CA2112825A1 - System for a cooler and gas purity tester - Google Patents
System for a cooler and gas purity testerInfo
- Publication number
- CA2112825A1 CA2112825A1 CA002112825A CA2112825A CA2112825A1 CA 2112825 A1 CA2112825 A1 CA 2112825A1 CA 002112825 A CA002112825 A CA 002112825A CA 2112825 A CA2112825 A CA 2112825A CA 2112825 A1 CA2112825 A1 CA 2112825A1
- Authority
- CA
- Canada
- Prior art keywords
- gas
- heat exchange
- exchange tube
- during
- cooler
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B9/00—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point
- F25B9/02—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point using Joule-Thompson effect; using vortex effect
Abstract
ABSTRACT OF THE DISCLOSURE.
A system for a cooler comprises: a heat exchange tube receiving a supply of pressurized gas, a gas escape aperture communicating with the interior of the heat exchange tube for permitting escape of the pressurized gas and expansion thereof during a cooling mode, and a bypass assembly associated with said heat exchange tube and located after said gas escape aperture which during a cleaning mode enables most of the pressurized gas to exit the heat exchange tube without flowing through said gas escape aperture. The bypass assembly comprises a flush valve which is closed during said cooling mode and which is opened during said cleaning mode. According to a preferred embodiment, the heat exchange tube is helically wound over a cylindrical core and installed inside an insulated housing. The system may also be utilized as a gas purity tester, optionally with an additional gas pressure regulator, wherein a sensor will indicate the extent of the gas purity.
A system for a cooler comprises: a heat exchange tube receiving a supply of pressurized gas, a gas escape aperture communicating with the interior of the heat exchange tube for permitting escape of the pressurized gas and expansion thereof during a cooling mode, and a bypass assembly associated with said heat exchange tube and located after said gas escape aperture which during a cleaning mode enables most of the pressurized gas to exit the heat exchange tube without flowing through said gas escape aperture. The bypass assembly comprises a flush valve which is closed during said cooling mode and which is opened during said cleaning mode. According to a preferred embodiment, the heat exchange tube is helically wound over a cylindrical core and installed inside an insulated housing. The system may also be utilized as a gas purity tester, optionally with an additional gas pressure regulator, wherein a sensor will indicate the extent of the gas purity.
Description
~ 1 - ~
A SYSTEM FOR A COOLER AND GAS PURITY T,ESTE;R
The present invention relates ger,erally to a system to be useful as a cryGger!ic cocler and more specifically to cleaning of such a cooler as well as a gas purity tester.
BACKGROUND OF THE INVENTION
Gas decompression coolers, such as Joule-Thomson coolers, ut:ilize the fact that a gas undergoing adiabatic expan-sion will be cooled. In such coolers, coniprese~ sas is continuously fed irto a tube which has a small aperture ~-in it. The gas which esccpeC thrcuyh the small aperture IO cools through its rapid expansi(r~ an~ e~changes heat with the incoming gas, thus partially cooling the incoming, ;~
gas.
Joule-Thomson coolers are described in detail in the book Mlnlature Refrigerators for Cryogenic Sensors and Cold lS Electronics, written by Graham Walker and published by . , , ; Oxford University Press, ~ew York, 1989.
Due to the low temperature ach-ieved at the aperture, impurities fGund in the gas accrete in the form of liquid drcps or solids deposited over the interior of the tube near the aperture and/or within the aperture itself. This can cause partial or complete stoppage of the flow of the ,~
gas.
~-~ llrder prevailing practices, in cases of light contamina- -tion, the operation of the cooler must be stcpped, the cooler mu~t ~e allowed to warm up, ~hich takes approxi- ~ ;
' ' ' ... :. .
' :"
A SYSTEM FOR A COOLER AND GAS PURITY T,ESTE;R
The present invention relates ger,erally to a system to be useful as a cryGger!ic cocler and more specifically to cleaning of such a cooler as well as a gas purity tester.
BACKGROUND OF THE INVENTION
Gas decompression coolers, such as Joule-Thomson coolers, ut:ilize the fact that a gas undergoing adiabatic expan-sion will be cooled. In such coolers, coniprese~ sas is continuously fed irto a tube which has a small aperture ~-in it. The gas which esccpeC thrcuyh the small aperture IO cools through its rapid expansi(r~ an~ e~changes heat with the incoming gas, thus partially cooling the incoming, ;~
gas.
