Shutdown Valve: is one of main parts on the technology line and installed at the inlet and outlet of each air supply line, and Heater’s, , Filter/Seperator’s technology air passages. SDV has a function which isolate lines, equipment in case of emergency as well as operation.
The working principle of SDV:
Using gas pressure acting on the Piston face, compressing the strings, through the swing arm makes the valve open. When Piston face pressure drops lower than working, The compression of the spring pushing the piston causes the lever arm to move in the opposite direction, causing the valve to close.
- On valve: The control gas flow, after passing through the Filter and being depressurized, goes to the manual valve No. 1, continues through the Solenoid valve ESD and ICS, then to the manual valve No. 3 and through the quick release element to the control gas cylinder, pushing the Piston moves the Actuator and holds the valve in the open position.
- Off Valve: Close the hand valve number 1, push the hand lever from the bottom to the top by hand, then the control gas will not be supplied to the cylinder → Actuator spring force pushes and holds the valve in the closed position.
Drawing of control gas and solenoid system of SDV
Position of latch knob and lever in each state
– Emergency case: In case of power failure, the Solenoid valve switches to the closed position so the control gas does not enter the cylinder, then the actuator’s spring force will push and hold the valve in the closed position. In the event of a loss of control gas, the Actuator’s spring force pushes and holds the valve in the closed position.
The twin SDV Solenoid can be operated forcibly by hydraulic oil, mechanical handwheel, electric or gas driven.
- Forced hydraulic oil:
+ Close the hand valve of the return oil to the tank
+ Operate the oil pump through the pump lever to inject hydraulic oil into the cylinder and monitor the oil pressure displayed through the PI pressure gauge within the permissible range of 10 ÷ 50 barg.
- Forced removal of hydraulic oil:
+ Open the hand valve to return the oil to the tank.
+ Then the hydraulic oil in the cylinder will return to the tank, monitor the oil pressure displayed through the PI gauge with 0 barg.
Hydraulic oil pump forced valve
– Forced mechanical crank:
+ Turn the handwheel counterclockwise until the hand is tight and can’t be turned anymore, the SDV will gradually open.
– Remove forced mechanical handwheel:
+ Turn the handwheel valve clockwise (except for the SDV-1409 which rotates counterclockwise) until the hand is tight and can no longer be turned, the SDV will gradually close.
– Forced by controlled gas:
Open the manual valve No. 2 to control Bypass through the Solenoid, close the manual valve No. 3 to avoid exhausting air when the Solenoid loses power, causing a pressure drop in the cylinder.
– Unforcible opening of SDV when bypassing the control airway:
Open the manual valve number 3 with gas controlled via Solenoid, close the manual valve No. 2 bypass.
Control gas bypass status
