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EPDT-193d
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3
4. Structure
5. Operation
Blowout operation
As the inlet pressure approaches the blowout pressure, the force of fluid pushing up the valve [3]
approaches the force of the spring [8] pressing down the valve [3]. The safety relief valve commences to
blow when the inlet pressure gets lower than the blowout pressure.
Then, when the inlet pressure rises and reaches the blowout pressure, the valve [3] pops.
Closing operation
Since the inlet pressure of the safety relief valve decreases when the fluid is released into the atmosphere
by the pop action of valve [3], the force of fluid lift is lowered. At this point, the repelling force of the spring
[8] becomes larger than the force of fluid lift and thus the valve closes. In addition, while the safety relief
valve discharges, pressure of fluid entering into the back of the valve [3] (back pressure) adds to the closing
force.
AL-150T
AL-140T
No.
Part name
1 Spring case
2 Valve seat
3 Valve
4 Valve cover
5 O ring
6 C ring
7 Spindle
8 Spring
9 Bottom spring plate
10 Top spring plate
11 Adjusting screw
12 Lock nut
13 Cap
14 Gasket
15 Gasket
16 Name plate
17 Rivet
18 Handle
19 Lever
20 Spring pin
21 Spring pin
22 O ring
23 Connecting rod
24 Pressure groove
Fig.2 Structure
AL-150TR
AL-150TML, AL-140TML