Joule-Thomson coolers are described in detail in the book Mlnlature Refrigerators for Cryogenic Sensors and Cold lS Electronics, written by Graham Walker and published by . , , ; Oxford University Press, ~ew York, 1989.
Due to the low temperature ach-ieved at the aperture, impurities fGund in the gas accrete in the form of liquid drcps or solids deposited over the interior of the tube near the aperture and/or within the aperture itself. This can cause partial or complete stoppage of the flow of the ,~
gas.
~-~ llrder prevailing practices, in cases of light contamina- -tion, the operation of the cooler must be stcpped, the cooler mu~t ~e allowed to warm up, ~hich takes approxi- ~ ;
' ' ' ... :. .
' :"
- 2 ~ r~ ~3 2 5 ~ ~
mately one-half hour, and then t~e cooler must be flushed with pure gas.
In cases of extreme cGntamination, the tube must be dismantled prior to its fl~shing with a cleaning liquid.
The cleaning process is cumbersome and lengthy, typically taking a few hours.
As well-known in the art, some prior coolers are also utilized as gas purity testers, testinc the Furity of the gas by the amourlt of contamir,ants accumulated during a "test". At the start of each test, the cooler must be at a starting temperature ~hich is typically considerably higher than the operatiny temperature to which the cooler is brought during a test. Thus, at the end of any test, a prior art coGler must be returned to its starting tempe-rature, a process which typically takes again about 30minutes.
It is an object of the present inver,tion to provide a system ~2~able to be used as a cooler which comprises ;; improved means of expelling contaminants which accumul2te - 20 inside a heat exchange tube and the aperture of the g2s decompression cooler, such as a Joule-Thomscn cryogenic ~ cooler and/or a gas purity tester.
- It is a further object cf the present invention to `~ provide an improved cocler comprising a cleaning system which does not require dismantling of the ~eat exchange ,- ':..' - 3 '~ ~-'"J'J ~;
tube and whose cl~aning and warm-up periods are much shorter than those of the prior art.
BRIEF DESCRIPTION OF THE IN~ENTION.
In accordance with a preferred embodiment of the present invention, the system for a cooler will include:
(a)a heat exchar,ge t;ube receiving a supply of pressurized gas; (b) a gas escape aperture commuricating with the interior of the heat exchange tube for permitting escape cf the pressurized gas and ex~ansion thereof during a coolirg mode, and (c) a by-pass assembly, associated with the heat exchange tube and located after the gas escape aperture, which during a cleaning mode, enables most cf the pressurized gas to exit the heat exchange tube with-out flowin~ through the gas escape aperture, and (d) a sensing apparatus for indicating the extent of the gas purity, wherein a prolonged continuous operating time indicates a more pure gas. Optionally, a pressure regula-tor may be added in order to ensure a better reproducibi~
lity and accuracy of the purity test.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS --In accordance with a preferred embodiment of the present invention, the bypass assembly comprises a flush valve ~~ which is closed during the cooling mode and which is -~ opened during the cléaning mode. In this marner, during a ~ 25 cleaning cycle, high velocity gas is forced to pass `- through the tube and flush out the contaminants.
:~
, 2 ~
Moreover, in accGrdance with a preferred embodiment of the present invention, the heat exchange tube is helical-ly wound over a cylindrical core and installed inside an insulated housing (dewar). The by-pass assembly is formed of an extension to the heat exchange tube inside the cylindrical core. Further, in accordance with the prefer-¦ red embodiment of the invention, during the cooling mGde, the gas escapes through the gas escape aperture to the ¦ housing, thereby cooling the heat exchange tube and the warm gas flowing in until liquefaction occurs. During the cleaning mode, the gas generally bypasses the gas escape aperture, thereby the warm gas flowing in warms the heat exchange tube.
Still further, in accordance with a preferred embodiment15 of the present invention, the cooler includes a sensor Whlch pre~erably controls apparatus for switching the cooler from the cooling mode to the cleaning mode. The , sensor may be a flow measuring apparatus responsive to the quantity of gas flowing through the gas escape aper-- 20 ture or a temperature sensing element, such as thermocou-ple, located at the vicinity of the gas escape aperture.! I
Mcreover, in accordance with a preferred embodimert cf the present invention, the cooler is characterized in that the cleaning mode raises a temperature of the cooler ;~
25 ~ to a desired temperature.
.,.~
~' ' ''"';' ~' `: ' ' ' . .
