New oil-free, dry compressing screw vacuum pump


The Leybold specialists named the new 100% oil-free, dry compressing screw vacuum pump Varodry. These pumps will initially be available in the sizes for 65 m³/h and 100 m³/h, the 160 and 200 m³/h versions are already in preparation.

The pumps of the Varodry series are developed for the manufacturing industry. In industrial processes, vacuum pumps do not only need to handle clean air, but also dirt, particles, outgassing of media and vapors. Processes do also not always work stable, other disturbance factors might also be involved. The pump must be able to tolerate all of this. In addition, these pumps are able to handle vapors in the best possible way. Aand due to its integrated silencer the pump offers also a quiet and pleasant sound profile.

However, there are other factors, which make a significant contribution to improving production processes. The variable inlet flange arrangement enables a flexible installation of the pump within the plant. Furthermore, the design of the silencer without “sponge-like” damper materials and the exhaust flange located at the lowest point of the pump facilitates pushing-out liquids or condensed vapors, which might incur in some industrial processes. This prevents potential formation of rust and contributes significantly to process reliability.

A further process advantage is the reliability and efficiency of the pump. It can be operated continuously at any inlet pressure and is fully resistant even against repeated shock venting. Any number of cycles can be run without overload.

A major advantage of the Varodry is its complete oil-freeness. With this construction there is no chance for oil migration from the gear chamber into the pumps compression chamber where this oil might react with the pumped gases or in worst case even migrate backwards to the process chamber. According an information of the manufacturer “The Varodry is the first pump on the market which is 100% oil-free which will have a significant impact on cost reduction and process room cleanliness.”

Another technical advantage for industrial use is the complete air cooling of the pump. This simplifies the integration of the pump into the plant. This pump has a moderate temperature profile. The low internal temperatures which peak around 100 to 130°C (depending on operation point) also allow a handling of temperature sensitive media, often preventing that those react immediately and build-up layers inside the pump. This moderate heat is the optimum for many applications enabling long-time operation without need for compression room cleaning.

Qualifing for a number of applications

  • Optical coatings such as spectacle lenses or decorative coatings, e.g. for bathroom fittings, usually produce dust in the sputtering process. A dry compressing screw-pump simply blows such dust through while in oil-sealed pumps the dust is trapped which causes strong wear of the motive parts.
  • Drying processes and industrial cleaning systems, e.g. for casted machine parts. Such parts must be dried thoroughly after cleaning to avoid immediate flash rust corrosion. The best method to dry such massive parts which have sometimes hidden solvent reservoirs inside bore-holes or cavities is vacuum drying. The moisture is extracted from even the smallest holes and the part is completely dried.
  • Cryo-pump regeneration. Cryo-pumps freeze the gases and require a regular regeneration, during which the pump is heated and the stored gas will be released and must be pumped out. Large quantities of water are appearing during this process.
  • Freeze drying application, pharmaceutical and food-related.
  • Drying applications are also necessary in lithium-ion battery production and in the manufacture of power storage devices.
  • Another target market which involves vacuum drying is the manufacturing of transformers or other high-voltage transmission components. Such components contain insulation materials, i.e. paper windings, which must be absolutely dry. Under vacuum, the moisture in the insulation is reduced to a few ppm only. Water vapor compatibility is also important here.
  • In composite applications, the resin must be degassed prior to usage to ensure bubblefreeness. During the following infiltration step, the resin is then pulled into the preevacuated fiber material. In both process steps the resin is outgassing and vapors enter the pump which needs to tolerate this.
  • Plasma applications such as surface cleaning and activation or sterilization where bacteria arekilled by the hot surface plasma without a real heat-load for heat-sensitive products.


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