The difference between oil-free and oil-injected air compressors

The difference between oil-free air compressor and oil-injected air compressor is mainly reflected in the following aspects:

1. working principle

1. oil-free air compressor:

   • definition: The oil-free air compressor does not involve the participation of oil during operation, and the compressed air discharged by it is completely oil-free (or the oil content is extremely low, reaching below 0.01ppm).
   • Lubrication method oil-free air compressors are usually lubricated with resin materials or other non-oil lubricants, and some models use water lubrication technology.
   • Working principle: The compressor is driven to rotate by a permanent magnet synchronous motor or other types of motors, and the air is compressed by screws, pistons and other structures. In the compression process, since lubricating oil is not used, oil pollution will not occur.

2. Fuel injection air compressor:

   • definition oil injection air compressor needs to add lubricating oil during operation, and the compressed air discharged will contain a certain amount of oil.
   • Lubrication method: The oil-injected air compressor lubricates and cools the compressor through the oil lubrication system. During the compression process, lubricating oil will be injected into the compression chamber to play the role of lubrication, cooling and sealing.
   • Working principle: The motor drives the compressor to rotate, so that the air enters the compression chamber through the air filter. In the compression chamber, lubricating oil is continuously injected, mixed with air, and compressed together. The compressed air and oil mist mixture is separated by the oil-gas separator, and finally the compressed air with low oil content is discharged.

2. compressed air quality

1. oil-free air compressor:

   • air quality: Since the oil-free air compressor does not use lubricating oil during operation, the compressed air it discharges is highly pure and does not contain oil and other pollutants.
   • Scope of application oil-free air compressor is especially suitable for occasions with high air quality requirements, such as food, medicine, electronics, precision instruments and other industries.

2. Fuel injection air compressor:

   • air quality: The compressed air discharged by the oil-injected air compressor contains a certain amount of oil. Although it has been treated by the oil-gas separator, the oil content is still higher than that of the oil-free air compressor.
   • Scope of application oil injection air compressor is suitable for occasions with low air quality requirements, such as machinery manufacturing, chemical industry, metallurgy and other industries. However, in food, medicine and other industries with high air quality requirements, fuel injection air compressors are usually not allowed to be used.

3. maintenance

1. oil-free air compressor:

   • maintenance costs: Oil-free air compressors do not require regular replacement of lubricating oil, so maintenance costs are relatively low.
   • Maintenance content: The main maintenance content includes replacing the air filter, cleaning the radiator, checking the motor and compressor parts, etc.

2. Fuel injection air compressor:

   • maintenance costs: The oil injection air compressor needs to replace the lubricating oil and filter element regularly, and the maintenance cost is relatively high.
   • Maintenance content: The main maintenance contents include replacement of lubricating oil, filter element, inspection of oil and gas separator, cleaning of cooler, etc. In addition, it is necessary to regularly check the quality and oil level of the lubricating oil to ensure the normal operation of the compressor.

4. Performance and Cost

1. oil-free air compressor:

   • performance: Oil-free air compressors usually adopt advanced energy-saving technology and high-efficiency motors, which have the advantages of low energy consumption, low noise and stable operation.
   • Cost: Due to the complex manufacturing process and high material requirements of oil-free air compressors, their initial purchase costs are usually high. However, due to low maintenance costs and low energy consumption, long-term operating costs are relatively low.

2. Fuel injection air compressor:

   • performance oil injection air compressor technology is mature, low production costs, so the market price is relatively close to the people. Its stable performance, long life, suitable for most industrial applications.
   • Cost: The initial purchase cost of oil-injected air compressors is low, but due to the high maintenance costs such as regular replacement of lubricating oil and filter elements, the long-term operating cost may be higher than that of oil-free air compressors.

5. Summary

oil-free air compressors and oil-injected air compressors have their own advantages and disadvantages. The choice of which type of air compressor should be based on actual needs and budget factors for comprehensive consideration. For occasions with high air quality requirements, it is recommended to choose an oil-free air compressor; for occasions with low air quality requirements and limited budget, an oil-injected air compressor is a cost-effective choice.