1 r J 3 ~ 5 There is also provided, in accordance with a preferred embodiment of the present invention, a gas purity tester including (a) a heat exchange tube receiving a supply of pressurized gas, (b) a gas escape aperture ccmmunicating with the interior of the heat exchange tube for permit-ting escape of the pressurized gas and expansion thereof during a cooling mode, (c) a by-pass assembly, associated with the heat exchange tube and located after the gas escape aperture, which during a cleaning mode, enables most of the pressurized gas to exit the heat exchange tube without flowing through the gas escape aperture, and (d) a sensor apparatus indicating the extent of the gas purity, according to the quantity of gas flowing through the gas escape aperture or to the coolers temperature. A
prolonged cperating time will indicate a more pure gas.
Optionally, a gas pressure regulator is also installed in order to obtain more reliable results.
BRIEF DESCRIPTION OF THE DRA~INGS
The present inventlon will be understood and appreciated from the following detailed description taken in conjunction with the drawing in which:
Figure 1A is a schematic illustration of a typical Joule-Thomson cryogenic cooler with a downstream continu-ation in accordance with a preferred embodiment of the invention; and --~- - 6 ~ L i 2 3 ~ ~
Figure 1B is a detailed illustration of an aperture section of the cooler shown in Figure lA in accordance with a preferred embodiment of the irvention.
Reference is now made to Figures 1A and lB which illus-trate a cryogenic cooler constructed and operative in accordance with a preferred embodiment of the invention.
As an example only,the cooler shown in Figures lA and 1B
is of the Joule-Thomson type. As known in the art, this type of cooler can be utilized as a gas purity tester.
As in the prior art, the cooler typically comprises a heat exchange tube 12 wrapped around a core 14, both of which are located within a housing 16. In accordance with the present invention, tube 12 is extended out of the housing 16 and ends in an exit 18 to which is attached a high pressure valve 20. The extension of tube 12 is referenced herein 22.
The tube 12 can be of any appropriate diameter, such as 0.3 mm inner diameter and 0.5 mm outer diameter.
- During operation, a highly pressurized gas, such as Nitrogen, Oxygen, Argon and any other suitable gas, is fed into heat e~change tube 12 at an entrance 24. During a cooling mode, valve 20 is maintained in a closed posi-~ tion and gas escapes through a small aperture 26 in tube :~ 12 at a section 28 near the non-valve end cf extension ~ 2s 22. Aperture 26 can be of any suitable size tc effect '~ ' ' ' ~ 2 ~ 2 5 cooling. Fcr example, for the tube size given herein-above, aperture 26 preferably has a diameter between 0.04 and O.OE mm. The gas is typically at a pressure between 1500 and 6000 psi. ;~
S Cooling is effected when the highly pressurized gas escapes to the low pressùre inside the housing 15, after having exchanged heat with the high pressure gas. The low pressure gas exits through an exit 30 before which is located a flow rate meter 32 for measuring the flow through exit 30. ~,;
Due to the decompression and COGl ing of the gas in the , cooling mode described above, contaminants contained in the high pressure gas accumulate inside tube 12, near or inside aperture 26, in the fcrm of liquid or solid accumulations 34.
In a preferred embodiment of the invention, a cleaning --~ mode is provided for removing the accumulations 34. In this cleaning mode, which typically occurs immediately after the cooling mode, high pressure valve 20 is opened, either manually or automatlcally, and the high pressure gas is allc~ed to exit through exit 18.
D~ue to the pressure differential between the high pres-sure at the entrance 24 and the outside pressure at exit 18, most of the gas passes at high velocity through tube ;? 2s 12, carrying with it accumulations 34.
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Typically, the cleaning mode lasts for about. 2 minutes, during which time the high pressure gas is continuously fed through tube 12. Because very little gas exits through aperture 26, very little cooling occurs. The ~ :~
., ~-.
little gas which does exit the aperture 26 serves to -.;.. ~
clean the aperture and the gas which flows by the .^ ^
aperture 26 serves to warm and clean the tube 12 in the area of the aperture. It is noted that the warmer the ; .~
tube 12 is, the more easily the contaminants flow. ~ --Due to the movement of the warm gas through the tube 12, .
the cleaning mo.de typically rapidly returns the cooler to near the room tempera^ture, the typical starting tempera~
ture suitable for restarting of the cooling operation.
