Mechanical knowledge base: filter press

The filter chamber is composed of a plurality of filter plates and a filter frame, and the pressure is the filter that drives the force. The filter press is an intermittent operation with plate and frame filter presses, chamber filter presses and vertical filter presses.

1 Frame filter press: A set of filter chambers is formed by alternately arranged filter plates and filter frames. The surface of the filter plate has grooves, and its protruding parts are used to support the filter cloth. The through holes are formed in the corners of the filter frame and the filter plate, and they form a complete channel after assembly, and can pass the suspension, the washing water and the filtrate. There are handles on both sides of the plate and frame supported on the beam, and the pressing device presses the plate and frame. The filter cloth between the plate and the box functions as a gasket. Suspension hydraulic pressure is fed into the filter chamber by a feed pump and a filter residue is formed on the filter cloth until the filter chamber is filled. The filtrate passes through the filter cloth and flows along the filter plate groove to the corner channel of the plate frame, and is discharged collectively. After the filtration is completed, the filter residue may be washed with clear washing water. After washing, compressed air is sometimes introduced to remove the remaining washing liquid. Then open the filter press to remove the filter residue, clean the filter cloth, re-press the plate, frame and start the next working cycle.

Frame filter presses are suitable for filter suspensions with high compressibility or near-incompressible suspensions. Suitable suspensions generally have a solids concentration of less than 10%, operating pressures of typically 0.3-0.6 MPa, and special up to 3 MPa or higher. The filter area can be increased or decreased with the number of used frames. The frame is usually square, the inside length of the filter frame is 320-2000 mm, the frame thickness is 16-80 mm, and the filter area is 1-1200 m2. The plate and frame are compacted by manual screw, electric screw and hydraulic pressure. The panels and frames are made of wood, cast iron, cast steel, stainless steel, polypropylene and rubber.

2 Chamber filter press: Its structure and working principle are similar to that of the plate and frame filter press. The difference lies in the fact that the filter plate is recessed on both sides. Each two filter plates are combined into a one-box filter chamber, eliminating the filter frame and filtering. The board has a round hole in the center. The suspension thus flows into the filter chambers. This filter is suitable for suspensions that require filtration at higher pressures without the need for washing.

3 vertical filter press: The filter plate is horizontally and vertically stacked to form a set of filter chambers with a small footprint. It uses a continuous filter belt to complete the filtration, moving the filter belt to remove slag and clean the filter belt, and the operation is automated.

The filter press has a wide range of applications and a simple structure. The pressing and pulling of the plate and the frame, the unloading of the slag and the cleaning of the filter cloth can be automated, which is conducive to the development of the filter press.

After the elastic rubber diaphragm is added in the filter chamber of the filter press, the filter residue can be compressed with high-pressure water or compressed air through the rubber diaphragm at the end of filtration, so that the residue is further pressed and deliquored to form a diaphragm with variable filter chamber volume and filter residue. Press filter, the pressure up to 1 ~ 2 MPa.