If you have decided on the size and type of compressor, the question remains whether to choose an oil-lubricated or oil-free air compressor. To avoid making the answer too complicated, your choice should be based on the application of the compressed air.
Do I need an oil-free compressor?
The first step in selecting a compressor is to evaluate the needs of the equipment. In some cases, the consequences of oil contamination are too high, and in this case, an oil-free air compressor is necessary. However, most manufacturing industries, industrial plants and small factories are suitable for using oil-lubricated compressors because the consequences of oil contamination in these applications are not as serious as those of food production facilities. The role of oil in air compressors is to lubricate, seal and cool the compressed air. If there is no specific need to use oil-free compressed air, a more economical method is to use an oil-lubricated compressor such as an oil-injected
Screw Compressor.Oil-free compressors are much more expensive than oil-lubricated compressors. Although there are trace amounts of oil in compressed air, these can be filtered out using appropriate air filtration products. Using a coalescing filter can purify the dust contained in the compressed air to a size of 0.01 microns. If an activated carbon filter is added for further purification, the air cleanliness level 1 requirement can be achieved.
How to judge the air cleanliness level?
Oil-free air compressors are used in the production of a variety of oil-sensitive products, such as semiconductors, pharmaceuticals, and paper. In the production of these products, even trace amounts of oil can have adverse effects on the product or even people. Class 0 and “technically oil-free” are often used to indicate that the compressor meets the oil-free requirements of certain standards. While these terms are similar, their key differences can lead to unintended consequences if not considered. To better understand all of this, let's take a deeper look at what "oil-free" means. Oil-free is a term used to describe a compressor that does not use any lubrication in the compression chamber. Level 0 and "technically oil-free" indicate how clean the air is after filtering. There are some important differences between the two, which will be explained later in this article. The International Organization for Standardization (ISO) sets global standards for products used in residential, industrial, and commercial applications. The compressed air industry also has its own set of ISO standards. Based on the final air cleanliness (determined by the number of particles per cubic meter and taking into account the particle size), the compressed air cleanliness grade ISO is divided into six levels from 0 to 5. The original 1991 version of the ISO compressed air purity standard was developed by filter manufacturers and tailored for their filter products. This version of the standard divided the cleanliness into only five levels based on oil content, with level 1 being the best. ISO Cleanliness Class 1: Technically Oil-Free Cleanliness Class 1 compressed air specifies an oil content of 0.01 mg/m³ at 1 bar (a) and 20°C. Compressed air that meets this standard through filtration is said to be "technically oil-free". The standard was revised in 2001 and updated in 2010.The current standard specifies the limit values for oil content (aerosol, liquid oil and oil vapor) and specifies the specific measurement standards for oil vapor. ISO Cleanliness Class 0: True Oil-Free The new ISO standard adds a new level of cleanliness (class 0) to meet more stringent quality requirements. Class 0 is the cleanest level. They guarantee 100% oil-free air. Using air that only meets Class 1 standards when Class 0 clean air is truly needed may result in unexpected damage to sensitive products and equipment. When choosing an oil-free compressor, make sure you choose a Class 0 oil-free compressor rather than a product labeled "technically oil-free." While the initial price of a Class 0 oil-free compressor is generally higher, it's a much safer choice for sensitive applications. With Class 0 compressed air, you can be sure your terminal equipment will never be contaminated and your equipment assets will be protected. When choosing an oil-free or oil-lubricated air compressor, it is always best to seek the advice of a compressed air professional.You can contact ZAKF staff to recommend a model suitable for you.
