When it comes to industrial compressed air systems, one of the most efficient and widely used technologies is the rotary screw air compressor. Within this category, two main types exist: oil-injected screw compressors and oil-free screw compressors. This blog focuses on answering the critical question: Why is oil injected in a screw air compressor? In doing so, we’ll explore the working principle of oil-injected compressors, highlight key components such as the inlet valve and motor speed, and examine how these machines meet application requirements across a wide range of industries including food and beverage, manufacturing, and more.
An oil-injected rotary screw compressor works by drawing air into a compression chamber through the inlet valve, where two interlocking helical rotors compress the air. What sets this type of compressor apart is the injection of oil into the compression chamber during this process. The oil serves several vital purposes:
Without oil, the compressor would suffer from increased wear and tear, overheating, and reduced performance.
Oil-free screw compressors are designed for environments where even the slightest oil contamination is unacceptable—common in food and beverage, pharmaceutical, and electronics industries. These compressors use special coatings and materials to eliminate the need for oil, but they often come at a higher initial cost and may require more maintenance over time.
On the other hand, oil-lubricated (oil-injected) models are ideal for most industrial uses due to their high quality, durability, and energy savings. When used with proper filtration systems, they can even meet stringent air purity standards required by some specific applications.
Modern oil-injected compressors often come with variable speed drive (VSD) technology, which adjusts motor speed based on air demand. This feature enables the system to deliver just the right amount of compressed air needed at any given moment, resulting in substantial energy savings. In fact, VSD-equipped compressors can reduce energy consumption by up to 35% compared to traditional fixed-speed units.
Oil-injected screw compressors are engineered to handle a wide range of application requirements. Whether you're operating a small workshop or a large manufacturing plant, these systems offer flexibility and scalability. Compared to piston compressors, screw models deliver smoother airflow, quieter operation, and better reliability under continuous loads.
Leading manufacturers like Dream Compressor have developed advanced oil-injected systems that not only meet rigorous performance standards but also incorporate intelligent controls for remote monitoring and diagnostics.
So, why is oil injected in a screw air compressor? Because it enhances performance, reliability, and efficiency—three essential pillars of industrial productivity. While oil free air is necessary for some sensitive environments, oil-injected rotary screw compressors remain the go-to solution for most industries due to their versatility, continuous operation, and outstanding energy savings.
Whether you're comparing piston compressors or exploring the benefits of VSD in rotary systems, it's crucial to consider your specific application needs. With the right compressed air system, you can ensure high quality output while optimizing operational costs—making oil-injected compressors a smart and practical choice.
