Application

Vacuum pumps for vacuum drying

In vacuum drying, water or solvent is removed from the material at reduced pressure: under vacuum, moisture evaporates at a low temperature, according to Becker from 20ā€“40 Ā°C. For this, Leybold names less energy, shorter time and gentler drying, Busch and Elmo Rietschle days instead of weeks for wood. Below you can see how the application works, what vacuum the manufacturers name and which of their series are intended for it ā€“ 632 models from 7 manufacturers.

Compare 632 modelsHow it works

  • 632Models
  • 52Series
  • 7Manufacturers
  • above 1 hPatypical process pressure for evaporation and drying (Busch)
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Touch the points: each part of the system explains itself.

In short

Vacuum drying: the key facts

  • Low temperatureUnder vacuum, water evaporates at a low temperature ā€“ for powders, spices and fruit, Becker names evaporation from 20ā€“40 Ā°C, Leybold less energy, shorter time and gentler drying.
  • Days instead of weeksFor wood drying, Busch names a reduction from weeks to a few days, Elmo Rietschle days instead of weeks ā€“ both through drying at a lower temperature.
  • Pressure rangeFor evaporation and drying in the pharmaceutical industry, Busch names typically above 1 hPa; for vacuum drying, Leybold lists screw vacuum pumps down to below 0.1 mbar, Elmo Rietschle the S-VSI 300 with 0.1 mbar abs.
  • Water vapourFor vacuum drying, Elmo Rietschle names rotary vane versions with high water vapour tolerance (V-VC 40ā€“150, 40ā€“180 mĀ³/h); according to Leybold, moisture and the solvent NMP are removed from electrodes, according to Busch, moisture and solvents are removed gently from slurry.
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  • Air and gas (vacuum)
  • Exhaust

Operating principle

How it works: Vacuum drying

The drawing shows the basic principle in section. The systems and pumps of the individual manufacturers differ in detail.

  1. LoadingThe material to be dried goes into the vessel or drying cabinet; depending on the process, it is heated. For electrode drying, Leybold names 12ā€“30 h per batch, Atlas Copco batch or continuous drying.
  2. EvacuationThe vacuum pump lowers the pressure. As the pressure falls, so does the boiling point: according to Becker, water evaporates from 20ā€“40 Ā°C; Atlas Copco names evaporation at low temperature.
  3. CondensationThe vapour is drawn off and condensed in the condenser, and the pump removes the residual gases. Drying ends when the material has reached the desired residual moisture.

Vacuum and sizing

Vacuum drying: how much vacuum is needed

What the manufacturers say about pressure, pumping speed and sizing.

Which vacuum

For evaporation and drying in the pharmaceutical industry, Busch names typically above 1 hPa. For vacuum drying, Leybold names screw vacuum pumps down to below 0.1 mbar, Elmo Rietschle the S-VSI 300 with 0.1 mbar abs. The process determines the pressure: the lower the pressure, the lower the temperature at which water evaporates.

Pumping speed and time

For vacuum drying, Elmo Rietschle names the V-VC 40ā€“150 with 40ā€“180 mĀ³/h and, for short evacuation times, the S-VSI 300 with up to 380 mĀ³/h. For the vacuum drying of electrodes, Leybold states 12ā€“30 h per batch; for wood, Busch names a few days instead of weeks and Elmo Rietschle days instead of weeks.

Vapours and solvents

The vapour from the material passes through the pump: Elmo Rietschle therefore names versions with high water vapour tolerance, Leybold the solvent NMP for electrodes, Atlas Copco solvents and moisture. For slurry, Busch names the gentle removal of moisture and solvents and, for active ingredients, protection against oxidation.

Temperature and energy

For drying at low temperature, Leybold names less energy, shorter time and a gentler process; Atlas Copco names lowering the boiling point for the gentle drying of active ingredients. Becker names evaporation from 20ā€“40 Ā°C.

Technology

Vacuum drying: the vacuum pumps the manufacturers name

Listed are the series the manufacturer itself names for this application. ā€œShow only ā€¦ā€ sets the filter of the product overview.

