SI
SI
discoversearch

We've detected that you're using an ad content blocking browser plug-in or feature. Ads provide a critical source of revenue to the continued operation of Silicon Investor.  We ask that you disable ad blocking while on Silicon Investor in the best interests of our community.  If you are not using an ad blocker but are still receiving this message, make sure your browser's tracking protection is set to the 'standard' level.
Technology Stocks : Helix Technology, a cold play on semiconductor equipment
HELX 37.77+2.7%Nov 24 4:00 PM EST
 Public ReplyPrvt ReplyMark as Last ReadFilePrevious 10Next 10PreviousNext  
To: robert b furman who wrote (1050)10/17/2002 11:07:03 PM
From: j t jackson  Read Replies (1) of 1227
 
Bob. Helix makes and services a smart (computer-on-board)vacuum pump. It sells cryopumps to OEMs and directly to end uses to many industries and science labs throughout the world.
The cryopump is basically a closed-cycle helium gas refrigerator which reaches an operating temperature of about 10 degree Kelvin and 80 degrees Kelvin. Copper panels are cooled to these two operating temperatures to condense and reduced the vapor pressure of all condensed air gases except neon, hydrogen and helium to off scale pressure measurements, ie below 10 to the minus 14 Torr. The 80 degree station is also used as a thermal shield for the 10 degree station. Neon, hydrogen and helium gases are adsorbed in activated charcoal at the 10 degree level.
The pump can be mounted on a vacuum chamber in any orientation and is usually isolated with a high vacuum valve. As the pump is a capture pump it must eventually be regenerated, defrosted, by simply closing the high vacuum valve, turning off the helium refrigerator and letting the copper panels come back to ambient temperature. A rough vacuum pump is used to produce a starting pressure of 50 microns in the valved off cryopump. Then the roughing pump is isolated and the refrigeration system restarted. The whole cryopump regeneration process takes about one to two hours and is usually automatically controlled by the cryopump on-board computer when needed during down time of the semicondutor processing system for system maintenance.
Does this help? jtj
Report TOU ViolationShare This Post
 Public ReplyPrvt ReplyMark as Last ReadFilePrevious 10Next 10PreviousNext  

HomeMailHotSubjectMarksPeopleMarksKeepersSettings
Terms Of UseContact UsCopyright/IP PolicyPrivacy PolicyAbout UsFAQAdvertise on SI
© 2025 Knight Sac Media.  Data provided by Twelve Data, Alpha Vantage, and CityFALCON News