US5060481A — Method and apparatus for controlling a cryogenic …

Claim 1

Independent Claim 89 words

A cryogenic refrigeration system, comprising: (a) a path through which a refrigerant flows; (b) at least one Joule-Thomson valve positioned in the path through which the refrigerant flows for cooling the refrigerant; (c) at least one heater positioned near the at least one Joule-Thomson valve for heating the at least one value to remove blockage caused by freezing of contaminants at the at least one valve; and (d) a temperature sensor to measure a temperature in the system to determine when to turn on the at least one heater.

Claim 2

Dependent Claim 89 words

A cryogenic refrigeration system, comprising: (a) a path through which a refrigerant flows; (b) at least one Joule-Thomson valve positioned in the path through which the refrigerant flows for cooling the refrigerant; (c) at least one heater positioned near the at least one Joule-Thomson valve for heating the at least one value to remove blockage caused by freezing of contaminants at the at least one valve; and (d) a temperature sensor to measure a temperature in the system to determine when to turn on the at least one heater.

Claim 3

Dependent Claim 23 words

A cryogenic refrigeration system as recited in claim 1 wherein the system is a cryogenic recondenser for recondensing refrigerant gas to refrigerant liquid.

Claim 4

Dependent Claim 19 words

A cryogenic refrigeration system as recited in claim 1 wherein a separate heater is provided for each Joule-Thomson valve.

Claim 5

Dependent Claim 18 words

A cryogenic refrigeration system as recited in claim 1 wherein a sensor is situated at each J-T valve.

Claim 6

Dependent Claim 18 words

A cryogenic refrigeration system as recited in claim 1 further comprising a closed-cycle refrigerator to cool the refrigerant.

Claim 7

Dependent Claim 22 words

A cryogenic refrigeration system as recited in claim 5 wherein a sensor is situated at a refrigerator of the cryogenic refrigeration system.

Claim 8

Dependent Claim 14 words

A cryogenic refrigeration system as recited in claim 1 wherein the refrigerant is hellium.

Claim 9

Dependent Claim 16 words

A cryogenic refrigeration system as recited in claim 1 wherein the sensors are temperature sensing diodes.

Claim 10

Dependent Claim 28 words

A cryogenic refrigeration system as recited in claim 1 further comprising at least one adsorber situated in the path through which the refrigerant flows for cleansing the refrigerant.

Claim 11

Dependent Claim 28 words

A cryogenic refrigeration system as recited in claim 9 wherein sensors are positioned after the at least one adsorber to measure the temperature of refrigerant exiting the adsorber.

Claim 12

Dependent Claim 68 words

In a cryogenic refrigeration system, a method of preventing blockage of a Joule-Thomson valve caused by freezing of contaminants, comprising the steps of: (a) monitoring temperature in the system using a sensor; and (b) heating the Joule-Thomson valve with a heater as dictated by a control system when temperature readings from the sensor indicate that a blockage has occurred at the Joule-Thomson valve due to freezing of contaminants.

Claim 13

Dependent Claim 68 words

In a cryogenic refrigeration system, a method of preventing blockage of a Joule-Thomson valve caused by freezing of contaminants, comprising the steps of: (a) monitoring temperature in the system using a sensor; and (b) heating the Joule-Thomson valve with a heater as dictated by a control system when temperature readings from the sensor indicate that a blockage has occurred at the Joule-Thomson valve due to freezing of contaminants.

Claim 14

Dependent Claim 38 words

A method as recited in claim 11 further comprising the step of using the control system to direct the heater to heat the Joule-Thomson valve during a predetermined time period when the cyrogen refrigeration system is powered up.

Claim 15

Dependent Claim 16 words

A method as recited in claim 11 wherein the cryogenic refrigeration system is a cryogenic recondenser.

Claim 16

Dependent Claim 68 words

A control system for controlling the operation of a cryogenic refrigeration system having a Joule-Thomson valve, comprising: (a) a heater positioned near said Joule-Thomson valve; (b) a temperature sensor for sensing temperature in the cryogenic refrigeration system; (c) a heater controller for selectively controlling the heater positioned near the Joule-Thomson valve, wherein the heater controller responds to temperature readings received from the temperature sensor to regulate the heater.

Claim 17

Dependent Claim 68 words

A control system for controlling the operation of a cryogenic refrigeration system having a Joule-Thomson valve, comprising: (a) a heater positioned near said Joule-Thomson valve; (b) a temperature sensor for sensing temperature in the cryogenic refrigeration system; (c) a heater controller for selectively controlling the heater positioned near the Joule-Thomson valve, wherein the heater controller responds to temperature readings received from the temperature sensor to regulate the heater.

Claim 18

Dependent Claim 27 words

A control system as recited in claim 14 wherein the control system monitors temperature at the Joule-Thomson valve to determine whether the valve is blocked by contaminants.

Claim 19

Dependent Claim 22 words

A control system as recited in claim 14 wherein the control system automatically turns on the heater during a start up routine.

Claim 20

Dependent Claim 68 words

A control system for controlling the operation of a cryogenic refrigeration system comprising (a) a starting means for initializing the cryogenic refrigeration system upon powering up the refrigeration system; (b) a display means for displaying status information; (c) a shutdown means for shutting down the refrigeration system in response to certain conditions; and (d) a heater control means for controlling the operation of heaters connected to Joule-Thomson valves.

