PURPOSE: To effectively prevent gas influx from a bent line by furnishing on a valve seat a diaphragm which opens and shuts the communication between an flow-in path and flowout path, and equipping the valve seat with a gas flow hole which puts the flow-in path in communication with the flowout path.
CONSTITUTION: In case the present invention is applied to a breeder valve configured with a metal diaphragm valve of manual type, a valve seat 10 is installed over a flow-in path 1a and flowout path 1b in the central part of the body 1 by the use of a seat holder 11, and a diaphragm 12 to open and shut the flow path is installed between over the valve seat 10 and a diaphragm holder 9. A junction ball 13 is accommodated in a communication hole provided in the center of the diaphragm holder 9. In this valve construction, a gas flow hole 10a is formed at the periphery of the valve seat 10 so that the fluid can flow from the flow-in path 1a to the flowout path 1b even when the diaphragm 12 is in close operation, and gas influx from a bent line is prevented in an arrangement where bent line is connected with the flowout path while a purge gas is connected with the flow-in path.
UCHISAWA OSAMU
YAMASHIMA ATSUSHI
