Technology
Screw vacuum pumps
Two counter-rotating screw rotors convey the gas through the pump without contact ā dry-running or with oil injection. 163 current models from 6 manufacturers ā comparable by pumping speed, ultimate pressure and rated motor power.
Compare 163 modelsHow the technology works
- 163models
- 19series
- 6manufacturers
- 1 Ć 10ā»Ā³ mbarlowest ultimate pressure
Touch the points: the parts explain themselves.
Manufacturers and series
6 manufacturers, 19 series
Each series leads to its page with all models. āShow only ā¦ā sets the filter of the product overview.
Atlas Copco
38 models Ā· 160ā5,136 mĀ³/h
Becker
2 models Ā· 290ā1,380 mĀ³/h
Busch
58 models Ā· 70ā7,385 mĀ³/h
Edwards
35 models Ā· 160ā5,760 mĀ³/h
Elmo Rietschle
12 models Ā· 300ā5,740 mĀ³/h
Leybold
18 models Ā· 63ā1,600 mĀ³/h
Product overview
Compare all 163 models
The filters on the left narrow down the selection by the key figures of the models ā for 50 or 60 Hz.
Atlas Copco DHS VSD+ series 1 model
Atlas Copco DWS C series 7 models
Atlas Copco DWS series 3 models
Atlas Copco DWS VSD+ series 6 models
Atlas Copco GHS VSD+ series 21 models
GHS 350 VSD+Pumping speed 400 mĀ³/h 50 Hz400 mĀ³/h 60 HzUltimate pressure 0.35 mbarRated motor power 5.5 kW 50 Hz5.5 kW 60 HzVariants 29Becker VADS series 2 models
Busch COBRA Industry series 36 models
Busch COBRA Semicon series 22 models
Edwards EDS series 3 models
Edwards EOSi series 10 models
Edwards EXS series 11 models
Edwards GXS series 10 models
Edwards IDX series 1 model
Elmo Rietschle S-SVT series 11 models
Elmo Rietschle S-VSI series 1 model
Leybold DRYVAC series 9 models
Leybold DURADRY series 3 models
Leybold NOVADRY series 4 models
Leybold SCREWLINE series 2 models
No model matches these filters.
Atlas Copco DHS VSD+ series 1 model
Atlas Copco DWS C series 7 models
Atlas Copco DWS series 3 models
Atlas Copco DWS VSD+ series 6 models
Atlas Copco GHS VSD+ series 21 models
Becker VADS series 2 models
Busch COBRA Industry series 36 models
Busch COBRA Semicon series 22 models
Edwards EDS series 3 models
Edwards EOSi series 10 models
Edwards EXS series 11 models
Edwards GXS series 10 models
Edwards IDX series 1 model
Elmo Rietschle S-SVT series 11 models
Elmo Rietschle S-VSI series 1 model
Leybold DRYVAC series 9 models
Leybold DURADRY series 3 models
Leybold NOVADRY series 4 models
Leybold SCREWLINE series 2 models
Models that a manufacturer no longer carries in its current range are not part of this overview; they are listed in its āOutdated modelsā section ā for example under outdated Leybold models.
Operating principle
How a screw vacuum pump works
In the pump housing, two parallel, screw-shaped rotors turn in opposite directions ā without contact and with very narrow gaps; a gearbox synchronises them. Between the threads and the housing, chambers form that transport the gas axially from the inlet connection to the discharge connection.
The drawing shows the basic principle. The designs of the individual manufacturers differ in detail.
- SuctionThe chamber connected to the inlet connection (A) grows as the screws turn and fills with gas.
- TransportThe chambers (C) travel axially to the discharge side between the rotors (B) and the housing (D).
- Compression and dischargeOn the discharge side the chamber shrinks until the discharge channel opens and the gas is discharged through the discharge connection (F).
Key figures
The technology in figures
The ranges result from the current models in our range.
Pumping speed (50 Hz)
63 to 7,385 mĀ³/hin our range
Ultimate pressure
1 Ć 10ā»Ā³ to 350 mbarin our range
Rated motor power (50 Hz)
1.5 to 90 kWin our range
Ultimate pressure compared (mbar, logarithmic)
For comparison: the oil-lubricated rotary vane vacuum pumps in our range reach 1 Ć 10ā»Ā³ to 20 mbar.
What characterises the technology
Dry or with oil
In dry-running screw vacuum pumps the compression chamber is oil-free. Oil-injected series such as the GHS VSD+, by contrast, work with oil in the compression chamber.
Contact-free
The rotors touch neither each other nor the housing; the narrow gaps provide the seal.
Cooling
Depending on the manufacturer and size, cooling is provided by water chambers in the housing, by additional cooling gas or in a similar way.
Speed control
In series with an integrated frequency converter, the pumping speed adapts to the actual demand.
Advantages
What speaks for this technology
- Oil-free compression chamber in dry-running series
- Low ultimate pressures in a single stage
- Good water vapour tolerance
- Insensitive to liquid slugs
- Short evacuation times
- Long service life, low maintenance
- Versions suitable for flushing and CIP
- Low noise level
Applications
Where they work
- Chemical industrydrying, distillation, rectification, evaporation, degassing, cooling
- General industryextraction systems, drying, coating, cleaning, industrial furnaces
- Surface technology and electronicsvacuum metallurgy
- Packagingfood processing and packaging, central vacuum systems
- Pneumatic conveyingcentral vacuum systems
- Research and laboratory
Frequently asked questions
Questions about screw vacuum pumps
How does a screw vacuum pump work?
Two screw-shaped rotors turn in opposite directions and without contact in the housing. Between their threads and the housing, chambers form that transport the gas from the inlet connection to the discharge side and compress it there. The drawing in the section Operating principle shows every step.
Are screw vacuum pumps oil-free?
Dry-running screw vacuum pumps have an oil-free compression chamber. Oil-injected series such as the GHS VSD+ from Atlas Copco, by contrast, work with oil in the compression chamber. The product page of a model states which design it has.
What ultimate pressure do screw vacuum pumps reach?
The models in our range state ultimate pressures from 1 Ć 10ā»Ā³ to 350 mbar ā depending on the series and design. In the product overview, the āUltimate pressureā filter narrows down the selection.
From which manufacturers does Ehrler & Beck carry this technology?
Currently from Atlas Copco, Becker, Busch, Edwards, Elmo Rietschle and Leybold. The series are listed in the section Manufacturers and series.
How do I find the right model?
In the product overview, the filters narrow down the selection by the key figures of the models. For sizing, it is best to tell us the gas to be conveyed, the working pressure and the flow rate you need ā we will be glad to advise you.
What do the figures for 50 Hz and 60 Hz mean?
Flow rate and rated motor power depend on the mains frequency. The overview therefore shows both values wherever the manufacturer states them, and the size filters can be switched between 50 Hz and 60 Hz.
Does Ehrler & Beck also supply spare parts and service?
Yes. Ehrler & Beck offers original spare parts and accessories as well as maintenance and repair.
Which model fits your process?
Tell us the gas to be conveyed, the working pressure and the flow rate you need ā we will advise you on selection, spare parts and service.
