Application
Vacuum pumps for steel degassing
In steel degassing, the ladle with liquid steel stands in a vacuum vessel: according to Leybold, the vacuum removes carbon, hydrogen, oxygen and nitrogen from the liquid steel – as vacuum degassing (VD), vacuum oxygen decarburisation (VOD) or the RH process with circulating melt. Leybold names mechanical pumping systems instead of steam ejectors for this. Below you can see how the application works, what vacuum the manufacturers name and which of their series are intended for it – 194 models from 4 manufacturers.
Compare 194 modelsHow it works
- 194Models
- 11Series
- 4Manufacturers
- 0.67–1.33 mbarVacuum degassing VD (Leybold)
Touch the points: each part of the system explains itself.
In short
Steel degassing: the key facts
- Three processesLeybold describes vacuum degassing (VD) with the ladle in the degasser, vacuum oxygen decarburisation (VOD), in which oxygen is added to the melt and CO/CO₂ is pumped off, and the RH process (Ruhrstahl-Heraeus), in which the steel circulates through the degassing chamber.
- VD pressureLeybold names 1.33–0.67 mbar in the degassing chamber for vacuum degassing (VD).
- VOD pressureLeybold names 50–200 mbar for vacuum oxygen decarburisation (VOD).
- Instead of ejectorsEdwards names up to 97 % lower energy costs compared with ejectors and, for VD, VOD and RH, the GXS, IDX, EXS, EH and GMB series; Leybold names DRYVAC DV 1200–1600 with RUVAC WH 7000.
Operating principle
How it works: Steel degassing
The drawing shows the basic principle in section. The systems and pumps of the individual manufacturers differ in detail.
- ChargingThe ladle with liquid steel is placed in the degasser (VD) or connected to the degassing chamber through which the steel circulates (RH) – this is how Leybold describes it.
- EvacuatingThe pumping station lowers the pressure in the degasser; Leybold names 1.33–0.67 mbar for vacuum degassing and 50–200 mbar for oxygen decarburisation.
- DegassingUnder vacuum, hydrogen, nitrogen and oxygen leave the melt; in the VOD process, oxygen is added to the melt and the resulting CO/CO₂ is pumped off (Leybold).
Vacuum and sizing
Steel degassing: how much vacuum is needed
What the manufacturers say about pressure, pumping speed and sizing.
What vacuum
Leybold names 1.33–0.67 mbar for vacuum degassing (VD) and 50–200 mbar for vacuum oxygen decarburisation (VOD).
What pumping capacity
The pumping speed of the pumping station depends on the vessel volume, the gas load and the required evacuation time. As pumps, Leybold names DRYVAC DV 1200–1600 with RUVAC WH 7000, Edwards GXS, IDX, EXS, EH and GMB.
What determines the design
The process (VD, VOD, RH) and the gas load: decarburisation produces CO/CO₂ (Leybold), degassing produces hydrogen and nitrogen (Edwards). For steel degassing, Busch names COBRA and PANDA/PUMA, and in the product finder also DOLPHIN; Pfeiffer Vacuum names HiLobe.
What the manufacturers point out
The replacement of steam ejectors by mechanical pumping systems (Leybold) – Edwards names up to 97 % lower energy costs for this.
Technology
Steel degassing: the vacuum pumps the manufacturers name
Listed are the series the manufacturer itself names for this application. “Show only …” sets the filter of the product overview.
Liquid ring vacuum pumps
70 models · 25–16,160 m³/h
Screw vacuum pumps
67 models · 70–5,760 m³/h
Roots vacuum pumps
57 models · 250–44,300 m³/h
Product overview
Steel degassing: all 194 models compared
Use the filters on the left to narrow the selection – by manufacturer, technology and the models’ key figures, for 50 or 60 Hz.
