Liquid/vapor bypass valve

A bypass valve assembly selectively operated to bypass a delivery fluid, comprising:

• a housing having a fluid inlet, a bypass fluid outlet and a pressure inlet;
• a cage assembly slidably supported within the housing and having a plunger end and a piston retaining end, the plunger end forming with the housing an interior chamber in fluid communication with the pressure inlet;
• a piston assembly slidably supported by the cage assembly;
• first spring supported in the cage assembly between the plunger end and the piston retaining end for biasing the piston assembly to a closed position in which fluid flow is prevented between the fluid inlet and the bypass fluid outlet;
• a second spring supported between the housing and the piston assembly, the second spring biasing the plunger toward the pressure inlet;
• and
• wherein the piston assembly is slidable between a closed position, a first open position and a second opened position, the piston assembly preventing fluid flow from the inlet to the bypass fluid outlet in the closed position, the piston assembly biased to the closed position when the delivery system pressure is between an upper first threshold pressure value and a lower second threshold pressure value, to the first open position when the delivery system pressure exceeds the first threshold pressure value whereby fluid flow is permitted from the fluid inlet through the bypass fluid outlet, and to the second open position when the delivery system pressure is less than the second threshold pressure value whereby fluid flow is permitted from the fluid inlet through the bypass fluid outlet.

A bypass valve assembly which selectively operates to establish a bypass path for a fluid in a delivery system, comprising:

• a body member having a fluid inlet connectable to the delivery system, a bypass fluid outlet and a pressure inlet orifice;
• a piston assembly supported within the body member, the piston assembly slidable between a closed position, a first open position and a second open position, the piston assembly preventing fluid flow from the inlet to the bypass fluid outlet in the closed position;
• and
• means for biasing the piston assembly in the closed position when the delivery system pressure is between an upper first threshold pressure value and a lower second threshold pressure value, for moving the piston assembly to the first open position when the delivery system pressure exceeds the first threshold pressure value whereby fluid flow is permitted from the fluid inlet through the bypass fluid outlet, and for moving the piston assembly to the second open position when the delivery system pressure is less than the second threshold pressure value whereby fluid flow is permitted from the fluid inlet through the bypass fluid outlet, wherein the means for biasing the piston assembly comprises:
• a cage assembly slidably supported in the body member and having a plunger member and annular collar, the plunger member connected to the annular collar by at least one standoff flange member, the plunger collar forming with the body member an interior chamber in fluid communication with the pressure inlet orifice;
• means for biasing the piston assembly toward the fluid outlet;
• and
• means for biasing the cage assembly toward the pressure inlet orifice.