Developed as a direct and improved successor to the widely used Fisher Model 95 Sub-Sieve Sizer (FSSS), HEL has improved the FSSS’s performance by offering easy-to-use automated functions together with electronically recorded data.
The SAS is designed to generate “Fisher number” results identical to that of its predecessor (the Fisher FSSS). This is a crucial point, as the air permeability technique and the FSSS have been used as a benchmark for decades in many industries. Many applications use historical data and quality control standards, and a modern source of comparable, repeatable results is necessary.
What is Air-permeability Particle Sizing?
The air-permeability technique is well established for measurement of the Specific Surface Area (SSA) of a sample powder. The SSA measured by this technique has been found to be a useful parameter in various industries such as pharmaceutical, metal coatings, paints, and even geological samples.
The SAS utilizes dual pressure transducers to measure pressure drop across a packed bed of powder. By varying the sample height and porosity while controlling the flow rate of air through the sample, the SSA and average particle size can be determined using the Kozeny-Carman equation.