Schulze Shear Cell
Dietmar Schulze Shear Cell. This device is capable of testing as little as 12 g of powders. The main part of Schulze RTS-XS ® Shear Tester is an annular cell, where the powder specimen is placed. A series of vanes on the bottom of the cell and on the lid prevent powder slipping against the cell boundaries during shearing. The lid is subjected to a vertically acting normal force in order to attain the desired compression level. The normal load is applied by a loading system, which also contains a displacement transducer to measure the lid displacement during shearing in order to capture volumetric changes occurring in the assembly. The shear stress acting on the assembly is continuously monitored by two additional load beams connected to the lid of the annular cell.
Freeman FT4 Powder Rheometer
This device consists of a cylindrical column into which powder is placed and a range of attachments for measuring various aspects of powder flow. The standard test drives a rotating impeller downward into a powder bed and measures the force acting on the cell base and the torque acting on the impeller. A value of ‘flow energy’ is determined by summing the rotational and translational work required to drive the impeller a given distance into the bed. The bed can be pre-conditioned by gently slicing into the bed prior to the test with the impeller rotating in the opposite direction. A porous plate can be placed at the base and air driven up through the bed at a range of velocities to see the influence on the flow energy. The permeability of the bed can be assessed by measuring the pressure drop across the bed under varying consolidation stresses and air flow rates. In addition, a shear cell attachment with radial vanes can be attached instead of the blade to measure the shear stress required to initiate steady-state flow under a given normal stress.