FT4 Powder Rheometer®: Universal Powder Flow Tester

The FT4 Powder Rheometer^® is a universal powder flow tester that provides sensitive, dependable, and process-relevant analysis.

• Simulate powder processing conditions to guarantee process-relevant data
• Multi-faceted powder characterization—evaluate dynamic flow, and bulk and shear characteristics
• Unrivaled sensitivity
• Fully automated data analysis and test programs

FT4 Powder Rheometer System. Image Credit: Micromeritics Instrument Corporation

Description

The FT4 Powder Rheometer^® is a universal powder tester that can be used to measure powder behavior and powder flow properties.

The FT4 was created to characterize the rheology (or flow qualities) of powders. This is still its main function, but the instrument, accessories, and techniques have evolved to the point that the FT4 is now called a universal powder flow tester.

Four testing procedures are combined in a single instrument:

• Unique Dynamic Flow
• Fully Automated Shear Cell (per ASTM Standard D7891)
• Bulk Properties
• Process Variables

Technology

The FT4 uses advanced technology to measure the resistance of the powder to flow while the powder is in motion. To create an accurate flow pattern, a precision “blade” is rotated and transferred downwards through the powder. Many thousands of particles interact or flow relative to one another as a result of this, and the resistance experienced by the blade represents the difficulty of this relative particle movement or the bulk flow characteristics.

The blade moves precisely and reliably, resulting in excellent reproducibility. The FT4’s advanced control systems precisely set the vertical and rotational speeds of the blade, defining the Helix Angle and Tip Speed.

Image Credit: Micromeritics Instrument Corporation

Why Are Powders Complex?

Powders are extremely complicated materials. They are often regarded as merely a collection of particles, but they are a complex combination of solids, liquids, and gases. They comprise solids in the form of particles; water, either within the structure of a particle or on its surface; and gas, typically in the form of air between the particles. The behavior of these unique materials is hard to model and predict from fundamental principles.

Image Credit: Micromeritics Instrument Corporation

Powders demonstrate numerous behavioral characteristics that influence how they operate during processing and in the final application. These qualities are frequently independent of one another, thus understanding and measuring the effect of each is critical if a powder is to be fully characterized. 

The nature of all processing environments means that numerous conditions are unavoidable, and the powder being processed will be handled under various stress regimens. To completely predict the in-process performance of the powder, it is necessary to test and quantify how it responds to each of these external factors.

Dynamic Methodology

The FT4 is a universal powder tester, with four methodology categories: Bulk, Dynamic Flow, Shear, and Process.

Image Credit: Micromeritics Instrument Corporation

Specification

System

The FT4 Powder Rheometer is designed for laboratory use. It measures the rheological characteristics of powders, pastes, and semi-solids, and complies with the EMC requirements and ASTM International standards listed below:

• EN61000-3-2:2001
• EN61000-3-3: 1995
• EN61326: 1997 + A2:2001
• ASTM D7891

Performance

• Force
  • ± 50 N maximum
  • 0.0001 N resolution
  • ± 900m Nm resolution
• Torque
  • 900 mNm maximum
  • 0.002 mNm resolution
• Vertical travel
  • 185 mm
• Rotor speed
  • 120 rpm maximum
• Axial speed
  • 30 mm/sec maximum
• Residual energy level in the air
  • <2 mJ

Construction

• Working force
  • 316 stainless steel
• Contact parts
  • 316 stainless steel
  • Borosilicate glass
  • Delrin and Peek plastics

Dimensions

• Main instrument
  • 306 × 306 × 760 mm high

Weights

• Main instrument: 22 kg net

Power Requirements

• Supply voltage range: 90 to 264 VAC
• Input current range: 1.6A at 120 VAC; 0.8A at 230 VAC
• Input frequency range: 47Hz to 63 Hz
• Minimum fault protection limit: 30 mA

Environmental Conditions

• Humidity range 20-80 % non-condensing
• Temperature range (operating) 10 ˚C to 40 ˚C
• Temperature range (storage) 0 ˚C to 50 ˚C

Vessels

Precision bore, borosilicate glass tube.

Standard sized:

• 25 mm × 10 ml Split Vessel
• 25 mm × 25 ml Split Vessel
• 25 mm × 35 ml Vessel
• 50 mm × 85 ml Split Vessel
• 50 mm × 160 ml Split Vessel
• 50 mm × 260 ml Vessel
• 62 mm × 137 ml Split Vessel
• 62 mm × 240 ml Split Vessel
• 62 mm × 400 ml Vessel

Blades

Hardened stainless steel.

Standard sizes:

• 23.5 mm diameter × 6 mm wide
• 48.0 mm diameter × 10 mm wide
• 60.0 mm diameter × 10 mm wide

Calibration Kit

• Torque, force, height, spindle speed, and carriage velocity are configured for calibration
• The calibration kit includes calibration fixtures, weights, and height gauges
• A calibration log of the current and prior calibrations is automatically preserved

Accessories

• 25 mm Accessories Kit
• 50 mm Accessories Kit
• 62 mm Accessories Kit
• Aeration Control Kit
• 24 mm Shear Cell
• 48 mm Shear Cell
• 24 mm Wall Friction Kit
• 48 mm Wall Friction Kit
• 1 ml Shear Cell

Accessories

Unique Blade Technology

Image Credit: Micromeritics Instrument Corporation

The FT4 measures the resistance that a powder exerts on a twisted blade as it passes through a sample. This resistance is expressed as “Flow Energy,” determined using direct torque and force measurements.

Range of Vessel Sizes

Image Credit: Micromeritics Instrument Corporation

In addition to a 1 ml Shear Cell kit for testing valuable, scarce, or hazardous powders, there are vessel kits in 25 mm, 50 mm, and 62 mm sizes to suit the materials being assessed.

Aeration Control Unit

Image Credit: Micromeritics Instrument Corporation

The base of the vessel containing the powder receives an accurately controlled air flow from the Aeration Control Unit. The unit can deliver a wide range of air velocities, making it suitable for a variety of materials, and is completely automated and software-controlled.

Shear Cell and Wall Friction

Image Credit: Micromeritics Instrument Corporation

Wall Friction and Shear Cell Kits can be attached to the FT4 to determine the wall friction angle associated with a given construction material, and the shear properties of a powder, including flow function and unconfined yield strength, per ASTM D7891. The Hopper Design function in the FT4 Data Analysis software can be utilized to determine important hopper geometries using shear and wall friction parameters.

Vented Piston

Image Credit: Micromeritics Instrument Corporation

To quantify properties like compressibility and permeability, a vented piston is utilized to apply consolidating stress to a powder sample. This is done to comprehend the impact of handling and storage.

Supplies and Consumables

Source: Micromeritics Instrument Corporation

Applications

Powder processing sectors such as pharmaceuticals, fine chemicals, food, cosmetics, toners, metals, ceramics, plastics, powder coatings, cement, and additive manufacturing could all profit from the use of the FT4.

Applications include:

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

Video Credit: Micromeritics Instrument Corporation