This is in contrast to the prior art which requires a ^.
lS significant amount of time to return to the starting -~
- :^. ^^
temperature.
~^ It will be appreciated that the apparatus described here~
in allows for a relatively rapid flushing of contaminants .. . .
-~ found in the gas as well as a relatively rapid returning .~ - .
of the cooler to its startin~ temperature.
It will .further be.appreciated by those skilled in the art that the present invention encompasés a valve 20 located anywhere after the aperture 26. .
Furthermore, any device which enables gas to flow through --2s the cooler generally without performing the cooling and :
'`~: , '', . ~ .
g heat exchanging operation is included within the present invention.
In a preferred errbodiment of the invention, the flow I meter 32 provides flow rate information to a controller S (not sho~n). The controller is typically programed to switch the cooler to the cleaning mode when the flow rate is reduced to under a predeter-mined rate, such as 20%
less than a desired rate, or a change in the gas quality is involved. The controller switches the modes of the i10 cooler by selectively opening (for the cleaning mode) and closing (for the cooling mode) valve 20.
Alternatively, as shown in Figure 2, a temperature sensor 33, such as a thermocouple, may be located at the vicini-ty of the gas escape aperture and providing temperature information to the controller. As cooling stops due to blockage of the aperture by contaminants, the temperature rises. The controller is typically programmed to switch the cooler to the cleaning mode at a predetermined tempe-rature-value.
;~ 20 In accordance with an additional embodiment of the pre-- sent invention, a pressure regulator 40 can be included ~ just after entrance 24. The pressure regulator 40 ensures -~ a steady pressure and, as a result, ensures that the type .~
of stoppage achieved is repeatable for each pressure level.
~ : :
.. . .
,~
,~ , .~. .
- lQ ~ 2~
It will be appreciated that the length of the cleaning mode depends on the size of the tubes, the extent tc which the system needs to be heated and the minimu~ loss of gas, duriny cleaning, allowable.
It is a feature of the present invention that the flushing mechanism is an integral part of the cooler and enables cleaning of the heat exchange tube without dis~
mantling the cooler.
As well known in the art, the system based on a Joule-Thomson cryogenic cooler, is most suitable for a gas purity tester. Using the system according to the present invention, the gas purity tester will comprise: ~a) a heat exchange tube receiving a supply of pressurized gas; (b) a gas escape aperture communicating with the interior of the heat exchange tube for permitting escape of the pressurized gas and expansion therecf during a cooling mode; (c) a by-pass assembly, associated with said heat exchange tube which is substantially enclosed in a housing and lccated after said gas escape aperture, wherein during a cleaning mode gas escapes through said ; escape aperture into said housing, and (d) a sensor for -indicating the extent of the gas purity wherein a longer .
continuous operating tlme indicates a purer gas. Option--~ ally, a pressure regulator at the gas inlet is installed .~. . .
~ 25 in order to ensure a better reproducibility and accuracy ~
~. ~; .. .
-~ ~ of the purity test of the respective gas.
.~ ' ', .
~' ~,i ;~J'~
It will be appreciated by persons skilled in the art that the present invention is not limited by the description provided hereinabove. Rather, the scope of this invention c defined only by the appended Claims.
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ry ~ ~
,, ~
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mately one-half hour, and then t~e cooler must be flushed with pure gas.
In cases of extreme cGntamination, the tube must be dismantled prior to its fl~shing with a cleaning liquid.
The cleaning process is cumbersome and lengthy, typically taking a few hours.
As well-known in the art, some prior coolers are also utilized as gas purity testers, testinc the Furity of the gas by the amourlt of contamir,ants accumulated during a "test". At the start of each test, the cooler must be at a starting temperature ~hich is typically considerably higher than the operatiny temperature to which the cooler is brought during a test. Thus, at the end of any test, a prior art coGler must be returned to its starting tempe-rature, a process which typically takes again about 30minutes.
It is an object of the present inver,tion to provide a system ~2~able to be used as a cooler which comprises ;; improved means of expelling contaminants which accumul2te - 20 inside a heat exchange tube and the aperture of the g2s decompression cooler, such as a Joule-Thomscn cryogenic ~ cooler and/or a gas purity tester.
- It is a further object cf the present invention to `~ provide an improved cocler comprising a cleaning system which does not require dismantling of the ~eat exchange ,- ':..' - 3 '~ ~-'"J'J ~;
tube and whose cl~aning and warm-up periods are much shorter than those of the prior art.
