MIL'S EVISA Series, General Commissioning And Maintenance Instructions, Page: 4 / 40

General instructions for installation and maintenance
EVISA-Series VACUUM PUMPS
Page 3/16 08/2015 Manual N° 516917 version 6 - GB
SECTION 1. OPERATING PRINCIPLE AND GENERAL INFORMATION
1.1. Description
The E-type pumps in the EVISA series are lubricated-vane vacuum pumps.
1
2
3
SUCTION EXHAUST
Suction
Filter
(optional)
Built-in
suction
valve
screen
protective
Exhaust
valve
Exhaust
unit
Separating
filter
oil
filter
oil
injection
Reinjection of
separated oil
by drainer
Air ballast system (optional)
rotor
body
vanes
cooler
The ambient air necessary to the cooling of oil through radiator is sucked in permanently by a turbine directly coupled
with the rotor of the pump.
The gas is sucked in through the suction filter (optional), the protective screen and the built-in valve, to fill the inlet
section of the pump (1). The centrifugal force resulting from rotation of the rotor forces the vanes against the inner wall of
the pump body, thereby forming three chambers leading to a succession of variable volumes that create a vacuum and
flow.
(1) suction / start of filling (2) maximum filling volume (3) compression and exhaust phase
During phase (1), oil is injected for lubrication, sealing and cooling purposes. It can either be injected directly or passed
through an oil filter prior to injection. The gas / oil mixture is delivered from the body through the exhaust valve to the
exhaust unit where a first gas / oil separation takes place. Oil is removed from the gas by coalescence in the separating
filter, then the gas is discharged outside the pump. An automatic drain with float re-injects the oil separated by the
separating cartridge into the body of the pump.
The ambient air necessary to the cooling of oil through radiator is sucked in permanently by a turbine directly coupled
with the rotor of the pump.
When the pump is stopped, the suction valve prevents the entry of air and transfer of oil to the network under vacuum.
Bypassing of the exhaust valve enables the body to be brought to atmospheric pressure to avoid oil accumulating in the
body and thereby prevent irregular oil injection at start-up.
An gas ballast (optional) prevents the condensation of water vapour in the pump in the event of limited vapour suction.