Advantages and disadvantages of diaphragm filter presses

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This post was last edited by ztj1118 on 2012-11-10 09:51. Working principle of diaphragm filter presses: With the assistance of a feed pump, a diaphragm filter press feeds the material to be filtered into the filter chamber of the device. As the fluid passes through the filter cloth in this chamber (which generally allows only liquids and very small solid particles to pass through), the liquid is filtered out while the solids get trapped on the filter cloth, thus fulfilling the function of a conventional filter press. The greatest feature of diaphragm filter presses is their ability to perform secondary drying and pressing on the filter cake. Thanks to the special design of its filter chamber, after the chamber becomes filled with filter cake, the feed valve automatically closes. Gas or liquid is then introduced into the chamber, causing the filter cloth to expand and deform. This process enables secondary pressing of the filter cake, thereby further reducing its moisture content. Further introduction of gas is also intended to further reduce the moisture content in the filter cake. High-pressure air passes through the filter cake, causing moisture such as capillary water and structural water within the filter cake to be expelled and separated. This is the air-drying method. Diaphragm filter presses have the following advantages: 1. Diaphragm filter presses feature a filter plate expansion design. Gas is introduced into the filter plates to cause them to expand and deform, thereby squeezing the filter cake in between the plates and reducing its moisture content. 2. Gas reverse blowing technology is employed. Once the filter press stops feeding, high-pressure gas is introduced into the filter cake on the filter plates to further dry the filtered residue, thereby reducing capillary water and structural water within it. (The combined effect of the first two advantages can reduce the moisture content of the filter cake from the filter press to around 9%. ) 3. The filter plate features a sloped design. Above the feed inlet of the diaphragm filter press, an inclined filter plate is used to ensure thorough contact between the filtrate and the diaphragm, thereby achieving maximum filtration efficiency, increasing the filtration speed, and boosting work productivity. 4. Structure of the filter plate. Each filter plate is composed of a composite plate and a polypropylene filter plate; the composite plate consists of two filter frames, which is equivalent to having two filter cloths working simultaneously. This not only facilitates the replacement of the filter cloths but also doubles the efficiency. 5. Material of the filter plate. The filter plates of diaphragm filter presses are generally made of glass fiber-reinforced polypropylene, while the diaphragms are made of natural rubber; such equipment operates stably, with a crack resistance test score of 100,000 cycles. 6. Automation. The diaphragm filter press is equipped with a design for automatic cleaning of the filter cloth, which saves water as well as time. It also features an automatic unloading design, allowing it to be basically controlled by one person. The downside is that, compared to other devices, the pressing time is a bit longer.