BRIEF DESCRIPTION OF THE IN~ENTION.
In accordance with a preferred embodiment of the present invention, the system for a cooler will include:
(a)a heat exchar,ge t;ube receiving a supply of pressurized gas; (b) a gas escape aperture commuricating with the interior of the heat exchange tube for permitting escape cf the pressurized gas and ex~ansion thereof during a coolirg mode, and (c) a by-pass assembly, associated with the heat exchange tube and located after the gas escape aperture, which during a cleaning mode, enables most cf the pressurized gas to exit the heat exchange tube with-out flowin~ through the gas escape aperture, and (d) a sensing apparatus for indicating the extent of the gas purity, wherein a prolonged continuous operating time indicates a more pure gas. Optionally, a pressure regula-tor may be added in order to ensure a better reproducibi~
lity and accuracy of the purity test.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS --In accordance with a preferred embodiment of the present invention, the bypass assembly comprises a flush valve ~~ which is closed during the cooling mode and which is -~ opened during the cléaning mode. In this marner, during a ~ 25 cleaning cycle, high velocity gas is forced to pass `- through the tube and flush out the contaminants.
:~
, 2 ~
Moreover, in accGrdance with a preferred embodiment of the present invention, the heat exchange tube is helical-ly wound over a cylindrical core and installed inside an insulated housing (dewar). The by-pass assembly is formed of an extension to the heat exchange tube inside the cylindrical core. Further, in accordance with the prefer-¦ red embodiment of the invention, during the cooling mGde, the gas escapes through the gas escape aperture to the ¦ housing, thereby cooling the heat exchange tube and the warm gas flowing in until liquefaction occurs. During the cleaning mode, the gas generally bypasses the gas escape aperture, thereby the warm gas flowing in warms the heat exchange tube.
Still further, in accordance with a preferred embodiment15 of the present invention, the cooler includes a sensor Whlch pre~erably controls apparatus for switching the cooler from the cooling mode to the cleaning mode. The , sensor may be a flow measuring apparatus responsive to the quantity of gas flowing through the gas escape aper-- 20 ture or a temperature sensing element, such as thermocou-ple, located at the vicinity of the gas escape aperture.! I
Mcreover, in accordance with a preferred embodimert cf the present invention, the cooler is characterized in that the cleaning mode raises a temperature of the cooler ;~
25 ~ to a desired temperature.
.,.~
~' ' ''"';' ~' `: ' ' ' . .
1 r J 3 ~ 5 There is also provided, in accordance with a preferred embodiment of the present invention, a gas purity tester including (a) a heat exchange tube receiving a supply of pressurized gas, (b) a gas escape aperture ccmmunicating with the interior of the heat exchange tube for permit-ting escape of the pressurized gas and expansion thereof during a cooling mode, (c) a by-pass assembly, associated with the heat exchange tube and located after the gas escape aperture, which during a cleaning mode, enables most of the pressurized gas to exit the heat exchange tube without flowing through the gas escape aperture, and (d) a sensor apparatus indicating the extent of the gas purity, according to the quantity of gas flowing through the gas escape aperture or to the coolers temperature. A
prolonged cperating time will indicate a more pure gas.
Optionally, a gas pressure regulator is also installed in order to obtain more reliable results.
BRIEF DESCRIPTION OF THE DRA~INGS
The present inventlon will be understood and appreciated from the following detailed description taken in conjunction with the drawing in which:
Figure 1A is a schematic illustration of a typical Joule-Thomson cryogenic cooler with a downstream continu-ation in accordance with a preferred embodiment of the invention; and --~- - 6 ~ L i 2 3 ~ ~
Figure 1B is a detailed illustration of an aperture section of the cooler shown in Figure lA in accordance with a preferred embodiment of the irvention.
Reference is now made to Figures 1A and lB which illus-trate a cryogenic cooler constructed and operative in accordance with a preferred embodiment of the invention.
As an example only,the cooler shown in Figures lA and 1B
is of the Joule-Thomson type. As known in the art, this type of cooler can be utilized as a gas purity tester.
As in the prior art, the cooler typically comprises a heat exchange tube 12 wrapped around a core 14, both of which are located within a housing 16. In accordance with the present invention, tube 12 is extended out of the housing 16 and ends in an exit 18 to which is attached a high pressure valve 20. The extension of tube 12 is referenced herein 22.
The tube 12 can be of any appropriate diameter, such as 0.3 mm inner diameter and 0.5 mm outer diameter.
