Pfeiffer Vacuum

4.4.3 Portfolio overview

HeptaDry pumps are dry screw pumps for applications in the low and medium vacuum ranges where high volume flow rates are required. The pumping speeds of this product line range from 100 to 600 m3 · h-1. Ultimate pressures of under 0.1 hPa are attained. Their pumping speed and the attainable final pressure depend on the mains frequency.

Regardless of the model in question, HeptaDry pumps can be continuously operated in their particular operating range. Their effective pumping speed declines in the p < 1 hPa pressure range due to the ever-stronger backflow between the individual sealed volumes within the pump. There is a similar reason for the decrease in pumping speed toward high pressure, as in this case the gas is compressed to pressures in excess of atmospheric pressure through internal compression, and consequently backflow increases significantly due to the high differential pressure.

The standard equipment that comes with the pumps includes: inlet sieve, water-flow cooling with thermostatic valve and thermometer, silencer with non-return valve and frame-mounted design with vibration dampers. The pumps are driven by a three-phase, temperature-monitored asynchronous motor that is suitable for 50 and 60 Hz (3,000 or 3,600 rpm).

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