Edwards nES Series User Manual

2. Descripon
2.1 General descripon
The nES40 to nES750 are single-stage, oil-sealed and air or water-cooled rotary vane
vacuum pumps driven by an electric motor. nES470, nES570, nES630 and nES750 are belt
driven.
The pumps have been specically designed to work with clean air, inert gas or small
amounts of water vapour. The ambient temperature must be between 12 °C and 40 °C.
Note:
Lower temperatures are possible with reduced viscosity oil. This temperature range is
dened by the standards body Pneurop for performance conformity tesng, but the
ambient temperature given is most crical at motor start-up..
2.2 Airow
▪
Air drawn through the inlet protecon screen and the inlet non-return valve is
displaced by the vacuum pump element towards the air end exhaust valve. This
valve ejects a mixture of air and oil into the exhaust lter element. Aer passing
the exhaust lter element, clean air (condioned to a few parts per million) is
discharged through the outlet.
▪
The vacuum pump is driven by an electric motor.
2.3 Oil ow
Oil injected into the pump chamber serves to seal, lubricate and cool the pump. The oil
mixed with the compressed gas is coarsely trapped in the boom part of the oil casing.
Then ne ltering occurs in the integrated exhaust lter elements. The proporon of oil
in the exhaust gas is reduced below the visibility threshold (over 99% entrapment rate).
The oil trapped in the exhaust lters is returned to the generator by the oil return line.
To prevent gas ow at atmospheric pressure from the oil reservoir into the inlet port, the
oil return line is controlled by a oat valve. The oil cycle is maintained by the pressure
dierence exisng between the oil casing (pressure above atmospheric pressure) and
the inlet port (pressure below atmospheric pressure).
Page 12 - 07/2020
A35104880_B - Descripon

Edwards nES Series Specifications

General

Brand	Edwards
Model	nES Series
Category	Water Pump
Language	English