10
GA01208_002_C0 - 11/2016 - © Leybold
Description
1.1 Function
The rotor (2/7), mounted eccentrically in the pump housing (2/6), has two
radially sliding vanes (2/5) which divide the pump chamber into several
compartments. The volume of each compartment changes periodically with
the rotation of the rotor.
As a result, gas is sucked in at the intake port (2/1). The gas passes through
the dirt trap sieve (2/2), flows past the open anti-suckback valve (2/3) and
then enters the pump chamber. In the pump chamber, the gas is passed on
and compressed, after the inlet aperture is closed by the vane.
The oil injected into the pump chamber is used for sealing and lubricating.
The slap noise of the oil in the pump which usually occurs when attaining the
ultimate pressure is prevented by admitting a very small amount of air into
the pump chamber.
The compressed gas in the pump chamber is ejected through the exhaust
valve (2/10). The oil entrained in the gas is coarsely trapped in the internal
demister (2/11); there the oil is also freed of mechanical impurities. The gas
leaves the TRIVAC-B-DOT through the exhaust port.
During compression, a controlled amount of air – the so-called gas ballast –
can be allowed to enter the pump chamber by opening the gas ballast valve.
The gas ballast stops condensation of vapours in the pump chamber up to
the limit of the water vapour tolerance as specified in the technical data for
the pump.
Fig. 2 Schnitt durch eine TRIVAC-B-DOT
1 Intake port
2 Dirt trap
3 Anti-suckback valve
4 Intake channel
5 Vanes
6 Pump chamber
7 Rotor
8 Cover plate, connection for inert gas ballast
9 Exhaust channel
10 Exhaust valve
11 Internal demister
12 Spring buckles
13 Cover plate, connection for oil filter
