TFP1090
Page 4 of 20
• Low Body Drain Valve
• Alarm Test Valve
• Automatic Drain Valve
• Provision For An Optional Accelerator
Air Supply
Table B provides system air pressure
requirements as a function of the water
supply pressure. The air (or nitrogen)
pressure in the sprinkler system is rec-
ommended to be automatically main-
tained by using one of the following
pressure maintenance devices, as
appropriate:
• Model AMD-1 Air Maintenance
Device (pressure reducing type)
refer to Technical Data Sheet
TFP1221
• Model AMD-2 Air Maintenance
Device (compressor control type)
refer to Technical Data Sheet
TFP1231
• Model AMD-3 Nitrogen Maintenance
Device (high pressure reducing
type) refer to Technical Data Sheet
TFP1241
Quick Opening Device
As an option, the Model DPV-1 Dry
Pipe Valve may be acquired with the
Model ACC-1 Dry Pipe Valve Accelera-
tor (Ref. Figure 4). The Model ACC-1
Dry Pipe Valve Accelerator is used to
reduce the time to valve actuation fol-
lowing the operation of one or more
automatic sprinklers.
Operating
Principles
Dry Pipe Valve Operation
The TYCO Model DPV-1 Dry Pipe Valve
is a differential type valve that utilizes a
substantially lower system (air or nitro-
gen) pressure than the supply (water)
pressure, to maintain the set position
shown in Figure 3A. The differential
nature of the Model DPV-1 Dry Pipe
Valve is based on the area difference
between the air seat and the water
seat in combination with the ratio of the
radial difference from the Hinge Pin to
the center of the Water Seat and the
Hinge Pin to the center of the Air Seat.
The difference is such that the Model
DPV-1 has a nominal trip ratio of 5.5:1
(water to air).
Table B establishes the minimum
required system air pressure that
includes a safety factor to help prevent
false operations that occur due to water
supply fluctuations.
The Intermediate Chamber of the Model
DPV-1 Dry Pipe Valve is formed by the
area between the Air Seat and Water
Seat as shown in Figure 3B. The Inter-
mediate Chamber normally remains
at atmospheric pressure through the
Alarm Port connection and the valve
trim to the normally open Automatic
Drain Valve (Ref. Figures 7 through
14). Having the Intermediate Chamber,
Figure 3B, open to atmosphere is criti-
cal to the Model DPV-1 Valve remain-
ing set, otherwise the full resulting
pressure of the system air pressure on
top of the Clapper Assembly cannot be
realized. For example, if the system air
pressure is 1,7 bar and there was 1,0
bar pressure trapped in the Interme-
diate Chamber, the resulting pressure
across the top of the Clapper would
only be 0,7 bar. This pressure would be
insufficient to hold the Clapper Assem-
bly closed against a water supply pres-
sure of 6,9 bar.
When one or more automatic sprin-
klers operate in response to a fire,
air pressure within the system piping
is relieved through the open sprin-
klers. When the air pressure is suf-
ficiently reduced, the water pressure
overcomes the differential holding
the Clapper Assembly closed and the
Clapper Assembly swings clear of the
water seat, as shown in Figure 3C.
This action permits water flow into the
system piping and subsequently to be
discharged from any open sprinklers.
Also, with the Clapper Assembly open,
the intermediate chamber is pressur-
ized and water flows through the Alarm
Port (Ref. Figure 3B) at the rear of the
Model DPV-1 Dry Pipe Valve. As the
flow through the Alarm Port exceeds
the drain capacity of the Automatic
Drain Valve, the alarm line is pres-
surized to actuate system water flow
alarms.
After a valve actuation and upon subse-
quent closing of a system Main Control
Valve to stop water flow, the Clapper
Assembly will latch open as shown in
Figure 3D. Latching open of the Model
DPV-1 Dry Pipe Valve will permit com-
plete draining of the system (including
any loose scale) through the main drain
port.
During the valve resetting procedure
and after the system is completely
drained, the external reset knob can be
easily depressed to externally unlatch
the Clapper Assembly as shown
in Figure 3E. As such, the Clapper
Assembly is returned to its normal set
position to facilitate setting of the dry
pipe sprinkler system, without having to
remove the Handhole Cover.
Accelerator Operation
The Inlet Chamber of the TYCO Model
ACC-1 Dry Pipe Accelerator (Ref. Figure
5), is pressurized via its connection to
the system. The Pilot Chamber is, in
turn, pressurized through its inlet port
which is formed by the annular opening
around the lower tip of the Anti-Flood
Valve. As the Pilot Chamber increases
in pressure, the Differential Chamber
is pressurized through the Restriction.
The Accelerator is in its set position
while it is being pressurized as well
as after the Inlet, Pilot Chamber and
Differential Chamber pressures have
equalized. When in the Set position,
the Outlet Chamber is sealed off by
the Exhaust Valve which is held against
its seat by a combination of the Spring
pushing up against the Lever and the
net downward force exerted by the
pressure in the Pilot Chamber.
Both small and slow changes in
system pressure are accommodated
by flow through the Restriction. When,
however, there is a rapid and steady
drop in system (that is, Inlet and Pilot
Chamber) pressure, the pressure in
the Differential Chamber reduces at
a substantially lower rate. This condi-
tion creates a net downward force on
the Plunger which rotates the Lever.
As the Lever is rotated (Ref. Figure
6), the Relief Valve is raised out of the
406 mm
or GxG
FxG 348 mm
FxF 346 mm
FIGURE 2
DN100 AND DN150 MODEL DPV-1 DRY PIPE VALVE
TAKE-OUT DIMENSIONS
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