In stock preparation for paper machines for example: pulp and wood pulp as well as waste paper fibres are mixed in a certain proportion depending on the type of paper, and then dissolved in water. Chemical bulking agents and additives are also added. This aggressive liquid must be “agitated” repeatedly. For this application, the engineers have developed DEPRAG POWER LINE air motors with acid-resistant stainless steel housing made from V4A material. The high quality non-corrosive stainless steel drive spindle is resistant to aggressive chemicals. It has a particularly robust radial shaft sealing. The POWER LINE vane motors achieve 1.6 kW at a nominal speed of 4500 1/min, 2.6 kW at a nominal speed of 3500 1/min or 3.6 kW at a nominal speed of 3000 1/min. Furthermore, they are available with stainless steel gears with a gear ratio of 18.3 or 32.6 and a stainless steel adaptor plate.

Air motors can be used in a wide spectrum of applications due to their diverse range of designs, simple construction, light performance weight, high speed ranges and explosion safety. The air motor works on a simple principle. The air created by the compressor causes the motor shaft to rotate.

In the vane motor: the rotor starts to turn in the eccentric cylinder. The vanes held in the rotor slits are pushed against the edge of the cylinder wall by centrifugal force. This creates working chambers for the expanding air. The expansion of compressed supply air changes the compressed air into kinetic energy and rotational movement is generated.

There are many advantages to using air motors as a drive. The main benefit is the high performance density. Depending on design they only need a fifth of the weight of a standard electric motor or a third of the size.

The performance generated is almost constant for this motor type over wide speed ranges. It can be operated over a wide range of varying loads. The motor performance can be adapted by altering the operational pressure and the speed can be smoothly controlled by throttling the air quantity. The air motor can be loaded until standstill without problems or any kind of damage. After the load has been reduced, it restarts immediately and successively as many times as required even on high duty cycles.

Another of the advantages of this type of drive is that air decompression cools down the frictional heat created by the air motor. Therefore, it is cool when loaded and overheating is almost impossible. Additionally, the inner overpressure prevents the intrusion of dust and dirt.

Even when operated oil free in a dry run, air motors up to 1.6 kW will only lose approx. 10 – 20% of their power.

“Whether used for stock preparation in paper manufacturing, in the transfer unit of a paper machine or for cutting raw paper into strips, our air vane motors are extremely versatile”, explains Product Manager Dagmar Dübbelde.

DEPRAG offers a large selection of stainless steel motors for the paper industry alone. These motors are attractive because of their robustness and high performance. As well as POWER LINE motors, the stainless-steel motors in the ADVANCED LINE programme can be used for certain applications in the paper industry. The air vane motors are manufactured as standard with external parts made from V2A stainless steel. They are completely sealed so that no air can escape and no dirt from the surrounding environment can get into the motors. The performance range of the ADVANCED LINE motors spans 20 W up to 1.2 kW in an idle speed range of 16 to 24,000 rpm. “This wide-ranging spectrum of stainless steel motors means we are the market leader in this sector. We have the ideal solution for every performance requirement”, explains Dagmar Dübbelde. The sophisticated modular principle also offers an outstanding price-performance ratio.