Suspension is an important part of the filter, which is related to the filtration effect of suspension. There are usually three types of filters, i.e. residue layer filtration, deep filtration and sieve filtration. These three types of filters usually appear simultaneously or successively in the process of filtration.
The filtering speed of the filter is affected by the filtration rate. If the fixed particles in the suspension are uniform in size, they will pass through the filter slag layer smoothly and the filtering speed will be fast.
For the suspension with fast settling speed of solid particles, it is applied to the filter which feeds on the upper part of the filter medium to make the direction of filtration consistent with the direction of gravity. Coarse particles settle first, which can reduce the clogging of the filter medium and the filter slag layer.
Coarse solid particles, such as diatomite and expanded perlite, can be mixed into the suspension (e.g. colloid) of the sad filter to make the filter slag layer loose. When the viscosity of the filtrate is high, the suspension can be heated to reduce the viscosity.
Vacuum filter is the driving force of filtration by forming negative pressure at the outlet of filtrate. This kind of filter can be divided into intermittent operation and continuous operation.
Intermittently operated vacuum filters can filter suspensions of various concentrations. Continuously operated vacuum filters are suitable for filtering thick suspensions containing more solid particles.
Therefore, the operator should choose the filtration mode according to the actual situation of suspension. The improper filtration mode not only affects the efficiency of filtration, but also may cause damage to the filter itself.