Vacuum filter is a device for solid-liquid separation by vacuum vacuum pressure as the driving force. In structure, the filter section is arranged along the horizontal direction, and the filter, washing, drying and regenerating of filter cloth can be completed continuously. The rubber belt filter has the advantages of high filtration efficiency, large production capacity, good washing effect, low moisture content of filter cake, flexible operation and low maintenance cost. Rubber belt filter can be widely used in metallurgical, mine, chemical, paper, food, pharmaceutical, environmental protection and other fields of solid-liquid separation, especially in the flue gas desulfurization of gypsum dehydration (FGD) has a good application.
Vacuum filters form negative pressure at the outlet of filtrate as a driving force for filtration. The filter is divided into two types: intermittent operation and continuous operation. Intermittent operation of the vacuum filter can filter various concentrations of suspension. The continuous operation of the vacuum filter is suitable for filtering thick suspensions containing more solid particles.
Intermittent operation of filter has been developed because of automation, and the filtration area is increasing. In order to get the filter residue with low moisture content, the mechanical press has been developed.
The filter is used to separate the container into the upper and the lower cavity, which forms a simple filter. The suspension is added to the upper chamber. Under the pressure, the filter medium enters the lower cavity into the filtrate, and the solid particles are intercepted on the surface of the filter medium to form filter residue (or filter cake).
During the filtration process, the filtration layer of the filter media is thickened gradually, and the resistance of the liquid through the filtration layer increases, and the filtration speed decreases. When the filter chamber is filled with filter residue or the filtration rate is too small, stop filtering, remove the filter residue, and regenerate the filtering medium so as to complete a filtration cycle.
Liquid must overcome resistance through filtration and filtration media. Therefore, there must be pressure difference on both sides of the filter medium, which is the driving force for filtering. Increasing the pressure difference can accelerate filtration, but the particles deformed after compression are easy to plug the pores of the filtration medium when the differential pressure is large, and the filtration slows down.
Suspension filtration consists of three ways: filtration, filtration and filtration. Filtration in the filter layer refers to the formation of the initial slag filter layer after the initial filtration process. After that, the filter slag layer plays a major role in the filtration, when the large and small particles are intercepted, and the deep filtration means that the filter media is thicker, the solid particles in the suspension are less, and the particles are smaller than the filter medium, when the filter is filtered, the particles enter after entering the filter. Filtration is adsorbed in the channel; sieve filtration is the pore of the filtered solid particles larger than the filter medium, and the filtration mode of the solid particles is not adsorbed inside the filter medium, for example, the coarse grained impurities in the sewage are filtered through the cylinder filter screen.