EDS 200 and EDS 300 look the same, they differ 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 solutions in industrial and chemical applications. The EDS pumps in general are
designed for general vacuum use only and operation in rough and fine vacuum to evacuate
vessels and to pump gas mixtures.
The pump is a dry, positive displacement screw vacuum pump in which pairs of
intermeshing, non-contacting screw rotors are turning contrawise in phase by timing-gears.
The screw rotors are driven by an asynchronous electrical motor. Blow-off valves within the
mechanism minimize pumping power at high pressures and allow the pump to be started
direct-on-line. The rotational speed of screw rotors is increased by transmission gears. Gears
and bearings are oil lubricated.
The EDS pumps are supplied with different 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 flow
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 connections: 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 shaft-seal purge system and a gas-ballast system.
The shaft-seal purge delivers the supplied gas, e.g. dry compressed air or nitrogen, to the
internal shaft seal system to protect it and ensure lifetime and functionality. Shaft-seal purge
ensures that the shaft-seals are maintained at a positive pressure gradient to pumping
chamber during pump operation; therefore it prevents the entry of corrosive or toxic
process vapours into the pump gearbox; prevents contamination of the process gases by
pump oil; prevents damage to shaft-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 application and can e.g. reduce temperature load or
increase water vapour capability. The air-flow is filtered 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 application, it is possible to connect dry nitrogen supplies to the pump, to deliver
nitrogen gas ballast and nitrogen shaft-seal purge instead of air.
Page 14
