Scroll discharge decanter, centrifugal

Figure 8.4 Three common sedimenting centrifuge designs. A) Scroll discharge decanter, B) Tubular bond C) Disc stack, no solids discharge [Courtesy of Alpha Laval Separation Ltd.]...

The Sorticanter has a scroll with reversing pitch on one side, which skims a floating solids layer off the top of the carrier hquid, usually an aqueous brine of intermediate density. Sinking solids are scrolled out similarly to normal decanter centrifuges, and liquid is discharged under pressure via a stationary but variable impeller. The Sorticanter is utihzed in the plastics recycling industry. 

Scroll/decanter Continuous 5-50,000 200 1. Continuous solid discharge 2. High-feed solid concentration 1. Turbulence created by scroll 2. Low centrifugal force Antibiotic production... 

Laboratory test tube centrifuges can determine if there is a sufficient density difference between the two phases to consider sedimentation as an alternative. If there is a sharp separation, one can anticipate the same in the field. One can also answer the following questions. Do the solids settle or float Is the solid phase granular or amorphous What is the moisture content The characteristics of the solids indicate the solids discharge design required, i.e., scroll in decanters, or in disk centrifuges, flow-through nozzles or wall valves. 

To recover liquid and solids in order of preference of settlers. Section 5.8, CCD, Section 5.11 and sedimentation centrifuges. Section 5.12 continuous countercurrent decanter circuit CCD, horizontal solid bowl centrifuge with scroll discharge. 

The solid-bowl scroll-discharge centrifuge — now almost universally known as the decanter centrifuge — has, indeed, become the workhorse of a wide range of liquid/solid separation activities. Its application to the dewatering of waste sludges has made it a most valuable tool in combating environmental pollution. This has made the decanter a well-known and widely appreciated piece of equipment. 

Decanter centrifuges, for process applications, are typically solid bowl scroll-discharge machines, capable of continuous sohd and centrate discharge. They are ideally suited to handling high feed solids concentrations and delivering dry solid products. They are generally able to convey the soft solids often encountered in the pharmaceutical and fermentation industries. 

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