Fisher Sub Sieve Sizer Principle 201-1

Jan 28, 2022

What a standard Fisher sub sieve sizer consist of ?

HMK-22 Fisher Sub-Sieve Sizer is manufactured by HMKTest, a world leading manufacturer of fisher sub sieve sizer particle size analyzer. HMK-22 fisher sub sieve sizer conforms to ASTM STANDARD B330-12. In addition to fisher sub sieve sizer manual, an HMK-22 fisher sub sieve sizer consists of following fisher sub sieve sizer parts and accessories:

  • Air pump

HMK-22 Fisher Sub Sieve Sizer P/N 020198

  • Air filter
3. Fisher Sub Sieve Sizer Principle

3. Fisher Sub Sieve Sizer Principle/HMK-22 Fisher Sub Sieve Sizer P/N 020198

  • Constant pressure regulator

3. Fisher Sub Sieve Sizer Principle/HMK-22 Fisher Sub Sieve Sizer P/N 020198

  • Pressure control
  • Sample tube
  • High needle valve
  • Low needle valve
  • Manometer
  • Calculator chart
  • Sub-sieve sizer calibrator etc.

hmk-22-fisher-sub-sieve-sizer-2016-03-18/HMK-22 Fisher Sub Sieve Sizer

How a fisher sub sieve sizer works?

Turn on HMK-22 Fisher Sub-Sieve Sizer, the air pump generates compressed air and the air passes air filter to filter out impurities, after constant pressure regulator, the air goes through the dryer made up of allochroic silicagel to dehydrate, then the air enters sample tube, after passing through the packed powder sample, part of compressed air enters manometer, read on the calculator chart average particle size (Fisher Number) according to the water level height in manometer, excessive air exits via high needle valve. There is void among tested particles, pressure drop △P is generated after passing the tested powders, when the mass of powder is fixed, the bigger the particle is, the bigger the void among particles is therefore more easily the air passes the powder and the smaller pressure drop is and the higher the manometer water level is and the bigger the size on the calculator chart is, vise versa. The obtained value is fisher number particle size, i.e. averaged particle diameter of surface area of tested powders.

Please view more at Fisher Sub-Sieve Sizer Manual


fisher-sub-sieve-sizer-principle-picture-1/HMK-22 Fisher Sub Sieve Sizer

  • 1-1 Constant Pressure Regulator
  • 1-2 Pressure Control
  • 1-3 Air Filter
  • 1-4 Air Pump
  • 1-5 Dryer
  • 1-6 Packed Powder Sample
  • 1-7 Sample Tube
  • 1-8 Range Control
  • 1-9 Manometer
  • 1-10 Calculator Chart
  • 1-11 Manometer Level Control


  • dvs(Fisher Number)- average diameter in microns (one micron = 10-6 meters
  • k- shape factor
  • g- acceleration of gravity
  • ɛ- powder porosity (percentage of voids of tested sample)
  • η- viscosity of air
  • L- length or height of compacted sample in cm (measured by operator)
  • u- flow rate passing sample layer in cm/second
HMK-22 Fisher Sub Sieve Sizer

HMK-22 Fisher Sub Sieve Sizer P/N 020198

-Tungsten powder fisher sub sieve sizer
HMK-22 Fisher Sub Sieve Sizer/Average Particle Size Analyzer (FSSS) is an optimal tool for sub sieve particle size analysis and has become the best successor of discontinued Fisher Scientific Sub-Sieve Sizer(FSSS) Fisher Model 95. It uses Air Permeability Principle to fast determine the Average Particle Size i.e. Fisher Number of powders. HMK-22 Fisher Sub-Sieve Sizer completely meets international standards about fisher sub sieve sizers ASTM B 330 Standard Test Method for Fisher Number of Metal Powders and Related Compounds and ISO 10070 Metallic powders Determination of envelope-specific surface area from the measurements of the permeability to air of a powder bed under steady-state flow conditions. HMK-22 Fisher Sub Sieve Sizer meets the urgent requirement of the industry to find a quality successor to particle sizing technique by air permeability device such as fisher model 95. It gives operators completely same test experience and the results agrees completely with all the tested data obtained by a discontinued Fisher Scientific Sub-Sieve Sizer Model 95.

HMK-22 Fisher Sub-sieve Sizer


The Sub-Sieve Sizer operates on the air-permeability principle for measuring the average particle size of powders. The principle is based upon the fact that particles in the path of a regulated airflow will affect that airflow in relation to their size. More specifically, however, the principle finds its basis in the fact that a current of air flows more readily through a bed of coarse powder than through an otherwise equal bed of fine powder that is eaual in shape of bed, apparent volume, and percentage of voids; but by reason of difference in general coarseness of material (differing in average pore diameter and in total interstitial surface), measurements of average particle sizes are obtained.