Edwards
The Edwards XDS 35 i is a dry scroll vacuum pump. The Edwards XDS 35 i has a peak pumping speed of 35 m3/h. The Edwards XDS 35 i has a nominal rotation speed of 1750 rpm.[1][2]

The XDS 35 i has a peak pumping speed of 35 m³/h (21 cfm) and an ultimate total pressure of 0.01 mbar (0.008 Torr) without gas ballast. The pump weighs 48 kg (105 lb) and operates at a nominal rotation speed of 1750 rpm. The XDS 35 i is available in multiple variants including a standard version, a version with no gas ballast (NGB), a corrosion-resistant version with Chemraz valves and stainless steel fittings (C), and Enhanced versions (E) with bypass valves for improved roughing performance.[1][4]
The XDS 35 i uses a single-sided scroll design with one fixed and one orbiting spiral. The orbiting scroll compresses gas in crescent-shaped pockets from the outer periphery toward the center, where it exits through the exhaust port. The bearings are isolated from the process gas by a bearing shield, ensuring that the pump is truly dry and that no hydrocarbon lubricant can contaminate the vacuum.[1][5]
A smart motor drive provides consistent global performance, pump overload protection, and remote start/stop capability. The pump includes an adjustable gas ballast that allows pumping of condensable vapors, including water vapor up to 240 g/h. The Enhanced variants incorporate bypass valves that reduce peak power consumption by up to 20% during initial pump-down and provide up to 25% more pumping speed at roughing pressures.[1]
The XDS 35 i is used as a roughing or backing pump for high-vacuum systems such as turbomolecular pumps, diffusion pumps, and cryopumps. In semiconductor and analytical instrumentation, it provides the primary vacuum stage to evacuate chambers from atmospheric pressure to the medium-vacuum range, after which a secondary pump achieves high or ultrahigh vacuum.
Additional application areas include cryogenics, degassing and curing of oil and epoxy resin, distillation and extraction/filtration, laboratory bench-top vacuum, lasers (gas recovery and recirculation), and surface science instruments. The adjustable gas ballast enables handling of condensable vapors, broadening the range of compatible processes.[1][4]
Documented failure modes, common issues, and field considerations.
| Designation | Generation | Vintage | Changes | Source |
|---|---|---|---|---|
| XDS35i Enhanced | — | — | Uses bypass valves, has up to 20% lower peak power requirements during initial pump down, has up to 25% more pumping speed at roughing pressures, and is not limited for continuous full-speed pump down. | edwardsvacuum.com[1] |
| XDS35i NGB | — | — | No gas ballast version. | edwardsvacuum.com[1] |
| XDS35iC | — | — | Features Chemraz internal valves and stainless steel fittings. | edwardsvacuum.com[1] |
| XDS35iE | — | — | Enhanced version. | edwardsvacuum.com[1] |
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The ultimate total pressure without gas ballast is 0.01 mbar (0.008 Torr).[1][4]
The following facts about the XDS 35 i are absent from this record as of this revision. First-hand knowledge or a citation closes a gap; every submission is reviewed before publication.
No publicly documented production dates or lifecycle milestones (introduction, end of production, EOL) for the XDS 35 i are on record.
Answerable by: OEM historical records or a trade-press announcement
The control-system platform and OS era of the XDS 35 i are not on record.
Answerable by: an engineer who operated it or OEM installation records
The process node or technology generation of the XDS 35 i is not on record.
Answerable by: an OEM datasheet or a fab qualification report
No publicly documented compatible parts, consumables, or accessories for the XDS 35 i are on record.
Answerable by: an OEM parts catalog or a service engineer
No publicly hosted manuals, SOPs, or datasheets for the XDS 35 i are on record.
Answerable by: university cleanroom staff or an OEM application specialist
Last updated Oct 5, 2026.