Emerson 91 Installation And Maintenance Instructions Manual - Page 10
Browse online or download pdf Installation And Maintenance Instructions Manual for Control Unit Emerson 91. Emerson 91 12 pages. Pilot operated safety relief valves
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ANDERSON GREENWOOD TYPE 91 AND 94 PILOT OPERATED SAFETY RELIEF VALVES
INSTALLATION AND MAINTENANCE INSTRUCTIONS
FIGURE 7
Inlet
Item
Description
1
Hex head cap screw
2
Upper body
3
Diaphragm
4
Nut
FIGURE 8
Flow
Item
Description
5
Lower body
6
Spring pin
7
Lockwasher
8
Diaphragm support washer
Item
190, 190A
200, 200A
235A
440A
460, 460A
470, 470A
555A
Secondary set
750
pressure
760, 760A
770A
790, 790A
810
810A
820 820A
840, 840A
A = First auxiliary setter
Primary set
pressure
Outlet
Description
Nut-lock pressure adjuster
Bonnet assembly
Adapter
Swage nut
Wire
Seal - ½" diameter
Extension rod
Hex nut
Cap
Bonnet bolt
Pressure adjustment screw
Bonnet vent
Bonnet plug
Spring washer
Spring
5 ACCESSORY REPAIR
5.1 Check valve
The check valves used on the Dual pilot, Backflow
preventer, and Field test consist of an upper body,
a lower body, and a diaphragm. Refer to Figure 7.
The check valve diaphragm is the only part that
should require servicing. If the diaphragm is
to be replaced, care should be taken not to
scratch or distort it in the center nozzle sealing
area. When reassembling the check valve,
uniformly tighten the body bolts, first one
side, then the opposite side until all are tight.
DO NOT OVERTIGHTEN bolts as this will distort
the diaphragm and cause leakage.
5.2 Auxiliary pilot valve setting device
The auxiliary pilot setting device is used in those
application where multiple settings are required.
Figure 8 shows one auxiliary pilot setting device
mounted on a primary pilot. A maximum of two
auxiliary pilot setting devices can be added to
the primary pilot. Each auxiliary pilot setting is
adjusted and set at the factory to the required
set pressure but is not installed on the valve.
Each device is to be installed per the customer's
requirements. (see paragraph 5.2.1 Installation
and Removal in the field)
The combined valve set pressure with auxiliary
pilot setting devices installed will be the value
stamped on the top most device. There should
be no adjustment required to the primary pilot
or the auxiliary pilot setting device after it has
been installed. Furthermore, there should be
no adjustment required to the primary pilot
setting once the auxiliary device has been
removed.
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