| 摘要 |
<p>PURPOSE:To prevent a plug from being damaged by foreign matters carried in together water, by enlarging the clearance between the plug and retainer than water communicating holes made on the retainer when the pressure in the water chamber has reached a preset level. CONSTITUTION:A casing accommodating a rubber plug 3 is composed of a gas side member 1 and liquid side member 4 and the pressure in a gas chamber 5 is increased through a gas valve 2. A retainer 8 for preventing the plug 3 from protruding toward a water port 7 has water communicating holes 9 and is equipped with a rod 10 for fixing it to the liquid side member 4. When the water pressure has reached a preset level, the minimum clearance A between the plug 3 and the retainer 8 is designed to be larger than the diameter B of water communicating holes 9. This construction does not allow foreign matters such as sand passing through the holes 9 to be accumulated in the plug 3 and on the retainer 8.</p> |