- During operation, a highly pressurized gas, such as Nitrogen, Oxygen, Argon and any other suitable gas, is fed into heat e~change tube 12 at an entrance 24. During a cooling mode, valve 20 is maintained in a closed posi-~ tion and gas escapes through a small aperture 26 in tube :~ 12 at a section 28 near the non-valve end cf extension ~ 2s 22. Aperture 26 can be of any suitable size tc effect '~ ' ' ' ~ 2 ~ 2 5 cooling. Fcr example, for the tube size given herein-above, aperture 26 preferably has a diameter between 0.04 and O.OE mm. The gas is typically at a pressure between 1500 and 6000 psi. ;~
S Cooling is effected when the highly pressurized gas escapes to the low pressùre inside the housing 15, after having exchanged heat with the high pressure gas. The low pressure gas exits through an exit 30 before which is located a flow rate meter 32 for measuring the flow through exit 30. ~,;
Due to the decompression and COGl ing of the gas in the , cooling mode described above, contaminants contained in the high pressure gas accumulate inside tube 12, near or inside aperture 26, in the fcrm of liquid or solid accumulations 34.
In a preferred embodiment of the invention, a cleaning --~ mode is provided for removing the accumulations 34. In this cleaning mode, which typically occurs immediately after the cooling mode, high pressure valve 20 is opened, either manually or automatlcally, and the high pressure gas is allc~ed to exit through exit 18.
D~ue to the pressure differential between the high pres-sure at the entrance 24 and the outside pressure at exit 18, most of the gas passes at high velocity through tube ;? 2s 12, carrying with it accumulations 34.
s '` ~ .
...
l ~ ' i '" ' ' ~ ' I` ' '~ ~ ~' ' ' ~ ~ ! , : ~ , --- 2ii2~2~
Typically, the cleaning mode lasts for about. 2 minutes, during which time the high pressure gas is continuously fed through tube 12. Because very little gas exits through aperture 26, very little cooling occurs. The ~ :~
., ~-.
little gas which does exit the aperture 26 serves to -.;.. ~
clean the aperture and the gas which flows by the .^ ^
aperture 26 serves to warm and clean the tube 12 in the area of the aperture. It is noted that the warmer the ; .~
tube 12 is, the more easily the contaminants flow. ~ --Due to the movement of the warm gas through the tube 12, .
the cleaning mo.de typically rapidly returns the cooler to near the room tempera^ture, the typical starting tempera~
ture suitable for restarting of the cooling operation.
This is in contrast to the prior art which requires a ^.
lS significant amount of time to return to the starting -~
- :^. ^^
temperature.
~^ It will be appreciated that the apparatus described here~
in allows for a relatively rapid flushing of contaminants .. . .
-~ found in the gas as well as a relatively rapid returning .~ - .
of the cooler to its startin~ temperature.
It will .further be.appreciated by those skilled in the art that the present invention encompasés a valve 20 located anywhere after the aperture 26. .
Furthermore, any device which enables gas to flow through --2s the cooler generally without performing the cooling and :
'`~: , '', . ~ .
g heat exchanging operation is included within the present invention.
In a preferred errbodiment of the invention, the flow I meter 32 provides flow rate information to a controller S (not sho~n). The controller is typically programed to switch the cooler to the cleaning mode when the flow rate is reduced to under a predeter-mined rate, such as 20%
less than a desired rate, or a change in the gas quality is involved. The controller switches the modes of the i10 cooler by selectively opening (for the cleaning mode) and closing (for the cooling mode) valve 20.
Alternatively, as shown in Figure 2, a temperature sensor 33, such as a thermocouple, may be located at the vicini-ty of the gas escape aperture and providing temperature information to the controller. As cooling stops due to blockage of the aperture by contaminants, the temperature rises. The controller is typically programmed to switch the cooler to the cleaning mode at a predetermined tempe-rature-value.
;~ 20 In accordance with an additional embodiment of the pre-- sent invention, a pressure regulator 40 can be included ~ just after entrance 24. The pressure regulator 40 ensures -~ a steady pressure and, as a result, ensures that the type .~
of stoppage achieved is repeatable for each pressure level.
~ : :
.. . .
,~
,~ , .~. .
- lQ ~ 2~
It will be appreciated that the length of the cleaning mode depends on the size of the tubes, the extent tc which the system needs to be heated and the minimu~ loss of gas, duriny cleaning, allowable.