Busch COBRA Industry series 36 models
COBRA NS 0070 CPumping speed 70 m³/h 50 Hz85 m³/h 60 HzUltimate pressure 0.03 mbarRated motor power 4 kW 50 Hz4.4 kW 60 HzVariants 
COBRA NC 0100 BPumping speed 110 m³/h 50 Hz130 m³/h 60 HzUltimate pressure 0.05 mbarRated motor power 3.5 kW 50 Hz4.8 kW 60 HzVariants 4
COBRA NC 0100 B ECOTORQUEPumping speed 130 m³/h 50 Hz130 m³/h 60 HzUltimate pressure 0.05 mbarRated motor power 4.8 kW 50 Hz4.8 kW 60 HzVariants 
COBRA NS 0160 CPumping speed 135 m³/h 50 Hz170 m³/h 60 HzUltimate pressure 0.03 mbarRated motor power 5.5 kW 50 Hz6.6 kW 60 HzVariants 
COBRA NC 0200 BPumping speed 220 m³/h 50 Hz265 m³/h 60 HzUltimate pressure 0.05 mbarRated motor power 6 kW 50 Hz7.6 kW 60 HzVariants 4
COBRA NC 0200 B ECOTORQUEPumping speed 265 m³/h 50 Hz265 m³/h 60 HzUltimate pressure 0.05 mbarRated motor power 7.6 kW 50 Hz7.6 kW 60 HzVariants 
COBRA NC 0300 BPumping speed 320 m³/h 50 Hz385 m³/h 60 HzUltimate pressure 0.05 mbarRated motor power 7.5 kW 50 Hz9.5 kW 60 HzVariants 4
COBRA NC 0400 BPumping speed 350 m³/h 50 Hz420 m³/h 60 HzUltimate pressure 0.05 mbarRated motor power 7.5 kW 50 Hz9.5 kW 60 HzVariants 
COBRA NX 0450 APumping speed 350 m³/h 50 Hz420 m³/h 60 HzUltimate pressure 0.1 mbarRated motor power 7.5 kW 50 Hz9.5 kW 60 HzVariants 
COBRA NC 0300 B ECOTORQUEPumping speed 385 m³/h 50 Hz385 m³/h 60 HzUltimate pressure 0.05 mbarRated motor power 9.5 kW 50 Hz9.5 kW 60 HzVariants 
COBRA NC 0400 B ECOTORQUEPumping speed 420 m³/h 50 Hz420 m³/h 60 HzUltimate pressure 0.05 mbarRated motor power 9.5 kW 50 Hz9.5 kW 60 HzVariants 
COBRA NX 0450 A ECOTORQUEPumping speed 420 m³/h 50 Hz420 m³/h 60 HzUltimate pressure 0.1 mbarRated motor power 11 kW 50 Hz11 kW 60 HzVariants 
COBRA NC 0500 BPumping speed 490 m³/h 50 Hz490 m³/h 60 HzUltimate pressure 0.01 mbarRated motor power 9 kW 50 Hz9 kW 60 HzVariants 
COBRA NC 0630 C VRPumping speed 580 m³/h 50 Hz680 m³/h 60 HzUltimate pressure 25 mbarRated motor power 22 kW 50 Hz22 kW 60 HzVariants 
COBRA NS 0600 CPumping speed 600 m³/h 50 Hz600 m³/h 60 HzUltimate pressure 0.01 mbarRated motor power 15 kW 50 Hz15 kW 60 HzVariants 
COBRA NC 0630 CPumping speed 630 m³/h 50 Hz630 m³/h 60 HzUltimate pressure 0.01 mbarRated motor power 15 kW 50 Hz17 kW 60 HzVariants 
COBRA NC 0630 C ECOTORQUEPumping speed 630 m³/h 50 Hz630 m³/h 60 HzUltimate pressure 0.01 mbarRated motor power 17 kW 50 Hz17 kW 60 HzVariants 
COBRA DX 0650 A PLUSPumping speed 650 m³/h 50 Hz650 m³/h 60 HzUltimate pressure 0.1 mbarRated motor power 15 kW 50 Hz15 kW 60 HzVariants 
COBRA NX 0650 APumping speed 650 m³/h 50 Hz650 m³/h 60 HzUltimate pressure 0.1 mbarRated motor power 12.5 kW 50 Hz15 kW 60 HzVariants 
COBRA NX 0650 A ECOTORQUEPumping speed 650 m³/h 50 Hz650 m³/h 60 HzUltimate pressure 0.1 mbarRated motor power 15 kW 50 Hz15 kW 60 HzVariants 
COBRA NF 0750 APumping speed 750 m³/h 50 Hz750 m³/h 60 HzUltimate pressure 0.05 mbarRated motor power 15 kW 50 Hz15 kW 60 HzVariants 
COBRA NC 1000 BPumping speed 840 m³/h 50 Hz1,000 m³/h 60 HzUltimate pressure 0.05 mbarRated motor power 22 kW 50 Hz25 kW 60 HzVariants 
COBRA DX 0950 A PLUSPumping speed 950 m³/h 50 Hz950 m³/h 60 HzUltimate pressure 0.01 mbarRated motor power 18.5 kW 50 Hz18.5 kW 60 HzVariants Busch DOLPHIN series 70 models
Busch PANDA/PUMA series 26 models
Edwards EH series 5 models
Edwards EXS series 11 models
Edwards GMB series 2 models
Edwards GXS series 10 models
Edwards IDX series 1 model
Leybold DRYVAC series 9 models
Leybold RUVAC WH/WHU series 7 models
Pfeiffer Vacuum HiLobe series 17 models
No model matches these filters.
