Valve for use in handling abrasive materials and method of wear

Abstract

A valve, comprising: a cylindrical casing, closed at its ends by covers, and having axially aligned inlet and outlet chambers midway of its length disposed at right angles to the axis of the casing. Communication between said chambers is controlled by a ported, fluid pressure operated, movable valve plate assembly, including parallel cylinders, each containing a stationary piston connected to the inner end of a pair of axially aligned rods, or guides, fixed at their outer end to the covers. Each rod has a passageway communicating at its inner end with one end of its associated cylinder for supplying operating fluid thereto to bodily reciprocate the valve plate assembly on said rods within the casing. An adjustable collar positions a fixed wear plate in sealing engagement with one side of the valve plate assembly, and a fluid pressure actuated loading ring urges a floating wear plate into contact with the other side of said valve plate assembly. The casing may be pressurized by gas or liquid, but in any event, such pressure is maintained equal to or preferably slightly lower than the fluid pressure applied to the loading ring, but higher than the pressure in the system in which the valve is installed. With such pressure relationship, any abrasive material being handled by the system is prevented from entering between the movable valve plate assembly and the fixed and floating wear plates, respectively, thereby eliminating or reducing leakage and wear to a minimum. When liquid is used as the casing pressurizing fluid and/or the operating fluid supplied to the cylinders, it is preferably filtered, and may also be circulated through heat exchange means, if cooling thereof is necessary or desirable. The invention further includes a method of preventing abrasion, i.e., scoring and galling of the valve seating surfaces when the valve is installed in a system handling abrasive material.