Product overview

Vacuum drying: all 632 models compared

Use the filters on the left to narrow the selection ā€“ by manufacturer, technology and the modelsā€™ key figures, for 50 or 60 Hz.

Atlas Copco AWC series 9 models

AWC 30Pumping speed 27 mĀ³/h 50 Hz32 mĀ³/h 60 HzUltimate pressure 33 mbarRated motor power 1.1 kW 50 Hz1.5 kW 60 HzVariants 6
AWC 50Pumping speed 52 mĀ³/h 50 Hz62 mĀ³/h 60 HzUltimate pressure 33 mbarRated motor power 1.5 kW 50 Hz2.4 kW 60 HzVariants 6
AWC 80Pumping speed 80 mĀ³/h 50 Hz96 mĀ³/h 60 HzUltimate pressure 33 mbarRated motor power 3 kW 50 Hz4 kW 60 HzVariants 6
AWC 110Pumping speed 110 mĀ³/h 50 Hz130 mĀ³/h 60 HzUltimate pressure 33 mbarRated motor power 3.85 ā€“ 4 kW 50 Hz6.3 kW 60 HzVariants 9
AWC 160Pumping speed 165 mĀ³/h 50 Hz185 mĀ³/h 60 HzUltimate pressure 33 mbarRated motor power 4 kW 50 Hz5.5 ā€“ 6.3 kW 60 HzVariants 15
AWC 220Pumping speed 230 mĀ³/h 50 Hz265 mĀ³/h 60 HzUltimate pressure 33 mbarRated motor power 5.5 kW 50 Hz7.5 ā€“ 8.2 kW 60 HzVariants 15
AWC 290Pumping speed 280 mĀ³/h 50 Hz310 mĀ³/h 60 HzUltimate pressure 33 mbarRated motor power 7.5 kW 50 Hz11 ā€“ 12.6 kW 60 HzVariants 15
AWC 390Pumping speed 400 mĀ³/h 50 Hz420 mĀ³/h 60 HzUltimate pressure 33 mbarRated motor power 11 kW 50 Hz15 ā€“ 16.5 kW 60 HzVariants 15
AWC 500Pumping speed 500 mĀ³/h 50 Hz535 mĀ³/h 60 HzUltimate pressure 33 mbarRated motor power 15 kW 50 Hz18.5 kW 60 HzVariants 15

Atlas Copco AWS series 22 models

AWS 180Pumping speed 168 mĀ³/h 50 Hz202 mĀ³/h 60 HzUltimate pressure 33 mbarRated motor power 5.5 kW 50 Hz7.5 kW 60 HzVariants 6
AWS 280Pumping speed 246 mĀ³/h 50 Hz290 mĀ³/h 60 HzUltimate pressure 33 mbarRated motor power 7.5 kW 50 Hz11 kW 60 HzVariants 6
AWS 360Pumping speed 340 mĀ³/h 50 Hz412 mĀ³/h 60 HzUltimate pressure 33 mbarRated motor power 11 kW 50 Hz15 kW 60 HzVariants 6
AWS 450Pumping speed 450 mĀ³/h 50 Hz535 mĀ³/h 60 HzUltimate pressure 33 mbarRated motor power 15 kW 50 Hz22 kW 60 HzVariants 8
AWS 600Pumping speed 600 mĀ³/h 50 Hz700 mĀ³/h 60 HzUltimate pressure 33 mbarRated motor power 18.5 kW 50 Hz30 kW 60 HzVariants 8
AWS 800Pumping speed 750 mĀ³/h 50 Hz888 mĀ³/h 60 HzUltimate pressure 33 mbarRated motor power 22 kW 50 Hz30 kW 60 HzVariants 8
AWS 1100Pumping speed 1,080 mĀ³/h 50 Hz1,320 mĀ³/h 60 HzUltimate pressure 33 mbarRated motor power 37 kW 50 Hz45 kW 60 HzVariants 8
AWS 1300Pumping speed 1,230 mĀ³/h 50 Hz1,452 mĀ³/h 60 HzUltimate pressure 33 mbarRated motor power 37 kW 50 Hz55 kW 60 HzVariants 8
AWS 1600Pumping speed 1,700 mĀ³/h 50 Hz2,000 mĀ³/h 60 HzUltimate pressure 33 mbarRated motor power 45 kW 50 Hz75 kW 60 HzVariants 8
AWS 2500Pumping speed 2,450 mĀ³/h 50 Hz2,780 mĀ³/h 60 HzUltimate pressure 33 mbarRated motor power 75 kW 50 Hz90 kW 60 HzVariants 8
AWS 3300Pumping speed 3,200 mĀ³/h 50 Hz3,840 mĀ³/h 60 HzUltimate pressure 33 mbarRated motor power 75 kW 50 Hz110 kW 60 HzVariants 8
AWS 3800Pumping speed 3,750 mĀ³/h 50 Hz4,520 mĀ³/h 60 HzUltimate pressure 33 mbarRated motor power 90 kW 50 Hz132 kW 60 HzVariants 8
AWS 5500Pumping speed 5,300 mĀ³/h 50 Hz5,850 mĀ³/h 60 HzUltimate pressure 33 mbarRated motor power 160 kW 50 Hz185 kW 60 HzVariants 8
AWS 6500Pumping speed 6,510 mĀ³/h 50 HzUltimate pressure 33 mbarRated motor power 169 kW 50 HzVariants 8
AWS 8000Pumping speed 8,100 mĀ³/h 50 HzUltimate pressure 33 mbarRated motor power 200 kW 50 HzVariants 8

