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Characteristic<br />
Pure turbo stages<br />
Turbo stages and<br />
drag stages<br />
(Holweck)<br />
www.pfeiffer-vacuum.net<br />
Table 2.14: Comparison between turbopumps and turbo drag pumps<br />
Advantages<br />
2.8.3.2 Magnetic-levitation turbopumps<br />
With their high pumping speeds of over 1,500 l / s, magnetic-levitation turbopumps require<br />
large backing pumps. Since diaphragm pumps with base pressures of over 1 mbar are out of<br />
the question, these turbopumps are not equipped with Holweck stages. These pumps, too,<br />
are available as:<br />
Classical HiPace turbopumps offering pumping speeds of over 2,000 l / s with ISO-K<br />
flanges to generate high vacuum for standard applications, or<br />
with bakeable CF flanges to generate ultra high vacuum<br />
Classical HiPace C turbopumps with coating and sealing gas system for<br />
corrosive gas applications<br />
Insensitive to particulate matter,<br />
dust and condensates<br />
High gas loads possible<br />
Robust / High flood rates possible<br />
Higher compressions<br />
Higher backing vacuum tolerance<br />
Smaller backing pump with base<br />
pressure > 1 mbar can be used<br />
Figure 2.25: HiPace MC magnetic-levitation turbopump<br />
Disadvantages<br />
Lower compressions<br />
Lower backing vacuum tolerance<br />
Larger backing pump with base<br />
pressure < 0.1 mbar required<br />
Sensitive to particulate matter,<br />
dust and condensates<br />
Lower gas loads (narrow gap)<br />
Page 67<br />
<strong>Vacuum</strong><br />
<strong>Technology</strong>
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