In our flat bed gravity strainers C series filtration occurs by gravity and the used filtering mean - the non woven fabric - is capable to retain contaminating particles of any kind, both metallic and non-metallic particles produced by different industrial processes and found suspended in liquid lubrocoolants. The average degree of filtration that can be obtained varies according to the type of filtering fabric used and to the caking on the fabric itself due to the layer of accumulated sludge. The flow rate of lubrocoolant to filtrate determines the size of the gravity strainer and the extention of the filtering surface necessary for the purpose.