What is the working principle of the high-dry belt sludge dewatering machine?

The working principle of the high-dry belt sludge dewatering machine is based on the multi-stage physical and chemical synergy, and the deep dehydration of sludge is achieved through step-by-step pressurization and mechanical shearing. Its core process can be divided into the following five stages:

1. Pretreatment and flocculation reaction
The sludge is first mixed with a polymer flocculant in a stirring tank, and the flocculant agglomerates the sludge particles through bridges, net capture and electrical neutralization. This step destroys the sludge colloidal structure through chemical modification, converts bound water into free water, and creates favorable conditions for subsequent dehydration.

2. Gravity dehydration stage
The mixed sludge is evenly distributed to the gravity dehydration area of ​​the filter belt. During the slow movement of the filter belt, free water naturally seeps out through the filter cloth, and the sludge moisture content is significantly reduced.

3. Wedge pre-pressing dehydration
The sludge enters the wedge area, and the upper and lower filter belts gradually approach to form an angle layer, and the capillary water and interstitial water are further removed by slow pressurization. This stage prevents the sludge from being squeezed out of the filter belt due to sudden pressure changes, ensuring that the mud layer is uniformly hardened.

4. High-pressure pressing and shear dehydration
The mud cake enters the "S"-shaped pressing section and is repeatedly squeezed by multiple high-pressure rollers. The filter belts are staggered to form a wave path, which applies shear force to the mud cake, destroying the combination of water and sludge, and further removing capillary water and part of the bound water. The high-pressure belt dehydrator achieves deep dehydration through the "fast opening door" design and high-strength rollers, and the moisture content of the mud cake can be reduced to less than 60%.

5. Thermal drying and deep dehydration
Some high-drying models integrate thermal drying technology, which evaporates the residual water through hot air or low-temperature drying, so that the moisture content of the mud cake is further reduced to about 30%.