Rebuilt Edwards Blowers
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Hydrokinetic Drive
Edwards boosters are unique in utilizing a hydrokinetic fluid coupling to connect the electric motor shaft to the lobe rotor. When the gas load is high the rotational speed of the rotor is reduced. As the gas load decreases, the rotor accelerates to full speed. The blower can operate continuously over a wide vacuum range without the risk of overloading the motor and without the need for a gas bypass or pressure sensor switch.
The motor shaft drives one of the rotors through the fluid coupling. The 1:1 gears inside the coupling cover drive the second rotor in the opposite direction inside the stator housing.
QMB Booster
| Specifications | QMB-250F | QMB-500F | QMB-1200F |
|---|---|---|---|
| Weight (lb) | 143 | 172 | 345 |
| Minimum cooling water flow (l/hr) | 75 | ||
| Oil capacity (l) Coupling cover Shaft seal reservoir Gear case | 1.5 0.125 - | 1.5 0.125 - | 2.4 0.125 1.25 |
| Rotational speed (rpm) 60 Hz supply | 3,500 | ||
| Vacuum connections | |||
| Inlet connection Outlet connection | ISO 63 ISO 40 | ISO 100 ISO 63 | ISO 160 ISO 100 |
| Cooling-water connections | |||
| Inlet (BSP) Outlet (BSP) | Hansen quick connect 3/8 inch male Hansen quick connect 3/8 inch female | ||
| Noise data Continuous A-weighted sound pressure level (dBA) | 66 | 66 | 70 |
EH Booster
| Specifications | EH-250 | EH-500A | EH-1200 |
|---|---|---|---|
| Pumping speed @ 60Hz w/ backing pump (cfm) | |||
| E2M40 E2M80 | 169 193 | 247 283 | 594 658 |
| Connection | |||
| Inlet | ISO 63 | ISO 100 | ISO 160 |
| Outlet | ISO 40 | ISO 63 | ISO 100 |
| Electrical supply, 3 Φ | 208 - 230V/460V | ||
| Motor | 2 hp | 4 hp | |
| Weight (lb) | 134 | 163 | 329 |
General
Edwards QMB mechanical booster pumps maximum continuous inlet pressure is 20 mbar for the QMB-250F and QMB-500F and 1 mbar for the QMB-1200F.
The QMB-250F and QMB-500F pumps are air cooled and the QMB-1200F pump is water cooled. All the QMB pumps have enclosed, water cooled motors and are therefore suitable for applications in clean environments where fan cooling is unacceptable.
The pump coupling cover is connected to the pump outlet and forms an integral part of the vacuum system. The connecting pipelines have a filter which removes debris and so prevents contamination of the lubricating oil and bearings. For an even cleaner system, the coupling cover and bearings can be evacuated by connection to the inlet or to an external vacuum pump.
Three motor protection thermistors,one on each winding, are fitted to the motor of the QMB pump. These thermistors are solid state devices which have an electrical resistance of 100 to 500 W at normal motor operational temperature. When the motor is too hot, the electrical resistance rises quickly to 3000 W.
The thermistors are connected in series and you can connect the thermistors to control equipment to automatically shut down the system if a motor is too hot.
The QMB pumps are positive displacement Roots vacuum pumps. The pump mechanism is driven by a three phase electric motor through a hydrokinetic fluid coupling. The motor is enclosed and is cooled by integral cooling water coils.
The pump shafts and rotors are made of corrosion resistant, cast iron. The internal and external shaft seals are made of polytetrafluoroethylene (PTFE) or fluoroelastomer. The bearings, gears and seals are lubricated by oil fed from reservoirs in the coupling cover. A series of seals stops the oil from reaching the vacuum side of the pump. The coupling cover is evacuated. You can inspect the oil-levels through sight glasses which are fitted to the coupling cover. Oil filler, oil drain and external evacuation connections are provided on the cover.
The QMB-250F and QMB-500F pumps have rear bearings which are lubricated by perfluoropolyether (PFPE) grease. The QMB-1200F pump gears are lubricated by oil in the gear cover. The gear cover of the QMB-1200F has oil filler and oil drain plugs and an oil level sight glass. The QMB pumps are suitable for use only with PFPE oils.