When the plate and frame
Filter Press filters different materials or the same material, due to different moisture content and even temperature, the filtration effect (speed, moisture content) may be different. Some materials even need to add filter aids such as flocculation before filtering. Agent, carbide slag, etc. to adjust the filtration characteristics of the material. So the filter cakes will not be exactly the same. Before filtration, the
Filter Cloth and
Filter Plate should be checked. If washing or air blowing is required, the washing plate, non-washing plate and washing hole should be checked, and the blowing hole should be checked to see if it is clear. Is the pressing force sufficient?
(1) Open the filtrate outlet valve, start the feed pump, and gradually increase the feed valve. Depending on the filtration speed and filtration time, the filtration pressure can be gradually increased, generally not more than 0.6Mpa (plate and frame type not more than 0.4Mpa) at the beginning The filtrate may be turbid during filtration. This is because the material has not formed a pre-coating on the filter cloth and can continue to be used. It will clear up naturally later. If there is a
For larger leaks, the pressing force can be appropriately increased. Due to the capillary phenomenon of the filter cloth, it is normal for a small amount of filtrate to seep out. (2) Monitor the filtrate. If turbid liquid is found in the open flow type, close the turbid water nozzle. In the undercurrent type, stop filtration, check the filter cloth and repair or replace it. (3) If a pneumatic diaphragm pump is used, the pressure reducing valve can be adjusted to set the filtration pressure at one time, without human operation during the filtration process. If a feed pump such as a screw pump is used, not only must a return system be installed, but the size of the return valve must be adjusted at any time according to changes in filter pressure to control the filter pressure. Someone needs to operate it, otherwise the equipment will be damaged.
(4) When the filtration pressure is large and the water output is small, the filtration can be regarded as completed and the pressing plate is returned. If the moisture content of the filter cake is found to be high, the pressing plate can be closed to continue filtration.
(5) If the filtration time is too long or the filter cake cannot be formed, you should consider reducing the moisture content of the material, such as increasing the sedimentation time, adding a concentration
Sedimentation Tank, or adding flocculants and filter aids (quicklime, diatomaceous earth, perlite) to replace the filter media. Wait for a solution.
(6) If the filter cake needs to be rinsed, close the water outlet on the open-flow washing plate, close the feed valve, open the wash water valve, and release water for flushing. The pressure of the flushing water is generally not greater than the rated filtration pressure of the equipment. The flushing time It should be determined according to the flushing effect. If the flushing effect is not satisfactory at one time, it can be flushed several times during the filtration process.
(7) In order to reduce the moisture content of the filter cake, the compressed air drying method can be used. The method is the same as the flushing method. The method of air intake through the feed hole or the use of a diaphragm squeeze filter press can also be used.