Atlas Copco DBD series 6 models

Atlas Copco DBDt series 17 models

Atlas Copco DBS series 29 models

Atlas Copco DBSt series 12 models

Atlas Copco DRB series 4 models

Atlas Copco DWS VSD+ series 6 models

Atlas Copco GVD series 13 models

Atlas Copco LRP VSD+ series 3 models

Atlas Copco ZRS series 5 models

Becker RBP series 3 models

Becker SV series 16 models

Becker U4 series 6 models

Becker U series 8 models

Becker VADS series 3 models

Becker VASF series 6 models

Busch COBRA Industry series 36 models

Busch COBRA Semicon series 22 models

Busch DOLPHIN series 70 models

Busch HUCKEPACK series 4 models

Busch MINK series 32 models

Busch PANDA/PUMA series 26 models

Busch R5 series 58 models

Edwards E2S series 3 models

Edwards EOSi series 10 models

Edwards LR1A series 12 models

Edwards LR1C series 9 models

Edwards LR1D series 12 models

Elmo Rietschle S-SVT series 11 models

Elmo Rietschle S-VSI series 1 model

Elmo Rietschle V-KTR series 4 models

Elmo Rietschle V-VCA/VCE series 2 models

Elmo Rietschle V-VCB series 2 models

Elmo Rietschle V-VCS series 13 models

Elmo Rietschle V-VCX series 7 models

Elmo Rietschle V-VGD series 2 models

Elmo Rietschle V-VTN series 3 models

Elmo Rietschle V-VTR series 2 models

Leybold CLAWVAC series 5 models

Leybold DRYVAC series 9 models

Leybold NOVADRY series 4 models

Leybold RUVAC WA/WAU series 8 models

Leybold RUVAC WH/WHU series 7 models

Leybold RUVAC WS/WSU series 8 models

Leybold SCREWLINE series 2 models

Leybold SOGEVAC series 23 models

Leybold TRIVAC series 20 models

Pfeiffer Vacuum ACP series 4 models

Pfeiffer Vacuum DuoVane series 12 models

Pfeiffer Vacuum HiLobe series 17 models

Pfeiffer Vacuum HiScroll series 4 models

Model comparison

Models a manufacturer no longer carries in its current range are listed in its ā€œOutdated modelsā€ section.

Industries

Vacuum drying: where the manufacturers name it

The manufacturers list these uses on their own pages.

Battery manufacturing

According to Leybold, electrode vacuum drying removes moisture and the solvent NMP from electrode coils (12ā€“30 h per batch, families VARODRY, LEYVAC, DRYVAC and RUVAC); according to Atlas Copco, solvents and moisture are drawn off in batches or continuously; Busch names slurry drying with R5 and COBRA; Pfeiffer Vacuum names the application for the industry without describing it.

