Low pressure filter press named ZNS-5A is a professional instrument, mainly used for measuring the filtration amount of drilling fluid and make filter cake after filtering. The filter is mainly composed of bracket, drilling fluid cup, pressure regulator，measuring cylinder and inflator, etc.

This filter has the characteristic of reasonable structure, convenient use, accurate measurement, sturdy and durable quality. It has been widely used in the analysis and determination of drilling fluid in oil fields, geological exploration and laboratories.

The main body is a cylindrical drilling fluid cup with inner-diameter 76.2mm and the minimum height 64mm. This cup is made of strong alkali solution resistant material, and assembled into pressurized medium, which can be easily put in and out form its top. When assembling, put a filter paper in size diameter 90mm and filter area 1140px² on the base of the drilling fluid cup, a discharge pipe is installed at the lower part of the base to discharge the filtrate into the measuring cylinder. After sealing with sealing ring, place the whole devise on the bracket. In order to get better measure results, the diameter of filter paper must be 90mm.