Minnich A-1C, Operators & Service Manual

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Feed Regulator
P/N 002880-00000
Repair Kit
P/N 002880-00001
Regulating Spring
P/N 002880-00004
PRESSURE REGULATOR
MINNICH P/N 002880-00000
OPERATION
A regulator is used in a compressed air system to maintain nearly constant outlet pressure despite changes in the inlet air pressure
and changes in downstream flow requirements.
Outlet pressure is controlled by the adjusting screw (1). clockwise rotation increases and counter- clockwise rotation decreases
outlet pressure setting. When the adjustment (1) is rotated fully counter- clockwise, no force is applied to the regulating spring (2), and
the valve (6) is held closed by the valve spring (7). clockwise rotation of the adjustment (1) compresses the regulating spring (2) which
applies a downward force on top of the diaphragm (4). The diaphragm (4) and valve pin (5) move downward forcing valve (6) off its
seat (10) which allows air to flow through the regulator to the downstream system.
Outlet pressure increases in the downstream system and sensing chamber (9) and applies an upward force on bottom of the
diaphragm (4). The diaphragm (4), valve pin (5); and valve (6) move upward, compressing the regulator spring (2). Upward movement
stops when the forces below the diaphragm balance the forces above the diaphragm. When there is no downstream flow demand, the
balance of forces occurs with the valve (6) closed. When there is downstream flow demand, the balance of forces occurs when the
valve opens sufficiently to compensate for demand, thus maintaining the desired outlet pressure.
RELIEVING TYPE REGULATORS. With relieving regulators, outlet pressure can be reduced even though the system is dead-
ended. When the adjustment (1) is turned counterclockwise, the force on the regulating spring (2) is reduced, and air pressure in the
sensing chamber (9) moves the diaphragm (4) upward. This upward movement opens the relief passage (8) in the diaphragm and
allows air to escape from the outlet side of the regulator through the relief passage (8) and vent (3) to atmosphere. As the outlet air
pressure decreases to the reduced pressure setting, the diaphragm moves downward and closes the relief passage.
The diaphragm will likewise move upward in a response to an increase in outlet pressure above the regulator setting, allowing air to
escape to the atmosphere as described above. However, the flow capacity of the relief passage is limited, and depending upon the
source of the overpressure condition, the outlet pressure might increase to a point significantly higher than the regulator setting. For
this reason, the relief feature of a regulator must not be relied upon as an overpressure safety device. See WARNING note below.
ADJUSTMENT
1. Before turning on system air pressure, turn regulator adjustment
counterclockwise until all load is removed from regulating spring.
2. Turn on system air pressure.
3. Turn regulator adjustment clockwise until the desired outlet pres-
sure is reached.
4. To avoid minor readjustment after making a change in pressure
setting, always approach the desired pressure from a lower pres-
sure. When reducing from a higher to a lower setting, first reduce
to some pressure less than the desired, then bring up to the desired
point.
5. Tighten jam out to lock pressure setting.
MAINTENANCE
The regulator can be disassembled for servicing without removal from pipe line. to disassemble, shut off the inlet air and reduce
pressure in inlet and outlet lines to zero. Turn adjusting screw (1) counterclockwise until all load is removed from regulating spring (7 or
7a): Remove bonnet screws (4), bonnet (3), upper springrest (5), spring (7), and diaphragm assembly (8). The intermediate springrest
(6) and compound spring (7a) are used only on 3/4" and 1" models with 5 to 125 psi adjustment range. Unscrew and remove bottom
plug (16), O-ring (15) and valve spring (14). Pull valve assembly (11) together with O-ring (12) out of body. Do not remove valve seat
(10) unless replacement is necessary. Remove O-ring (9) using a hook shaped tool, taking care not to damage O-ring seating surfaces
or valve seat.
Clean parts using warm water and soap. Dry thoroughly. Inspect each part carefully. Replace any parts which are damaged.
At reassembly, apply a wipe coat of silicone base grease to O-rings (9, 12, 15), to stem and body of valve assembly (11), and to
center bore in bottom plug (16). Apply a light even coat of light grease to full length of threads and tip of adjusting screw (1). Tighten
valve seat (10), if previously removed, to 80 to 100 inch-pounds torque (1/4", 3/8" and 1/2" sizes) or 25 to 30 foot-pounds torque (3/4"
and 1" sizes). Tighten bottom plug (16) snugly by hand. Tighten bonnet screws (4) to 20 to 30 inch-pounds torque (1/4", 3/8" and 1/2"
sizes) or 50 to 60 inch-pounds torque (3/4" and 1" sizes).
WARNING
THESE REGULATORS ARE INTENDED FOR USE IN INDUSTRIAL COMPRESSED AIR SYSTEMS ONLY. DO NOT USE THESE
REGULATORS WHERE PRESSURE OR TEMPERATURE CAN EXCEED RATED OPERATING CONDITIONS. SEE
SPECIFICATIONS.
IF OUTLET PRESSURES IN EXCESS OF THE REGULATOR PRESSURE SETTING COULD CAUSE DOWNSTREAM
EQUIPMENT TO RUPTURE OR MALFUNCTION, INSTALL A PRESSURE RELIEF DEVICE DOWNSTREAM OF THE REGULATOR.
THE RELIEF PRESSURE AND FLOW CAPACITY OF THE RELIEF DEVICE MUST SATISFY SYSTEM REQUIREMENTS.
BEFORE USING WITH FLUIDS OTHER THAN AIR, OR FOR NON-INDUSTRIAL APPLICATIONS, OR FOR LIFE SUPPORT
SYSTEMS, CONSULT C.A. NORGREN CO.