Industry page: Battery manufacturing ā†’

Chemicals

Atlas Copco names evaporation at low temperature, Busch drying and evaporation with COBRA, R5, DOLPHIN, MINK, PANDA/PUMA and HUCKEPACK; Edwards lists drying with screw, claw and liquid ring vacuum pumps (LR1A, LR1C, LR1D) and the series E2S and EOSi; Elmo Rietschle and Pfeiffer Vacuum name it without a description.

Industry page: Chemicals ā†’

Pharmaceuticals and biotechnology

Atlas Copco names tray, freeze and rotary drying with the GVD series and lowering the boiling point for the gentle drying of active ingredients, Busch typically above 1 hPa and the protection of active ingredients against oxidation; Pfeiffer Vacuum names vacuum drying for the industry without describing it.

Industry page: Pharmaceuticals and biotechnology ā†’

Woodworking

For wood drying, Busch names MINK and DOLPHIN and a reduction from weeks to a few days, Elmo Rietschle days instead of weeks; Leybold lists wood drying and impregnation with CLAWVAC and NOVADRY, Becker drying and impregnating in autoclaves.

Plastics and recycling

Busch names material drying with MINK and COBRA, Becker granulate drying by the circulating air method; Elmo Rietschle lists the drying of hygroscopic resins, Pfeiffer Vacuum vacuum drying, both without a description.

Industry page: Plastics and recycling ā†’

Mechanical engineering and manufacturing

Leybold names vacuum drying at low temperature with SOGEVAC, TRIVAC, DRYVAC, SCREWLINE and CLAWVAC (screw vacuum pumps down to below 0.1 mbar); Becker lists the evacuation of drying plants.

Industry page: Mechanical engineering and manufacturing ā†’

Oil and gas

Busch names pipeline drying with COBRA ā€“ vacuum lowers the boiling point of the water in the lines ā€“ and the removal of moisture from drilling mud; Edwards lists dehydration and pipeline drying without a description.

Industry page: Oil and gas ā†’

Packaging

Becker names the vacuum drying of powders, spices and fruit with VADS, for fruit U and U4 with RBP; water evaporates from as low as 20ā€“40 Ā°C.

Industry page: Packaging ā†’

Semiconductors, electronics and displays

Becker lists the vacuum drying of electronic components, Elmo Rietschle the drying of electronic components ā€“ both without a description.

Industry page: Semiconductors, electronics and displays ā†’

Construction

Becker names the drying of screed insulation layers with side channel blowers of the SV and VASF series: humid air is extracted and dry air blown in, also after water damage.

Industry page: Construction ā†’

Medical and healthcare

Atlas Copco names the vacuum drying and degassing of plastics, adhesives and coatings, for example for catheters and tubes.

Industry page: Medical and healthcare ā†’

Hydrogen and fuel cells

Leybold names the VPSA drying of hydrogen with the SCREWLINE series: the sorbents are regenerated cyclically under vacuum.

Industry page: Hydrogen and fuel cells ā†’

Textiles

Elmo Rietschle names the dewatering and drying of dyed carpets with vacuum pumps on suction rolls.

Industry page: Textiles ā†’

Research, laboratory and analytics

Busch names vacuum drying in analytics and the laboratory with the COBRA Industry series.

Industry page: Research, laboratory and analytics ā†’

Refrigeration and air conditioning

Busch and Pfeiffer Vacuum also name vacuum drying for refrigeration and air conditioning, without describing the process there.

Industry page: Refrigeration and air conditioning ā†’

Beverages and bottling

Under food and beverages, Elmo Rietschle lists the drying of ham without describing it.

Industry page: Beverages and bottling ā†’

Frequently asked questions

Vacuum drying: frequently asked questions

How does vacuum drying work?

The material to be dried lies in a vessel whose pressure is lowered by a vacuum pump. As the pressure falls, so does the boiling point: according to Busch, moisture evaporates under vacuum at a low temperature; Becker names evaporation from 20ā€“40 Ā°C. The vapour is condensed in the condenser, and the pump removes the residual gases. For this, Leybold names less energy, shorter time and gentler drying.

How much vacuum does vacuum drying need?

