General Cryopumping Study

Wang, E. S. J.; Collins, James D.; Haygood, J. D.

doi:10.1007/978-1-4757-0531-7_6

Cited by 13 publications

(9 citation statements)

References 4 publications

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“…4). Then, with the cryosurface visibly coated with C02 and at liquid nitrogen temperature, the chamber was pumped down to approximately 2 x 10 -7 torr, the vacuum valve was closed to isolate the mechanical pumps from the chamber, and a constant C02 inleakage, or flow, to the chamber was established, continued for approximately 3 minutes and shut off.…”

Section: Methodsmentioning

confidence: 99%

“…The details of the chamber are the same as those previously reported (Ref. 4), with the exception that the 4-inch pumpout line and high vacuum gate valve were replaced by 6-inch components.…”

Section: Apparatusmentioning

confidence: 99%

“…Another test (Ref. 4) was performed under the same conditions with the exception that the C02 contained approximately 400 parts noncondensables for every 106 parts C02. In this case, it was observed that the visible C02 deposit appeared only on the tips of the fins, and the capture coefficient was calculated to be approximately 0.…”

Section: Aedctdr-62-46 42 18fin Cylinder Cryosurfacementioning

confidence: 99%

“…An earlier investigation (Ref. 4) was made of the pumping rate for several gases as a function of chamber pressure. That investigation showed that L. the freemolecular flow region experiment agrees with kinetic theory in that volumetric pumping speed is constant.…”

Section: Introductionmentioning

confidence: 99%

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Initial Study of the Effect of Cryosurface Geometry on Cryopumping

Collins¹,

Haygood²,

Wang³

1962

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An experimental study of cryogenic pumping using siEveral cryosurfaces in the pressure ranges of 10-4 and 1C-3 mm Hg is presented. At these pressures, where the mean free path of the condensable gas is on the order of the cryosurface dimensions, it is shown that the pumping rate is no longer a constant as it is in free-molecular flow, but increases through what is terme.d the transition range and presumably approaches a higher constant value in the continum flow regime. Flow in the gas kinetic, gas dynamic, and transition regimes is discussed.Experimental results are presented showing the effects on cryopumping of the addition of fins or ribs to a cryosurface, and the effect of pumping with parallel cryosurfaces at different separations.ii

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Section: Methodsmentioning

confidence: 99%

Section: Apparatusmentioning

confidence: 99%

Section: Aedctdr-62-46 42 18fin Cylinder Cryosurfacementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Initial Study of the Effect of Cryosurface Geometry on Cryopumping

Collins¹,

Haygood²,

Wang³

1962

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“…The effect of surface geometry, surface temperature, surface condition and temperature of the gas being condensed have all been reported as affecting the capture coefficient (25,26).…”

mentioning

confidence: 99%

Design and Development of A Cryogenic Pumping Evaluation Facility

Albero

1966

Naval Engineers Journal

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A cryogenic pump is a cold surface employed to remove large volumes of gases from a vacuum system by condensing and freezing the gas molecules.Experimental results are presented for the cryopumping rate of carbon dioxide gas on a surface cooled by liquid nitrogen, and for nitrogen gas on a surface cooled by liquid helium. The nature of the problems encountered in the design and construction of a cryogenic pumping system are also discussed.ii ACKNOWLEDGMENTS

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Capture Coefficients of Gases at 77°K

Brown¹,

Wang²

1965

Advances in Cryogenic Engineering

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General Cryopumping Study

Cited by 13 publications

References 4 publications

Initial Study of the Effect of Cryosurface Geometry on Cryopumping

Initial Study of the Effect of Cryosurface Geometry on Cryopumping

Design and Development of A Cryogenic Pumping Evaluation Facility

Capture Coefficients of Gases at 77°K

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