Abstract: Operation of a system for injecting a predetermined amount of a secondary fluid into a primary fluid stream. The system uses a liquid additive injection pump driven by a fluid powered motor that is driven by the primary fluid stream and can be selectively suspended by an on/off switch mechanism. The fluid powered motor includes a housing enclosing a differential pressure piston assembly having a piston movable within housing between upstroke and down stroke positions; a valve mechanism establishing a differential pressure within the housing to produce movement of the piston; an over-center mechanism coupled to the valve mechanism to toggle the valve mechanism between open and closed positions; and an actuating shall coupled to the over-center mechanism.

Abstract: A hydraulic actuator has a housing, a piston drive chamber in the housing, a fluid inlet into the chamber, and a piston reciprocable in the drive chamber. The piston has diametrical steps exposed to fluid under pressure to cycle the piston. A sleeve spaced from and surrounds over a length of the piston to define a return chamber therebetween. The housing has first and second seats. The first seat and a first surface of the sleeve define an exhaust valve, which has an exhaust port, for the return chamber. The exhaust port is opened and closed by reciprocating the sleeve. The second seat and a second surface of the sleeve an inlet valve for the return chamber. Reciprocating the sleeve opens and closes the return chamber to the drive chamber. The housing also has a bore through which a portion of the sleeve reciprocates to close the exhaust valve and seal the drive chamber.

Abstract: A valve assembly including a valve housing with a spool valve mounted for reciprocation within the valve housing, with a detent mechanism disposed on the spool valve and the valve housing for selectively locking the spool valve against reciprocal movement, and for providing an externally observable indicator of valve position. In an illustrative embodiment, the detent assembly of the present invention includes at least one detent pin disposed on the spool valve, with at least one guide flange disposed on the valve housing. The guide flange is adapted to at least partially surround the detent pin. At least one retaining clip is provided which is adapted for insertion through the guide flange to engage the detent pin. When the retaining clip is inserted through the guide flange and in engagement with the detent pin, the spool valve is locked into a predetermined stationary position, and cannot reciprocate.

Abstract: A reciprocating piston fluid powered motor having fluid inlet and outlet, wherein reciprocation is controlled by a reciprocable valve spool carrying a manifold communicating with said fluid inlet and outlet and cooperating with a valve slide shiftable on said valve spool to control reciprocation of said valve spool.