Design and maintenance of belt filter press

   1. Drive mechanism
Original state: The filter belt drive of the dehydrator is driven by a reducer, but the output speed cannot be adjusted.
Analysis: Because at the beginning of the dehydration machine debugging, its processing capacity cannot meet the design requirements all at once, which has a great relationship with the on-site debugging conditions and the overall performance of the equipment. Since the walking speed of the filter belt cannot be adjusted, it is impossible to make corresponding adjustments at any time according to the changes in the nature and flow of the sludge during the debugging process.
Modification: Change the reducer to a combination of transmission and reducer, and adjust the speed of the filter belt through the handwheel of the continuously variable transmission. The walking speed of the filter belt can be adjusted to a certain range, so that the dehydrator can be adjusted for different sludge properties and sludge flow rates. The performance is adjusted to meet customer needs.

2. Flushing mechanism
Original state: The peripheral pipeline of the flushing mechanism is made of U-PVC material, and the flushing pipe is made of stainless steel 304, and the two are connected by U-PVC inner wire joints.
Analysis: Because it is connected with an inner wire joint, it is not easy to take out the flushing tube when the nozzle is blocked. Even if it is taken out, all the cleaning pipes on the dehydrator need to be taken out, so cleaning the nozzle becomes more difficult. Modification: The U-PVC pipeline and each stainless steel flushing pipe are connected by flanges, and the flushing pipe chute is added to facilitate the installation of the flushing pipe and the maintenance of the nozzle.
3. Flocculation mixing tank
Original state: Before entering the flocculation tank, a pipeline mixer is used for sludge flocculation. The flocculation tank uses swirling water to enter the water, and finally flows to the thickening part of the drum for sludge concentration to achieve the pressing conditions.
Analysis: Because the loss of the pipeline mixer is relatively large, and it is easy to break the flocculated sludge again. When the sludge enters the flocculation tank, there is no baffle. The sludge swirls along with the water flow, and the sludge cannot contact the flocculant again, thus losing the function of the flocculation tank.
Modification: Add a baffle in the flocculation tank, the purpose is to make the flocculation more thorough and achieve a better treatment effect. However, considering that both a pipeline mixer and a flocculation tank are used, it is better to combine the two into one. It is recommended to eliminate the pipeline mixer and use a flocculation mixing tank. That is, adding a mixer to the flocculation tank to perform flocculation stirring also ensures that the flocculation reaction is more complete, and the flocculation effect can be intuitively reflected from the flocculation stirring tank. (This is a suggestion)
4. Tensioning mechanism
Original state: The tensioning mechanism adopts screw tension, rigid connection.
Analysis: Due to the actual use of the dehydrator, as the sludge flow changes, the sludge intercepted on the filter belt also changes relatively. If the sludge flow becomes smaller, the filter belt will appear looser, and the moisture content of the mud cake may not meet the requirements. If the sludge flow is too large, the filter belt will collapse very tightly, and the surface tension of the filter belt will increase, which will easily cause mud running. Therefore, if it is a rigid connection, it is not a good thing for the equipment and the filter belt.
Modification: Screw tensioning is still used for tensioning, but a spring adjustment mechanism is added in the middle, so that as the sludge flow changes, the spring can adjust its expansion and contraction by itself to achieve adjustments to the tension of the filter belt and changes in peripheral conditions.

5. Pneumatic system
Original status: According to observations, the filter belt adopts double cylinders to correct deviation, and only the lower filter has a filter belt limit switch to protect the filter belt from deviation. Analysis: In the actual operating experience, the double-cylinder correction effect is obviously better than the single-cylinder correction effect. However, using a single cylinder to correct deviation can also meet the needs of equipment operation.
Modification: One end of the filter belt adopts a correction cylinder to correct the deviation, and the other end adopts a screw adjustment structure, which is adjusted according to the on-site operation. The upper filter belt limit switch is added to protect the filter belt and extend its service life.
6. Compression system
Original state: In the rolling system, the pressing force is relatively small. The two drums are welded with steel pipe angles to facilitate the squeezing of water.
Analysis: Because the pressing surface is the top of the angle steel, the contact form between the filter belt and the angle steel is line contact, which will increase the wear of the filter belt and reduce the life of the filter belt. In addition, since the welds of angle steel and steel pipes are exposed to air and sewage, the welds may corrode more severely. Once the angle steel falls off due to weld corrosion, the consequences will be disastrous.
Modification: The welding angle steel outside the steel pipe is now removed, but it may affect the squeezed water. However, according to the actual operating conditions on site, most of the water still passes through the filter belt or is removed from both sides of the filter belt. If you want to consider better results, you can drill holes on the surface of the pressure roller, which can also be achieved, and this will not affect the service life of the filter belt.

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