Slide sleeve valve having integral leak prevention

A method for operating a slide of a hydraulic valve, wherein the hydraulic valve includes a housing that defines a first port, a second port, a third port for a hydraulic fluid, and a sleeve disposed within the housing that defines openings in fluid communication with the second port and the third port, wherein the slide comprises a head at a first end and a shaft at a second end, and wherein the slide is disposed within the sleeve and is movable in a lengthwise direction from a closed position to an open position, the method comprising:

• displacing the slide from the open position to the closed position such that an inner surface of a circumferential lip extending perpendicularly to the lengthwise direction of the head and facing the sleeve abuts an annular protrusion on an end face of the sleeve that protrudes in the lengthwise direction to form a seal between the slide and the sleeve to stop flow of the hydraulic fluid through the first port into the sleeve;
• maintaining the slide in the closed position in response to pressure from the hydraulic fluid applied to the circumferential lip from outside of the sleeve;
• and
• displacing the slide from the closed position to the open position, thereby enabling the hydraulic fluid to flow across the head through the sleeve to the second port.

An apparatus comprising:

• a sleeve that includes an annular protrusion that protrudes from an end face of the sleeve in a lengthwise direction;
• and
• a slide disposed within the sleeve and movable in the lengthwise direction, the slide comprising:
• a head disposed at a left end of the slide, comprising:
• a head protrusion forming a leftmost portion of the head;
• a circumferential lip that is disposed rightward of the head protrusion, and that includes an inner surface extending perpendicularly to a length of the slide and facing the sleeve, wherein the inner surface abuts the annular protrusion of the sleeve when the slide is in a closed position such that flow of a hydraulic fluid through an inlet port is stopped;
• and
• circumferentially disposed flow grooves which are located rightward of the circumferential lip and extend rightward;
• and
• a shaft disposed rightward of the head, comprising:
• a shaft body having a width less than a width of the sleeve;
• and
• a shaft base having a diameter corresponding with an inner diameter of the sleeve.