3
The vacuum pump is applicable to continuous operation (Pay attentions to
precautions of oil circulation; see Oil Circulation in Page 3; see Oil return in
Page 8).
The vacuum pump is ultimate pressure proof.
Principle of operation
The vacuum pump works on the rotating vane principle.
A circular rotor (14) is positioned centrically on the shaft of the vacuum
pump. The shaft of the vacuum pump is driven by the drive motor shaft by
means of a flexible coupling (310).
The rotor (14) rotates in an also circular, fixed cylinder (1), the centerline of
which is offset from the centreline of the rotor such that the rotor and the
inner wall of the cylinder almost touch along a line. Vanes (22), sliding in
slots in the rotor, separate the space between the rotor and the cylinder into
chambers. At any time gas is sucked in and at almost any time ejected.
Therefore the vacuum pump works almost pulsation free.
In order to avoid the suction of solids, the vacuum pump is equipped with a
mesh screen (261) in the suction connection.
In order to avoid reverse rotation after switching off, the vacuum pump is
equipped with a non-return valve (257)
NOTE
: This valve shall not be used as a non-return valve or shut –off valve
to the vacuum system and is no reliable means to prevent suction of oil into
the vacuum system while the vacuum pump is shut down.
In case the vacuum pump is equipped a gas ballast (optional):
Through the gas ballast valve (440) a small amount of air is sucked into the
pump chamber and compressed together with the process gas. This
counteracts the accumulation of condensates from the process gas inside
the vacuum pump (see “Conveying Condensable Steams” in Page 8).
The gas ballast is designed with paper filter (Note: 1RV0020-1RV0040 gas
ballasts are configured with sintered metal filters).
Gas ballast version with ball valve:
The gas ballast line can be closed partially or completely by means of a ball
valve.
In order to improve the operating characteristics the outlet of the pump
chamber is equipped with a discharge valve (159).
Oil Circulation
The vacuum pump requires oil to seal the gaps, to lubricate the vanes (22)
and to carry away compression heat.
The oil reservoir is located on the pressure side of the vacuum pump (i.e.
high pressure) at the bottom of the bottom chamber of the oil separator (75).
The feed openings are located on the suction side of the vacuum pump (low
pressure).
Forced by the pressure difference between pressure side and suction side
oil is being drawn from the oil separator (75) through the oil supply lines
(210) and injected on the suction side.
Together with the sucked gas the injected oil gets conveyed through the
vacuum pump and ejected into the oil mist separator (75). Oil that separates
before the exhaust filter (120) accumulates at the bottom of the bottom
chamber of the oil separator (75).
Oil that is separated by the exhaust filter (120) accumulates at the bottom of
the upper chamber of the oil separator (75).
The flow resistance of the exhaust filters (120) causes the inside of the
exhaust filters (which is connected to be bottom chamber of the oil separator)
to be on a higher pressure level than the outside of the exhaust filters (the
upper chamber of the oil separator). Because of the higher pressure in the
bottom chamber it is not possible to let oil that drips off the exhaust filters
simply flow down to the bottom chamber.
As the vacuum pump is equipped with float valve (200) and oil return pipe at
the inlet:
The oil accumulated in the upper chamber of the oil separator flows in the
air inlet (250) through the float valve (200) and oil return pipe (195)
As the vacuum pump is equipped with oil return valve (280):
In continuous operating conditions, it is possible that the oil sucked into
pump chamber accumulates at the bottom of the upper chamber of the oil
separator, and then drains out along with the gas discharge/pressure,
resulting in oil-free pump operation; therefore, turn off the vacuum pump
and wait for at least 15 minutes for every 10 hours’ continuous operation.
Depending on different working environments, the period of continuous
operation may be even shortened (See Operation Notes in Page 8). After
the vacuum pump is turned off, the pressure difference in and out of exhaust
filter (120) is zero. The pressure in both chambers of oil separator is
balanced. Open the oil return valve (280) between two chambers to drain
the oil accumulated in the upper chamber of the oil separator by gravity into
the bottom chamber.
Cooling
The vacuum pump is cooled by
：
-the ambient air around the vacuum pump, including oil mist separator (75)
-he air flow from the fan wheel (400)
-the conveyed gas
-he air flow from the fan wheels (321) on the shaft of the vacuum pump
On/Off switch
The vacuum pump comes without on/off switch. The control of the vacuum
pump is to be provided in the course of installation.
Safety
Intended use
DEFINITION
: For the purpose of these instructions, “handling” the vacuum
pump means the transport, storage, installation, commissioning, influence
