Seismic/California Valves are earthquake sensitive gas shut-off
valves. They are intended to close in the event of an earthquake to
prevent gas flow into a structure where earthquake damage may have
occurred. The valve reduces the potential for fire or explosion due
to the release of natural gas into a structure where gas
lines, gas fixtures, or gas appliances.
PSP's valves do not use any source of
internal or external electrical power. They are designed to remain
closed until manually reset. The valves are intended to be mounted
in the gas line upstream or downstream of the gas-line pressure
regulator and gas meter outside the structure. These valves do not
replace the manual upstream shut-off valves provided in the gas
Our valve consists of a
swing check valve arrangement with an acceleration-sensitive
triggering mechanism. The trip mechanism consists of a steel ball
resting on a tapered cup-shaped support. The horizontal motion of an
earthquake causes the ball to move from the center of the support.
This allows the balls mass to act upon the movable pipe of the trip
mechanism, activating the valve and initiating closure. Springs
assist the valve- flapper to close and gas pressure assists in
holding the valve disc in the closed position. The trip mechanism is
factory set and sealed. A sight glass is provided so that the Open
or Closed indicator can be seen, and the trip mechanism status of
the valve can be easily determined.