It is a feature of the present invention that the flushing mechanism is an integral part of the cooler and enables cleaning of the heat exchange tube without dis~
mantling the cooler.
As well known in the art, the system based on a Joule-Thomson cryogenic cooler, is most suitable for a gas purity tester. Using the system according to the present invention, the gas purity tester will comprise: ~a) a heat exchange tube receiving a supply of pressurized gas; (b) a gas escape aperture communicating with the interior of the heat exchange tube for permitting escape of the pressurized gas and expansion therecf during a cooling mode; (c) a by-pass assembly, associated with said heat exchange tube which is substantially enclosed in a housing and lccated after said gas escape aperture, wherein during a cleaning mode gas escapes through said ; escape aperture into said housing, and (d) a sensor for -indicating the extent of the gas purity wherein a longer .
continuous operating tlme indicates a purer gas. Option--~ ally, a pressure regulator at the gas inlet is installed .~. . .
~ 25 in order to ensure a better reproducibility and accuracy ~
~. ~; .. .
-~ ~ of the purity test of the respective gas.
.~ ' ', .
~' ~,i ;~J'~
It will be appreciated by persons skilled in the art that the present invention is not limited by the description provided hereinabove. Rather, the scope of this invention c defined only by the appended Claims.
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ry ~ ~
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Claims (11)
1. A system for a cooler comprising:
a heat exchange tube receiving a supply of pressurized gas;
a gas escape aperture communicating with the interior of the heat exchange tube for permitting escape of the pressurized gas and expansion thereof during a cooling mode; and a bypass assembly, associated with said heat exchange tube and located after said gas escape aperture, which during a cleaning mode, enables most of the pressurized gas to exit the heat exchange tube without flowing through said gas escape aperture.
a heat exchange tube receiving a supply of pressurized gas;
a gas escape aperture communicating with the interior of the heat exchange tube for permitting escape of the pressurized gas and expansion thereof during a cooling mode; and a bypass assembly, associated with said heat exchange tube and located after said gas escape aperture, which during a cleaning mode, enables most of the pressurized gas to exit the heat exchange tube without flowing through said gas escape aperture.
2. The system according to Claim 1, wherein in the cooler said bypass assembly comprises a flush valve which is closed during said cooling mode and which is opened during said cleaning mode.
3. The system according to any of the previous Claims wherein said cooler is installed in a housing comprising most of said heat exchange tube and wherein said bypass assembly is formed of an extension of said heat exchange tube outside of said housing.
4. The system according to Claim 3, wherein during said cooling mode, gas escapes through said gas escape aper-ture to said housing, thereby to cool said gas which, in turn, cools said heat exchange tube and wherein, during said cleaning mode, said gas generally bypasses said gas escape aperture, thereby warming said heat exchange tube.
5. The system according to any of the previous claims and including sensing means responsive to the quantity of gas flowing through the gas escape aperture.
6. The system according to Claim 5, and wherein said gas flow measuring means include means for switching the cooler from the cooling mode to the cleaning mode at a predetermined gas flow rate.
7. The system according to Claims 1 to 4, including means responsive to the cooler's temperature.
8. The system according to any of the previous claims and characterized in that the cleaning mode raises a temperature of said apparatus to a desired temperature.
9. The system according to any of the previous claims and also including a pressure regulator.
10. The system for a gas purity tester comprising:
a heat exchange tube receiving a supply of pressuri-zed gas;
a gas escape aperture communicating with the interior of the heat exchange tube for permitting escape of the pressurized gas and expansion thereof during a cooling mode;
a bypass assembly, associated with said heat exchange tube which is substantially enclosed in a housing and located after said gas escape aperture, wherein during a cleaning mode, gas escapes through said escape aperture to said housing; and sensing means for indicating the extent of the gas purity according to the respective time of a stable cooling operation.
a heat exchange tube receiving a supply of pressuri-zed gas;
a gas escape aperture communicating with the interior of the heat exchange tube for permitting escape of the pressurized gas and expansion thereof during a cooling mode;
a bypass assembly, associated with said heat exchange tube which is substantially enclosed in a housing and located after said gas escape aperture, wherein during a cleaning mode, gas escapes through said escape aperture to said housing; and sensing means for indicating the extent of the gas purity according to the respective time of a stable cooling operation.
