Abstract: A spool slides in a bore to open and close a valve. The spool moves in a first direction until the spool forcibly engages a seat in the bore, closing the valve. The spool moves in a second direction opposite the first direction so that the spool disengages with the seat, opening the valve. Proper configuration of the spool and bore geometries in the vicinity of the seat keeps static pressure from developing that could otherwise retard spool valve opening.

Abstract: A spool slides in a bore to open and close a valve. An armature moveable relative to the spool is biased in a first direction. A coupling biasing member biases the armature and the spool toward each other. When a solenoid is actuated the armature and the spool move in a second direction opposite the first direction until the spool forcibly engages a seat in the bore, closing the valve and stopping the spool movement. The armature continues to move in the second direction, causing the coupling to apply additional force to keep the spool engaged against the seat, until the armature reaches a second position where it forcibly engages with the spool. This stops the armature from moving further in the second direction, but allows the stationary armature to continue applying force to keep the spool engaged against the seat. When the solenoid is de-energized the armature bias sends the armature back in the first direction until it strikes the spool, causing the spool to rapidly unseat, thus opening the valve.