Elmo Rietschle L-BV7 - Manual (Page 18)

610.48060.40.000 18 / 64 © Gardner Denver Deutschland GmbH
Description of Vacuum Pump/Compressor
5 Description of Vacuum Pump/Compressor
1
3
5
4
8
7
6
2
Fig. 3: Design and operation of liquid-ring
vacuum pumps/compressors (cross-section of
operating chamber)
1 Discharge
connection
2 Operating-liquid port
3 Inlet connection
4 Impeller
5 Housing
6 Discharge
port
7 Inlet port
8 Operating liquid
5.1 Design
The L-BV7 2BV7s are liquid-ring vacuum
pumps compressors. They consist of the
vacuum pump/the compressor itself and an
electric motor. For the detailed design, see
Fig. 3, Pg. 18.
The pumped gases/vapors are sucked via the
inlet connection (3) into the pump-motor unit
and pushed out via the discharge connection
(1).
The impeller (4) with the blades is located in
the cylindrical housing (5). The impeller is
arranged eccentrically relative to the housing.
In addition, the housing also contains the
operating liquid (8). This liquid is fed in via the
operating-liquid port (2) and output together
with the pumped gases/vapors via the
discharge connection (1).
5.2 Operating
method
When the impeller turns, the operating liquid is
put into motion and accelerated. This forms a
liquid ring that also rotates. Due to centrifugal
force, this ring is arranged concentrically to the
housing and eccentrically to the impeller.
During a complete rotation of the impeller, the
following occurs:
 The impeller cells are completely filled with
operating liquid at the upper vertex.
 During the first half rotation, the liquid ring
lifts off the impeller hub. The space in the
cells increases so that the pumped
gases/vapors are sucked in through the
inlet port (7).
 The space in the cells is largest at the lower
vertex, as these are virtually free of
operating liquid.
 During the second half rotation, the liquid
ring approaches the hub again. The space
in the cells decreases so that the pumped
gases/vapors are compressed and pushed
out through the discharge port (6).