Brookfield AMETEK

RST Plus Soft Solids Tester

New, enhanced encoder allows for increased measuring and control capabilities while maintaining sophisticated rheological analysis at an affordable price.

Product Description

RST Soft Solids Tester

Brookfield's high end, touch screen rheometer uses vane spindle geometry in both controlled stress and controlled rate modes to characterize creep behavior as well as yield stress and viscosity profiles.

Features & Benefits

  • Vane spindle geometry allows spindle insertion without compromising sample structure
  • Easy-to-test method for materials with particulates, slurries, and stiff pastes
  • Provides data that relates to viscoelastic characteristics such as yield stress, shear modulus (stiffness of material structure when intact) and creep
  • Quantifies meaningful properties like wobbliness, sloppiness, consistency and texture
  • Automated data analysis under PC control
  • Rugged design for years of trouble-free operation in QC and R&D applications
  • Can also be used with coaxial cylinders for flow curve analysis
  • Optional Rheo200 software with Soft Solids Module allows you to program the R/S Plus Soft Solids Tester and generate data such as yield point, shear modulus, creep and relaxation

Principle of Operation

The flow properties of these materials are not easily measured using traditional coaxial cylinder or cone & plate equipment. Vane spindle geometry provides a solution. The vane spindle is lowered into the test sample with minimal disruption. The test is easily run in the sample's original container.

There are two significant Test Methods easily accomplished by the Soft Solids Tester:

  1. Constant Rate Yield Test
    For Products Like
    Stiff pastes, slurries, set gels, waxes
    Properties Measured
    Yield Stress, Yield Strain, Modulus
    Test Description
    This is a Constant Shear Rate Test. The vane is rotated at a constant low rotational rate and the Stress (torque) is measured against Time, Rotational Angle or Strain.
    Example Method for Mayonnaise
    Constant Rotation at 0.2 rpm, 60 data points are taken in 60 seconds
    Typical Results Plot
    R/S Soft Solids Tester
  2. The Creep/Recovery Test
    For Products Like
    Gels, lumpy products like custard, gravy, sauces and jams
    Properties Measured
    Instantaneous Strain, Viscous Creep, Elastic Recovery, Permanent Flow
    Test Description
    This is a Constant Stress Test. The Stress (torque) is applied to the sample for a fixed time period, usually from one to five minutes. The degree of sample movement is recorded against time as Angular Displacement, Strain or Compliance. The Stress is removed and the Elastic Recovery and Permanent Flow is determined.
    Example Method for Fruit Preserves
    Constant Stress of 1,250 Pa is applied over 120 seconds and 60 data points are taken. The stress is then removed and 60 data points are taken for another 120 seconds.
    Typical Results Plot
    R/S Soft Solids Tester

Consult with Brookfield to determine if the Soft Solids Tester with Vane Spindle Geometry is a suitable solution to your testing needs.


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Spindle Ranges


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Annual Calibration Service (recommended)

We recommend that this instrument be returned to Brookfield or an authorized dealer on an annual basis for our Calibration & Certification Service. Having this annual maintenance done will ensure the instrument's long life and optimal performance.