PURPOSE: To prevent freezing of a city water valve only by replacement of a stem by holding a small mover with a small valve for opening and closing a small through hole disposed in the central lower portion of a stem main body by two springs, one of which is formed by a shape memory alloy.
CONSTITUTION: A small through hole 3 is communicated with the central lower portion of a stem main body, and a water passing groove 12 connected to the small through hole 3 is provided in a dished portion 11 of the stem. When a small mover 5 having a water passing path at a part thereof is strongly pressed upward by spring repulsive force of a spring 6 made by a shape memory alloy to closely contact a hole inlet 31 of the small through hole 3, a water valve completely stops water. The spring 6 changes in its shaped right before water is freezed, and the small mover 5 is moved down by spring repulsive force of a confronting spring 7, so that water passes through a part of the water passing path 9 of the small mover 5 to flow through the small through hole 3 and the water passing groove 12.
TSUJI SHIRO
HAYAKAWA SHINICHI
SUMIKAMA YASUYUKI
OKADA NAOTAKE
KITAMURA HARUHIRO
| JPS60223542A | 1985-11-08 | |||
| JPS6228583A | 1987-02-06 |