Working principle and workflow:

1 Working principle

The dewatering process of belt press filter can be divided into four important stages: pretreatment, gravity dewatering, wedge-shaped zone preloading dewatering, and press dewatering.

1.1 Preprocessing stage:

The flocculated material is gradually added to the filter belt, causing the free water outside the flocs to separate from the flocs under the action of gravity, gradually reducing the moisture content of the sludge flocs and deteriorating their fluidity. Therefore, the dewatering efficiency of the gravity dewatering section depends on the properties of the filter medium (filter belt), the properties of the sludge, and the degree of coagulation of the sludge. The gravity dewatering section removes a significant amount of water from the sludge.

1.2 Wedge preloading dehydration stage:

After gravity dewatering of sludge, the flowability significantly decreases, but it is still difficult to meet the requirements of the pressing dewatering section for sludge flowability. Therefore, a wedge-shaped pre pressing dewatering section is added between the pressing dewatering section and the gravity dewatering section of sludge. The sludge undergoes slight pressing dewatering in this section to remove free water on its surface, and its flowability is almost completely lost. This ensures that the sludge will not be squeezed out in the pressing dewatering section under normal circumstances, creating conditions for smooth pressing dewatering.

1.3 Extraction and dehydration stage:

After the sludge enters the first press dewatering roller, under the tension of the filter belt, the upper and lower filter belts clamp the filter cake and repeatedly deform, bend, squeeze, and shear around different sizes of press rollers in their axis system, causing relative displacement between filter cake particles and further removing a large amount of capillary free water, gradually reducing the moisture content of the filter cake. Finally, the moisture content of the filter cake is 68-80%. At the material outlet, there are upper and lower filter strips with scraper plates to remove the mud cake stuck to the filter strip that has not fallen off.