Edwards EDS 300

EDS 200 and EDS 300 look the same, they dier only in their performance.
A. EDS 200/300 water-cooled B. EDS 200/300 air-cooled (with heat exchanger)A. EDS 200/300 water-cooled B. EDS 200/300 air-cooled (with heat exchanger)
4.1 Design
The EDS dry pump range has been developed to meet the demanding requirements for
pumping soluons in industrial and chemical applicaons. The EDS pumps in general are
designed for general vacuum use only and operaon in rough and ne vacuum to evacuate
vessels and to pump gas mixtures.
The pump is a dry, posive displacement screw vacuum pump in which pairs of
intermeshing, non-contacng screw rotors are turning contrawise in phase by ming-gears.
The screw rotors are driven by an asynchronous electrical motor. Blow-o valves within the
mechanism minimize pumping power at high pressures and allow the pump to be started
direct-on-line. The rotaonal speed of screw rotors is increased by transmission gears. Gears
and bearings are oil lubricated.
The EDS pumps are supplied with dierent motors concerning main voltage and supply
frequencies.
Cooling system
The motor is air-cooled by an integrated cooling-fan. The EDS pump itself is water or air
cooled.
Water cooled: cooling-water circulates around the pump-body and then passes out of the
pump. The cooling system is open-loop and unregulated such that the cooling water ow
rate and temperature will directly the temperature of the pump.
Air cooled: glycol/water mixture circulates around the pump-body and through the water to
air cooled heat exchanger via an integrated water pump. The cooling system is closed-loop.
The pumps have a thermal snap-switch on the pump-body as temperature monitoring.
The output of the thermal snap-switch has two connecons: one will open circuit when the
temperature of pump-body is higher than 90 °C. Use this output to provide a warning of high
temperature. The second output will open circuit when the temperature of pump-body is
higher than 110 °C. Use this output to shut-down the pump when it is too hot.
Gas system
The EDS pumps have a sha-seal purge system and a gas-ballast system.
The sha-seal purge delivers the supplied gas, e.g. dry compressed air or nitrogen, to the
internal sha seal system to protect it and ensure lifeme and funconality. Sha-seal purge
ensures that the sha-seals are maintained at a posive pressure gradient to pumping
chamber during pump operaon; therefore it prevents the entry of corrosive or toxic
process vapours into the pump gearbox; prevents contaminaon of the process gases by
pump oil; prevents damage to sha-seals by debris.
As supplied, the gas-ballast system can deliver ambient air to the pump gas-ballast inlet.
Gas-ballast use depends on your applicaon and can e.g. reduce temperature load or
increase water vapour capability. The air-ow is ltered and is controlled by a valve. A check-
valve in the system prevents the escape of process gases out of the gas ballast. If required
for your applicaon, it is possible to connect dry nitrogen supplies to the pump, to deliver
nitrogen gas ballast and nitrogen sha-seal purge instead of air.
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