Liquid ring vacuum pump working principle

liquid ring vacuum pumps

advantages:

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

disadvantages:

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

How it works:

liquid ring vacuum pump - principle

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

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

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.

Manufacturers and suppliers

liquid ring vacuum pump manufacturers

possible applications of liquid ring pumps

industries using liquid ring pumps

how to reach more vacuum?

Use a colder liquid ring, or 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