Calibration and Control of the Supercentrifuge for the Fractionation of Oil-well Drilling Muds

Drilling mud can be an item of great expense on the Gulf Coast. In order tounderstand the nature of a drilling mud, it is desirable to know thecomposition and size of the mineral particles that are present. Thesupercentrifuge has been adapted to the fractionation of mud, and this paperdiscusses the calibration and methods of operation and control. An alignmentchart has been prepared, which was found useful in this work. Typical data areincluded, showing the comparative reliability of the method. Introduction The application of the Sharples supercentrifuge to the determination of bothparticle size and the particle-size distribution in colloidal systems has beenpresented previously. While other methods such as elutriation, the Casagrandesedimentation method, microscopy, and the ultracentrifuge are available fordetermination of the sizes of particles, the supercentrifuge has the advantagesof large capacity, rapidity of determination, simplicity of operation, and lowmaintenance and operating costs. The Sharples supercentrifuge consists essentially of a balanced cylindersuspended from a vertical drive shaft that is driven by either air, steam, oran electric motor. The supercentrifuge and the equipment used for its operationare shown in Fig. I as set up in the laboratory. The mud suspension to be centrifuged, usually 2 per cent or less of solidsby weight, is allowed to flow into the bottom of the hollow rotating cylinderthrough a small nozzle. From the nozzle, the suspension flows upward parallelto the wall of the bowl and out through channels that open into the bowl nearthe axis of rotation. T.P. 1530