The solid-liquid separation with horizontal scraper (peeler) centrifuges is effected discontinuously in a sequence of specific process steps. The individual process steps last from a few minutes to several hours depending on the characteristics of the product. Depending on the type of control system, the process can be fully automatic, semi-automatic or manual.
The suspension is applied evenly to the centrifuge basket via a feed pipe with deflector. The fill level control prevents overfilling of the basket.
The basket accelerates to centrifuge the liquid from the cake.
After the intermediate centrifugation, wash liquid is applied evenly to the product cake. The liquid reaches the product cake via the wash pipe.
After washing, centrifugation takes place until the required residual moisture content in the filter cake is achieved.
At reduced speed, the scraper knife swings into the filter cake and scrapes out the product vertically downward via the discharge chute. Depending on the characteristics of the product and the basket width, a discharge screw conveyor may be fitted instead of the chute.
A residual heel is left on the filter cloth to protect the cloth during scraping. The heel can be used to prevent fine content in the filtrate passing through the filter cloth during subsequent batches. The residual heel in the Horizontal Scraper centrifuge is removed after each batch, or periodically, to suit the specific application. The heel can be blown out via the discharge chute using gas pressure pulses provided via nozzles outside the basket. If the process area is purged with inert gas, nitrogen is used for this process.