Screw Pumps


Dry Screw Pumps. Optimum Ultimate Pressure. Absolutely Oil-Free. Cool-Running.


With HeptaDry, Pfeiffer Vacuum is once again providing the industry with another reliable, high-quality product. The pumps from this new series of dry screw pumps are optimally suited for their applications in connection with low and medium vacuum.

HeptaDry is a complete line of dry screw pumps. The line is designed for both industrial and coating applications. HeptaDry is the ideal solution for all areas in which oil-free vacuum is required. The pumping speeds that are offered by this series of products range from 100 to 600 m3/h. One special advantage consists of their single-piece, variable-pitch rotors. They assure the efficient internal compression to reduce energy cost requirements in the HeptaDry pumps. This enables thermally sensitive gases to be pumped as well. Moreover, the direct gas flow in the pump prevents deposits. High-quality axial face seals between the bearing and suction chamber make for increased reliability.

Can be used ideally either as stand-alone pumps or in combination with our OktaLine Roots pumps.


  • Complete series of pumps with pumping speeds from 100 to 600 m3/h
  • Optimum ultimate pressure and broadest range of applications
  • Absolutely dry and oil-free
  • Water cooling with thermostatic valve
  • Lower energy costs due to efficient internal compression
  • High-quality axial face seals
  • Direct gas flow minimizes deposits
  • Low energy consumption, low noise level


  • Metallurgy
  • Coating
  • Freeze-drying
  • Load-locks
  • Electron beam welding
  • Gas separation
  • Vacuum filling

Series Overview

The HetpaDry pumps are dry screw pumps for applications in low and medium vacuum ranges where high volume flow rates are required. Pumping speed of the product line can range from 100 – 600 m3/h. Ultimate pressure of under 0.1 can be attained. Operating ranges are displayed below ;

(Figure 2.10)

Figure 1: HeptaDry operating range

Regardless of the model however, the HeptaDry pumps can be continuously operated within the ranges above. Their effective pumping speed however declines after p < 1 mbar pressure ranges due to the increased backflow between individually sealed volumes within the pump itself. This occurs with pumping speeds towards high pressure also given as gas is compressed to pressure > atmospheric pressure through internal compression, backflow increases significantly due to the high differential pressure.

Table 2.10: HeptaDry™ series connections

Figure 2: HeptaDry series connections

Table 2.11: HeptaDry™ performance data

Figure 3: HeptaDry performance data