Disc Stack Centrifuges. A disc stack centrifuge is a clarifier whose base is wrapped around a center line. Slurry is fed into a scroll at the center from which it is accelerated circumferentially and forced through distribution ports into the bowl. The slurry rotates with the bowl and forms a concentric layer at the bowl wall. Solids are deposited against the bowl wall by centrifugal force. The scroll rotates at a different speed than the bowl and moves the solids toward the conical end of the bowl from which they are ejected through ports to fall through to the discharge chute.
Things to Consider: Throughput capacity, Bowl speed, Bowl volume, Sludge space, Motor speed, Motor power, Starting time, Stopping time without brake, Inlet pressure, Outlet pressure, Sound pressure level, Overhead hoist lifting capacity, Electric power consumption, Operating liquid consumption, Cooling water consumption, Sealing liquid consumption, Flushing liquid needed per discharge, Materials of construction, Shipping weights of components, Shipping volume, Warranty.
Peeler Centrifuge. This type of centrifuge inputs a suspension into its basket. Under the influence of the centrifugal force the liquid is drained from the solids, through filter elements. The solids are collected as ‘cake’ in the basket. After washing or other treatment, if necessary, solids are allowed to dry. Solids are ‘peeled’ off using a full-basket-width scrapper, and is discharged.
Things to Consider: Ease of cleaning, Full access to all process wetted parts, Effective residual heel removing system, Cleaning-in-place system, Materials and construction, Vibration isolating mounts, Centrifuge monitoring casing designed without dead corners allowing solids to accumulate, Bearing housing quality, Peeler plow assembly and discharge should have highly polished surfaces with no dead corners for solid accumulations, Charge detector to limit maximum case thickness, Drive type. Motor electrical requirements, Motor power, Variable speed, Brake system, Programmable logic controller, Vibration monitoring system, Temperature monitoring system for main bearings, Basket diameter, Basket depth, Volume, Maximum load, Maximum rotation speed, Maximum centrifugal acceleration, Motor power output, Dimensions, Weight, Warranty.
Pusher Centrifuges. A continuous filtering type centrifuge used for solid-liquid separation. Slurry is fed into the center of the pusher basket. The slurry accelerates in the rotating funnel and is distributed at the back of the rotating screen. The funnel, which is anchored to the pusher plate, accelerates the slurry to the basket speed in order to form an even cake. As the pusher plate moves into its back position, a clean wedge slot screen surface is exposed. The accelerated slurry is deposited on the wedge slot screen and cake is built as the mother liquor drains through the basket. Then, the pusher plate moves forward and pushes the cake forward, to pass out the discharge end.
Things to Consider: Basket diameter, Materials of construction, Pusher method (e.g. oscillating), Basket enclosure details, Access door, Drive power, Hydraulic drive, Dimensions, Weight, Warranty.
Solid bowl Centrifuge. A centrifuge designed to handle solid particles and slurries. It is used to separate slurries into one or two liquid phases and a solid phase. Solids are continuously separated from the liquid phase by centrifugal force. Denser particles are sedimented against the walls of a rotating steel bowl. The less dense liquid phase forms a concentric inner layer. A helical screw conveyor or scroll continuously removes the sedimented solid particles. This conveyor rotates at a lower speed than the bowl. Centrifugal force compacts the solids and expels surplus liquor. Dry solids discharge out of the lip of the bowl. Clarified liquid flows over adjustable dam plates at the opposite end of the bowl. These centrifuges are effective for clarifying liquids and dewatering solids.
Things to Consider: Feed port location, Continuous operation capability, Variable speed drive, Integral feed pump, Cover safety interlock, Inlet strainer, Portable mounting, High temperature modification for operating up to 400F, Ease of installation and operation, Ease of cleaning to minimize downtime, Servicing requirements, Machine lifetime, Attention to elimination of vibration, Maximum ‘G’ force, Sludge capacity, Basket diameter, Maximum feed rate, Dimensions, Weight, Warranty.
Top Unloading Centrifuges. These centrifuges, of several different types, are characterised by providing access to the processed material through a door or bulkhead at the top of the unit. Usually found in medical or laboratory environments.
Things to Consider: Materials of construction, Unloading location, Maximum bowl speed, Basket solids holding capacity, Maximum flow rate, Motor electrical requirments, Motor rpm, Automatic feed, Automatic sludge chute, Mounting stand, Dimensions, Weight, Warranty.
