The DV-5 Deluge Valve is a
diaphragm style valve that depends
upon water pressure in the Diaphragm
Chamber to hold the Diaphragm
closed against the water supply pressure.
When the DV-5 Valve is set for
service, the Diaphragm Chamber is
pressurized through the trim connections
from the inlet side of the system’s
main control valve, for example
an O.S.&Y. gate valve or butterfly valve
(Ref. Figures 1 and 4).
Opening of a wet pilot sprinkler releases
water from the Diaphragm
Chamber faster than it can be replenished
through the 1/8 inch (3,2 mm)
restriction provided by the Model
ASV-1 Automatic Shut-Off Valve in the
diaphragm supply connections (Item
5 - Fig. 3A and 5, also described in
Technical Data Sheet TFP1384). This
results in a rapid pressure drop in the
Diaphragm Chamber and the force
differential applied through the Diaphragm
that holds it in the set position
is reduced below the valve trip point.
The water supply pressure then forces
the Diaphragm open permitting water
to flow into the system piping, as well
as through the Alarm Port to actuate
the system alarms.
As water flows into the system, the pilot
chamber of the Model ASV-1 Automatic
Shut-Off Valve (Item 5 - Fig.
3A and 5) becomes pressurized and
the ASV-1 automatically shuts off the
diaphragm chamber supply flow to
the DV-5 Diaphragm Chamber. Shutting
off the diaphragm chamber supply
flow prevents the DV-5 Diaphragm
Chamber from becoming re-pressurized,
thereby preventing inadvertent
closing of the DV-5 during a fire (as
may be the case if an actuation device
other than a pilot sprinkler were
to be closed after its initial operation,
for example a remote manual control
station).