When ammable materials are present within the equipment you must:
▪ Ensure the system is leak ght.
▪ Use an inert gas purge to dilute any ammable gases or vapours entering the
pump inlet, and/or use an inert gas purge to reduce the concentraon of
ammable gases or vapours in the pump and in the exhaust pipeline to less than
one quarter of the gases, published Lower Explosive Limits (LEL).
Refer to the safety booklet P40040100 (secon - Avoiding the ammable zone) for
details on methods to avoid the ammable zone.
Our pumps are not intended for use in explosive dust atmospheres.
WARNING:
The oil‑sealed vacuum pumps are supplied with a sealed Gas Ballast. Plugs have been
ed to prevent ammable atmospheres accidentally entering the pump. If the gas
ballast facility is required, a purge gas must be used. Failure to obey these instrucons
may cause harm, injury or death to persons.
For further informaon, contact us: refer to the addresses page at the end of this manual for
details of your nearest Edwards company.
1.3 Descripon
The Edwards range of rotary vacuum pumps are single or two‑stage oil sealed, sliding vane,
high vacuum pumps designed for reliable, long term operaon in both laboratory and
industrial environments.
The E2M175 and E2M275 pumps incorporate an inlet valve, which when the pump is
switched o seals the inlet and prevents back migraon of oil into system being evacuated.
The pump is designed to meet the requirements of Group II Category 2 equipment in respect
to ignion sources external to the pump.
The pump is ATEX Group II Category 3 cered in respect to ignion sources internal to the
pump.
The pump is intended for use in explosion groups IIB and IIC (internal only).
A four‑pole, three‑phase ATEX approved ameproof motor provides direct drive through an
ATEX cered exible coupling to the E2M40/80/175 and 275 pumps.
A plasc cooling fan is aached to the drive coupling on the E2M40/80 pumps. The
E2M175/275 are water‑cooled.
Lubricaon is provided by a sliding vane oil pump, which delivers pressurised oil to the
vacuum pumping mechanism.
An inert purge gas can be introduced into the pumping mechanism via the gas ballast inlet.
The nal stage of the pump will exhaust to atmospheric pressure and there is a start‑up and
shutdown period where the whole pump is briey operang at atmospheric pressure.
A surface temperature thermal snap switch is ed to the body of the E2M175 and 275
rotary vacuum pumps. If the pump temperature should rise due to a fault condion, the
thermal snap switch acvates and the pump is shut down.
The thermal snap switch must be connected to an intrinsically safe circuit suitable for the
classicaon of the hazardous zone in which the pump will be located. If this is not possible,
the circuit should be placed in a safe zone.
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A36418880_A - Introducon
