Fisher D450003T012 Thermostat User Manual


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Type N201
D450003T012
Instruction Manual
MCK-1023
May 1980
www.FISHERregulators.com/lp
R
Type N201
Install, use, and maintain this equipment
according to Fisher instructions and all
federal, state, local laws and codes, and
NFPA Pamphlet 58. Periodic inspection and
maintenance is essential.
Introduction
Type N201 automatic cylinder filling valve is supplied
completely piped up, and consists of a filler valve assembly,
two Type 67 regulators with pressure gauges, a trip valve,
and special parts for alternate scale installations.
Principle of Operation
Refer to Figure 1. Supply pressure registers at
regulators 1 and 2. Pressure from regulator 1 registers
beneath the lower diaphragm of the filler valve, see “A”
in Figure 1. This pressure holds the lower valve closed,
preventing pressure from regulator 2 from registering on
the upper diaphragm. Spring force holds the upper valve
open, and liquid from the charging pump can enter the
cylinder to be filled.
When the cylinder reaches the predetermined weight set on
the scale, the beam button on the scale beam contacts the
trip valve, see “B” in Figure 1. The trip valve opens to exhaust
pressure from under the lower diaphragm. Spring force opens
the lower valve, allowing pressure from regulator 2 to register
on the upper diaphragm. This closes the upper valve, and
stops flow through the orifice. A red button indicates that the
filler valve is closed and that the cylinder is full. Removing the
full cylinder from the scale closes the trip valve and permits
the system to reset itself for the next cylinder.
Installation
Refer to Figure 2.
1. Connect the top 1/2-inch FNPT connection “C” of the
filler valve to the charging manifold.
2. Determine if the trip valve hose is long enough to reach
the scale frame as shown. If not, insert 1/8-inch pipe
as needed.
3. Standard trip valve installation (also see alternate
methods, 3.A and 3.B):
a. The trip valve should be installed at approximately 1/5
of the scale beam length, measured from the pivot point to
the beam stop, see drawing. Although the trip valve can
be installed to operate directly off the scale beam, it is not
recommended because of the side play in most scale beams
can resuIt in failure to contact the trip valve.
b. Drill a 5/8-inch (16 mm) hole through the scale frame
directly above the point on the scale beam, determined in
step 3 (a).
c. Remove locknut “D” and insert trip valve through the
5/8-inch (16 mm) hole. Replace locknut.
d. Place beam button “J” on the scale beam directly
beneath the trip valve.
e. Using locknuts “D” and “E”, position trip valve stem “B”
so that it barely contacts beam button “J” with the scale
beam in a level position, see drawing.
Be certain that the beam button cannot
contact the trip valve housing at point “A”
when the scale beam is in the uppemost
Figure 1. Operational Schematic
SCALE
FRAME
BEAM
BUTTON
TRIP VALVE
SCALE BEAM
FILLER
VALVE
A. FILLING CYLINDER
B. FULL CYLINDER
FILLER
VALVE
SUPPLY
PRESSURE
REG
# 1
REG
# 1
REG
# 2
REG
# 2
SCALE
FRAME
FROM CHARGING
PUMP
FROM CHARGING
PUMP
SUPPLY
PRESSURE
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