Compact integrated buffer for pulse tube refrigerator
AssigneesSumitomo Heavy Industries, Ltd., SHI-APD Cryogenics, Inc.
InventorMingyao Xu
Life of this patent
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Abstract
A range of buffer volume/pulse tube volume ratios for two-stage hybrid GM type pulse tube cold-heads that are designed to produce refrigeration at 4 K are provided. The ranges of volume ratios for the first and second stages provides a good balance between the inefficiencies but compact size of a four-valve phase shifting mechanism and the better efficiency but larger size of a double-orifice phase shifting mechanism. The buffer volumes are small enough to be conveniently machined into the warm end housing, or as an option, one can be part of a valve disc housing. The drive motor for the valve disc is in an attached housing to make the valve disc readily accessible for service.
Claims15
A GM pulse tube cold-head selected from one stage and two stage hybrid type cold heads comprising,
- a pulse tube assembly attached to a warm housing,
- the warm housing containing a first stage buffer volume and, in the case of a two stage pulse tube, a second stage buffer volume,
- a valve motor assembly attached to the warm housing,
- where the first stage buffer has a volume relative to the volume of the first stage pulse tube between 0.5 and 5.5 and the second stage buffer, in the case of a two stage pulse tube, has a volume relative to the volume of the second stage pulse tube between 0.2 and 3.5.
The pulse tube of claim one which is a two-stage pulse tube.
Dependencies are inferred from the claim text.