Gas recirculation flow control method and apparatus for use in vacuum system
Number of patents in Portfolio can not be more than 2000
United States of America Patent
Stats
-
Aug 31, 2004
Grant Date -
Sep 26, 2002
app pub date -
Mar 21, 2002
filing date -
Mar 22, 2001
priority date (Note) -
Expired
status (Latency Note)
Importance
Abstract
A gas recirculation flow control method and apparatus for use in an evacuation system having a vacuum chamber into which a gas is introduced, a first vacuum pump for exhausting the gas from the vacuum chamber and reducing the pressure in the vacuum chamber to a desired pressure, a second vacuum pump for performing evacuation to lower the back pressure of the first vacuum pump below an allowable back pressure, and a gas recirculation line for returning a part of gas exhausted from the first vacuum pump to the vacuum chamber. The recirculation flow rate Q.sub.2 of the gas returning to the vacuum chamber through the gas recirculation line is controlled by adjusting the differential pressure Pd-Pc in the gas recirculation line by varying the effective pumping speed of the second vacuum pump using the following relationship: Q.sub.2 =C.times.(Pd-Pc) where: Q.sub.2 denotes the recirculation flow rate of the gas returning to the vacuum chamber through the gas recirculation line; Pc denotes the pressure in the vacuum chamber; Pd denotes the pressure in the upstream side of the gas recirculation line; and C denotes the conductance of the gas recirculation line.
First Claim
Family
International Classification(s)
- [Classification Symbol]
- [Patents Count]
Cited Art Landscape
Patent Citation Ranking
Advertisement
Advertisement
Advertisement
Recipient Email Address
Recipient Email Address
Comment
Recipient Email Address
Add to Portfolio(s)
To add this patent to one, or more, of your portfolios, simply click the add button.
This Patent is in these Portfolios:
Add to additional portfolios:
Last Refreshed On:
Changes done successfully