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Welch™ Direct-Drive High-Vacuum Pumps: Model 8905

Compact, portable, two-stage direct-drive pumps suitable for vacuum ovens, freeze dryers, concentrators, and chambers

Manufacturer:  Welch™ 8905A

Catalog No. 01-115-4

This item has been discontinued by the manufacturer and is no longer available. Please call customer service for assistance: 1-800-766-7000. View substitute products »

Includes: Line cord, switch, plug and vacuum Oil, 3/4-20 outlet connector thread



All models are an efficient two-stage design for continuous high vacuum operation. Use gas ballast valve to prevent condensation of vapors and to remove water vapor contamination from oil reservoir. Not for continuous operation at pressures above 10 torr.

  • Available in pumping ranges of 1.8 to 11.3cfm (51 to 320L/min.)
  • Ultimate pressure to 1 × 10-4 torr (based on model)
  • Aluminum UNIBARB™ style inlet connector accepts two sets of tubing I.D. (3/16 to 13/16 in. [5 to 20mm]) and has a screen
  • Outlet connector has a 1-20 thread (Model 8905A has a 3/4-20 outlet connector thread)


115V models are CSA certified; 230V models are available online or contact your Fisher Scientific™ Customer Service Rep



115 V
0.25 hp
11.8 kg
Line cord, switch, plug and vacuum Oil, 3/4-20 outlet connector thread
14.12 x 5.12 x 8.37 in. (35.9 x 13 x 21.3 cm)
52 dB (A)
11.1 kg
Vacuum ovens, freeze dryers, concentrators and chambers
8.4 in.
14.12 in.
5.12 in.
Direct-Drive High-Vacuum Pump
2 x 10-3 torr
26 lb.
3.8 A
3450 rpm
115 V 60 Hz
24.5 lb.
1.8 CFM
60 Hz
21.3 cm
35.9 cm
13 cm
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