Roots Vacuum Pumps 2016 by Leybold

More catalogs by Leybold | Roots Vacuum Pumps 2016 | 40 pages | 2017-05-08


Page 11 of Roots Vacuum Pumps 2016

types flange mounted motor the drive shaft of the pump is di­rectly connected to an electric motor via a flexible coupling the required seal of the drive shaft against atmospheric pressure is obtained by oiled shaft seals canned motor in the canned motor rotor and ­stator pack are separated by a vacuum-tight can made of a non-magnetic material the rotor ­ope-rates on the drive shaft of the pump in the vacuum so that a shaft seal which would be subject to wear is not required hermetically sealed motor the hermetically sealed motor is the latest technology step for roots vacuum pumps it integrates the complete motor assembly into the vacuum reaching the same efficiency as a standard flange mounted motor without the need of a shaft seal the hermetically sealed motor is the most compact efficient and reliable motor technology available for roots pumps  pressure equalization line the integrated pressure equalization line connects the exhaust flange to the intake flange by means of a differential pressure valve in the event of an excessively high pressure difference between the leybold flanges the valve will open then a part of the pumped gas will flow through this line back to the intake flange therefore the pump may be switched on together with the backing pump at atmospheric pressure this increases the pumping speed of the pump combination also at high intake pressures special ace vibration absorber these pumps are best used in applications involving frequent pumpdown cycles the vibration absorber is of an oil sealed or f­illed design where minute a ­ mounts of oil may enter the ­vacuum system via the piston of the vibration attenuator ruvac wa/wau ws/wsu the series wa/wau roots vacuum pumps are provided with directly flange-mounted air-cooled standard three-phase motors the oiled radial ­sealing rings of the ruvac wa/wau for seal­ing the shaft against the atmosphere are made of fpm fkm fluor polymer the ws/wsu series pumps have a aircooled hermetically canned motor roots ­vacuum pumps of the series wau/wsu/whu are provided with an ­additional integrated pressure equalization line and a diffe­rential pressure valve pumps from these series are ­supplied with a vertical pumping action as standard leybold full line catalog fall 2016 ruvac wh/whu the series wh/whu pumps are technological leaders in the area of roots vacuum pumps both motors and oil reservoirs are water cooled thereby perfectly balanc­ ing the internal temperature management of the pumps resulting in significantly lower oil temperatures and thus a longer oil service life at ultimate pres­sure emissions are reduced by approximately 50 and the motor coils can sustain higher loads while at the same time offering improved efficiency the new drive concept with potted motors replaces the can for hermetically sealed drives this improves efficiency even further whereby the motors are capable of complying with the ie2 requirements of the new efficiency standard without problems in order to increase pumping speed thereby cutting pumpdown times op­tionally available specially para­me­ter­ ized frequency converters can be used moreover the pump may be operated at its maximum power already at at­mospheric pressure especially for short cycles the new whu pump is being equipped with improved valve technology due to the bypass line this pump can be operat­ed starting at atmospheric pressure the bypass valve already closes at a very early stage whereby the cycle times can be significantly reduced pumps from the whu series should not be operated over longer periods of time at high pressures 11 roots vacuum pumps various types of roots vacuum pumps have been developed to ensure optimum adaptation to the widely varying applications for this type of pump.