Tyco ACC-1 User Manual

Operation
The Inlet Chamber of the Accelerator,
Figure 1, is pressurized via its connec-
tion to the system (at a point above the
maximum expected level of drain back
water). 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 in-
creases 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 Dif-
ferential 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 sys-
tem pressure are accommodated by
flow through the Restriction. When,
however, there is a rapid and steady
drop in system (i.e., Inlet and Pilot
Chamber) pressure, the pressure in
the Differential Chamber reduces at a
substantially lower rate. This condition
creates a net downward force on the
Plunger which rotates the Lever. As
the Lever is rotated, Figure 2, the Re-
lief Valve is raised out of the Relief Port
and the Anti-Flood Valve is depressed
downward into the Pilot Chamber Inlet
Port, venting the Pilot Chamber.
The system pressure in the Inlet
Chamber then forces (raises) the Ex-
haust Valve off its seat. This continues
the rotation of the Lever into the
tripped (latched) position, Figure 2. As
the Exhaust Valve is raised off its seat,
system pressure is transmitted to the
intermediate chamber of the dry pipe
valve which neutralizes the differential
pressure holding the valve closed.
Following the dry pipe valve trip, major
water borne debris is prevented from
entering the Accelerator (via the con-
nection to the system piping) by the
Strainer located at its Inlet. Water and
any fine water borne debris such as silt
is prevented from entering the Pilot
Chamber by virtue of the Anti-Flood
Valve having sealed off its inlet port.
The Check Valve located downstream
of the Accelerator Outlet prevents any
water borne debris from entering the
Accelerator via the connection to the
intermediate chamber of the dry pipe
valve.
After the accelerator/dry pipe valve
has tripped and the sprinkler system
FIGURE 1
MODEL ACC-1 ACCELERATOR IN SET POSITION
FIGURE 2
MODEL ACC-1 ACCELERATOR IN TRIPPED POSITION
Page2of10
TFP1112

Tyco ACC-1 Specifications

General

Brand	Tyco
Model	ACC-1
Category	Control Unit
Language	English