| 摘要 |
PURPOSE:To facilitate the fitting and removal of a cover in and from an opening of a hot water storage tank and to prevent the loosening of the cover due to thermal expansion and the leaking of steam from the tank by a method wherein the cover is formed by a part of the body of the tank. CONSTITUTION:A cystern section 12 bulges from the upper part of the hot water storage tank 11 and a hollow raised section 13 communicating with the cystern section 12 is formed integral with the upper part of the cystern section 12. Further, a collar 14 is provided at substantially the center of the raised section 13 and the outer diameter of the top of the raised section is made equal to, or somewhat larger than, the inner diameter of the base section 16 thereof but is made smaller than the outer diameter of the base section 16. After the completion of the tank 11 of the above structure, a part of the raised section 13 is cut off along the intermediate position shown by the dotted line between the base section 16 and the collar 14 so that the opening 17 is provided. At the same time, the cut part of the raised section 13 which is in the shape of a hat is turned upside down and fitted into the opening 17 such that the top 15 is thrusted deep into the base section 16 with the collar 14 butted against the peripheral edge of the opening 17, to thereby make itself the sealing type cover A. Thus, since the cover A is formed in such a manner that the part of the hot water storage tank 11 is cut off to provide the opening 17 in the cystern section 12 and the cut-off part makes itself the cover A, it is manufactured easily as compared to the conventional like cover which is formed independently of the drilling of a hole or an opening to which the cover is applied. |
