Description - Edwards RV3 Instruction Manual

A652-18-880 Issue C
When flammable materials are present within the equipment you must:
Not allow air to enter the equipment.
Ensure the system is leak tight.
Use an inert gas purge (for example, a nitrogen purge to dilute any flammable gases or vapours entering the
pump inlet, and/or use an inert gas purge to reduce the concentration of flammable gases or vapours in the
pump and in the exhaust pipeline to less than one quarter of the gases, published Lower Explosive Limits
(LEL).
See Section 6.5 of the safety booklet P400-40-100 for details on how to avoid the flammable zone.
Edwards pumps are not intended for use in explosive dust atmospheres.
The oil-sealed vacuum pumps are supplied with a sealed Gas Ballast. Plugs have been fitted to
prevent flammable atmospheres accidentally entering the pump. If the gas ballast facility is
required, a purge gas must be used, or clean air supplied from a safe area. Failure to obey these
instructions may cause harm, injury or death to persons.
For further information, please contact Edwards: refer to the addresses page at the end of this manual for details of
your nearest Edwards company.
1.3

Description

The Edwards range of rotary vacuum pumps are single or two-stage oil sealed, sliding vane, high vacuum pumps
designed for reliable, long term operation in both laboratory and industrial environments.
The RV3, RV5, RV8, RV12 and EM175 and EM275 pumps incorporate an inlet valve, which when the pump is switched
off seals the inlet and prevents back migration of oil into system being evacuated.
The pump is designed to meet the requirements of Group II Category 2 equipment in respect to ignition sources
external to the pump.
The pump has already gained ATEX Group II Category 3 certification in respect to ignition sources internal to the
pump.
The pump is intended for use in explosion groups IIA, IIB and IIC.
A four-pole, single-phase and three phase ATEX approved flameproof motor provides direct drive through a flexible
coupling to the RV range and the EM18 and 28 pumps.
A four-pole, three-phase ATEX approved flameproof motor provides direct drive through an ATEX certified flexible
coupling to the EM 40/80/175 and 275 pumps.
A plastic cooling fan is attached to the drive coupling on the EM18/40/80 pumps. The EM175/275 are water-cooled.
Lubrication 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.
For much of the operating cycle the pump operates at pressures significantly below 0.8 bar absolute. However the
final stage of the pump will exhaust to atmospheric pressure and there is a start-up and shutdown period where the
whole pump is briefly operating at atmospheric pressure.
A surface temperature thermal snap switch is fitted to the body of the EM175 and 275 rotary vacuum pumps. If the
pump temperature should rise due to a fault condition, the thermal snap switch activates and the pump is shut down.
The thermal snap switch must be connected to an intrinsically safe circuit suitable for the classification 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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WARNING
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