The central transmission structure is generally used for scraping and collecting sediment from various circular sedimentation tanks with a diameter of 18m for small rain (usually 600T/h for small rain in a single tank). Normally, the sediment enters the center and is discharged from the center, while the surrounding water exits.The ZXG type center drive scraper is generally used for municipal sewage and similar sewage (such as petrochemical, papermaking and other industries). The sludge density is relatively light (generally less than 1.2T/m?), and it is not easy to plate the bottom sediment of the tank. Generally, it does not have a floating slag scraping function, and inclined plates or inclined pipes can be installed in the tank to improve the sedimentation effect.The NZS type center drive thickener is similar to the ZXG and is mainly used to further concentrate the sludge discharged from ordinary sedimentation tanks. In terms of structure, it has more grid bars than the scraper to increase the compactness of the sludge.