That depends on the material and the permissible temperature. For evaporation and drying in the pharmaceutical industry, Busch names typically above 1 hPa, i.e. above 1 mbar. For vacuum drying, Leybold lists screw vacuum pumps down to below 0.1 mbar, Elmo Rietschle the S-VSI 300 with 0.1 mbar abs.

Which vacuum pump is suitable for vacuum drying?

The manufacturers name pumps of many designs: Leybold the oil-lubricated rotary vane vacuum pumps SOGEVAC and TRIVAC, the screw vacuum pumps DRYVAC and SCREWLINE and the claw vacuum pump CLAWVAC; Busch R5, COBRA, MINK, DOLPHIN, PANDA/PUMA and HUCKEPACK; Pfeiffer Vacuum DuoVane, HiScroll, ACP and HiLobe; Atlas Copco GVD, DWS VSD+, DRB, ZRS, AWC, AWS and LRP VSD+; Edwards E2S, EOSi and the series LR1A, LR1C and LR1D; Elmo Rietschle V-VC versions with high water vapour tolerance as well as the S-VSI 300. The choice depends on pressure, vapour quantity and solvents.

Oil-free or oil-lubricated for vacuum drying?

Both are named. Leybold lists oil-lubricated rotary vane vacuum pumps (SOGEVAC, TRIVAC) alongside dry screw vacuum pumps (DRYVAC, SCREWLINE) and the claw vacuum pump CLAWVAC; Busch the oil-lubricated R5 alongside the dry COBRA and MINK and the liquid ring vacuum pump DOLPHIN. For electrodes with the solvent NMP, Leybold names the families VARODRY, LEYVAC, DRYVAC and RUVAC. Where there is a lot of water vapour, Elmo Rietschle names rotary vane versions with high water vapour tolerance.

Why does wood dry faster under vacuum?

Because water evaporates at a lower temperature when the pressure is lower. For wood drying, Busch names drying at a lower temperature and a reduction from weeks to a few days, Elmo Rietschle days instead of weeks. Busch names the MINK and DOLPHIN series for this, Leybold lists wood drying and impregnation with CLAWVAC and NOVADRY.

How are battery electrodes vacuum-dried?

According to Leybold, electrode vacuum drying removes moisture and the solvent NMP from electrode coils; Leybold names 12ā€“30 h per batch with the families VARODRY, LEYVAC, DRYVAC and RUVAC. According to Atlas Copco, solvents and moisture are drawn off in batches or continuously. Busch names slurry drying with R5 RA and COBRA NC/NX, in which moisture and solvents are removed gently.

What if water vapour gets into the vacuum pump?

A condenser upstream of the pump condenses most of the vapour. For the rest, Elmo Rietschle names rotary vane versions with high water vapour tolerance for vacuum drying (V-VC 40ā€“150, 40ā€“180 mĀ³/h). Busch also names the liquid ring vacuum pump DOLPHIN for drying, Atlas Copco the liquid ring series AWC, AWS and LRP VSD+.

At what temperature is material dried under vacuum?

For powders, spices and fruit, Becker names evaporation from 20ā€“40 Ā°C. Atlas Copco names lowering the boiling point for the gentle drying of active ingredients, Busch the protection of active ingredients against oxidation. The temperature results from the pressure: the deeper the vacuum, the lower the evaporation temperature.

Which vacuum pump for drying granulate?

Becker names granulate drying by the circulating air method, in which circulating air dries the granulate. Busch names material drying in the plastics industry with MINK and COBRA. Elmo Rietschle lists the drying of hygroscopic resins without naming a series.

How are pipelines dried with vacuum?

Busch describes pipeline drying with the COBRA Industry series: the vacuum lowers the boiling point of the water in the lines so that it evaporates and is extracted. Edwards lists dehydration and pipeline drying for oil and gas without describing them.

A single pump or a central vacuum system?

A central system in a room of its own keeps noise and heat away from production and matches its output to the demand. Central vacuum systems are planned and built by Eugen Theis Vakuum, a company of the Ehrler & Beck group ā€“ more under Central Vacuum.

Does Ehrler & Beck also supply spare parts and service?

Yes. Ehrler & Beck offers original spare parts and accessories as well as maintenance and repair.

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