US4835979A — Surge control system for a closed cycle cryocooler

Claim 1

Independent Claim 208 words

A closed Brayton cycle, cryogenic refrigeration system for cooling at least one load comprising: a compressor section having an inlet and outlet, including a first compressor and a second compressor mounted on a common shaft and driven by a first motor; a third compressor and a fourth compressor mounted on a common shaft and driven by a seocnd motor; and an aftercooler located downstream of each compressor, a cooling section, having an inlet and an outlet for high and low pressure sides, including a plurality of recuperators in parallel relationship, each having an inlet and an outlet for high and low pressure sides and at least one expansion turbine; said inlet to said cooling section flow connected to the outlet of the compressor section and said cooling section outlet flow connected to the inlet of said compressor section; and including means for generating electrical power, said means powered by the working fluid bled off the high pressure side of said plurality of recuperators, and means for controlling surge in said compressor section including a bypass passage between said compressor section inlet and outlet; a surge control valve in said bypass passage; and means responsive to a variable condition in said compressor section for opening and closing said valve.

Claim 2

Dependent Claim 208 words

A closed Brayton cycle, cryogenic refrigeration system for cooling at least one load comprising: a compressor section having an inlet and outlet, including a first compressor and a second compressor mounted on a common shaft and driven by a first motor; a third compressor and a fourth compressor mounted on a common shaft and driven by a seocnd motor; and an aftercooler located downstream of each compressor, a cooling section, having an inlet and an outlet for high and low pressure sides, including a plurality of recuperators in parallel relationship, each having an inlet and an outlet for high and low pressure sides and at least one expansion turbine; said inlet to said cooling section flow connected to the outlet of the compressor section and said cooling section outlet flow connected to the inlet of said compressor section; and including means for generating electrical power, said means powered by the working fluid bled off the high pressure side of said plurality of recuperators, and means for controlling surge in said compressor section including a bypass passage between said compressor section inlet and outlet; a surge control valve in said bypass passage; and means responsive to a variable condition in said compressor section for opening and closing said valve.

Claim 3

Dependent Claim 17 words

The cryogenic refrigeration system of claim 1 wherein each aftercooler is cooled by the same heat sink.

Claim 4

Dependent Claim 127 words

The system of claim 1 wherein the cooling section comprises: a first, second, third, fourth and fifth recuperator mounted in parallel relationship; a first and a second turbine having an inlet and an outlet mounted on a common shaft; an alternator mounted about said common shaft; bleed lines from the outlet of said high pressure side of said cooling section to direct said working fluid to said first and second turbines; return lines from said outlets of said turbines to said low pressure side of said cooling section; a heat exchanger in said return line from said second turbine; and fan means, driven by a third turbine, for circulating a cooling medium through a heat exchanger, said third turbine being powered by the high pressure working fluid.

Claim 5

Dependent Claim 82 words

The system of claim 1 wherein the cooling section comprises: a plurality of recuperators mounted in parallel relationship; first, second and third turbines mounted on a common shaft, each turbine having an inlet and outlet; an alternator mounted about said common shaft; bleed lines from the high pressure side of said cooling section to direct said working fluid to said first, second and third turbines; return lines from said outlets of said turbines to said low pressure side of said cooling section.

Claim 6

Dependent Claim 93 words

The cryogenic refrigeration system of claim 1 wherein said cooling section comprises: a first, second, third, fourth and fifth recuperators mounted in parallel relationship, each having a low and high pressure side, each side having an inlet and outlet; a turbo-alternator including a first, second and third turbine, each turbine mounted on a common shaft and an alternator mounted about said shaft; bleed means for conducting high pressure working fluid to each of said three turbines; and means for returning said bleed working fluid to said low pressure side of the cooling section.

Claim 7

Dependent Claim 71 words

The system of claim 5 wherein said bleed means comprises: a first conduit flow connecting the outlet of the high pressure side of said first recuperator and the first turbine; a second conduit flow connecting the outlet of the high pressure side of the third recuperator and the second turbine; and a third conduit flow connecting the outlet of the high pressure side of the fifth recuperator to the third turbine.

Claim 8

Dependent Claim 29 words

The system of claim 6 wherein there are three loads on the system each connected in series with the low pressured sides of said first, third and fifth recuperators.

Claim 9

Dependent Claim 53 words

The system of claim 7 wherein the first load is flow connected between the outlet of said third turbine and the inlet to the low pressure side of said fifth recuperator and the second load is between the fourth and third recuperator and the third load is between the second and first recuperators.

Claim 10

Dependent Claim 154 words

A closed Brayton cycle, cryogenic refrigeration system for cooling at least one load comprising: a compressor section, having an inlet and an outlet, including at least one motor driven compressor for compressing and means for cooling a working fluid; a cooling section, having an inlet and an outlet and a high and low pressure side, said inlet to the high pressure side flow connected to the outlet of the compressor section and the outlet to the low pressure side flow connected to the inlet of the compressor section, including a plurality of recuperators in a parallel relationship and a turbo-alternator means for generating power within said system; and means for controlling surge in said at least one motor-driven compressor including a bypass passage between said compressor section inlet and outlet; a surge control valve in said bypass passage; and means responsive to rotational speed of said motor-driven compressor for opening and closing said valve.

Claim 11

Dependent Claim 154 words

A closed Brayton cycle, cryogenic refrigeration system for cooling at least one load comprising: a compressor section, having an inlet and an outlet, including at least one motor driven compressor for compressing and means for cooling a working fluid; a cooling section, having an inlet and an outlet and a high and low pressure side, said inlet to the high pressure side flow connected to the outlet of the compressor section and the outlet to the low pressure side flow connected to the inlet of the compressor section, including a plurality of recuperators in a parallel relationship and a turbo-alternator means for generating power within said system; and means for controlling surge in said at least one motor-driven compressor including a bypass passage between said compressor section inlet and outlet; a surge control valve in said bypass passage; and means responsive to rotational speed of said motor-driven compressor for opening and closing said valve.

Claim 12

Dependent Claim 20 words

The system of claim 9 wherein said means for cooling comprises an aftercooler downstream of said at least one compressor.

Claim 13

Dependent Claim 53 words

The system of claim 9 wherein said compressor section comprises: a first and second compressor mounted on a common shaft and driven by a first constant torque motor; a third and fourth compressor mounted on a common shaft and driven by a second constant torque motor; an aftercooler immediately downstream of each compressor.

Claim 14

Dependent Claim 31 words

The system of claim 9 wherein said means for opening and closing said valve includes an electronic controller and speed sensors for sensing the speeds of the motors and the turbo-alternator.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1992-06-05	1992-12-05	1993-06-06	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1996-06-05	1996-12-05	1997-06-06	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2000-06-05	2000-12-05	2001-06-06	$7700.00	Window Closed / Lapsed

Surge control system for a closed cycle cryocooler

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