What are the three core stages of the working principle of the screw press sludge dewatering machine?

The working principle of the screw press sludge dewatering machine includes the following three core stages, and their synergistic effect realizes efficient dehydration of sludge and continuous and stable operation of the equipment:

1. Concentration stage

Core mechanism: Through the initial combination of gravity and mechanical extrusion, the free water in the sludge is quickly separated.

Physical process: After the sludge enters the equipment, the spiral shaft begins to rotate, driving the outer multi-layer fixed ring and the floating ring to move relative to each other. At this time, under the action of gravity, the sludge water seeps out from the tiny filter gaps between the moving and fixed rings, the sludge volume gradually decreases, and the solid content increases to 3%-5%.

Structural support: The spiral shaft pitch of the concentration section is larger and the filter gap is wider, ensuring that the sludge is initially concentrated under low resistance and avoids clogging.

2. Dehydration stage

Core mechanism: Deep dehydration of sludge is achieved through pitch compression and back pressure plate pressurization.

Dynamic compression: After the sludge enters the dehydration section from the concentration section, the pitch of the spiral shaft gradually decreases, and the filter gaps between the rings are narrowed synchronously. The continuous contraction of the spiral cavity volume exerts radial extrusion pressure on the sludge, and the back pressure plate at the end forms a reaction force. The superposition of the two significantly increases the internal pressure, further squeezing out the bound water and capillary water.
Mud cake formation: The final sludge solid content can reach 15%-25%, forming a continuously discharged dry mud cake, and its moisture content can be controlled by adjusting the back pressure plate gap and the spiral shaft speed. For example, reducing the speed can extend the extrusion time, thereby reducing the moisture content.
Structural optimization: The dehydration part uses wear-resistant materials to cope with high-pressure environments and ensure long-term stable operation.

3. Self-cleaning stage

Core mechanism: Dynamic filter seams are combined with spray flushing to achieve uninterrupted anti-blocking.
Dynamic self-cleaning: When the spiral shaft rotates, the floating ring moves eccentrically with the shaft, forming periodic dislocation friction with the fixed ring. This movement can automatically scrape off the sludge particles attached to the filter seams to prevent the filter seams from clogging.
Auxiliary flushing: The equipment is equipped with a spray system to regularly flush the filter seams with high-pressure water to enhance the cleaning effect.
Technical advantages: Compared with the filter cloth cleaning of belt machines, which relies on high-pressure water pumps and regular shutdown maintenance of centrifuges, the self-cleaning function of the spiral stacking machine significantly reduces maintenance frequency and energy consumption, and supports 24-hour continuous operation.