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FT4 Powder Rheometer

Powder Flow Testing with the FT4 Powder Rheometer®

The FT4 Powder Rheometer - a universal powder tester for measuring powder flow properties and powder behavior

Measuring and understanding powder flow properties

The FT4 was designed with one purpose in mind – to characterize the rheology, or flow properties, of powders. This remains a primary function today, but the instrument, accessories and methodologies have been continuously developed to the point where the FT4 is now considered a universal powder flow tester.

Four testing methodologies in one instrument:

  • Unique Dynamic Flow
  • Fully Automated Shear Cell (in accordance with ASTM Standard D7891)
  • Bulk Properties
  • Processing Variables


  • Fully automated test programs and data analysis
  • Conditioning mode provides unparalleled repeatability
  • Range of sample size, 10ml to 160ml (in addition a 1ml Shear Cell can be selected for limited sample size)

The FT4 employs unique technology for measuring the resistance of the powder to flow, whilst the powder is in motion. A precision ‘blade’ is rotated and moved downwards through the powder to establish a precise flow pattern. This causes many thousands of particles to interact, or flow relative to one another, and the resistance experienced by the blade represents the difficulty of this relative particle movement, or the bulk flow properties.

Excellent reproducibility is achieved by moving the blade in a precise and reliable way. The advanced control systems of the FT4 accurately set the rotational and vertical speeds of the blade, which defines the Helix Angle and Tip Speed.

Powders are complex materials. Often perceived as just a collection of particles, they are in fact a complex mixture of solids, liquids and gases. They comprise of solids in the form of particles; gas, usually in the form of air between the particles; and water, either on the surface of the particle or within its structure. The behavioral characteristics of these unique materials are difficult to model and predict from first principles.

Powders exhibit many behavioral characteristics, which determine how they perform during processing and in final application. These characteristics are often independent of one another, so it is important to understand and to be able to measure the influence of each, if a powder is going to be fully characterized.

The nature of all processing environments is such that a range of conditions is unavoidable, and the powder being processed will be handled under different stress regimes. To fully predict the powder’s in-process performance, it is essential to measure and quantify how it responds to each of these external variables.

FT4 Methodologies

The FT4 is a truly universal powder tester, with four categories of methodologies, defined as Bulk, Dynamic Flow, Shear and Process.

Proven applications:

The FT4 has application in all powder processing industries, including Pharmaceuticals, Fine Chemicals, Food, Cosmetics, Toners, Metals, Ceramics, Plastics, Powder Coatings, Cements and Additive Manufacturing.

Applications extend to:

  • Die / Capsule Filling
  • Humidity Effects
  • Attrition
  • Wall Friction & Adhesion
  • Tablet Compression
  • Electrostatic Charge
  • Dry Powder Inhalers
  • Hopper Design
  • Hopper Flow
  • Mixing / Blending
  • Caking
  • Compact Hardness & Payoff
  • Wet Granulation End Point & Scale Up
  • Feeding
  • Milling
  • Vacuum Filling
  • Flow Additive Selection & Optimization
  • Segregation
  • Conveying
  • Agglomeration

FT4 Powder Rheometer Online Demonstration: