How to choose a filter cloth suitable for one’s own filter press?

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This post was last edited by Black gold on 2011-10-25 20:17. In the daily industrial use of filter presses, the most common question is how to choose a filter cloth suitable for one’s own industry How to choose the filter cloth for different types of filter presses? Let’s talk about these issues today! In general, when selecting the filter cloth for a filter press, we take into account our requirements as well as the properties of the material to be filtered, that is, its separability, chemical properties, and physical properties ； Drying property of the filter cake after filtration ； The filtered substances and their scope, etc. – we will explain each of these below. First of all. The most important thing for us is to consider the properties of the material to be filtered; these factors account for over 75% of the importance in selecting the filter cloth for a pressure filter. A. The sludge stripping performance, which directly reflects the working efficiency of the filter press equipment. When the filter residue has a smooth surface without adhesion, the filtrate will quickly permeate through the filter cloth, resulting in an efficient filtration process over a short time period. On the contrary, the filter residue is sticky, which prolongs the filtering time and thus reduces efficiency accordingly. Moreover, the stronger the adhesion, the lower the efficiency. At this point, we need to choose either a single-filament filter cloth or a twill-woven filter cloth. B. Selection is based on the chemical properties of the filtrate, such as its acidity or alkalinity; different levels of acidity or alkalinity require the use of appropriate types of filter cloth. Polyester filter cloth has the strongest acid resistance, while vinylon filter cloth has the strongest alkali resistance. Polypropylene filter cloth is the one that possesses both acid and alkali resistance. C. The shape of the filter residue, whether the particles are uniform and whether their shape is hard, in order to assess the wear resistance of the filter cloth. They vary in size and have corners; the choice is made depending on the degree of variation. The ones with the best wear resistance are the longitudinal filter fabrics and transverse filter fabrics. D. The temperature of the filter material; temperature also affects the filter cloth and operational efficiency of the filter press. The filter cloth with the highest temperature resistance is the strip-type one. Once again, it comes down to our requirements: we are interested in the efficiency of the filter press as well as the degree of drying of the filter residue. Regeneration performance of the filter cloth. When selecting filter cloth, it is also important to choose one with good regeneration properties. Filter cloths with good regeneration properties can be washed directly on a filter press, reducing the frequency of cloth replacement. After simple treatment (drying, washing, etc.), the filtration efficiency of the replaced filter cloth is restored to over 80%. Therefore, depending on the specific circumstances, the choice is made based on the temperature of the filtrate, its pH level, and the filtration process. The properties of four commonly used filter cloths are listed below. Performance: Polyester, Nylon, Polypropylene, Vinylon. Acid resistance: Poor, Fair, Poor; Alkali resistance: Fair, Strong, Very strong. Electrical conductivity: Very poor, Fair, Good, Average. Elongation at break: 30%-40%, 18%-45%; similar to polyester, 12%-25%. Recovery property: Very good, with a recovery rate of over 90% at 10% elongation; slightly better than polyester, but worse than other materials. Wear resistance: Very good, Very good, Very good, Good. Heat resistance: 170 °C, 130 °C; slight shrinkage at 90 °C, slight shrinkage at 100 °C, with shrinkage occurring as well. Softening point: 230-240 °C, 180 °C, 140-150 °C, 200 °C. Melting point: 255-265 °C, 210-215 °C, 165-170 °C, 220 °C. Data source: Rongcheng Filter Press Equipment