Comparison of working principle between chamber filter press and diaphragm filter press

(1) Working principle of the box filter press The working principle of the box filter press.

When the filter press is working, press all the filter plates between the movable head plate and the fixed tail plate so that the filter plates around the adjacent filter plates form a sealed filter chamber. The slurry is fed into the feed hole of the fixed tail plate. . After all the filter chambers are filled with the slurry, the pressure filtration process begins, and the slurry is subjected to solid-liquid separation by the pressure of the feed pump to the slurry. The solid particles remain in the filter chamber due to the blocking of the filter cloth, and the filtrate is discharged through the drain groove along the filter plate through the filter cloth, and the dehydration process is completed when the filtrate is no longer discharged. At this time, the feeding can be stopped, the head plate is returned to the original position, and the filter plate moving device pulls the filter plates one after another. The filter cake falls off by its own weight. At this point, the pressure filtration process is completed.

(2) Working principle of diaphragm filter press The main difference between the diaphragm filter press and the current ordinary box filter press is that an elastic film is added between the filter plate and the filter cloth. During the operation, when the feed is finished, the high-pressure fluid medium can be injected between the filter plate and the diaphragm. At this time, the entire diaphragm will bulge the filter cake, thereby further dewatering the filter cake, that is, press filtration.

(3) Compared with the two types of filter press process, when the material with fine particle size and high viscosity is treated, the filtration resistance is large, and the filter press of the ordinary filter plate requires a longer filter time. The diaphragm type filter press can appropriately terminate the constant pressure feed and switch to the press filter, and replace the longer constant pressure feed filter time of the ordinary filter press with a short press filter time.

When the filter press has a coarse particle size and no viscosity, the filtration resistance is small, and in a short time, the filtrate is not substantially discharged and the feed is terminated. The next operation of the ordinary filter press is to pull the start plate and the filter plate to start unloading. The filter cake has a very low drop rate. Even if most of the artificial mash does not fall off, the filter cake has high moisture, and it is difficult to remove the cake. The next cycle can be carried out after rinsing the filter cloth, resulting in high labor intensity and long discharge time. The diaphragm filter press enters a short press filtration process after the feed is terminated, so that the diaphragm bulges to pressurize the filter cake for further dehydration; the diaphragm bulges to compact the filter cake, and the filter cake can basically fall off during the discharge process. Clean and complete the unloading process in a short time.

The above is the main difference between the diaphragm filter press and the ordinary filter press. These differences have made the diaphragm filter press a significant effect in terms of handling capacity per unit area, reducing moisture of the filter cake, and adaptability to the properties of the treated material, and have been widely used in various fields in which solid-liquid separation exists. Diaphragm filter presses are now considered an alternative upgrade to conventional van filter presses.