Claw vacuum pumps and compressors

Claw vacuum pumps and compressors – principle of operation

Claw vacuum pumps and compressors are used for pumping a mixture of air and neutral gases. Including those with a high water vapor content. Pumps with a claw mechanism are available in a vacuum version up to 120mbar (a), a pressure version up to 2.5bar (g), as well as a vacuum-pressure version of ± 600mbar.

The name “claw pumps” indicates the impellers in the form of claws. Two synchronized moving claw rotors placed in a suitably formed compression chamber rotate in opposite directions. They are not in contact with each other as well as with the housing / compression chamber. The chamber consists of the body and 2 side covers. The rotors set in rotation cause the suction of gases in the upper part, where the inlet stub is provided. After compression, the gases get into the tank located directly below the pump. It reduces the degree of pulsation and is also a noise damper.

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As a result, the volume of the pumped medium produced is sucked into the inlet channel. After that  the medium is compressed. Then thrown through the outlet channel into the chamber. The chamber reduces pulsation and at the same time suppresses the noise level. Accuracy of manufacturing and assembly of centers eliminates the need for sealing and lubrication of rotors. Thanks to that the gas compression process is 100% oil-free.

One of the rotors (claws) drives the electric motor directly, and the other is driven by a gear transmission. The rotation synchronizing gear is responsible for the contactless operation of the rotors. It is equipped with 2 helical gear wheels, mounted on the rotor shafts. The oil chamber with a toothed gear is separated from the compression module by special seals. They prevent oil vapors from getting into the conveyed gases.

The negative pressure generated in this way on the suction side as well as the overpressure on the discharge side is very economical. The machine runs dry, eliminating the problem of contamination from the process and no wear of parts. Only the gears that synchronize the rotation of the rotors are lubricated, but they are separated and closed. No need to use operating fluids or lubricants and no wear of rotating parts reduces operating costs.

Oil-free claw vacuum pumps and compressors – advantages

The relatively small size and low noise level make it possible to install it at workplaces. High efficiency, low energy consumption combined with a robust structure and minimized maintenance make the operating costs relatively low. Almost maintenance-free operation is another of the undoubted advantages of these devices. Therefore, oil-free claw pumps and blowers, are an interesting alternative to liquid ring and Roots pumps.

Application of claw vacuum pumps and compressors

These pumps are widely used in a variety of industrial processes requiring constant vacuum or overpressure and oil-free gas transport. Some of the many examples are: filtration, evaporation, distillation, food processing, drying, solvent recovery, pneumatic transport (vacuum or overpressure), vacuum packing, paper, cardboard, plastic, rubber, or resin processing, as well as thermoforming, scribing CNC, woodworking and biogas processing, soil treatment and water aeration.

Every day, these devices work in the food, chemical and pharmaceutical industries (including hospitals and health care facilities), in printing, agriculture, mining, construction and many others. For applications requiring special safety rules, we offer pumps that comply with the requirements of ATEX standards.

Claw vacuum pump system

Our offer also includes claw dry vacuum pump systems. The combination of several pumps allows for the design of a flexible and effective modular solution, corresponding to the user’s needs.


The accessories useful for mounting the device are an external filter with a paper or polyester insert, a check valve at the pump inlet, and a silencer on the discharge side (DRY C). To control the operating parameters, pressure gauges or sensors dedicated to work with vacuum will be useful.

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