Solenoid actuated valve

In a valve having a valve body with a fluid inlet, a fluid outlet, a main valve seat, a pilot valve chamber, a main valve element seatable on said main valve seat, means forming a pilot valve seat connecting said pilot chamber to said outlet, a pilot valve element seatable on said pilot valve seat, means defining a restricted passage connecting said inlet to said pilot valve chamber, said passage having smaller flow capacity than said pilot valve seat, said main valve element having a first surface area in open communication with said pilot valve chamber so that said main valve is held by fluid pressure in its closed position when the pilot valve element is closed, said main valve element having a second surface area smaller than said first surface area exposed to said inlet pressure when said main valve element is moved by inlet pressure away from said main valve seat when said pilot valve element is opened, said pilot valve element being urged against its seat by pressure in said pilot valve chamber, and electromagnetic means for controlling the operation of said valve comprising:

• a main armature attached to said main valve element, being movable with said main valve element between valve open and valve closed positions;
• said main valve element including a stem section connected at one end to said main armature;
• a pilot armature attached to said pilot valve element and mounted for movement towards said main armature to open said pilot valve and being movable with said main armature;
• spring means urging said pilot valve element into engagement with said pilot valve seat and urging said pilot armature away from said main armature;
• coil means positioned in flux linking relation with said armatures;
• magnetic structure positioned adjacent said coil means and said armatures for providing a magnetic path for flux produced by said coil means, said coil means having sufficient power to complete a flux path through said armatures and to generate sufficient magnetic force to cause, during a first mode of operation, said pilot armature and said pilot valve element to move towards said main armature against fluid pressure urging the pilot valve closed to open said pilot valve element and bleed pressure from said pilot chamber, whereby fluid pressure existing in said inlet opens said main valve element and thus moves said main valve element into said valve open position, and to cause, during a second mode of operation, said pilot armature and said pilot valve element to move toward said main armature to open said pilot valve element whereby the pilot armature moves into engagement with said main armature, and then to move said pilot and main armatures together to open said main valve, all in the absence of fluid pressure urging the pilot valve closed;
• said magnetic structure including a fixed core portion spaced from said main armature when the main armature is in said valve closed position, said main armature and pilot armature being movable closer to said fixed core portion when said main valve is moved to its open position by either fluid pressure or magnetic force, in the first and second modes, respectively, whereby said fixed core portion completes a flux path having characteristics such that said coil means has sufficient power to hold said main armature and main valve element in said valve open position both in the presence and absence of said fluid pressure;
• said pilot chamber and said pilot valve seat being formed within the interior of said main valve element;
• said pilot valve element including a tubular stem section connected at one end to said pilot armature;
• said pilot armature having a tubular shape;
• and said main valve element's stem section being mounted within said pilot armature and said tubular stem section of said pilot valve element.