MATTHEW PALMER MITCHELL
Pilots at Alvarado Rd, Berkeley, CA

6732785, May 11, 2004

Sep 20, 2002

10/251708

Matthew P. Mitchell - Berkeley CA 94705

F28F 700

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

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.

4926639, May 22, 1990

Oct 10, 1989

7/420669

Matthew P. Mitchell - Berkeley CA
Luc Bauwens - Oakland CA

Mitchell/Sterling Machines/Systems, Inc. - Berkeley CA

F02G 104

60522

A double-acting, rotating piston reciprocating in a cylinder with the motion of the piston providing the valving action of the Sibling Cycle through the medium of passages between the piston and cylinder wall. The rotating piston contains regenerators ported to the walls of the piston. The piston fits closely in the cylinder at each end of the cylinder except in areas where the wall of the cylinder is relieved to provide passages between the cylinder wall and the piston leading to the expansion and compression spaces, respectively. The piston reciprocates as it rotates. The cylinder and piston together comprise an integral valve that seqentially opens and closes the ports at the ends of the regenerators alternately allowing them to communicate with the expansion space and compression space and blocking that communication. The relieved passages in the cylinder and the ports in the piston are so arranged that each regenerator is sequentially (1) charged with compressed working gas from the compression space; (2) isolated from both expansion and compression spaces; (3) discharged of working gas into the expansion space; and (4) simultaneously charged with working gas from the expansion space while being discharged of working gas into the compression space, in the manner of the Sibling Cycle. In an alterate embodiment, heat exchangers are external to the cylinder and ports in the cylinder wall are alternately closed by the wall of the piston and opened to the expansion and compression spaces through relieved passages in the wall of the reciprocating, rotating piston.

7174721, Feb 13, 2007

Mar 26, 2004

10/810380

Matthew P. Mitchell - Berkeley CA, US

F25B 9/00, F25D 23/12

62 6, 622592

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.

7887007, Feb 15, 2011

Feb 8, 2008

12/069308

Matthew P. Mitchell - Berkeley CA, US

B64B 1/02

244 30, 244 96, 244 97

A high-altitude long-endurance airship with a top surface that is highly emissive of infrared radiation and a bottom surface that is highly absorptive of infrared radiation. Movable displacer blankets inside the airship separate the upper and lower portions of the airship. Lifting gas in the airship is warmed by radiation from the earth when the displacer blankets are in their upper position. Lifting gas is cooled by radiation to space when the displacer blankets are in their lower position. The whole airship is a heat engine. By expanding the volume of lifting gas when it is relatively warm and compressing the lifting gas when it is relatively cold, net power output can be recovered in the form of electric power. The overall configuration of the preferred airship is a variable-thickness flying wing. If the whole airship is alternately expanded and compressed, imbalance between its weight and buoyancy allow gliding flight.

5966942, Oct 19, 1999

Nov 3, 1997

8/963366

Matthew P. Mitchell - Berkeley CA

F25B 900

62 6

Fluidic devices, including constant-rotation double diodes and constant-rotation double vortex tubes, are disclosed with which to construct pulse tube refrigerators having diode loops, constant-rotation double diodes, constant-rotation double vortex tubes, and asymmetrical diode stacks. Present orifice pulse tube refrigerators use an orifice connected at the warm end of the pulse tube to a reservoir. The orifice and reservoir serve to control flows at the warm end of the pulse tube so that they are not in phase with flows at the cold end. Present heat exchangers at the warm end suffer inefficiencies due to heat-regenerative effects caused by return flows through the orifice. The fluidic devices disclosed herein create dynamic replacement orifices for pulse tube refrigerators that also serve as efficient heat exchangers and supercoolers with minimal regenerative characteristics.

5966943, Oct 19, 1999

Dec 22, 1997

8/996227

Matthew P. Mitchell - Berkeley CA

F25B 900

62 6

A pulse tube refrigerator is equipped with a constant-diameter inertance tube (41) or a stepped or tapered intertance tube (48) which is coiled in a reservoir (20) to protect it from damage from external impacts and from structural failure due to differences between external and internal pressures. A tapered inertance tube (48) improves thermodynamic performance of the pulse tube refrigerator by improving heat transfer at the warm end of pulse tube (10).

6854509, Feb 15, 2005

Jul 10, 2001

09/903302

Matthew P. Mitchell - Berkeley CA, US

F28D019/00

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

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.

6109041, Aug 29, 2000

May 24, 1999

9/316975

Matthew P. Mitchell - Berkeley CA
Roy O. Sweeney - Cincinnati OH

F25B 900

62 6

Fluidic devices, including blind vortex tubes, constant-rotation double diodes and constant-rotation double vortex tubes, are disclosed with which to construct pulse tube refrigerators, including ones having diode loops, constant-rotation double diodes, constant-rotation double vortex tubes, and asymmetrical diode stacks. Present orifice pulse tube refrigerators use an orifice connected at the warm end of the pulse tube to a reservoir. The orifice and reservoir serve to control flows at the warm end of the pulse tube so that they are not in phase with flows at the cold end. Present heat exchangers at the warm end suffer inefficiencies due to heat-regenerative effects caused by return flows through the orifice. The fluidic devices disclosed herein create dynamic replacement orifices for pulse tube refrigerators that also serve as efficient heat exchangers and supercoolers with minimal regenerative characteristics.

4622813, Nov 18, 1986

Oct 29, 1984

6/668717

Matthew P. Mitchell - Berkeley CA

F02G 104

60522

Novel hot gas engines and heat pumps are provided which operate on an improved cycle related to the Stirling cycle. These hot gas engines and heat pumps use at least two separate heat exchanger assemblies and a plurality of valves to control fluid flow through the heat exchanger assemblies.

5429177, Jul 4, 1995

Jul 9, 1993

8/087894

Ran Yaron - Palo Alto CA
Matthew P. Mitchell - Berkeley CA

Sierra Regenators, Inc. - Berkeley CA

F28D 1702

165 10

This invention relates to compact, high efficiency foil regenerators for use in regenerative gas cycle (e. g. Stirling cycle, Ericsson cycle, Vuilleumier cycle, Gifford-McMahon cycle, Sibling Cycle and similar) cryocoolers, heat engines, refrigerators and heat pumps. Very thin foil us formed in patterns of slits and slots that produce highly efficient regenerators when the foil is stacked in layers as by rolling it upon itself.