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FLOW RATE IN LITRES PER MINUTE (LPM)
500 700 1000
9.0
7.0
5.0
4.0
3.0
2.0
1.0
0.7
0.5
0.4
0.3
0.2
0.1
100
200
FLOW RATE IN GALLONS PER MINUTE (GPM)
The approximate friction losses, based on the Hazen and Williams formula
and expressed in equivalent length of Schedule 40 pipe with C=100 are as
follows:
2.2 feet for the 2-1/2 inch valve at a typical flow rate of 250 GPM
4.9 feet for the 3 inch valve at a typical flow rate of 350 GPM
8.9 feet for the 4 inch valve at a typical flow rate of 600 GPM
22 feet for the 6 inch valve at a typical flow rate of 1500 GPM
MODEL DPV-1 DRY PIPE VALVES
NOMINAL PRESSURE LOSS VS. FLOW
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 DPV-1 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
1 psi (0,07 bar) of system air pressure
can hold approximately 5.5 psi (0,38
bar) of water supply pressure.
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.
(1 GPM = 3.785 LPM)
2000 3000
5000
300
500
700
1000
2000 3000
FIGURE 2
The Intermediate Chamber of the
DPV-1 is formed by the area between
the Air Seat and Water Seat as shown in
Figure 3B. The Intermediate Chamber
normally remains at atmospheric pres-
sure through the Alarm Port connection
and the valve trim to the normally open
Automatic Drain Valve (Fig. 4, 5, or
6). Having the Intermediate Chamber,
Figure 3B, open to atmosphere is criti-
cal to the DPV-1 Valve remaining set,
otherwise the full resulting pressure of
the system air pressure on top of the
Clapper Assembly cannot be realized.
For example, and assuming a water
supply pressure of 100 psi (6,9 bar), if
the system air pressure is 25 psi (1,7
bar) and there was 15 psi (1,0 bar)
pressure trapped in the Intermediate
Chamber, the resulting pressure across
the top of the Clapper would only be 10
psi (0,7 bar). This pressure would be
insufficient to hold the Clapper Assem-
bly closed against a water supply pres-
sure of 100 psi (6,9 bar). It is for this
reason that the plunger of the Auto-
10000
0,60
0,50
0,40
0,30
0,20
0,10
0,08
0,06
0,05
0,04
0,03
0,02
0,01
Page 5 of 20
Maximum
System Air
Water Supply
Pressure
Pressure
Range
psi
psi
20
60
15 - 23
80
20 - 28
100
25 - 33
120
30 - 38
145
35 - 43
165
40 - 48
185
45 - 53
205
50 - 58
225
55 - 63
250
60 - 68
TABLE B
SYSTEM AIR PRESSURE
REQUIREMENTS
matic Drain Valve must be depressed
during several of the resetting steps,
as well as during inspections, making
certain that the Automatic Drain Valve
is open.
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
DPV-1 Valve to actuate system water
flow alarms. The flow from the alarm
port is also sufficient to close the oth-
erwise normally open Automatic Drain
Valve in the valve trim.
After a valve actuation and upon sub-
sequent 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 DPV-1 will permit complete drain-
ing 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.
TFP1020
10
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