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. The classification of the vacuum filter is as follows:
Intermittent vacuum filter:
The mechanism of vacuum filter and pressure filter is basically the same, but the pressure of one side of filter medium is lower than atmospheric pressure, and the driving force is small. Vacuum filter: the structure is simple, and the driving force of filtration is larger than that of gravity filter. The vacuum leaf filter is simple in structure and suitable for filtration of general slurry materials, but the operation conditions are poor and the labor intensity is high.
Continuous vacuum filter:
External filter drum vacuum filter: continuous and automatic operation, it can effectively filter, wash, dehydrate, clean the operation site, easy to check and repair. The disadvantage is that the cost is high, the steam pressure of the hot liquid or the volatile liquid is limited, the boiling point is low or the volatile material can not be filtered at the operating temperature. It is difficult to deal with the slurry with more solid content and larger particle characteristics, and the moisture content of the filter cake is about 30%, and it is rarely below 10%. It is mainly used in the chemical industry and food industry.
Internal filter surface drum vacuum filter:
It is suitable for the suspension of coarse and thin solid particles. It does not need a stirring device. The machine is low in cost and can adapt to the change of feed concentration. If it is needed to operate at high temperature, it is easy to take insulation measures. The disadvantage is that the drum surface can not be fully used, the filter cake needs certain viscosity, otherwise it is easy to fall off, resulting in the decrease of the vacuum degree, the change of the flow rate of feed, and the difficulty of replacing the filter cloth.
Disc vacuum filter:
According to the unit filter surface, the lowest price and small footprint, but the humidity of filter cake is higher than that of rotary drum vacuum filter. Because the filter surface is vertical, the cake thickness is uneven, easy to crack and difficult to wash. The thin layer cake is difficult to discharge, and the filter cloth is fast wear and easy to block. It is easy to handle the materials with low settling speed and easy filtration, and is not suitable for dealing with non viscous materials. The application range is the same as that of rotary drum vacuum filters.
Rotary table vacuum filter:
The structure is simple, the washing effect is good, the washing liquid and the filtrate are separated. For the fast dehydrated slurry, the single filter has a large amount of treatment. The disadvantages are the large area, the fast wear of the filter cloth and the easy jam.
Dump vacuum filter:
It can be used for separating the solid material with strong adaptability and suitable for separating the slurry with mass fraction of 20%, large density, easy separation and full washing of filter cake, which is commonly used in chemical industry, light industry and other industries.
Belt vacuum filter:
There are three kinds of fixed room type, mobile room type and filter belt intermittently movement. The belt vacuum filter is a horizontal filter surface. It is added material, high filtration efficiency, good washing effect, filter cake thickness adjustable, filter cloth can be washed both sides at the same time, operation is flexible, maintenance cost is low, it can be applied to chemical, pharmaceutical, food industry. The separation performance of slurry with faster settling speed is better than that of filter cake when it needs washing.
Disc vacuum filter: the filter surface is the lowest and the area is small, but the humidity of the filter cake is higher than the drum type vacuum filter. The filter cake needs certain viscosity, otherwise it is easy to fall off, resulting in the decrease of the vacuum degree, the change of the feed flow rate, and the difficulty of replacing the filter cloth.