Press release BoxID: 266563 (DEPRAG SCHULZ GMBH u. CO.)
  • Carl-Schulz-Platz 1
  • 92224 Amberg
  • Contact person
  • Lisa Hierold
  • +49 (9621) 371-153

The greatest thing since sliced bread!

(PresseBox) (Amberg, ) Germany is known worldwide for its wide-ranging selection of breads and pastries. This, in turn, poses a serious challenge to the country's over 700 mills, which supply Germany's baking industry with high-quality milled grains. According to the Verband Deutscher Müller ( Association of German Millers), more than 6,000 Germans now earn their daily bread milling grain. In Germany, the per-capita-consumption of milled grains is 67.1 kilograms per year, and increasing. In all Germany's milling industry generates revenues of about 2.1 billion Euros.

In contrast to years past, when the milling process consisted of hauling around sacks, sweeping up and manually changing mill wheels, today's mills employ a wide range of cutting-edge technologies, including high-tech digital milling programs, and computer controlled systems and quality monitoring in the milling laboratory. Automation is also on the rise, especially in the larger mills. Machine builders are constantly being pushed to the limit as they develop newer and better ways of both milling and material handling. No matter what the application, explosion prevention is a critical issue because of the amount of dust created in the typical mill. Hygienic standards are also a major concern. Therefore, the motors that the milling industry uses need to meet an especially high set of standards.

In practice, air-vane motors made from high quality stainless steel, like those manufactured by the screw-driving and automation equipment manufacturer DEPRAG SCHULZ GMBH & CO have proved ideal in these kinds of applications-especially those in DEPRAG's Advanced Line product range.

In fact, air-vane motors are well suited to a wide variety of applications, thanks to their versatile design options, simple construction, light performance weight, high speeds and explosion resistance. In operation, compressed air is first used to set a rotor in motion inside an eccentric cylinder. A number of vanes set in slots are then pushed outward against the edge of the cylinder wall by centrifugal force, creating a series of working chambers that transform the compressed air into kinetic energy and rotational movement.

As the decompressing air makes its way through the motor it loses temperature, keeping the motor cool, even under load. The fact that the motor is pressurized prevents the intrusion of dust and dirt.

The stainless steel air vane motors of the Advanced Line are well suited to oil-free operation, an essential feature with respect to clean rooms and throughout the food industry. The motors are available in standard capacities ranging from 20 W to 1.2 kW, and in a broad speed range from 16 up to 24,000 rpm. Different vane types are available for use in various specific applications.

Because there are no electric lines or other electrical sources causing sparks and other potential hazards, compressed air represents a largely trouble-free energy source. This is important because explosion safety is a serious issue in the milling industry, because of the fact that the fine dust found in grain produce, storage and packaging is highly explosive.

In response to the milling industry's hygiene concerns, DEPRAG's Advanced Line motors are made from noncorrosive, top-quality stainless steel and provided with a smooth outer surface so they will be easy to clean. The motors are completely sealed, so there is no chance of leakage or penetration of dirt. Motor spindles are also resistant to chemical cleaning agents and come equipped with a long-life radial shaft sealant ring.

DEPRAG has also created what it calls its ATEX line of certified brake motors for use in vat draining applications in the chemical industry. Developed in conjunction with bulk-good experts at Beer-Fördertechnik Bad König, Germany, these air motors are now an integral part of DEPRAG's standard product line, and come equipped with a pre-integrated set of compact planetary gears that can be specially adapted to the particular speed and torque requirements of each customer.

Each ATEX system is configured to act as a kind of holding brake and consists of three brake discs, a pressure spring and a piston, controlled by its own dedicated air line. When the air supply in the control line is over three bar and the spring load is less than the compression force, the stress is taken off the discs and the motor can rotate freely. When the pressure in the control line falls below three bar and the spring load is greater than the compression force, the brake discs are forced against each other and the motor is blocked.

An additional safety valve is mounted onto the brake for applications in potentially explosive environments. In this configuration, the air supply is shut down as soon as the pressure falls below five bar. This ensures that the air pressure in the control line is equal to zero during the braking process.

"With this new complete system we have been able to launch an attractive system onto the market which fully complies with the ATEX standards (EX II 2GDc IIC T5 (95°)). In this way we have secured our position as the leading technical supplier of air motors on the market," says DEPRAG Product Manager Dagmar Hierl.


DEPRAG SCHULZ GMBH & CO. offers a full service package for almost every industrial sector and is represented by 600 employees in 40 countries. One of their main areas of expertise is the development and manufacture of air motors. The DEPRAG engineers have had decades of experience in the planning and design of air motors according to customer specifications. Individual customer requests often lead to innovative developments which then become great value additions to the standard programm.