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D 200318X 012
377 Series Trip Valves
The 377 Series pressure-nsing trip valves (e figures 1 and 2) are for control applications where a specific valve/actuator action is required when supply pressure falls below a specific point. When supply pressure falls below the trip point (e figure 3), the trip valve caus the actuator to fail up, lock in the last position, or fail down. When the supply pressure ris above the trip point, the 377 Series trip valve automatically rets, allowing the system to return to normal operation. The trip valve can be top-mounted on a manifold, yoke-mounted, or bracket-mounted to match the application
复利计算requirements. The 377 Series trip valves can be ud with 480, 585C, 1061, 1066, 1069, and G Series piston actuators.
Features
D Cost Effective —Single trip valve construction reduces costs and spare part requirements of tho systems using three parate switching valves to perform the failure functions. A single trip valve greatly simplifies piping requirements.
D Ea of Mode Conversion —Conversion to any of the fail modes requires only minor hookup changes.初中英语课件
D Adjustable Trip Valve —The trip point is
adjustable for specific supply pressure requirements.
D Reliable Operation —The trip valve design includes large diaphragm areas and few moving parts for efficient performance, minimum maintenance, and long rvice life.
W4292-1/IL
Figure 1. 377 Series Trip Valve
英语演讲小短文
W8435-1
Figure 2. Type 377 Trip Valve Mounted on Size 130 Type
585C Actuator
volts2. Values reprent nominal C v measures for each port pair using a trip valve/actuator combination.
3. The pressure/temperature limits in this bulletin and any applicable standard or code limitation should not be exceeded.
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NOTE:
TRIP POINT MAY BE SET TO ANY VALUE BETWEEN 2.8 BAR (40 PSIG) AND THE MAXIMUM TR
冰刀双人组IP POINT LINE.
RESET OCCURS AT 12.5 TO 33 PERCENT ABOVE ADJUSTED TRIP POINT.
SUPPLY PRESSURE, PSIG
A2779-2/IL
12Figure 3. Maximum Trip Point Settings
Principle of Operation
dermalogicaType 377D Trip Valve
In normal operation, supply pressure loads the upper diaphragm (e figure 4) of the unit. The valve plug spring keeps the exhaust port clod. Supply
pressure also loads the lower diaphragm through the restriction, causing the plug asmblies to move down and isolate ports C and F while connecting port A to B and port D to E. Normal actuator control pressure flows from the control device to the top of the cylinder through ports A and B and to
the bottom of the cylinder through ports D and E. A volume tank is charged to maximum supply pressure through a check valve in order to retain maximum supply
pressure in the volume tank if supply pressure drops.When supply pressure falls below the trip point pressure in the fail-down mode (e figure 5), the exhaust port opens, venting the supply pressure that is loading the lower diaphragm. This caus the
colleague是什么意思upper ports of the plug asmblies to clo and shut off normal pressure flow from the control device to the actuator.
PORT
RESTRICTION
PORT A
PORT B
PORT D PORT E PLUG
ASSEMBLIES
PORT F PORT C
CONNECTION LOWER
DIAPHRAGM
W4303-1/IL
Figure 4. Simplified Sectional View of Trip Valve
Volume tank pressure then flows through ports C and B to the top of the actuator cylinder, while pressure in the bottom of the actuator cylinder is vented through ports E and F. The pressure
imbalance created forces the actuator piston down.
When supply pressure is restored, it loads the upper and lower diaphragms, causing the trip valve to ret. The exhaust port clos. The upper ports of the plug asmblies open, and the lower ports clo.Normal actuator control pressure flow from the
control device is restored through ports A and B and ports D and E. The check valve opens and recharges the volume tank to the maximum supply pressure.
4Figure 5. Type 377D Trip Valve Shown Tripped
Type 377L Trip Valve
When supply pressure falls below the trip point in the lock-in-last-position mode (e figure 6), the exhaust port opens, venting supply pressure from the lower diaphragm. This caus the upper ports of the plug asmblies to clo and the lower ports to open. Since ports C and F are plugged, no pressure change occurs on either side of the actuator piston, and the piston is pressure-locked in position upon loss of supply pressure. No volume tank is necessary in this mode. When supply pressure is restored, the plug asmblies move back into the normal operating position, and supply pressure flows from the control device through ports A and B to the actuator.Type 377U Trip Valve
The fail-up mode of operation (figure 7) is similar to the fail-down mode of operation except that connections to port C and F are reverd. When supply pressure falls below the trip point, the top of the actuator cylinder vents, and volume tank pressure loads the bottom of the actuator cylinder. The pressure imbalance created forces the actuator piston up.
DIAPHRAGM LOWER
PORTS
PORT F PORT C
PLUG ASSEMBLIES
UPPER PORTS
PORT B
PORT A
杨振宁简历Figure 6. Type 377L Trip Valve Shown Tripped
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