Filter pressIt is a kind of mechanical equipment that uses a special filter medium to apply a certain pressure to the material to make the liquid percolate out. Its function is to extract the solids in the mixed liquid to realize the solid-liquid separation. As the filter press now exhibits its important role, it is widely used in the field of environmental protection and has become an important equipment for sewage sludge treatment. So, have we considered how the overpressure filter emerged and developed? What kind of innovation has the filter press experienced over the years? Next, let's find out with Su Dong.
Do you know that, in fact, in our country, there has been an enlarged filter press very early. In the Han Dynasty, relatively simple filter press and filtration equipment were used to separate wine and distiller's grains during wine making. In the West, Germany in the 19th century invented the world's first plate and frame filter press.
The development of the filter press from the beginning to the present has roughly gone through four stages:
The first generation filter press is suitable for the dehydration of coal slime and tailings with high ash content, fine particle size and high viscosity, as well as the dehydration of clean coal. But it has small processing capacity, intermittent production, long filter press time and low efficiency. In addition, the filter press body at that time was cumbersome, occupies a large space, and was complicated in operation, high in cost, short in life, and large in maintenance.
The main feature of the second generation filter press is the change of the filter plate. The difference between the working process of this new type of filter press and the first generation of filter press is that after the \"filter press process\" is over, it is squeezed onto the surface of the filter plate between the rubber film and the filter plate. Compressed air or water is used to inflate the rubber film. This working process is called the \"extrusion process\", which is represented by a filter press developed by Japan. The unique filter cavity structure squeezes the sludge twice to further reduce the moisture content of the sludge.
The third generation of filter press adds the \"blowing process\". After the \"extrusion process\" of the filter cake, air is used to replace the filtrate in the capillary. When the high-pressure air enters the capillary in the filter cake, the liquid in the capillary is gradually replaced by air, and the moisture in the filter cake will decrease again. Its representative is the VPA filter press developed by the United States.
The most significant difference of the fourth-generation filter press is its small body, simple structure, less space, less filter plates and fast circulation. In addition, it has a much longer lifespan and low energy consumption. Its representative is Spain's APN filter press.
With the innovation of the filter press from generation to generation, its size is continuously reduced, but its functions are continuously improved. Although the current filter press is not so perfect, but with the continuous development of science and technology, Su Dong believes that the unremitting efforts of the technicians will make the filter press more perfect in the near future. .