Patent ID: 6283441
Filing Date: 2001-09-04
Classification: F02M,F16K

Abstract:
A pilot actuated spool valve assembly comprising:a valve body defining a first passage, a second passage and a flow passage;a unitary pilot body at least partially positioned in said valve body and having a first valve seat and a second valve seat;a pilot member moveable in said pilot body between an up position in which said pilot member closes said first valve seat, and a down position in which said pilot member closes said second valve seat;a spool valve member having a control hydraulic surface and being positioned in said valve body and being moveable between a first position in which said first passage is open to said flow passage, and a second position in which said second passage is open to said flow passage;at least one of said valve body, said pilot body, said pilot member and said spool valve member defining a control volume fluidly connected to said first passage when said pilot member is in one of said up position and said down position; andsaid control hydraulic surface being exposed to fluid pressure in said control volume.