11. A system according to anyone of Claims 1 to 10, substantially as shown and described hereinabove and in the attached drawings.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IL104,496 | 1993-01-24 | ||
| IL104496A IL104496A (en) | 1993-01-24 | 1993-01-24 | System for a cooler and gas purity tester |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2112825A1 true CA2112825A1 (en) | 1994-07-25 |
Family
ID=11064441
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002112825A Abandoned CA2112825A1 (en) | 1993-01-24 | 1994-01-05 | System for a cooler and gas purity tester |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US5388415A (en) |
| CA (1) | CA2112825A1 (en) |
| DE (1) | DE4400556A1 (en) |
| FR (1) | FR2700834B1 (en) |
| GB (1) | GB2274505B (en) |
| IL (1) | IL104496A (en) |
Families Citing this family (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6505629B1 (en) | 1996-07-23 | 2003-01-14 | Endocare, Inc. | Cryosurgical system with protective warming feature |
| US5800488A (en) | 1996-07-23 | 1998-09-01 | Endocare, Inc. | Cryoprobe with warming feature |
| DE19648902C2 (en) * | 1996-11-26 | 1998-09-10 | Univ Dresden Tech | Method for realizing a mixture Joule-Thomson process and device for carrying out this method |
| US6044648A (en) * | 1997-09-19 | 2000-04-04 | Forma Scientific, Inc. | Cooling device having liquid refrigerant injection ring |
| US5974808A (en) * | 1997-11-21 | 1999-11-02 | Raytheon Company | Cooling apparatus employing a pressure actuated Joule-Thomson cryostat flow controller |
| US6251105B1 (en) | 1998-03-31 | 2001-06-26 | Endocare, Inc. | Cryoprobe system |
| JP2985882B1 (en) * | 1998-08-21 | 1999-12-06 | ダイキン工業株式会社 | Double tube heat exchanger |
| US6767346B2 (en) | 2001-09-20 | 2004-07-27 | Endocare, Inc. | Cryosurgical probe with bellows shaft |
| US6936045B2 (en) * | 2001-09-20 | 2005-08-30 | Endocare, Inc. | Malleable cryosurgical probe |
| JP4022429B2 (en) * | 2002-05-20 | 2007-12-19 | 東海旅客鉄道株式会社 | Cryogenic refrigerator |
| FR2883365B1 (en) * | 2005-03-16 | 2007-06-01 | Sagem | CRYOGENIC COOLING APPARATUS FOR AN AUTOGUIDE PROJECTILE SELF-DIRECTOR |
| US9522030B2 (en) * | 2013-01-23 | 2016-12-20 | Medtronic Cryocath Lp | Purge phase for cryoablation systems |
| CN107063731A (en) * | 2017-05-03 | 2017-08-18 | 黑龙江沧龙发电设备股份有限公司 | The test platform and its method of testing of a kind of oil cooler efficiency |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2943459A (en) * | 1958-04-07 | 1960-07-05 | Fairchild Engine & Airplane | Air conditioning system |
| US3314473A (en) * | 1965-07-16 | 1967-04-18 | Gen Dynamics Corp | Crystal growth control in heat exchangers |
| US3933003A (en) * | 1974-04-25 | 1976-01-20 | General Dynamics Corporation | Cryostat control |
| SU514999A1 (en) * | 1975-01-06 | 1976-05-25 | Предприятие П/Я В-8337 | Choke micro cooler |
-
1993
- 1993-01-24 IL IL104496A patent/IL104496A/en not_active IP Right Cessation
- 1993-12-30 GB GB9326568A patent/GB2274505B/en not_active Expired - Fee Related
-
1994
- 1994-01-05 US US08/177,726 patent/US5388415A/en not_active Expired - Lifetime
- 1994-01-05 CA CA002112825A patent/CA2112825A1/en not_active Abandoned
- 1994-01-11 DE DE4400556A patent/DE4400556A1/en not_active Withdrawn
- 1994-01-24 FR FR9400693A patent/FR2700834B1/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| GB9326568D0 (en) | 1994-03-02 |
| US5388415A (en) | 1995-02-14 |
| IL104496A0 (en) | 1993-05-13 |
| GB2274505A (en) | 1994-07-27 |
| IL104496A (en) | 1997-04-15 |
| GB2274505B (en) | 1996-09-11 |
| DE4400556A1 (en) | 1994-07-28 |
| FR2700834B1 (en) | 1995-12-01 |
| FR2700834A1 (en) | 1994-07-29 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued |