ANDERSON GREENWOOD
SERIES 93T PILOT OPERATED SAFETY RELIEF VALVES
INSTALLATION AND MAINTENANCE INSTRUCTIONS
Before installation these instructions must be fully read and understood
WARNING
Removal of the seal wires in an attempt to adjust
and/or repair this product by unauthorized or
unqualified persons voids the product warranty
and may cause damage to equipment and serious
injury or death to persons.
The product is a safety related component
intended for use in critical applications. The
improper application, installation or maintenance
of the product or the use of parts or components
not manufactured by Anderson Greenwood may
result in a failure of the product.
Any installation, maintenance, adjustment, test,
etc. performed on the product must be done
in accordance with the requirements of all
applicable Anderson Greenwood procedures and
instructions as well as applicable National and
International Codes and Standards.
SAFETY PRECAUTIONS
When the pressure relief valve is under
pressure never place any part of your body
near the pilot exhaust nor the outlet of the
main valve.
The main valve outlet should be piped or vented
to a safe location.
Always wear proper safety gear to protect
head, eyes, ears, etc. anytime you are near
pressurized valves. Never attempt to remove
the pressure relief valve from a system that is
pressurized.
Never make adjustments to or perform
maintenance on the pressure relief valve while
in service unless the valve is isolated from
the system pressure. If not properly isolated
from the system pressure, the pressure relief
valve may inadvertently open resulting in
serious injury.
Remove the pressure relief valve prior to
performing any pressure testing of the system.
STORAGE AND HANDLING
Pressure relief valve performance may be
adversely affected if the valve is stored for an
extended period without proper protection.
Rough handling and dirt may damage, deform,
or cause misalignment of valve parts and may
alter the pressure setting and adversely affect
valve performance and seat tightness. It is
recommended that the valve be stored in the
original shipping container in a warehouse
or as a minimum on a dry surface with a
protective covering until installation. Inlet and
outlet protectors should remain in place until
the valve is ready to be installed in the system.
VCIOM-03093-US 15/01
Engineering Doc. #05.9040.082 Rev. E
1 GENERAL VALVE DESCRIPTION AND
START UP
1.1 Operation
The Anderson Greenwood Pilot Operated Safety
Relief Valves utilize the principle of back-
loading the top, or large area, of a differential
area diaphragm with line pressure to hold
the diaphragm closed up to set pressure.
At set pressure the pilot valve relieves,
partially evacuating the dome (volume above
the diaphragm) and the seat assembly lifts
permitting discharge from the main valve.
When the pilot reseats, line pressure is diverted
to the dome closing the main valve.
1.2 Installation
Both inlet and outlet may be standard ANSI of
DIN flange connections and are to be installed
in accordance with accepted piping practices.
The installed position of the safety valve should
be in the upright position as shown in Figure 1.
When remote pressure pick-up is used the pilot
supply tube is connected to a remote location
rather than to the inlet neck of the valve. If a
block valve is used in the remote pilot supply
line, be sure it is opened before pressurizing
the system or opening the isolating block valve
under the main valve, if one is used.
Installation and maintenance instructions
for Series 93T POSRV (Pilot Operated Safety
Relief Valves).
The intent of these instructions is to acquaint
the user with the storage, installation and
operation of this product. Please read these
instructions carefully before installation.
The safety of lives and property often depends
on the proper operation of the pressure relief
valve. The valve must be maintained according
to appropriate instructions and must be
periodically tested and reconditioned to ensure
correct function.
Note:
remote pressure pick-up piping must
have the equivalent flow area of ½” tubing for
lengths up to 20 feet. For lengths greater than
20 feet, larger tubing or pipe should be used.
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