Abstract: The invention attenuates higher frequency vibrations or oscillations which can result in wear and/or less than optimal performance of a valve positioner. The invention provides a low pass mechanical filter which can be realized, for example, in a dash pot like damper device. The damper includes a pair of diaphragms associated with a pair of chambers, which are in communication with one another by an orifice. The chambers associated with each diaphragm are filled with oil or a hydraulic fluid such that the rate of relative motion (for example between a summing beam of the positioner and the location at which a signal force is applied) is controlled by flow of oil through the orifice.

Abstract: A valve having an assembly for live loading of the packings of the valve. The assembly includes a plurality of large belleville disk springs arranged such that the shaft or stem of the valve extends through the center of the belleville springs, with threaded studs arranged symmetrically with respect to the valve shaft also extending through the belleville springs. Utilizing the larger spring arrangement, a smaller number of springs are required, and favorable deflection characteristics are provided. Preferably, a compression ring is provided having a portion extending up through the belleville disk springs, with this portion including a visual indicator thereon which provides a visual indication that a desired load is achieved as the springs are loaded via hex nuts provided on the threaded studs of the valve assembly.

Abstract: A modular housing structure for rotatably positioning a cam on a shaft at a predetermined position relative to a limit switch. The modular housing includes upper and lower halves which are snap-fit together by an arrangement of projections and recesses which interconnect the housing halves, and hold a limit switch and a rotating cam in a fixed position relative to one another. Additionally, each limit switch module of the invention may be snap-fit onto the top or bottom of an adjacent limit switch module such that a number of modules may conveniently and easily be aligned along a single shaft. The cam rotatably received in each module is unitarily formed of a single material, and includes an inner spring collar which is deflected slightly when a shaft is inserted through the cam.

Abstract: A lever-operated rotary valve having a rotary body for permitting fluid flow therein includes a locking device for selectively locking and unlocking the operating handle such that the operating handle of the rotary valve can be locked in a plurality of predetermined positions. The operating handle of the rotary valve can be oriented in any one of a plurality of positions and locked in that position without requiring the removal of the locking device. The locking device is an L-shaped member which fits on the stem of the rotary valve and includes aligned holes for receiving a padlock so that the locking device and handle are locked together.

Abstract: A fluid pressure actuator having two connected pistons movable in a cylinder, and having a gear rack associated therewith to engage a pinion attached to the shaft to be rotated. Adjustable travel stops are located on each end of the cylinder to control the position of the actuator at the end of the stroke. Each stop has a pair of stop plates which have ramps on the mating faces such that rotation of one stop plate relative to the other adjusts the thickness of the pair, thereby adjusting the position of the end stop for the piston.

Abstract: A ball valve with a port (30) through the ball (26) has a groove associated with each end of the port with each groove (32,34) extending partially around the circumference of the ball. Each groove connects with its end of the port (30) and extends away from the port in the plane of rotation of the ball. The grooves decrease in size as they extend away from the port whereby the grooves serve to control the flow area depending on the degree of rotation of the ball. Diffusers (22,24) in the inlet and outlet of the valve assure that any cavitation will occur within the diffusers which are formed of material adapted to withstand the cavitation forces.