CS, CN series desander, desilter can be widely applied in the second-process and third-process cleaning of the drilling-fluid and when it is used efficiently, it can effectively clear the suspended solid-phase granules with more than 30 microns in the drilling fluid. It is one indispensable device for stabilizing and adjusting the drilling fluid technical parameters and suitable for those drillers as ZJ70, ZJ50 and ZJ40.It can be used together with the sealed circulatory system of the drilling fluid.