Claim 21

Dependent Claim 68 words

A control system for controlling the operation of a cryogenic refrigeration system comprising (a) a starting means for initializing the cryogenic refrigeration system upon powering up the refrigeration system; (b) a display means for displaying status information; (c) a shutdown means for shutting down the refrigeration system in response to certain conditions; and (d) a heater control means for controlling the operation of heaters connected to Joule-Thomson valves.

Claim 22

Dependent Claim 55 words

A control system as recited in claim 17 wherein the control system initializes the recondenser by activating a bypass valve in the cryogenic refrigeration system to make refrigerant in the refrigeration system follow a bypass path in which the refrigerant will cool more quickly than if the refrigerant did not flow through the bypass path.

Claim 23

Dependent Claim 26 words

A control system as recited in claim 17 wherein the control system initializes the refrigeration system by turning on the heaters connected to the Joule-Thomson valves.

Claim 24

Dependent Claim 29 words

A control system as recited in claim 17 wherein the display means displays status information indicative of whether critical conditions inside the refrigeration system are within a specified range.

Claim 25

Dependent Claim 56 words

A control system as recited in claim 20 wherein the display means displays whether the critical conditions inside the refrigeration system are within a cautionary mode range wherein operational limits of the critical conditions are being approached and whether the conditions are within a failure mode range wherein operational limits of the critical conditions are exceeded.

Claim 26

Dependent Claim 21 words

A control system as recited in claim 21 wherein the critical conditions include temperature in the refrigeration system and cryostat pressure.

Claim 27

Dependent Claim 19 words

A control system as recited in claim 21 wherein the display means displays in both printed and lighted form.

Claim 28

Dependent Claim 27 words

A control system as recited in claim 21 wherein the control system shuts down the refrigeration system if the critical conditions are in the failure mode range.

Claim 29

Dependent Claim 19 words

A control system as recited in claim 17 wherein the control system controls the capacity of the refrigeration system.

Claim 30

Dependent Claim 26 words

A control system as recited in claim 17 further comprising a keypad that allows an operator of the refrigeration system to communicate with the control system.

Claim 31

Dependent Claim 24 words

A control system as recited in claim 26 wherein the operator can gain access to monitored temperatures in the refrigeration system using the keypad.

Claim 32

Dependent Claim 27 words

A control system as recited in claim 17 wherein the control system time activates the heaters so that they operate at a given time for a duration.

Claim 33

Dependent Claim 17 words

A control system as recited in claim 17 wherein the cryogenic refrigeration system is a cryogenic recondenser.

Claim 34

Independent Claim 113 words

A method of controlling operation of a cryogenic refrigeration system having Joule-Thomson valves and heaters for heating said Joule-Thomson valves, comprising the steps of: a) initiating a start up routine in response to power being switched on for the cryogenic refrigeration system; b) displaying monitored temperatures and cryostat pressure; c) displaying warning signals if the system fails and if dangerous conditions arise; d) shutting down the refrigeration system if a maximum cryostat pressure level is exceeded; e) shutting down system if monitored conditions are outside a specified range; and f) activating said heaters of said Joule-Thomson valves in response to monitored conditions indicating blockage of said valves and during the start up routine.

Claim 35

Independent Claim 113 words

A method of controlling operation of a cryogenic refrigeration system having Joule-Thomson valves and heaters for heating said Joule-Thomson valves, comprising the steps of: a) initiating a start up routine in response to power being switched on for the cryogenic refrigeration system; b) displaying monitored temperatures and cryostat pressure; c) displaying warning signals if the system fails and if dangerous conditions arise; d) shutting down the refrigeration system if a maximum cryostat pressure level is exceeded; e) shutting down system if monitored conditions are outside a specified range; and f) activating said heaters of said Joule-Thomson valves in response to monitored conditions indicating blockage of said valves and during the start up routine.

Claim 36

Dependent Claim 16 words

A method as recited in claim 30 wherein the cryogenic refrigeration system is a cryogenic recondenser.

Claim 37

Independent Claim 59 words

A method of regulating the temperature of a cryogenic refrigeration system having a cryostat and a closed cycle refrigerator within a Joule-Thomson valve liquification system comprising the steps of: (a) monitoring cryostat pressure; and (b) using an electric heater, heating a cold finger of the refrigerator when the cryostat pressure becomes too low so as to regulate system temperature.

Claim 38

Independent Claim 59 words

A method of regulating the temperature of a cryogenic refrigeration system having a cryostat and a closed cycle refrigerator within a Joule-Thomson valve liquification system comprising the steps of: (a) monitoring cryostat pressure; and (b) using an electric heater, heating a cold finger of the refrigerator when the cryostat pressure becomes too low so as to regulate system temperature.

Claim 39

Dependent Claim 14 words

A method as recited in claim 32, wherein the refrigerator is a Gifford-MacMahon refrigerator.

Claim 40

Dependent Claim 15 words

A method as recited in claim 32, wherein the refrigerator is a two stage refrigerator.

Claim 41

Dependent Claim 20 words

A method as recited in claim 32 wherein the refrigerator is heated by an individual heater situated at the refrigerator.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1994-10-28	1995-04-29	1995-10-29	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1998-10-28	1999-04-29	1999-10-29	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2002-10-28	2003-04-29	2003-10-29	$7700.00	Window Closed / Lapsed

Method and apparatus for controlling a cryogenic refrigeration system

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