Coaxial valve

Claim 1

A compact fluid control valve comprising: a magnetically permeable body member of generally cylindrical shape having a central opening therethrough and having on its outside surface two reduced diameter portions intermediate the ends of said body, said second reduced diameter being of smaller diameter than said first reduced diameter and formed thereon and forming a thin wall portion between said second reduced diameter and the central opening; said body member including flanges at each end thereof defining the terminal ends of said first reduced diameter portion, said flanges and said reduced diameter portions constituting integrally formed sections of said body member; a solenoid coil wound on the first reduced outer diameter portion of said body member and overlying the second reduced diameter portion; a stop member of generally cylindrical shape having a central opening therethrough and attached in the central opening of said body member, the inner end of said stop member extending past the midpoint of said solenoid coil and terminating at a location within said second reduced diameter portion, the central opening of said stop member being in registry with the central opening in said body member, the central opening in said stop member having two diameters of different size connected by a tapered conical section; a valving assembly comprising: a thin malleable shell of two different outside diameters connected by a tapered conical section, said shell having a central passage therethrough and being attached in the central opening of said stop member such that: the conical portion thereof is in engagement with the conical portion of the central opening in said stop member, the central passage of said shell is concentric with the central opening in said stop member, and said shell terminates at one end within said second reduced diameter portion and is there threadedly connected to the terminal end of said stop member, the other end of said shell forming a valve seat; a valve rod slidably mounted in the central passage of said shell, said valve rod projecting from the ends of said shell, substantially all of said valve rod being disposed within said first diameter portion of said body member; a sealing member attached to an end of said valve rod adjacent said valve seat and being engageable with said valve seat to close the central passage of said shell; a spring engageable between said shell and said valve rod to bias said sealing member against said valve seat; an actuating member slidably mounted in said central opening adjacent said one end of said shell, said actuating member comprising: a solenoid armature engageable with the inner wall of said central opening and defining an inner recess, said armature being located such that the inner end thereof faces the inner end of said stop member and is disposed within the second reduced diameter portion when said solenoid armature is in an unenergized condition; and an actuating rod portion disposed in said recess in alignment with said valve rod, with said valve rod extending into said recess and terminating short of said acTuating rod portion during said unenergized condition; the inner end of said stop member being champhered to an external conical shape and the inner end of the armature facing the inner end of the stop member being formed with an internal complementary conical shape, there being a gap between said champhered ends during said unenergized condition; the thin wall portion of said body member forming a flux resistant section in said magnetically permeable body member causing flux generated by the energized solenoid coil to move said actuating member and its actuating rod portion toward said valve rod for opening said seating member such that access completely through the central opening of said body member is provided.