Expansion valve for air conditioning system with proportional solenoid

An expansion valve for controlling flow of expanded refrigerant material into an evaporator of a heat transfer system, comprising:

• a body, said body including an inlet for receiving liquid refrigerant material;
• an outlet for delivering expanded refrigerant material to an evaporator of a heat transfer system;
• and control element means for controlling the rate of flow of refrigerant material from said inlet to said outlet;
• said body further including an opening, said control element means accessible through said opening;
• a variable permeance element comprised of magnetic material, said variable permeance element in surrounding relation of said opening;
• an isolation member comprised of nonmagnetic material, said isolation member extending outward on said body through said opening and terminating at an outer end, said isolation member having an enclosed interior area, said interior area extending longitudinally in said isolation member;
• an actuating member, said actuating member positioned in said interior area of said isolation member and longitudinally movable therein, said actuating member comprised of magnetic material and sized for acceptance in said opening, said actuating member adapted for engaging said control element means, and wherein flow through said control element means varies with movement of said actuating member;
• biasing means for biasing said actuating member toward said outer end of said isolating member;
• sleeve member means for surrounding said isolating member, said sleeve member means comprised of magnetic material;
• electrical coil means in surrounding relation of said sleeve member means, for producing electromagnetic flux responsive to delivery of electrical power thereto, said electrical coil means having a first end adjacent said outer end of said isolating member, and a second opposed end adjacent said variable permeance element;
• frame means comprised of magnetic material for supporting said coil means, said frame means in connection with said sleeve means and extending between said ends of said coil means;
• flux saturation means disposed longitudinally between said opening and said sleeve member means for providing an area of magnetic flux saturation;
• and
• wherein electrical power delivered to said coil means moves said actuating member against the force of said biasing means and into said opening, whereby control of flow rate through said control element means is achieved.