Screw air compressors have played a transformative role in the industrial world, offering a powerful solution for delivering consistent, reliable, and efficient compressed air. From their conceptual beginnings in the 19th century to their wide-scale commercial applications today, rotary screw air compressors have evolved through decades of technological innovation, meeting the growing demands of industries that require high performance and energy efficiency.
The journey of the screw compressor began in 1878, when Heinrich Krigar of Germany filed the first patent for this technology. Unfortunately, a functional machine was never built, and the patent expired without industrial adoption.
The true innovation came in the 1930s, thanks to Alf Lysholm, the chief engineer at Ljungstroms Angturbin in Sweden. While addressing issues related to compressor surge in gas turbines, Lysholm sought a more efficient compression method. Although he initially experimented with Roots-type blowers, they failed to achieve a sufficient pressure ratio. In 1935, Ljungstroms successfully patented the helical lobe screw compressor, a milestone that led to global licensing and further development. By 1951, the company had rebranded as Svenska Rotor Maskiner (SRM), a name now synonymous with screw compressor innovation.
A year later, in 1952, British engineering firm Howden utilized the first Holroyd cutting machine to manufacture helical rotors, revolutionizing the production process and drastically reducing manufacturing costs and time.
In 1954, SRM and Howden jointly developed the first oil-flooded screw compressor. By injecting oil, the system achieved better cooling, which enabled higher pressure ratios, and removed the need for timing gears. This breakthrough led to the release of the first commercially available flooded screw air compressor by Atlas Copco in 1957.
Further enhancements came with SRM's introduction of slot valves in the late 1950s, significantly improving capacity control, a prior limitation for screw compressor applications.
Then, in 1969, Sullair brought asymmetric rotors to market, an innovation first patented by SRM. These rotors enhanced sealing efficiency, pushing the technology to new performance levels and further reducing oil carryover and maintenance costs.
Today's rotary screw compressors come in two primary types: oil-injected and oil-free.
Modern screw air compressors are engineered for energy savings. One of the key developments in recent years is the use of variable speed drives (VSD), which allow the compressor to automatically adjust its motor speed based on real-time air demand. This technology significantly reduces energy consumption, especially in applications with fluctuating air flows.
Compared to traditional piston compressors, screw compressors provide continuous operation, smoother airflow, and better energy efficiency, making them the preferred choice for both large-scale and small-scale operations across a wide variety of industries.
Thanks to their durability, positive displacement technology, and adaptable design, rotary screw air compressors are used in:
From small workshops to expansive factories, there's a wide range of models available to meet virtually any need for free air delivery and system optimization.
From an unbuilt idea in 1878 to a cornerstone of industrial productivity, the evolution of the screw air compressor is a testament to engineering innovation. As demands for efficiency, quiet operation, and energy savings continue to grow, so too does the relevance of rotary screw compressors in modern applications. Whether oil-lubricated or oil-free, today's systems represent the very best in compressed air technology—an enduring innovation that continues to evolve.
