Pilot valve with improved cage

A cage for positioning within a valve body of a two-position valve having a central valve axis, a fluid inlet port, and a fluid outlet port, a piston axially movable with respect to the valve body in response to pilot pressure, and a spool axially movable within the cage within the valve body in response to axial movement of the piston, the spool being axially movable between an open position such that the inlet port is in fluid communication with the outlet port and a closed position such that the inlet port is blocked by the spool from fluid communication with the outlet port, the cage comprising:

• an axially intermediate body formed from a selected plastic material and having an exterior surface for mating engagement with at interior surface of the valve body;
• an upper body removably secured to the intermediate body;
• a lower body removably secured to the intermediate body;
• the plastic material body having an upper portion axially overlapping a lower end of the upper body for radial alignment between the upper body and the intermediate body, and the plastic material body having a lower portion axially overlapping an upper end of the lower body for radial alignment between the lower body and the intermediate body;
• an external seal carried on the intermediate body for sealing between the intermediate body of the cage and the valve body;
• and
• an internal seal carried on the intermediate body for sag between the cage and the spool.

A method of servicing a two-position pilot-operated valve including a valve body having a central valve axis, a fluid inlet port, and a fluid outlet port, a piston axially movable with respect to the valve body in response to, pilot pressure, a spool axially movable within the valve body in response to axial movement of the piston, the spool being axially movable between an open position such that the inlet port is in fluid communication with the outlet port and a closed position such that the inlet port is blocked by the spool from fluid communication with the outlet port, a piston rod for structurally interconnecting the spool and the piston, a cage within the valve body for receiving the spool and including at least one radial upper throughport therein, an upper seal plate spaced axially between the cage and the piston for sealing engagement with the spool when in the closed position, a lower seal plate spaced axially between the cage and the fluid outlet port for sealing engagement with the spool when in the open position, and a spring to bias the spool toward the closed position, the method comprising:

• replacing a worn cage with another cage including an axially intermediate cage body formed from a selected plastic material;
• providing an external seal on the plastic material intermediate body for sealing between the intermediate body of the cage and the valve body and an internal on the plastic material intermediate body for continuous dynamic sealing between the cage and the spool during axial movement of the spool between the open and closed positions;
• removably securing an upper cage body including the one or more radial upper throughports therein to the intermediate body;
• removably securing a lower cage body to the intermediate body;
• and
• positioning the another cage including the intermediate cage body, the upper cage body, and the lower cage body within the valve body such that an exterior surface on the intermediate body is in mating engagement with an interior surface on the valve body and an internal cylindrical surface of the intermediate body is in sliding engagement with an external cylindrical surface of the spool during axial movement of the spool between the open and closed positions.