Milestone Compressed Air Technology/Compressors A Passion for Pumping Gases
The year is 1864 — The Bavarian fairy-tale king Ludwig II ascends the throne. The first pneumatic post dispatch system starts up in Hamburg. Lincoln wins the US presidential elections. And the 28-year old Wilhelm Meyer from Hanover/Germany founds a machine company (Maschinenfabrik) in Aerzen. Of all these things, only the company Aerzener Maschinenfabrik is still a presence today. It has grown. And it has benefited from a pioneering spirit and a richness of ideas, courage and hard work.
The roots of the machine company, which ultimately evolved into one of Germany's hidden champions, go back even further. In the mid-1850s, Meyer already ran a cement factory in nearby Reher. At the same time, he set up an agricultural machinery factory there in which around 50 workers manufactured steam-powered tractors (traction engines) among other things. The company’s business flourished. The second agricultural machinery factory was built in 1864 in Aerzen.
The location of the new machine company, which was called “Aerzener Maschinenfabrik Adolph Meyer” after Wilhelm Meyer’s father, turned out to be ideal. Here, the company was — and still is — free to grow around the founder’s villa, which still stands today. The first person to run the company was a full-blooded entrepreneur with a sense of technology and open eyes for new business opportunities. In 1867 he brought back the idea of an iron foundry from a trip to England, which was to enable the construction of large machines in Aerzen in the future. While attending the world exhibition in Paris in 1867, Meyer experienced the so-called Roots blower for the first time, which was used to generate the air flow required in portable forges.
Production of similar blowers was launched just a year later in Aerzen. They were of a simple design — two double-lobe wooden pistons ran in a conveyor housing that was cast using plaster — and could be operated with water power. The company’s own iron foundry, which was previously supplied with air using bellows, profited from this. It was not yet clear that this new “accessory” would soon become the starting point for a long product series that still to this day helps shape the business of Aerzener Maschinenfabrik.
In 1872 Wilhelm Meyer transferred the company Aerzener Maschinenfabrik to his brothers Sigmund and Emil. He appointed civil engineer Heinrich Meier as the factory director, who worked tirelessly to develop and refine agricultural machines and blowers. He obtained twelve patents, including one for rotary piston sealing strips in 1883. The first break in the history of the flourishing factory in the Weser Uplands happened when the company ceased manufacturing agricultural machinery. Instead, sales of blowers to the emerging heavy industry grew, where complete forging plants, pneumatic hammers, blowers etc. were in demand.
Finding a Way Out of the Crisis with Silencers and Turbos
At the start of the 20th century — after Wilhelm Muhlert had assumed management duties — the company ran into economic difficulties. This changed when the then 33-year old engineer Hermann Allstaedt joined the company in 1907. He brought capital into the company, which then traded under the name Aerzener Maschinenfabrik GmbH, and took over the management two years later. This era was the time of big sellers like dust removal systems for residential buildings. The company’s blowers also benefited from its innovative power: for example with silencers, which reduced operating noise levels. Another milestone was when the company started producing turbo blowers in 1911. With the aid of these blowers, it was possible to generate overpressure of up to around 600 hPa. In smelting furnaces and steel mills they were superior to positive displacement (Roots) blowers on account of the increasing daily output and the large amounts of air that were required.
Export business suffered during the First World War. But as a company that was considered important for the war effort and was required to manufacture armaments, the company based in Aerzen still managed to generate profits. The order books continued to be full in the post-war years. Allstaedt considered the rotary piston technology to be a key technology for machine building, which is why he promoted its development and refinement. A new model range with thicker shafts, enclosed wheelhouses and water-cooled side plates was suitable for pressure differences of up to 780 hPa.
The company had to cope with a decline in the 1920s, when competition increased. The company countered this with rotary piston pumps that were capable of pumping high and low-viscosity media. The product portfolio was optimized once again. The range of blowers was divided into medium and high-pressure types. Rolling bearings instead of plain bearings and other improvements delivered a significant increase in rotational speed. However, most importantly, Allstaedt added some vital fresh blood to the company in 1929 in the form of design engineers Karlheinrich Heller and Paul Grote, who brought great skills and competence with them. Nonetheless, it was impossible to escape the effects of the global economic crisis. Many workers had to be dismissed. The company’s own foundry was shut down, and castings would be bought in from external suppliers from then on.
Global Economic Crisis: Specialization Instead of Width
At the same time, Allstaedt decided to specialize production and focus on rotary piston technology. Alongside pumps and blowers, the company added rotary lobe compressors to its portfolio from 1930. After being granted a calibration approval, they quickly developed into a highly successful product.
Anti-Semitism brought about a radical change. The banking house Adolph Meyer, which still owned 50 percent of the company at this point, was expropriated; the shares were transferred via the company Berstorff to Hermann Allstaedt and Karlheinrich Heller, who was now married to Allstaedt’s daughter. In 1941, Allstaedt finally handed over management of the company to his son-in-law. A new technological era began right in the middle of the war: The Aerzen-based company started producing screw compressors for exhaust gases in submarines.
The principle behind this new technology had already been developed in 1879 by Heinrich Krigar. The compressors, which attained higher pressures than positive displacement blowers were produced for the first time by a Swedish company (which later became Svenska Rotor Maskiner) in the 1930s. From 1943 on they were manufactured by Aerzener Maschinenfabrik under license. But this was not enough for Karlheinrich Heller. He planned new screw compressor designs as a building block system that was designed to cover the widest possible range of applications. And it worked. In the post-war period, the screw compressor became one of the company’s most important products.
The economic miracle era brought growth to the entire machine building industry. The aspect that made the Aerzen products more efficient was the fact that, in future, all positive displacement machines would be based on the same components. This meant a radical boost in terms of productivity.