Common Faults and Solutions for the Screw Press
1. Clogging or Jamming of the Dewatering Main Body
Causes:
(1) Quality issues with the equipment, especially concerning the smoothness of the screw shaft and ring pieces. If the manufacturer neglects the leveling process on the surface of the shaft and ring pieces, the equipment is prone to sludge blockage during use.
(2) Related to the nature of the sludge. Organic sludge and inorganic sludge have different characteristics. Organic sludge is high in organic matter, easily putrefiable, foul-smelling, fine-grained, light, and has a high water content, making it resistant to dewatering. In contrast, inorganic sludge exhibits the opposite characteristics.
(3) Using the screw press to handle sludge with a high inorganic content or coarse particles may lead to blockage in the dewatering section due to the mismatch between sludge characteristics and the operating parameters of the screw press.
(4) Improper operation. Different models of screw presses correspond to different processing capacities. If the amount of sludge entering the screw press far exceeds its processing capacity, the screw press will operate under overload conditions. Failure to clean and empty the screw press before and after use can result in residual sludge adhering to the screw flights, leading to equipment blockage.
Solutions:
(1) Before use, let the screw press run idle for about 10 minutes, assisted by the spray device. After use, turn off the feed, let the screw press run idle for about 30 minutes, allowing complete drainage of residual sludge, and clean the screw flights with clean water.
(2) For mild blockages, attempt to use the reverse function of the screw press (there is a "frequency conversion reverse" button on the control interface) or open the spray for flushing.
(3) For severe blockages, immediately stop operation, conduct equipment inspection, rinse with a large amount of clean water, and, if necessary, dismantle the screw shaft to clean the adhered sludge.
(4) During the operation of the screw press, minor shaft blockage issues may occur. More importantly, following the equipment's operational requirements and mastering the correct operating methods can prevent shaft blockage issues.
2. Wet Sludge Discharge from the Screw Press
Causes:
(1) Coagulation issues. Due to the unique operating principle of the screw press, wastewater treated with the screw press must undergo pretreatment with coagulant agents. After the wastewater coagulates and settles, it is pumped into the equipment for dewatering. The size of flocs formed is influenced by the compatibility of chemicals, the proportion of chemical additives, and the solubility of the chemicals. Flocs that are too small cannot meet the feeding requirements between the screw flights, leading to insufficient dewatering, while excessively large flocs restrict more moisture in the sludge, reducing the cake dryness.
(2) Improper equipment debugging. In terms of debugging: firstly, adjust the coagulation effect of the sewage; secondly, adjust the speed frequency of the main shaft; thirdly, adjust the gap size of the back pressure plate according to the sewage flow rate at the inlet. Professional technicians will adjust the sewage inlet flow and the gap size of the back pressure plate based on the characteristics of the sewage and the size of the flocs.
Solutions:
(1) Proper coagulant adjustment is essential. Match suitable coagulants according to the characteristics of the treated wastewater. Adjust the proportion of coagulant addition based on the coagulation speed and size of the flocs to achieve good coagulation status when the wastewater enters the reaction tank.
In addition to coagulant adjustment, the adjustment of the back pressure plate is crucial. Therefore, after purchasing the screw press, it is advisable to have professional technicians perform adjustments to achieve better treatment results.