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US 6,256,997 B1Granted
Reduced vibration cooling device having pneumatically-driven GM type displacer
AssigneeIntermagnetics General Corporation
InventorRalph C. Longsworth
Life of this patent
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Abstract
A GM type displacer has an elastomer “O” ring at the warm end to absorb impact energy when the displacer reaches the bottom of the stroke before it would hit the cylinder end cap. When the displacer reaches the top of its stroke, before the displacer would hit the internal mechanism of the expander, another elastomer “O” ring absorbs the kinetic energy of the displacer. Both absorbers are at or near ambient temperature.
Claims13
An expander of a GM type for use in providing cryogenic refrigeration, comprising:
- a cylinder serving as at least one cold head, said cylinder having a longitudinal axis;
- a displacer assembly extending axially within said cylinder between a cold zone of said cylinder and a warm zone, said displacer being reciprocatably moveable axially in said cylinder between a first stroke end position and a second stroke end position;
- first mechanical means fixed relative to one of said cylinder and said displacer assembly for stopping said reciprocating motion of said displacer assembly in a first axial direction, said displacer assembly stopping at said first end position;
- second mechanical means fixed relative to one of said cylinder and displacer assembly for stopping said reciprocating motion of said displacer assembly in a second axial direction at said second end position;
- said first mechanical means including a first impact absorber connecting between said cylinder and displacer assembly when said displacer assembly is at said first end position;
- said second mechanical means including a second impact absorber connecting between said cylinder and said displacer assembly when said displacer assembly is at said second end position;
- said first and second absorbers being located closer to said first end position than to said second end position.
4 more elements
Dependencies are inferred from the claim text.