Flow ControlValve Assemblyby Moog, Parker Hannifin, Valcor, Marotta (and engine manufacturers)
Typical Specifications
Operating Pressure
1u201350 MPa
Actuation Time
20u2013200 ms (start/shutdown)
Temperature Range
-253u00b0C to 200u00b0C
Operating Principle
Pneumatic or hydraulic actuators open and close butterfly, ball, gate, or poppet valves to control propellant flow. Position sensors provide feedback for closed-loop control. Cryogenic valves use special seals and materials rated for -253°C operation.
Propellant valve assemblies control the flow of fuel and oxidizer into the engine, managing start, shutdown, throttling, and mixture ratio control. These valves must operate reliably under extreme pressure differentials and cryogenic temperatures while providing precise flow control. Main valves, prevalves, bleed valves, and check valves work together as an integrated flow control system.
Materials
Used In Engines
Common Failure Modes
Seal leakage, actuator failure, valve sticking (especially in cryogenic service), foreign object damage, thermal distortion
Recent Innovations
Electrically actuated valves replacing pneumatic (reducing helium needs), 3D-printed valve bodies, self-sealing check valves, rapid-acting prevalves
