Cryogenic check valve

A method for controlling fluid flow in one direction, comprising:

• providing a check valve comprising:
• a valve body having a bore having a longitudinal axis and a seat along the bore, a fluid inlet at a first longitudinal end of the bore, and a fluid outlet a second longitudinal end of the bore;
• a stopper selectively movable along the bore to contact the seat, the bore being occluded when the stopper is in contact with the seat;
• a first bias member on a first longitudinal side of the stopper within the bore, the first bias member providing a first bias force upon the stopper in a first longitudinal direction;
• and
• a second bias member on a second longitudinal side of the stopper within the bore, the second longitudinal side being opposite the first longitudinal side, the second bias member providing a thermally variable second bias force upon the stopper in a second longitudinal direction opposite the first longitudinal direction, the second bias member comprising a thermally sensitive shape memory material, the thermally variable bias force being less than the first bias force at temperatures below about −50° C. and equal to or greater than the first bias force at temperatures at or above about −50° C.;
• providing a fluid to the fluid inlet at a first temperature at or above about −50° C.;
• flowing the fluid past the first bias member, the stopper, and the second bias member to the fluid outlet;
• providing the fluid to the fluid inlet at a second temperature below about −50° C.;
• contacting, based on the second temperature, the stopper to the seat;
• and
• resisting, by the stopper and the seat, flow of the fluid to the fluid outlet.

A system for conditionally flowing a fluid based a temperature of the fluid, the system comprising:

• a valve body having a bore having a longitudinal axis and a seat along the bore, a fluid inlet at a first longitudinal end of the bore, and a fluid outlet a second longitudinal end of the bore;
• a stopper selectively movable along the bore to contact the seat, the bore being occluded when the stopper is in contact with the seat;
• a first bias member on a first longitudinal side of the stopper within the bore, the first bias member providing a first bias force upon the stopper in a first longitudinal direction;
• and
• a second bias member on a second longitudinal side of the stopper within the bore, the second longitudinal side being opposite the first longitudinal side, the second bias member providing a thermally variable second bias force upon the stopper in a second longitudinal direction opposite the first longitudinal direction, the second bias member comprising a thermally sensitive shape memory material, the thermally variable bias force being less than the first bias force at temperatures below about −50° C. and equal to or greater than the first bias force at temperatures at or above about −50° C.