Rotary metering valve assembly and method of modifying contact surface for reducing gauge wringing

摘要

A rotary metering valve assembly 10 includes a stationary body plate 12 having a first contact surface, and a valve plate 16 having a second contact surface disposed in contact with the first contact surface of the stationary body plate. The valve plate is configured to rotate relative to the stationary body plate. At least one of the first contact surface and the second contact surface comprises a surface flatness of less than about 2.4 µm and a surface roughness of at least about 0.2 µm. The surface roughness ranges from 0.2 microns to 0.8 microns. The valve may be a portion of a fuel metering device of a gas turbine engine of an aircraft. Also provided is a method of modifying a contact surface of a rotary metering valve for reducing gauge wringing. The method comprises smoothing a contact surface of a rotary valve, then roughening said surface.