Cryogenic apparatus

A cryogenic refrigerator comprising:

• cylinder means,
• displacer means movable within the cylinder means according to a four step sequence wherein it (a) dwells in an uppermost position, (b) moves downwardly, (c) dwells in a lowermost position and (d) moves upwardly again;
• first and second chambers the volumes of which are defined by movement of the displacer means,
• conduit means connecting said first and second chambers,
• thermal storage means associated with said conduit means,
• supply reservoir means for supplying high pressure fluid,
• exhaust reservoir means for receiving low pressure fluid;
• and
• refrigerator regulating valve means associated with the supply and exhaust reservoir means for causing high pressure fluid to enter the first chamber and the conduit during the first-mentioned and second-mentioned steps of the displacer means motion and to exhaust low-pressure fluid during the third and fourth steps of the displacer means motion, said valve means comprising a valve casing fixed with respect to the cylinder means and a valve member slidable relative to the casing, the casing having inlet and outlet ports communicating with said supply reservoir means and said exhaust reservoir means respectively, said valve casing and valve member also having cooperating means for alternately connecting said first chamber to one of said inlet and outlet ports while simultaneously disconnecting it from the other of said inlet and outlet ports according to the movement of the valve member between two limit positions, and cooperating means on the displacer means and valve member for (a) causing the valve member to be in one of its limit positions and the displacer means to be in its uppermost position concurrently, and (b) causing the valve member to be in its other limit position and the displacer means to be in its lowermost position concurrently.

A cryogenic refrigerant comprising:

• cylinder means,
• displacer means reciprocally movable within said cylinder means;
• first and second chambers in said cylinder means, with the volumes of said chambers varying with movement of said displacer means,
• conduit means connecting said first and second chambers,
• thermal storage means associated with said conduit means,
• supply reservoir means for supplying high pressure fluid;
• exhaust reservoir means for receiving low pressure fluid;
• and
• refrigerator regulating valve means associated with the supply and exhaust reservoir means for causing high pressure fluid to enter the first chamber and the conduit means during a predetermined portion of the displacer means reciprocal stroke and for causing low-pressure fluid to be exhausted during the remaining portion of the displacer means stroke, said valve means comprising a valve casing fixed with respect to the cylinder means and a valve member slidable relative to the casing, the casing having inlet and outlet ports communicating with said supply reservoir means and said exhaust reservoir means respectively, said valve casing and valve member also having cooperating means for alternately connecting said first chamber to one of said inlet and outlet ports while simultaneously disconnecting it from the other of said inlet and outlet ports according to the movement of the valve member between two limits positions, and cooperating means on the displacer means and valve member for (a) causing the valve member to be in one of its limit positions and the displacer means to be in its uppermost position concurrently, and (b) causing the valve member to be in its other limit position and the displacer means to be in its lowermost position concurrently.