CRYOPUMP APPARATUS

Abstract

A cryopump apparatus defines an open interior cavity with a process assembly received within the open interior cavity. The process assembly includes a refrigerant passage having a refrigerant inlet end to receive a refrigerant therein and a refrigerant outlet end to output used refrigerant. A process passage has a process inlet end to receive a process gas and a process outlet end to output a product gas. A heating element is thermally coupled to the process passage and a cap seals the open interior cavity.

Claims

1. A cryopump apparatus comprising: (a) a first housing defining a first passage, wherein the first passage is configured to receive a packing material therein; (b) a second housing defining a second passage in thermal communication with the first passage, wherein the second passage is configured to cyclically receive a temperature regulating fluid therein; (c) an outer housing configured to substantially receive the first housing and the second housing therein, wherein the outer housing is further configured to be evacuated under vacuum during operation of the cryopump apparatus; and (d) a heating element thermally coupled to one or both of the first housing and the second housing.

2. A cryopump apparatus comprising: (a) a housing defining an open interior cavity; (b) a process assembly dimensioned to be received within the open interior cavity, wherein the process assembly comprises; (i) a refrigerant passage having a refrigerant inlet end configured to receive a refrigerant therein and a refrigerant outlet end configured to output used refrigerant; (ii) a process passage having a process inlet end configured to receive a process gas and a process outlet end configured to output a product gas; and (iii) a first heating element thermally coupled to the process passage; and (c) a cap secured to the housing to seal the open interior cavity.

3. The apparatus of claim 2, wherein the refrigerant passage, the process passage, and the first heating element are each arranged as a respective helical coil.

4. The apparatus of claim 2, wherein the cap comprises: (i) a collar portion including a collar body having a first peripheral end secured to the housing and a second peripheral end opposite the first peripheral end; and (ii) a top plate secured to the second peripheral end of the collar portion, wherein the top plate has a cover portion dimensioned to seal the open interior cavity and a flange portion extending outwardly of the collar potion.

5. The apparatus of claim 4, wherein the top plate includes a first through bore and a second through bore, wherein the process inlet end passes through the first through bore and the process outlet end passes through the second through bore.

6. The apparatus of claim 5, wherein the flange portion is adapted to be secured to a glove box whereby the process inlet end and the process outlet end extend into the glove box.

7. The apparatus of claim 4, wherein the refrigerant inlet end and the refrigerant outlet end each extend outwardly of the collar body.

8. The apparatus of claim 2, further comprising a cavity evacuation valve fluidly coupling the interior cavity of the housing with the environment, wherein the cavity evacuation valve is configured to be coupled to a vacuum source.

9. The apparatus of claim 2, further comprising one or more assembly thermocouples, wherein each respective assembly thermocouple includes a temperature sensor end located proximate to the process passage and a plug end passing through the housing.

10. The apparatus of claim 2, wherein the housing is a dewar having an outer wall and an inner wall defining a sealed chamber therebetween, wherein the sealed chamber is under vacuum and wherein the inner wall defines the open interior cavity.

11. The apparatus of claim 5, wherein the top plate includes a third through bore in fluid communication with the interior cavity, wherein a first sealable fitting is secured within the third through bore, and wherein the first sealable fitting is either a burst disc or a pressure valve.

12. The apparatus of claim 11, wherein the top plate includes a fourth through bore in fluid communication with the interior cavity, wherein a second sealable fitting is secured within the fourth through bore, and wherein the second sealable fitting is the other of the burst disc or the pressure valve.

13. The apparatus of claim 2, further comprising a second heating element thermally coupled to the process passage.

14. The apparatus of claim 2, wherein the process passage has a length between about 20 feet and about 40 feet.

15. The apparatus of claim 14, wherein the housing has an inner diameter of about 18 inches and a length of about 40 inches.

16. The apparatus of claim 2, wherein the process passage is packed with a separation medium.

17. The apparatus of claim 16, wherein the separation medium is one or more materials selected from the list comprising a molecular sieve, a metal, a metal alloy, diamond, a ceramic, aluminum nitride, silicon nitride, palladium or palladium on kieselguhr (PdK).

18. The apparatus of claim 16, wherein the separation medium selectively concentrates protium wherein the product gas is high purity molecular hydrogen (H.sub.2).

19. The apparatus of claim 16, wherein the separation medium selectively concentrates tritium wherein the product gas is high purity molecular tritium (T.sub.2).

