The Differences Between Oil-Free Compressor and Oil-Injected Compressor

Although they are both compressors, there are differences between oil-free compressors and oil-injected compressors, which makes users need to weigh the actual needs when choosing. Next, we will discuss the difference between oil-free compressors and oil-injected compressors in detail.

Difference in Working Principle

Oil-Injected Compressor

The oil-injected compressor has a pair of precision-machined negative and positive rotors that engage with each other. A motor drives the male rotor, which in turn drives the female rotor. Inside the housing, the compressor oil is mixed with air to perform the suction, compression, and discharge processes. The oil not only lubricates and seals the compressor but also absorbs most of the heat generated during the compression process.

Oil-Free Compressor

The cathode and anode rotors of the oil-free compressor in China are also precision machined. The motor drives the male rotor, which is then synchronized with the female rotor through a timing gear at the other end of the male rotor. This design enables the air to be effectively compressed between the teeth and grooves. At the same time, the oil seal inside the main machine ensures that the lubricating oil in the bearing chamber m  will not enter the compression chamber, thus ensuring that the output air is completely oil-free.

Differences in Machine Construction

The oil-injected compressor system is relatively complex and requires an oil-air separator. In contrast, the oil-free compressor system has a simpler structure and does not require an oil-air separator, making the overall structure more compact.

Differences in the Composition of the Compressed Air Supplied

Since the oil-injected compressor injects oil during operation, the compressed air will contain a trace amount of oil. On the other hand, the oil-free compressor is able to provide completely oil-free compressed air, which meets the very high requirements of air quality.

Cost Difference

The oil-injected compressor requires regular replacement of the oil/air separator and compressor oil during operation. The oil-free compressor does not require the replacement of these parts, which reduces maintenance costs. Although the initial purchase cost of an oil-free compressor may be slightly higher, in the long run, its low maintenance costs and high energy efficiency may result in a lower overall cost.

In summary, oil-free compressors and oil-injected compressors differ in the way they are lubricated, how they work, their maintenance costs, and where they are used. After understanding the difference between oil-free compressors and oil-injected compressors, users can consider their own needs and choose the most suitable compressor type.