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 904ô replaced the popular NASH CL pump in the 1980's.
This 904ô 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

an introduction to gas removal systems and liquid ring vacuum pumps
Next to ejectors, Liquid-Ring Vacuum Pumps (LRVP) are the most used vacuum-producing devices in industry. Integration of Liquid-Ring Vacuum Pumps with Steam Jet Ejectors, commonly referred to as a hybrid system, is one of the more efficient methods of producing process vacuum. The LRVP is a specific form of rotary positive-displacement pump utilizing liquid as the principal element in gas compression.
The compression is performed by a ring of liquid formed as a result of the relative eccentricity between the pumpís casing and a rotating multi-bladed impeller. The eccentricity results in near complete filling then partial emptying of each rotor chamber during every revolution. The filing-and-emptying action creates a piston action within each set of rotor of impeller blades.
The pumpís components are positioned in such a manner as to admit gas when the rotor chamber is emptying the liquid, and then to allow the gas to discharge once compression is completed. Sealing areas between the inlet and discharge ports are provided, to close the rotor areas, and to separate the inlet and discharge flows.