Working principle of belt filter press and system dehydration process

      After the concentrated sludge is fully mixed with a certain concentration of flocculant in static and dynamic mixers, the tiny solid particles in the sludge aggregate into larger flocculent agglomerates, and the free water is separated at the same time. The sludge is transported to the belt filter press for concentrated gravity dewatering. The free water is separated under the action of gravity to form immobile sludge, which is then clamped between the upper and lower mesh belts and passes through the wedge-shaped pre-pressure zone. , Under the action of small to large squeezing force and shearing force in the low pressure area and high pressure area, the sludge is gradually squeezed to achieve a greater degree of mud and water separation, and then a filter cake is formed and discharged.

1. Chemical pretreatment and dehydration

In order to improve the dewaterability of the sludge, improve the properties of the filter cake, and increase the permeability of the material, the sludge needs to be chemically treated. This machine uses a unique “water flocculation granulation mixer” device to achieve chemical dosing and flocculation This method not only has good flocculation effect, but also saves a lot of chemicals, has low operating cost and obvious economic benefits.

2. Gravity concentration and dehydration section

The sludge is evenly sent into the mesh belt through the cloth hopper. The sludge moves forward with the filter belt. The free water flows into the water receiving tank through the filter belt under its own weight. Gravity dehydration can also be said to be a highly concentrated section. The main function is to remove the sludge. The free water in the sludge reduces the fluidity of the sludge and prepares for further extrusion.

3. Wedge-shaped zone pre-compression dehydration section

The fluidity of the sludge after gravity dehydration is almost completely lost. As the filter belt of the belt filter press moves forward, the distance between the upper and lower filter belts gradually decreases, and the material begins to receive a slight pressure, and as the filter belt runs, the pressure gradually increases The role of the wedge-shaped zone is to extend the gravity dehydration time, increase the extrusion stability of the flocs, and prepare for entering the pressure zone.

4. Squeeze roll high pressure dehydration section

When the material leaves the wedge-shaped zone, it enters the pressure zone. The material is squeezed in this zone. The pressure along the running direction of the filter belt increases with the decrease of the diameter of the squeezing roller. The volume of the material is compressed and the free water in the gap is squeezed out. At this time, the filter cake is basically formed, and the water content of the filter cake can be reduced to a lower level after high pressure in the high pressure area at the end of the pressure.

After the dehydration treatment of the above stages, the material forms a filter cake and is discharged. It is scraped by a scraper, and the upper and lower filter belts are separated. After the high-pressure washing water removes the trace material between the filter mesh holes, it continues to enter the next dehydration cycle.

      Doyen specializes in providing belt press equipment for the Southeast Asian market. Welcome to visit our workshop and formulate a more scientific  plan based on the actual situation of your company. Welcome to visit joyce@doyenchina.com or visit https://www.doyenchina.com.