Matthew Evan Mitchell

US Patent:

6347453, Feb 19, 2002

Filed:

May 24, 1999

Appl. No.:

09/317743

Inventors:

Matthew P. Mitchell - Berkeley CA 94705

International Classification:

B21D 5306

US Classification:

29890034, 29890036, 29506

Abstract:

A method of assembling a regenerator comprising multiple concentric layers of foil, each with an unbonded joint inside a generally cylindrical space, by inserting each successive layer of foil into the remaining space inside said generally cylindrical space and pressing it outward against the wall of the generally cylindrical space until its edges do not overlap.

US Patent:

6442947, Sep 3, 2002

Filed:

Jul 10, 2001

Appl. No.:

09/903305

Inventors:

Matthew P. Mitchell - Berkeley CA 94705

International Classification:

F25B 900

US Classification:

62 6, 60520

Abstract:

A double inlet passage connects a compressor to remote end of a vortex tube that serves as the heat-rejecting heat exchanger of an orifice pulse tube refrigerator. Double inlet passage includes means for controlling DC flow in that passage. Fluid flows between compressor and reservoir enhance heat-rejecting effectiveness of vortex tube.

US Patent:

6619046, Sep 16, 2003

Filed:

Jul 19, 2002

Appl. No.:

10/198554

Inventors:

Matthew P. Mitchell - Berkeley CA 94705

International Classification:

F25B 900

US Classification:

62 6

Abstract:

The pulse tube of a pulse tube refrigerator is equipped with a thin liner of low thermal mass and in poor thermal contact with pulse tube One surface of liner may be furnished with indented recesses making the recessed portions of the liner thinner than the remainder of the material of liner.

US Patent:

6732785, May 11, 2004

Filed:

Sep 20, 2002

Appl. No.:

10/251708

Inventors:

Matthew P. Mitchell - Berkeley CA 94705

International Classification:

F28F 700

US Classification:

165 79, 165 10, 165 4, 29890034, 29890039, 29 174

Abstract:

A joint connecting consecutive sheets of etched regenerator foil for a spiral-wrapped regenerator of a regenerative gas cycle machine such as a Stirling cycle engine or Stirling, pulse tube, or Gifford-McMahon cryocooler. The joint comprises a multiplicity of tabs on the end of one sheet of regenerator foil interlocked with a multiplicity of tabs on the end of another piece of regenerator foil. The joint is no thicker than the original thickness of the sheets of etched regenerator foil that it connects together, and the tabs substantially fill the holes into which they are locked, minimizing undesirable leakage through the joint after it has been incorporated in a regenerator.

US Patent:

6745822, Jun 8, 2004

Filed:

May 22, 1998

Appl. No.:

09/084042

Inventors:

Matthew P. Mitchell - Berkeley CA 94705

International Classification:

F28D 1700

US Classification:

165 10, 165 4, 62 6

Abstract:

A regenerator formed of concentric layers of regenerator foil assembled with unbonded joints and inside a generally cylindrical space and method of inserting and installing foil using foil rolling apparatus and foil installation apparatus employing an inflatable bladder to press foil against the wall of generally cylindrical space.

US Patent:

6854509, Feb 15, 2005

Filed:

Jul 10, 2001

Appl. No.:

09/903302

Inventors:

Matthew P. Mitchell - Berkeley CA, US

International Classification:

F28D019/00

US Classification:

165 10, 165 4, 165 77, 165 78, 165 79, 165146, 165170, 62 6

Abstract:

In a regenerator for a regenerative cycle machine, regenerator foil is grooved on both sides, with intersections of grooves on opposite side forming holes at which separate flows of fluid interact to induce flows ancillary to the overall direction of flow in the regenerator, thereby enhancing heat transfer to and from the material of the regenerator and improving thermodynamic performance of the gas cycle machine.

US Patent:

7114549, Oct 3, 2006

Filed:

Nov 16, 2004

Appl. No.:

10/990037

Inventors:

Matthew P. Mitchell - Berkeley CA, US

International Classification:

F23L 15/02

US Classification:

165 4, 165146

Abstract:

In a regenerator for a regenerative cycle machine, regenerator foil is grooved on both sides, with intersections of grooves on opposite side forming holes at which separate flows of fluid interact to induce flows ancillary to the overall direction of flow in the regenerator, thereby enhancing heat transfer to and from the material of the regenerator and improving thermodynamic performance of the gas cycle machine.

US Patent:

7174721, Feb 13, 2007

Filed:

Mar 26, 2004

Appl. No.:

10/810380

Inventors:

Matthew P. Mitchell - Berkeley CA, US

International Classification:

F25B 9/00
F25D 23/12

US Classification:

62 6, 622592

Abstract:

A cooling load is enclosed within the envelope of the pressure vessel that contains the working fluid in a pulse tube cooler in a load space adjacent to a regenerator of that pulse tube cooler. Flow-smoothing means , which include stacked screens and perforated plates, or diffuser nozzle or diffuser cone , spreads the flow of fluid that enters the cold end of pulse tube.