Adjustable servo type throttle valve - has sliding plug enclosed by ring of porous material

摘要

Valve has a throtting plug sliding in a cylindrical orifice with a valve seat under the action of an adjusting rod. The plug (4) is enclosed by a ring (12) of porous material, filling the space between the plug and the cylindrical orifice. The ring can be machined on the outside to give a cylindrical surface and a sliding fit. It can be sintered onto the main part of the plug. Alternatively it can be composed of up to three sections, clamped in a two-part plug, and the rings can be sintered, perforated or sieve-type plates. They can be of materials of different degrees of porosity of permeability.