The Wells-Brookfield Cone/Plate Viscometer/Rheometer gives researchers a sophisticated instrument for routinely determining absolute viscosity of fluids in small sample volumes. Its cone and plate geometry provides the precision necessary for development of complete rheological data.    
    
PRINCIPLE OF OPERATION    
    
The Wells-Brookfield Cone/Plate Viscometer/Rheometer is a precise torque meter which is driven at discrete rotational speeds. The torque measuring system, which consists of a calibrated beryllium-copper spring connecting the drive mechanism to a rotating cone, senses the resistance to rotation caused by the presence of sample fluid between the cone and a stationary flat plate.    
    
The resistance to the rotation of the cone produces a torque that is proportional to the shear stress in the fluid. This reading is easily converted to absolute centipoise units (mPa·s) from pre-calculated range charts. Alternatively, viscosity can be calculated from the known geometric constants of the cone, the rate of rotation, and the stress related torque.    
    
The correct relative position of cone and plate is obtained by following a simple mechanical procedure without the need for external gauges or supplementary instrumentation.    
    
The stationary plate forms the bottom of a sample cup which can be removed, filled with .5 ml to 2.0 ml of sample fluid (depending on cone in use), and remounted without disturbing the calibration. The sample cup is jacketed and has tube fittings for connection to a constant temperature circulating bath.    
    
The system is accurate to within ±1.0% of full scale range. Reproducibility is to within ±0.2%. Working temperature range is from 0°C to 100°C.    
    
Various cone spindles are available for use with the Wells-Brookfield Cone/Plate instruments. One cone spindle is provided with the instrument and is calibrated for use with the sample cup. Additional cone spindles may be purchased and will be calibrated for use with the same sample cup.