The new dry compressing screw vacuum pump VARODRY

What qualifies the pumps of the VARODRY series is their excellent suitability for the manufacturing industry. The reason: In industrial processes, 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 general, screw pumps are the best choice for such demanding requirements. You can compare their function a bit to an extruder that pushes out the disturbing particles together with the regular material at its exhaust. In addition, these pumps are able to handle vapors in the best possible way. All those advantages of the screw-pump functional principle apply to the VARODRY, but next to this, 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, which is still not the current market standard.

A major differentiation of the VARODRY is its complete oil-freeness. All other screw-type vacuum pumps on the market are “dry compressing”; nevertheless, all these pumps have gear compartments partly filled with oil to lubricate the bearings and gear wheels.

Exactly this is not the case with the VARODRY pumps. The VARODRY is 100% oil-free. Because of this 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.

This hazard cannot happen with the VARODRY, as it uses grease-lubricated bearings and as even oil-lubricated synchronization gears are not used. Drive and synchronization is done with a high-tech tooth-belt, which on demand can be exchanged in a few minutes by the user himself. This also eliminates the gear oil exchanges which are still required at other screw-type pumps. It is therefore impossible that any oil can migrate backwards to the process chamber, will be blown out of the exhaust or might leak on the floor during gear-box exchange. The VARODRY is therefore 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 as there is no need for the sometimes complicated water supply.

In contrast to most competitor products, the VARODRY 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.

These properties qualify VARODRY 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.

The VARODRY is also a perfect pump for 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. This application requires pumps that can tolerate a lot of vapors – such as the VARODRY vacuum pumps.

The same prerequisite applies for successful 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.

In addition to drying processes in industrial cleaning systems, the VARODRY is also used in freeze drying application, as well in pharmaceutical as also in food-related freeze drying. 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. In this application the VARODRY excels again with its moderate process room temperature, as the build-up of layers is widely prevented which ensures a long-time, trouble-free operation of the pumps.

Besides liquid, gaseous and solid, plasma is the fourth state of aggregation. Typical plasma applications are surface cleaning and activation or sterilization where bacteria are killed by the hot surface plasma without a real heat-load for heat-sensitive products. In plasma applications the pressure is typically reduced to <1 mbar, a reactive gas as O2 or H2O2 is introduced and then the plasma is ignited. The pumps need to handle the plasmagases plus the “burnt” by-products. Using plasma, it is mostly complicated to define exactly the gases which need to be handled by the pump. A dry pump with its robustness is therefore ideal in these applications because it can convey nearly all substances without trouble.

With the attributes “easy”, “reliable”, “efficient” and “dry”, the VARODRY is a very good alternative to the usual pumps on the market.