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Sapag Type 7700 pressure relief valves
Installation, Maintenance and Adjustment Instruction
Threaded connection type 7700
Testing
Testing should be performed by trained personnel using the applicable test procedure. Follow these
guidelines for performance of the set pressure test.
• Test fluids - set pressure test
The test fluid should be air or nitrogen for valves used on gas and vapor service and water for
valves used on liquid service.
Note: Valves for steam service should be tested on steam. When steam testing is not possible,
valves for steam service may be tested on air or nitrogen. In such cases it may be necessary to
make a correction to the adjusted set pressure to compensate for the difference in temperature of
the test fluids.
• Temperature correction
When a valve is set on air or water at room temperature and then used at a higher service
temperature, the cold differential set pressure shall be corrected to exceed the set pressure using
the following temperature correction:
Operating temperature
°F
°C
0 to +150
-18 to +66
+151 to +600
+66 to 316
+601 to +750
316 to 399
• Valve operation
Valves intended for compressible fluid service and tested on air, nitrogen or steam will open
with a sharp, clear popping action at the set point. Valves for liquid service tested with water
are considered open at the first continuous unbroken stream of liquid flowing through the valve.
Sometimes it is helpful to install a short piece of pipe in the valve outlet to determine the opening
on water.
Emerson reserves the right to change the contents without notice
O-ring soft
seat
Metal-to-metal
seat
% Pressure increase
None
1%
2%
Partslist
1
Base
2
Cylinder
3
Disc insert
4
Disc holder
5
Seat O-ring
6
Guide
7
Spindle
8
Spring
9
Spring washers
10
Adjusting bolt
11
Adjusting bolt nut
12
Type A cap
15
Seal and wire
27
Cap plug
28
Cap plug O-ring (test rod not shown)
page 2
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