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Cryogenic Pumping With COOLVAC: A Short Introduction

By Dr Graham Rogers
COOLVAC-Family

Like every cryo pump the COOLVAC binds the gas molecules which have to be pumped on cold surfaces.
There are surfaces at different temperature levels to capture gases with different freezing points. There are, for instance:

  • Argon & Nitrogen
  • Hydrogen
  • Water vapour

Water vapor is condensed at a temperature of about 100 K on the baffle of the inlet flange of the pump.  The battle is cooled by the first stage of the refrigerator and then connected to the first stage by the radiation shield which has a temperature of 80 – 100 K.

Argon or Nitrogen condense at about 15 K on the cold panels at the second stage of the refrigerator. During pumping the ice layer grows continuously. Hydrogen is absorbed by activated charcoal on the inner side of the cold panels.

Related: Browse our collection of Cryo Pumps, Cold Heads and Compressors on this product page

The Regeneration Process

The Regeneration processes of the COOLVAC starts after closing the high-vacuum valve.


Fast Regeneration

The cold panels of the second stage are warmed up locally by electrical heaters, whereas the battle at the first stage is not heated at all and maintains its temperature. First, at a temperature between 20-100 K, the Hydrogen is released and removed from the COOLVAC via the roughing pump. The forevacuum valve closes again.

Total Regeneration

The cold panels of the first and the second stage are warmed up locally by electrical heaters up to room temperature. Between 20-310 K all condensed and adsorbed gases are released and removed from the COOLVAC via the roughing pump at a controlled and safe pressure < 20 mbar. After a self-controlled cleaning step the COOLVAC starts to cool down automatically. The cool down takes about 90 minutes and the COOLVAC is ready to continue production.

After Regeneration

Between 100 and 140 K the process gases (Argon, Nitrogen) melt. The liquid starts to boil, so that the pressure within the C00LVAC rises, then the Fast Regeneration valve opens and the process gases are discharged.  After pressure relief, the forevacuum valve opens and the COOLVAC is further evacuated by the roughing pump.

A short time later the second stage cold panels are cooled down again and the forevacuum valve closes. After approx. 40 minutes a temperature of less than 20 K is reached and the COOLVAC is again ready to continue production.

Introducing COOLVAC

The video below introduces the cryogenic technology of Leybold's cryopump COOLVAC — a series of cryogenic high vacuum pumps. Get a closer look at how gases behave and how vacuum is produced, thanks to cryo technique.

 


Want to know more about COOLVAC or Leybolds range of products and services? Click the button below and get in touch! Our team is on hand to find out how we can help meet all your vacuum needs. 

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Tags: Ultra High Vacuum

About Dr Graham Rogers

Dr Graham Rogers
Dr Graham Rogers has extensive experience across the world of vacuum, having been involved in the detailed specification and technical selling of the complete range of products, principally for Leybold, over the past 30 years. He brings in-depth knowledge from the metallurgy, chemical, analytical, R&D and semiconductor sectors, and has a passion for helping customers in solving problems and developing solutions that will bring real process improvements and value. Graham is a science graduate from Oxford University, UK, where he gained his degree in Chemistry and a DPhil in Physical Chemistry. His journey into vacuum science began early on in his career when worked developing semiconductor processes particularly thin film coating, this led him into the exciting and inspiring world of vacuum and eventually Leybold. We are delighted to have Graham as a resident Consultant for Leybold, where he is able to share his knowledge and insight through our vacuum academy training, videos and blogs.

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