Solenoid-operated, three-way fuel valve with pressure balancing

Claim 1

A three-way, normally closed fluid valve comprising: a valve body having first and second chambers therein and a communicating third chamber joining said first and second chambers; an inlet port including a duct for applying fluid under pressure to said first chamber; an outlet port for applying said fluid under pressure from said third chamber to a utilization device when said valve is in the open condition, said fluid having passed from said first chamber through said third chamber; first means including a piston mounted with axial sliding freedom within said first chamber, and a poppet assembly mounted with axial sliding freedom within said second chamber, said first means including a hollow stem having an axial bore, said stem extending axially through said third chamber to mechanically join said piston and said poppet assembly, said bore extending axially through said stem, said poppet and said piston; a fourth chamber at a second end of said poppet assembly opposite said stem forming a closed cylinder into which said poppet assembly second end may slide, said bore being open to said fourth chamber; second means operatively associated with said first means and including upper and lower valve orifices, said upper orifice being arranged to be positioned open and said lower orifice being arranged to be positioned closed when said first means is in an axially translated position corresponding to the open position of said three-way valve, said upper orifice being closed and said lower orifice being open when said first means is in an axially translated position corresponding to the closed position of said three-way valve; third means comprising a bleed hole extending generally axially through said piston to permit fluid flow therethrough at a predetermined rate, thereby joining the portion of said first chamber on either side of said piston; fourth means for applying a generally axial mechanical force to a first end of said piston of said first means opposite said stem to operate said valve; fifth means comprising a third valving orifice at said first end of said first means, said fifth means being responsive to said fourth means for draining fluid pressure through said bore from the portion of said first chamber adjacent said piston first end to initiate opening of said three-way valve; a drain-back port and duct for draining said second chamber externally when said valve is in said closed position; and sixth means comprising an opening in the wall of said hollow stem within said third chamber, said hole permitting drainage of said bore and said fourth chamber into said third chamber and thereafter into said drain-back pOrt when said three-way valve is in said closed condition.