CC Cryostat Vacuum Pumping Efficiency [electronic resource].
- Published
- Washington, D.C. : United States. Dept. of Energy. Office of Science, 1987.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy. - Physical Description
- 22 pages : digital, PDF file
- Additional Creators
- Fermi National Accelerator Laboratory, United States. Department of Energy. Office of Science, and United States. Department of Energy. Office of Scientific and Technical Information
Access Online
- Restrictions on Access
- Free-to-read Unrestricted online access
- Summary
- This report calculates the effect of the conductances of the pumping lines on the pumping speeds of the vacuum pumps being used to pump the inner vessel, and annular space, vacuum tight during the CC Cryostat testing. Effective pumping speeds were calculated for various values of pressure via the above stated formulas (see calculations). Conductances of valves, elbows, and tees were calculated with the help of ref. 1, and the volumes of the inner vessel and annular space were calculated wtth the aid of ref. 2. The major results of these calculations follow. The attached graphs show the effective pumping speed vs. pressure, as well as the pressure vs. pumpdown time for both the inner vessel pumpdown and the annular space pumpdown. Many intervals of pressure were chosen in order to give a complete picture of the effects on the pumping speed, and pumpdown time. An important rule of thumb is that the effective pumping speed be close to the intrinsic pump speed in the region of interest for the best efficiency. With an infinite conductance, these quantities become equal. In the case of the annular space pumpdown. the effective pumping speed is within approximately 15% of the intrinsic pump speed for pressures down to 6000μ, and at that point, the conductance effects slow the system down and provide a 49% difference at 1000μ. To Improve these numbers, the line length must be shortened, or even better, the line diameter increased. As far as pumpdown time is concerned, the actual pumpdown was completed in a reasonable amount of time, and would have been even better if the pumping system did not lag due to a leaK and its repair time. The inner vessel pumpdown shows a pumpdown time near 1 hour to reach 100μ pressure. The effective pumping speed matches to within 10% of the intrinsic pump speed to 6000μ, and then the conductance effects become more important and provide a 41% difference at 1000μ. The actual pumpdown was completed in a reasonable amount of time which demonstrates that the pump used was in fact adequate for this application.
- Report Numbers
- E 1.99:fermilab-d0-en-117
fermilab-d0-en-117 - Subject(s)
- Other Subject(s)
- Note
- Published through SciTech Connect.
10/13/1987.
"fermilab-d0-en-117"
Fitzpatrick, J.B. - Funding Information
- AC02-07CH11359
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