20. The apparatus of claim 16, wherein the separation medium selectively separates helium from hydrogen isotopes.

21. The apparatus of claim 5, wherein the first through bore and the second through bore each have a respective bore diameter, wherein the bore diameter is larger than an outer diameter of the process passage, and wherein the apparatus further comprises a first process fitting secured within the first through bore and a second process fitting secured within the second through bore, wherein each respective process fitting has a wide bore portion and a narrow bore portion, the wide bore portion having an outer diameter substantially equal to the respective through bore diameter and an inner diameter larger than the outer diameter of the process passage, and the narrow bore portion having an inner diameter substantially equal to the outer diameter of the process passage, wherein each respective wide bore portion has a length greater than a thickness of the top plate, wherein a first portion of the wide bore portion is secured within the respective through bore, and wherein a second portion of the wide bore portion and the narrow bore portion extend outwardly from the top plate opposite the open interior cavity, and wherein the process passage is secured solely to the narrow portion of each respective process fitting.

22. The apparatus of claim 7, wherein the collar body includes a first collar through bore defining a first collar bore diameter, wherein the first collar bore diameter is larger than an outer diameter of the refrigerant passage, and wherein the apparatus further comprises a first refrigerant fitting secured within the first collar through bore, wherein the first refrigerant fitting has a wide bore portion and a narrow bore portion, the wide bore portion having an outer diameter substantially equal to the first collar bore diameter and an inner diameter larger than the outer diameter of the refrigerant passage, and the narrow bore portion having an inner diameter substantially equal to the outer diameter of the refrigerant passage, wherein the wide bore portion of the first refrigerant fitting has a length greater than a thickness of the collar body, wherein a first portion of the wide bore portion is secured within the first collar through bore, and wherein a second portion of the wide bore portion and the narrow bore portion extend outwardly from the collar body opposite the open interior cavity, and wherein the refrigerant inlet end of the refrigerant passage is secured solely to the narrow portion of the first refrigerant fitting.

23. The apparatus of claim 22, wherein the collar body includes a second collar through bore defining a second collar bore diameter, wherein the second collar bore diameter is larger than an outer diameter of the refrigerant passage, and wherein the apparatus further comprises a second refrigerant fitting secured within the second collar through bore, wherein the second refrigerant fitting has an outer diameter substantially equal to the second collar bore diameter and defines an inner bore having an inner diameter larger than the outer diameter of the refrigerant passage, wherein the second refrigerant fitting has a length greater than the thickness of the collar body, wherein a first portion of the second refrigerant fitting is secured within the second collar through bore, and wherein a second portion of the second refrigerant fitting extends outwardly from the collar body opposite the open interior cavity, and wherein the refrigerant outlet end of the refrigerant passage is secured solely within the inner bore of the second refrigerant fitting a spaced distance from a terminal end of the second refrigerant fitting.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

[0011] FIG. 1 is a schematic view of a glovebox system configured to use an exemplary cryopump apparatus in accordance with the present invention.

[0012] FIG. 2 is a perspective rendering of an exemplary cryopump apparatus in accordance with the present invention.

[0013] FIG. 3 is a perspective rendering of the exemplary cryopump apparatus shown in FIG. 2, with the housing shown in phantom view.

[0014] FIG. 4 is an exploded view of the exemplary cryopump apparatus shown in FIG. 2.

[0015] FIG. 5 is a top perspective view of an exemplary coil assembly configured for use within the exemplary cryopump apparatus shown in FIG. 2.

[0016] FIG. 6 is a cross section view of the exemplary coil assembly shown in FIG. 5, while FIG. 6A is an expanded view of as portion of the exemplary cryopump apparatus.

[0017] FIG. 7 is a top view rendering of the exemplary cryopump apparatus shown in FIG. 2.

[0018] FIG. 8 is a top view rendering of the exemplary cryopump apparatus shown in FIG. 7, with the top plate removed.

[0019] FIG. 9A is a side cross section view of an exemplary process fitting configured for use within the exemplary cryopump apparatus shown in FIG. 2.

[0020] FIG. 9B is a side cross section view of an exemplary sealable fitting configured for use within the exemplary cryopump apparatus shown in FIG. 2.

[0021] FIG. 10A is a side cross section view of an exemplary first refrigerant fitting configured for use within the exemplary cryopump apparatus shown in FIG. 2.

