Description
11
GA03108_002_C1 - 04/2018 - © Leybold
1 Description
1.1 Design and Function
The RUVAC WS and RUVAC WSU are Roots pumps driven by a canned
motor.
The WSU types have a pressure balance line between the discharge and
intake flanges.
The RUVAC WS and WSU are lubricated with mineral oil, synthetic oil or per-
fluorized polyether (PFPE) in the case of the PFPE models. Apart from the
lubricant the mineral oil and PFPE models are identical in type.
Only the RUVAC WS/WSU PFPE can be used for pumping greater than
atmospheric concentrations of oxygen or very aggressive or hazardous
gases.
1.1.1 Principle of Operation
Roots pumps - also known as Roots blowers - contain in their pump casing
(1.1/3) two symmetrical impellers (1.1/4) rotating in opposite directions. The
impellers have roughly the cross section of a figure “8” and are synchronised
by a toothed gear so that they move past each other and the casing without
contact but with a small clearance.
The principle of operation is explained in fig. 1.2.
Fig. 1.2 Functional diagram of a Roots pump (vertical flow)
Fig. 1.1 Schematic cross-section of a Roots pump (vertical flow)
1
2
3
4
5
1 Intake flange
2 Pumping chamber
3 Casing
4 Impeller
5 Discharge flange
