| 摘要 |
PROBLEM TO BE SOLVED: To provide a liquid storage tank tough for negative pressure and positive pressure.SOLUTION: A liquid storage tank comprises: a cylindrical trunk; an upper panel board closing the upper end of the trunk; and a lower panel board closing the lower end of the trunk. The trunk is provided with a plurality of projecting beads at equal spaces in the circumferential direction. The projection height of the projecting bead is formed to gradually increase as it goes toward the upper side of the trunk, so that the lower side strong for the negative pressure and weak for the positive pressure because of water head is provided with the projecting beads having a lower height of projection, and on the contrary, the upper side weak for negative pressure and strong for the positive pressure is provided with the projecting beads having a projection height higher than that of the lower side. Thus, the whole liquid storage tank can be uniformly protected from the negative pressure and while the disadvantages such as the risk of cracks of material in working, shrinkage of material, distortion of end face, lowering of complete roundness accuracy and the like caused by forming the higher projection height are held down to the utmost, reinforcement is well-balanced for the negative pressure and the positive pressure so as to provide the tank having little risk of breakage due to negative pressure and overpressure. |
