2 , wherein the circumferential portions of the heating-medium circulating holes are provided with sections having fitting shapes, and the sections having the fitting shapes are fitted into the facing heating-medium circulating holes in the positioning and pressing step, thereby performing positioning. 
     
     
         6 . A hot-water heater manufacturing method according to  claim 5 , wherein the sections having the fitting shapes are upright fitting flanges that are formed continuously in the circumferential directions of the heating-medium circulating holes. 
     
     
         7 . A hot-water heater manufacturing method according to  claim 6 , wherein, in the positioning and pressing step, the fitting flanges are fitted into the facing heating-medium circulating holes, and then, in the tube joining step, the fitting flanges are expanded in diameter toward radially outer sides of the heating-medium circulating holes, thereby joining the heating-medium circulating tubes. 
     
     
         8 . A hot-water heater manufactured by a hot-water heater manufacturing method according to  claim 1 .