liquid ring vacuum pumps


- tolerate entrained liquids and solids
- isothermal compression (for monomer recovery, explosive gases),
- oilfree,
- very safe for explosive gases,
- simple design for corrosion resistant materials,

- high power absorbed,
- process fluid and auxiliary fluid are mixed-up / contaminated

suction capacity: 10m³/h to 30.000m³/h

vacuum: down to 30 mbarA

liquid ring vacuum pump - principle How it works:

two-stage liquid ring vacuum pump
two-stage liquid ring vacuum pump, flat sided (axial distribution) (Travaini)

single stage liquid ring vacuum pump
single stage liquid ring vacuum pump, radial distribution (Alstom, Bell,...)

NASH 904

NASH 904 Vacuum Pump.
The NASH 904 replaced the popular NASH CL pump in the 1980's.
This 904 pump can be found in major industries, including Paper, Chemical, and Mining.

double lobe liquid ring vacuum pump
double lobe:
2 complete cycles (inlet, compression, discharge) for each revolution.

FAQ's - liquid ring vacuum pumps

liquid ring vacuum pumps manufacturers

Books about liquid ring technology

Liquid ring patents

more vacuum ?
- use a colder liquid ring
- use a sealant with a lower partial vapour pressure

using water at 15°C as sealant (Partial Vapour Pressure = 17 mbar), the end vacuum will be around 25 mbar.
with water at 35°C (PVP = 57 mbar), the end vacuum will be around 70 mbar.
with ethylenglykol at 80°C (PVP=1 mbar), the end vacuum will be around 10 mbar.

higher compression ratio ?
for example if discharge pressure higher than atm. pressure.
- increase tip speed, increase speed of rotation
- use a double lobe pump, the ring will be more stable
- use a two-stage pump, for less shaft deflection