[0022] FIG. 10B is a side cross section view of an exemplary second refrigerant fitting configured for use within the exemplary cryopump apparatus shown in FIG. 2.

[0023] FIG. 11 is a schematic of a representative isotope separation system configured to use a pair of exemplary cryopump apparatuses to perform TCAP separation.

[0024] FIG. 12 is a representative algorithmic flow chart for operating the representative isotope separation system shown in FIG. 11.

[0025] FIG. 13 is a schematic of a representative hydrogen compression system configured to use an exemplary cryopump apparatus.

[0026] FIG. 14 is a representative algorithmic flow chart for operating the representative hydrogen compression system shown in FIG. 13.

[0027] Corresponding reference characters indicate corresponding parts throughout the several views. The embodiments set out herein are examples only and illustrate currently preferred embodiments of the present invention, and such examples are not to be construed as limiting the scope of the invention in any manner.

DETAILED DESCRIPTION OF THE INVENTION

[0028] Turning now to the figures, and with particular reference to FIGS. 1 and 11 through 14, in an exemplary embodiment, gas handling system 100 includes a cryopump apparatus 100 adapted to be secured to a glove box 106 whereby the cryopump apparatus 102 is located outside of glove box 106 with process lines extending into the interior 108 of glove box 106, as will be described in greater detail below. With particular reference to FIGS. 11 and 12, an Isotopic Separation System (ISS) 100a may comprise a pair of cryopump apparatuses 102 (e.g., 102a, 102b), with each apparatus having a packed bed, such as but not limited to one apparatus having a packed bed of Palladium on Kieselguhr (PdK) while the other has a packed bed of 5A molecular sieve material. In certain embodiments, such as those requiring high throughput of the process gas, one or both of the packed beds may further include additional bed materials, such as but not limited to those possessing good thermal conductivity to assist in thermal management of the packing material during the hot/cold cycling of the ISS 100a, such as a metal including copper, silver, and aluminum, and non-metals/compounds such as ceramics, diamond, aluminum nitride and silicon nitride.

[0029] With continued reference to FIGS. 11 and 12, the two beds (i.e., cryopumps 102a, 102b) may be coupled together with feed (process), product and raffinate tanks 104a, 104b, and 104c, respectively, which allows gas to be loaded onto one of the columns and cyclically swung between the two columns, thereby enriching heavy isotopes drawn from one side (product 104b) and enriching light isotopes drawn from the other side (raffinate 104c). In this manner, gas with mixed isotopes of protium (i.e. elemental hydrogen) (H), deuterium (D), and tritium (T), e.g., H-D-T, can be fed into ISS system 100a and pure molecular tritium, T.sub.2, can be removed as product and pure molecular hydrogen, H.sub.2, or molecular deuterium D.sub.2, or mixed H-D (but no T) can be removed as raffinate.

[0030] With reference to FIGS. 13 and 14, a gas compression system 100b may comprise a single cryopump apparatus 102 having a bed packed with material suitable for gas adsorption and compression. By way of example and without limitation, a packing material suitable for hydrogen compression may be a molecular sieve, such as and without limitation thereto, molecular sieve 4A or 5A. Cryopump apparatus 102 may then be cooled to liquid nitrogen temperatures (196 C.) before loading with source/process gas, such as from a feed/process tank 105a. Hydrogen isotopes within the process gas may then preferentially adsorb to the packing material within cryopump apparatus 102. Any helium within the process gas will not adsorb to the packing material such that the helium contaminants 107b may be pulled from cryopump apparatus 102, such as via pump 107. Once cryopump apparatus 102 has become saturated with hydrogen ions, the supply of liquid nitrogen and process gas is stopped. Cryopump apparatus 102 is then heated to desorb the hydrogen ions from the packing material whereby high pressure hydrogen gas is output as a product gas, such as to pressure tank 105b.

[0031] An exemplary embodiment of a cryopump apparatus 102 is shown in FIGS. 2 through 10B. It should be noted that systems 100a/100b may be adapted for use for alternative gas separation/compression systems other than hydrogen gas. The exemplary cryopump apparatus 102 generally comprises a housing 110, at least a first passage, such as coil assembly 112, and cap 114. In an exemplary embodiment, housing 110 has a closed bottom wall 116, a sidewall 118 and an open top end 120, wherein the closed bottom wall 116 and sidewall 118 define an open interior cavity 122 accessible via open top end 120. Coil assembly 112 is dimensioned to be received within open interior cavity 122.

