2
DIMENSIONS
Figure 1
OPERATION (See Figure 3 )
With no pressure applied to the diaphragm
through Port 1, Port 3 (supply port) is connected
through this normally open relay to Port 2.
When sufficient pressure is applied to the
diaphragm through Port 1, the stem moves down and
forces the lower poppet on seat,
closing Port 3 to Port 2. Loss of pressure through Port
1 will allow the stem to return to its original position.
At the same time, the lower spring will force the
lower poppet off seat, opening Port 3, again, to Port
2. Also, the relay may be reopened by applying an
equalizing pressure through Port 4.
NOTE: Graph A indicates actuating pressure (Port
1) required to keep valve closed at various
supply pressures (Port 3). Also, Graph A
indicates actuating pressure (Port 1) minus
equalizing pressure (Port 4) required to
keep valve closed at various supply
pressures (Port 3).
NOTE: Graph B indicates decreasing actuating
pressure (Port 1) required to open valve at
various supply pressures (Port 3). Also,
Graph B indicates decreasing actuating
pressure (Port 1) minus equalizing
pressure (Port 4) required to permit same
action.
CAUTION: DO NOT EXCEED MAXIMUM PRESSURES.
Figure 2
