Shaft breakage may occur in filter press pumps during use, but this is rare, with a probability of almost one in a thousand. There are probably several reasons for this: poor material quality. The pump shaft of the filter press pump is generally made of chrome-vanadium steel or chrome-molybdenum-vanadium steel. Poor material quality is the main cause of pump shaft damage. Unreasonable selection. Among the four parallel feed pumps on the third floor of the old factory building, one has a power and flow greater than the other three, and this feed pump has never had a broken shaft. Imprecise installation. Among them, R is the pipeline constant, which is inversely proportional to the pipeline diameter, and is related to factors such as the material size of the pipeline, the opening degree of the pipeline gate, the straight pipe length and the resistance coefficient. When the pipeline is constant, R is a constant.
H is the head of the filter press pump, and H is the total energy loss of the material in the pipeline. Compared with the feed pipe of the quick-open filter press, the feed pipe of the chamber filter press has more elbows and short straight pipes, and the diameter is thin. The different opening degrees of the discharge gate valve cause large energy loss in the pipeline. The feed pump of the chamber filter press is outside the working range, resulting in large flow and low head. It is necessary to ensure the feed pressure of 0.8MPa, which increases the pump load. The discharge valve is always open. The operation of the filter press pump has always been to open the discharge valve to start the pump, causing the motor to overload and increase the load on the shaft. The use of closing the feed valve to control the flow will cause cavitation. The oxygen formed by cavitation will chemically corrode the metal and cause fatigue damage to the shaft and impeller. Correct operation should start the discharge valve slowly at normal speed. Because the discharge valve is manual, it takes more than 30 minutes to open and close each time, causing the pump discharge valve to always be open. An electric gate should be installed at the discharge point for operation. Fatigue damage.
The filter press pump is proportional to the flow rate of the pump and the speed. By changing the diameter of the pump's belt wheel to change the speed, the pump flow rate is reduced, the head is increased, and the pump operates within the efficient working range, which improves work efficiency and reduces the torque on the shaft, reducing the degree of fatigue damage. The flow rate deviates from the working range. From the performance curve of the filter press pump, it can be seen that the flow rate, head, power, and efficiency of the filter press pump are within the efficient working range. This range is within the efficient area of the filter press pump and is also the theoretical working area of the pump. However, the actual operation is to determine the other parameters on the basis of satisfying the feed pressure of the pump. At this time, the flow value is not within the working range, which causes the power and other parameters of the filter press pump to deviate from the efficient working range.