First, plate and frame sludge dewatering machine:
The plate and frame filter press is through the extrusion of the plate and frame, so that the water in the sludge is discharged through the filter cloth to achieve the purpose of dehydration. Advantages: low price, good at dewatering inorganic sludge, mud cake moisture content is low.
Disadvantages: easy to clog, the need to use high-pressure pumps, not suitable for the dehydration of oily sludge, difficult to achieve continuous automatic operation.
When selecting equipment, the following aspects should be considered:
① Requirements for solid content of mud cake. Compared with other types of dehydrators, the solid content of the mud cake can reach 35%, if the consideration is taken from the factors of reducing the footprint of the sludge pile, the plate and frame filter press should be the solution.
② Material of the frame.
③ Filter plate and filter cloth material. Corrosion resistance is required, and the filter cloth should have a certain tensile strength.
④ Filter plate movement mode. The requirements can be fully automatic or semi-automatic through a hydraulic-pneumatic device to reduce the labor intensity of the operator.
⑤ Filter cloth oscillation device to make the filter cake easy to fall off. Compared with other types of dehydrators, the disadvantage of plate and frame filter press is that it occupies a larger area. At the same time, because the plate and frame filter press is intermittently operating, low efficiency, poor operating room environment, and secondary pollution, large domestic sewage disposal plants are rarely used.
Two, decanter sedimentation centrifuge:
The decanter type sedimentation centrifuge is mainly composed of a spiral conveyor with a hollow rotating shaft. After the sludge is sent into the rotating cylinder by the hollow rotating shaft, it is immediately dumped into the hub cavity under the action of centrifugal force generated by high-speed rotation. The proportion of sludge particles is larger, so the centrifugal force generated is also larger, and it is dumped on the inner wall of the hub to form a solid layer; The density of water is small, the centrifugal force is also small, and only the liquid layer is produced inside the solid layer. The sludge of the solid layer is slowly pushed by the screw conveyor, which is transported to the cone end of the transfer, and is continuously discharged through the outlet around the transfer, and the liquid is discharged from the overflow of the weir four to the transfer, and the centrifuge is collected after the transfer.