[0032] As shown in FIGS. 3 through 6A, coil assembly 112 generally includes a refrigerant passage, e.g., coil 124, process passage, e.g., coil 126, and at least one heating element 128. Refrigerant coil 124 has a refrigerant inlet end 130 configured to receive a refrigerant therein and a refrigerant outlet end 132 configured to output used refrigerant. By way of example and without limitation thereto, the refrigerant may be liquid nitrogen (LN). Process coil 126 has a process inlet end 134 configured to receive the isotopically mixed hydrogen gas and a process outlet end 136 configured to output a high purity hydrogen isotope gas. First heating element 128 is thermally coupled to process coil 126 to selectively heat process coil 126, as will be discussed in greater detail below. As seen most clearly in FIGS. 5, 6 and 6A, refrigerant coil 124, process coil 126, and first heating element 128 may each be arranged as a respective helical coil.

[0033] It should be noted that alternative configurations of the cryopump apparatus may be employed. By way of example and without limitation thereto, while coils 124 and 126 may be suitable for lower through put operations (e.g., those using less than 1,000 grams of packing materials such as PdK or molecular sieve 4A or 5A), higher through put systems (e.g., those using greater that about 1,000 grams of packing material) may require an alternative configuration. One non-limiting example may include a cryopump apparatus having an inner housing defining central bore filled with packing material, along with concentric outer housings defining respective bores placed around the central bore. For instance, a first outer housing may define a first outer bore immediately adjacent the inner housing. The first outer bore may be cyclically filled and emptied of liquid nitrogen during the respective cold and hot cycles of the cryopump apparatus. A second outer housing may then encapsulate the first outer housing (and the inner housing) to define a second outer bore. In one aspect, the second outer bore may be evacuated to assist thermal switching of the inner bore and first outer bore, while also operating as a secondary containment vessel should there be any leak of product gas from the inner bore.

[0034] With reference to FIGS. 2 through 4, cap 114 is secured to sidewall 118 and includes a collar portion 140 and a top plate 142. Collar portion 140 includes a collar body 144 having a first peripheral end 146 secured to open top end 120 of housing 110 and a second peripheral end 148 opposite first peripheral end 146. Top plate 142 is secured to second peripheral end 148 of collar portion 140. Top plate 142 has a cover portion 152 dimensioned occlude open top end 120 and a flange portion 154 extending outwardly of collar potion 140 and sidewall 118.

[0035] As seen most clearly in FIGS. 7, 9A and 9B, top plate 142 includes a first through bore 156 and a second through bore 158. Process inlet end 134 passes through first through bore 156 while process outlet end 136 passes through second through bore 158. As shown in FIGS. 1 through 3 and 7, flange portion 154 is adapted to be secured to a glove box 106 whereby the process inlet end 134 and the process outlet end 136 extend into the interior 108 of glove box 106 while the remainder of cryopump apparatus 102 remains outside of glove box 106. As will be described in greater detail below, refrigerant inlet end 130 and the refrigerant outlet end 132 each extend outwardly of collar body 144 outside of glove box 106.

[0036] In one configuration, cavity evacuation valve 160 fluidly couples interior cavity 122 of housing 110 with the environment. Cavity evacuation valve 160 may be configured to be coupled to a vacuum source (not shown) whereby interior cavity 122 is evacuated to a negative pressure relative to the environment. One or more coil assembly thermocouples 162 may also be included. By way of example, three respective coil assembly thermocouples 162a, 162b, and 162c may be included, with each including a respective temperature sensor end 164 located proximate to process coil 126 and a plug end 166 passing through collar body 144 and terminating outside of housing 110. In an exemplary embodiment, housing 110 may a dewar wherein the sidewall 118 includes an outer wall 118a and an inner wall 118b defining a sealed chamber 118c therebetween. Inner wall 118b defines open interior cavity 122. Sealed chamber 118c is under vacuum so as to create a further temperature break between process coil 126 and the environment, and may also operate as an additional enclosure to contain any tritium permeation or gases expelled due to a process tube failure.

