The function of the stacked screw type sludge dewatering machine is to dewater the sludge from the thickening tank, so as to achieve the purpose of sludge reduction and save the cost of hazardous waste discharge. Generally, the moisture content of the sludge from the stacked screw type sludge dewatering machine is about 75% - 85%, and the moisture content of the sludge cake from the plate and frame filter press is generally below 65%. The low moisture content of the sludge from the plate and frame filter press is one of its major advantages, How to reduce the water content of sludge and increase the competitive advantage of the sludge dewatering machine has become an urgent problem to be solved.
In order to reduce the water content of sludge, the factors that affect the dryness of sludge should be considered firstly. The main factors that affect the dryness of sludge are: 1. The nature of sludge 2. The flocculation effect of sludge 3. The filtering length of the main body 4. The rotation speed of the main shaft 5. The back pressure gap of the back pressure plate.
1. Sludge properties: when other parameters are fixed, the sludge dryness of different industries will be different after dewatering. For example, the sludge dryness of paper industry is higher than that of petroleum industry.
2. Flocculation effect of sludge: factors influencing the flocculation effect of sludge:
a. Generally speaking, Cationic PAM can be used for sludge dewatering to flocculate. PAM dosage directly affects the flocculation effect of sludge. If the dosage is small, the flocculation effect is poor, and the sludge dryness is poor. If the dosage is too large, the sludge will be sticky and slippery, and the sludge dryness will become poor. The appropriate dosage can ensure the best sludge dryness.
b. The stability of the sludge inflow concentration and flow rate is also an important factor affecting the flocculation effect. Generally, the sludge concentration from the sludge pool will fluctuate obviously. When the sludge concentration becomes lower, the sludge inflow will increase. If there is no intervention, the dosage will be insufficient, resulting in poor flocculation effect.
3. The filter length of the main body of the screw stacking machine. In order to save the cost, some screw stacking machine manufacturers shorten the main body of the screw stacking machine. If the main body of the filter is too short, the filtrate will be discharged before it is completely filtered out, resulting in dry mud.
4. Spindle speed. In some sites, in order to increase the sludge output, the spindle speed is increased, which will also lead to the discharge of filtrate before it is completely filtered out, resulting in the sludge not dry.
5. If the back pressure gap of the back pressure plate is too large, it will not form squeezing force on the sludge, and the sludge will not dry out. The smaller the back pressure gap is, the greater the squeezing force is, and the greater the dryness of the sludge will be. However, if the back pressure gap is too small, the sludge will not be discharged, resulting in axle holding.
The above factors are the main factors affecting the sludge dryness of the stacked screw sludge dewatering machine. Only by controlling the above factors can the best sludge dryness of the stacked screw sludge dewatering machine be ensured.