Busch COBRA Industry series 36 models
Busch DOLPHIN series 70 models
Busch PANDA/PUMA series 26 models
Edwards EH series 5 models
Edwards EXS series 11 models
Edwards GMB series 2 models
Edwards GXS series 10 models
Edwards IDX series 1 model
Leybold DRYVAC series 9 models
Leybold RUVAC WH/WHU series 7 models
Pfeiffer Vacuum HiLobe series 17 models
Models a manufacturer no longer carries in its current range are listed in its “Outdated models” section.
Industries
Steel degassing: where the manufacturers name it
The manufacturers list these uses on their own pages.
Metallurgy and heat treatment
The manufacturers name steel degassing in metallurgy: Leybold and Edwards describe VD, VOD and RH, Busch and Pfeiffer Vacuum name their series for it without a description.
Frequently asked questions
Steel degassing: frequently asked questions
How does vacuum degassing of steel work?
The ladle with liquid steel stands in a degasser under vacuum; according to Leybold, the vacuum removes carbon, hydrogen, oxygen and nitrogen from the steel. Edwards names hydrogen and nitrogen from the melt and decarburisation with oxygen. The pumping station holds the pressure, and a dust separator protects the pumps.
What is the difference between VD, VOD and RH?
Leybold describes the three processes: in vacuum degassing (VD), the ladle stands in the degasser under vacuum. In vacuum oxygen decarburisation (VOD), oxygen is added to the melt and the resulting CO/CO₂ is pumped off. In the RH process (Ruhrstahl-Heraeus), the steel circulates through a degassing chamber.
How much vacuum does steel degassing need?
Leybold names 1.33–0.67 mbar for vacuum degassing (VD) and 50–200 mbar for vacuum oxygen decarburisation (VOD).
Which vacuum pump for steel degassing?
Leybold names mechanical pumping systems made up of DRYVAC DV 1200–1600 and RUVAC WH 7000. For VD, VOD and RH, Edwards names GXS, IDX, EXS, EH and GMB. Busch names COBRA and PANDA/PUMA, and in the product finder also DOLPHIN; Pfeiffer Vacuum HiLobe.
Why mechanical vacuum pumps instead of steam ejectors?
Leybold describes mechanical pumping systems as a replacement for steam ejectors in steel degassing. Edwards names up to 97 % lower energy costs compared with ejectors.
Which gases are removed from the steel?
According to Leybold, carbon, hydrogen, oxygen and nitrogen. Edwards names hydrogen and nitrogen from the melt as well as decarburisation with oxygen, in which, according to Leybold, CO and CO₂ are pumped off.
What happens in vacuum oxygen decarburisation (VOD)?
According to Leybold, oxygen is added to the melt; the carbon reacts with the oxygen to form CO and CO₂, which are pumped off at 50–200 mbar.
Does steel degassing need a Roots pump?
Leybold names the DRYVAC DV 1200–1600 screw vacuum pumps in combination with the RUVAC WH 7000 Roots pump. Alongside GXS, IDX and EXS, Edwards names the EH and GMB series, Pfeiffer Vacuum the HiLobe.
What can be done if the energy costs of the steam ejectors are too high?
Leybold and Edwards name mechanical pumping systems as the answer: Leybold DRYVAC with RUVAC WH 7000, Edwards GXS, IDX, EXS, EH and GMB with up to 97 % lower energy costs compared with ejectors.
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 – 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.
Which pump suits your process?
Tell us the application, the medium and the volume – we advise you on selection, spare parts and service.
