This type of motor-operated fuel shutoff valve is either a ball-valve style or barrel type and is designed with one or more of the following functions: (1) to cut-off fuel flow into the engine in the event of a fire, (2) to allow fuel cross transfer between left and right wing tanks for in-flight CG control, and (3), and to provide APU isolation.
The material and finishes used in the construction of the valve and those of similar, previously qualified, valves are unaffected by several environmental conditions listed in RTCA DO-160 and MIL-STD-810. This elegantly simple design is extremely reliable and several variations of this valve have been produced by Parker for over 30 years.
The actuator mounted on top of the valve is capable of driving the valve from OPEN to CLOSED and from CLOSED to OPEN with a nominal 28 VDC motor and maintains the last commanded position in the event of a dual command.
When the actuator is electrically commanded to open, supply voltage is applied directly to the motor to overcome the initial high-friction torque and drives the ball/barrel valve open. At the end of the stroke, the power-limiting switch turns off the supply voltage to the motor and causes the motor to stop. The end stroke-position switch is also activated; sending full open indication signal to the controller. Upon electrical command to close, a relay changes voltage direction to the motor and the actuator travels back to the closed position.
With its high-reliability design and ability to pass tough EMI requirements, this valve is an ideal choice when properly selected for the right application.
APPLICATIONS:
Commercial aircraft, military fighters and transports, business and general aviation.
FEATURES AND ATTRIBUTES:
Fundamental features of the motor-operated fuel shutoff valve include the following:
• A lightweight and high-reliability design
• End stroke position indication signals
• Outlet to inlet thermal relief capability (not available in all units)
• Manual override (not available in all units)
• Low internal leakage when closed and zero external leakage
OPTIONAL FEATURES:
Varying shapes and line sizes.