[0037] Returning now to FIGS. 7, 9A and 9B, top plate 142 may further include a third through bore 170 in fluid communication with open interior cavity 122. A first sealable fitting 172 may be secured within third through bore 170. By way of example and without limitation thereto, first sealable fitting 172 may be either a burst disc 174a or a pressure valve 174b. Top plate 142 may still further include a fourth through bore 176 in fluid communication with open interior cavity 122. A second sealable fitting 178 may be secured within fourth through bore 176. Second sealable fitting 178 may be the other of burst disc 174a or pressure valve 174b. In one configuration, a second heating element 180 may be thermally coupled to process coil 128. In an exemplary embodiment and without limitation thereto, process coil 126 may have a total (linear/uncoiled) length between about 20 feet and about 30 feet, and open interior cavity 122 of housing 110 may have an inner diameter ID of about 18 inches while sidewall 118 has length L of about 24 inches.

[0038] By way of further example and as shown in FIGS. 9A and 9B, first through bore 156 and second through bore 158 may each have a respective bore diameter BD, wherein the bore diameter BD is larger than an outer diameter OD of process coil 126. Cryopump apparatus 102 may also further include a first process fitting 182 secured within first through bore 156 and a second process fitting 184 secured within second through bore 158. Each respective first and second process fitting 182, 184 may have a wide bore portion 186 and a narrow bore portion 188. Each respective wide bore portion 186 may have an outer diameter WO substantially equal to respective through bore diameter BD, and an inner diameter DW larger than outer diameter OD of process coil 126 while each respective narrow bore portion 188 may have an inner diameter DN substantially equal to outer diameter OD of process coil 126. Each respective wide bore portion 186 may also have a length BL greater than a thickness T of top plate 142 such that a first portion 186a of wide bore portion 186 is secured within the respective first or second through bore 156, 158 and a second portion 186b of wide bore portion 186, along with narrow bore portion 188, extends outwardly from top plate 142 opposite open interior cavity 122. Process coil 126 may then be secured solely to narrow portion 188 of each respective process fitting 182, 184.

[0039] In a non-limiting example and as shown in FIGS. 8, 10A and 10B, collar body 144 may include a first collar through bore 190 defining a first collar bore diameter FD. The first collar bore diameter FD may be selected to be larger than an outer diameter RO of refrigerant coil 124. Cryopump apparatus 102 may then further comprise a first refrigerant fitting 192 secured within first collar through bore 190. First refrigerant fitting 192 may have a wide bore portion 194 and a narrow bore portion 196. Wide bore portion 194 may have an outer diameter RW substantially equal to the first collar bore diameter FD, and an inner diameter RI larger than outer diameter RO of refrigerant coil 124 while the narrow bore portion 196 may have an inner diameter ND substantially equal to outer diameter RO of refrigerant coil 124. Wide bore portion 194 of first refrigerant fitting 192 may have a length RL greater than a thickness BT of collar body 144 such that a first portion 194a of wide bore portion 194 may be secured within the first collar through bore 190 while a second portion 194b of wide bore portion 194, along with narrow bore portion 196, extends outwardly from collar body 144 opposite open interior cavity 122. The refrigerant inlet end 130 of refrigerant coil 124 may then be secured solely to narrow portion 196 of first refrigerant fitting 192.

[0040] Another non-limiting example may have collar body 144 including a second collar through bore 200 defining a second collar bore diameter SD. The second collar bore diameter SD may be larger than an outer diameter RO of refrigerant coil 124. Cryopump apparatus 102 may then further include a second refrigerant fitting 202 secured within the second collar through bore 200 wherein the second refrigerant fitting 202 has an outer diameter SO substantially equal to the second collar bore diameter SD. Second refrigerant fitting 202 may also define an inner bore 204 having an inner diameter SI larger than the outer diameter RO of refrigerant coil 124. Second refrigerant fitting 202 may also have a length SL greater than the thickness BT of collar body 144, wherein a first portion 206 of second refrigerant fitting 202 is secured within second collar through bore 200, and wherein a second portion 208 of second refrigerant fitting 202 extends outwardly from collar body 144 opposite open interior cavity 122. The refrigerant outlet end 132 of refrigerant coil 124 may then be secured solely within the inner bore 204 of second refrigerant fitting 202 a spaced distance DS from a terminal end 210 of second refrigerant fitting 202. Second refrigerant fitting 202 may further include a thermocouple mount 212 adapted to receive thermocouple 162d therein whereby temperature sensor end 164d may be located proximate to refrigerant outlet end 132. Thermocouple 162d may then monitor the temperature of the fluid within refrigerant coil 124 during operation of cryopump apparatus 102.

