Sewage pump is a kind of non-clogging pump, with various forms: such as submersible and dry type, dry type sewage pump with cam rotor, mainly used to transport urban sewage, feces or liquid containing fibers, paper scraps For mediums such as solid particles, the temperature of the medium to be conveyed is usually not greater than 80 ¡ãC. Because the conveyed medium contains fibers that are easily entangled or bunched. Therefore, the flow channel of this kind of pump is easy to be blocked. Once the pump is blocked, the pump will not work normally, and even the motor will be burned, resulting in poor sewage discharge. It has a serious impact on urban life and environmental protection. Therefore, blocking resistance and reliability are important factors for the quality of sewage sewage pump.