An experimental evaluation of powder flow predictions in small-scale process equipment based on Jenike's hopper design methodology

Impact of Shear History on Powder Flow Characterization Using a Ring Shear Tester

“…5 The flow function together with other parameters, such as bulk density, r B , effective angle of internal friction, d, and the wall friction angle, 4 w , on a representative wall material, serve as critical inputs for designing hoppers suitable for handling a particular bulk solid. 3,6,8,12 This extended analysis, however, requires at least 3-5 shear tests to create the flow function which demands more material and time. 13 The Schulze ring shear tester is one of the most widely used testers in the pharmaceutical industry.…”

“…This allows multiple shear tests to be conducted with one bulk solid specimen to measure several yield loci at different stress levels, that is, "a walk through different stress levels". 9,12,14 Thus, it provides a relatively rapid assessment of the stress dependence of powder flowability using the same bulk solid material. This makes the stress walk (SW), practically, one of the most attractive methods for material flow characterization using shear cell and that is, evidenced by its use in recent studies on powder flow.…”

“…This makes the stress walk (SW), practically, one of the most attractive methods for material flow characterization using shear cell and that is, evidenced by its use in recent studies on powder flow. 9,12,15 Notable among them is the generation of 9-point flow functions by this method in the preshear normal stress range of 0.25-15 kPa. In fact, this method can be used in any stress range accessible to the new ring shear tester.…”

“…Furthermore, the ability to estimate stresses in powder-containing vessels (i.e., intermediate bulk containers [IBCs]) during pharmaceutical operations such as tableting is gaining attention. 8,9,12 Under this new paradigm, powder flow properties obtained from shear cell are used to predict flow patterns during discharge and also predict the tendency of flow obstruction, or arching. Thus, we modeled the use of a pilot to commercial manufacturing scale bin/tote with a hopper, mainly to provide a basis for risk assessment and to demonstrate the effect of the powder shear history on hopper design analysis for the powders.…”

A Proposed Complete Methodology to Predict Gravity Flow Obstruction of Pharmaceutical Powders in Drug Product Manufacturing

“…9,10 It is not until in recent years that these concepts and procedures are introduced into the pharmaceutical industry with some success. 11,12 For example, a recent study by Søgaard et al, 11 using the Jenike's hopper design methodology, led to accurate prediction of powder flow pattern out of a real press hopper. The authors also reported general agreement between the predicted and observed critical outlet diameters for arching, though the powder flow experiments were conducted on a testing device instead of manufacturing equipment.…”