Browse Prior Art Database

Rapid Regeneration System for Cryogenic Pumps

IP.com Disclosure Number: IPCOM000040101D
Original Publication Date: 1987-Sep-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

Brown, WW: AUTHOR [+3]

Abstract

This method reduces the time required to regenerate cryogenic pumps. A third stage is incorporated into the cryopump using a "Polycold" system to provide sufficient heating to desorb materials. Cryogenic pumps used for vacuum systems reduce system availability, due to the need for periodic regeneration. In pumps for thin film evaporation systems, regeneration may take 6-8 hours due to the inability to introduce sufficient heat to rapidly desorb condensed gases. Some methods use a system whereby hot N2 gas bleeds through the secondary stage of the pump to speed regeneration by about 10-15%, but requiring a large volume of N2 at high temperatures. Here, cryopump 1 has a coil/shroud 2 surrounding the first stage of the pumping head 3 and extending to the bottom of pumping unit housing 4.

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Rapid Regeneration System for Cryogenic Pumps

This method reduces the time required to regenerate cryogenic pumps. A third stage is incorporated into the cryopump using a "Polycold" system to provide sufficient heating to desorb materials. Cryogenic pumps used for vacuum systems reduce system availability, due to the need for periodic regeneration. In pumps for thin film evaporation systems, regeneration may take 6-8 hours due to the inability to introduce sufficient heat to rapidly desorb condensed gases. Some methods use a system whereby hot N2 gas bleeds through the secondary stage of the pump to speed regeneration by about 10-15%, but requiring a large volume of N2 at high temperatures. Here, cryopump 1 has a coil/shroud 2 surrounding the first stage of the pumping head 3 and extending to the bottom of pumping unit housing 4. This modification is in addition to the hot N2 purge system 5. The coil/shroud is attached to a "Polycold" unit which pumps coolant into the coil/shroud 6 which exits at 7 of a closed loop. The heated coil/shroud 2 working in conjunction with the hot N2 purge and throttled pumping, greatly reduces cryopump regeneration time. The dual cycling "Polycold" unit has the advantage that after regeneration ends, it automatically switches to a cold cycle and acts as a first stage condensable pump to entrap mostly H2O leaving the original two stages to pump other fractions. This regeneration cycle increases tool availability, leading to improved p...