The lower discharge centrifuge of the PGD series jitter bag scraper is based on maintaining the main functions of the solid-liquid separation scraper discharge of LGZ series products, and adds the function of removing the residual filter cake layer by shaking the bag, and the removal rate can reach more than 99%. Cross-mixing batches of product separation between batches are avoided, and the influence of residual cake layers on filtration rate is solved. Mainly used in pharmaceutical, food, chemical, new energy and other industries solid-liquid separation process.