Four-way reversing valve with differential area operator

Abstract

The four-way reversing valve is utilized in refrigerating systems for heat pump applications to interchange the heating and cooling effects of the evaporator and condenser. The three-way pilot valve controls application of high or low system pressure to the end of the chamber adjacent the large piston. The different areas of the two pistons result in movement of the slide valve to the left (both modifications) when high pressure is applied and to the right when low pressure is applied.

I claim: 
     
       1. A reversing valve comprising, a body including a valve chamber, a high pressure inlet to the chamber, a low pressure outlet from the chamber, and a pair of ports adjacent the outlet,   a slide valve in the chamber movable between two positions in which it serves to connect either of said ports to said outlet while the other port communicates with the chamber,   said body including a large diameter cylinder and a small diameter cylinder,   a piston in each cylinder, the pistons being interconnected and being connected to the slide valve,   means supplying a constant pressure to the space between the pistons,   one side of the smaller piston being exposed to the chamber pressure and the other side of the smaller piston being .[.exposed to low pressure.]. .Iadd.connected to said low pressure outlet .Iaddend.so there is always a pressure differential acting across the smaller piston,   means .[.supplying high or low pressure to.]. .Iadd.for selectively connecting .Iaddend.the space between the larger piston and the head of the larger cylinder .Iadd.to high pressure or to the low pressure outlet .Iaddend.to cause the pistons and slide valve to move between said positions by reason of the pressure differential acting across the small piston area in one position and by reason of the pressure differential across the difference in piston areas in the other position.   
     
     
       2. A valve according to claim 1 in which the valve chamber is between the pistons. 
     
     
       3. A valve according to claim 1 in which both pistons are located at one end of the valve chamber and the space between the pistons is at low pressure.