[0041] Returning now to FIG. 12, and with additional reference to FIG. 11, an exemplary method 400 for separating and enriching hydrogen isotopologues, may generally start at block 410 wherein cryopump apparatus 102b having the molecular sieve packed bed is cooled, such as via introduction of LN thereto. By way of example and with reference to FIG. 11, LN valve 103b is opened to receive LN from LN supply 109 while LN valve 103a is closed. Once cryopump apparatus 102b has reached a predetermined temperature, such as for example, about 195 C. as measured by thermocouples 162, at block 420, cryopump apparatus 102a having the PdK packed bed is heated, such as via heating element 128 whereby gases adsorbed on the PdK material is released as described above.

[0042] The product tank pressure (block 421) and product draw pressure (block 422) are measured, such as via respective pressure gauges 220, 222. If the two pressures satisfy predetermined process thresholds, product valve 224 is opened to draw tritium product into product tank 104b at block 423. If the two pressures do not satisfy the predetermined process thresholds or should the thresholds be crossed due to drawing of tritium product gas, product valve 224 is closed at block 424. With product valve 224 closed, at block 430, swing valve 226 is opened whereby the desorbed gases from cryopump apparatus 102a are transferred to cryopump 102b.

[0043] Following gas transfer (block 430), swing valve 226 is closed at block 440 whereby hydrogen is enriched on the molecular sieve packed bed of cryopump apparatus 102b while LN valve 103a is opened to cool cryopump apparatus 102a. The temperature within cryopump 102a is monitored at block 441, such as via one or more thermocouples 162 until the separation medium, i.e., PdK and first passage 126 reach a predetermined temperature, e.g., less than about 150 C. At block 442, pressure within the process/feed tank 104a is measured, such as via pressure gauge 228, to ensure process/source feed gas is available. Valve 230 may then be opened at block 443 whereby process/source gas is loaded onto cryopump apparatus 102a for enrichment of tritium on the PdK packed bed.

[0044] While cryopump apparatus is being cooled and loaded with feed gas, cryopump apparatus 102b is heated, such as via its respective heating element 128 at block 450. As cryopump apparatus 102b is heated, raffinate, e.g., molecular hydrogen, deuterium, or hydrogen-deuterium, may be extracted. That is, at blocks 451 and 452, the raffinate tank pressure and raffinate draw pressure are measured by respective pressure gauges 232, 234. If the two pressures satisfy predetermined process thresholds, raffinate valve 236 is opened to draw raffinate into raffinate tank 104c at block 453. If the two pressures do not satisfy the predetermined process thresholds or should the thresholds be crossed due to drawing of raffinate, raffinate valve 236 is closed at block 454. With raffinate valve 236 closed, at block 460, swing valve 226 is opened whereby the desorbed gases from cryopump apparatus 102b are transferred back to cryopump 102a. Process steps 410 through 460 are then repeated for a preselected number of cycles, a selected length of time, or until an operator chooses to terminate the process.

[0045] Turning now to FIG. 14, and with additional reference to FIG. 13, a method 500 for compression of a purified gas may begin at block 510 wherein cryopump 102 is cooled, such as via opening of LN valve 240 to inject LN into cryopump 102 from LN supply 242. Feed valve 244 and raffinate valve 246 may then be opened whereby a process/source gas with trace impurities may be loaded onto the packed bed of cryopump 102 at block 520. The target gas is selectively adsorbed onto the pack bed while the impurities pass freely through cryopump 102. At block 530, raffinate pump 107 is turned on to assist removal of raffinate/impurity gas. Once cryopump 102 is filled with high purity target gas, each of valves 240, 244, and 246 is closed at block 540. Product output valve 248 is then opened as cryopump 102 is heated, such as via heating element 128 at block 550. At block 560, high purity product gas desorbs from the packed bed within cryopump 102 into high purity pressure tank 105b.

[0046] It should be noted that alternative cryopump designs may be configured to perform the same or similar operation as cryopump apparatus 102 and include all, some, or alternative column configurations, the number and sizes of through bores therein, and the type and number of fittings used. And accordingly, such alternative configurations are to be considered within the teachings of the present invention.

[0047] This disclosure has been described in detail with particular reference to an embodiment, but it will be understood that variations and modifications can be effected within the spirit and scope of the disclosure. The presently disclosed embodiments are therefore considered in all respects to be illustrative and not restrictive. The scope of the invention is indicated by the appended claims, and all changes that come within the meaning and range of equivalents thereof are intended to be embraced therein.