The use of a compressor is an increase in the industries, and it also contributes to raising the demand for the air oil separator that is a type of filter used to separate compressed air from the oil. In the phase of compression, oil is injected in order to perform the functions of sealing, lubricating, and absorbing the heat of the compressor. The compressor emits a mixture of air and oil that is separated by the help of an air oil separator. The selection of air-oil separators should be made by checking the requirements of the machine and the specifications of the equipment. The air-oil separator that is unable to separate oil from air poses several issues, such as the presence of oil inside the separator may fault the scavenge line. It is vital to choose a proper air-oil separator as the inability to do this will affect the quality of the compressed air, and failure of removing condensation fills the oil cap with dirt and sludge。 that contributes to degrading the performance of the compressor. The inability to separate the oil from the air also causes a decrease in the amount and quality of oil that increases the operational cost by increasing the downtime for maintenance. It is vital that the compressed air should be pure and clean when it reaches its destination. The presence of oil in the compressed air degrades the quality of the pneumatic operation that includes air drying and sanding. The presence of oil in the compressed air also captures dirt and impurities that also transmits with the compressed air in the absence of an air oil separator. The condition in which the air-oil separator is filled with oil, the excess oil spread to the other parts of the machine and causes a detrimental effect, and due to this, the selection of a proper air oil separator is essential for maintaining the functioning of the compressor.