Unique method of calibrating sieves from 20 - 3350mm

Certified using Electroform sieves NIST & NPL traceable  

Accurate to 1mm for the smaller aperture sieves

High speed calibration - complete in about 2 mins

Single shot bottles remove operator sampling errors

Aperture sizes independent of sieve shaking method

Analyses over 80% of the sieves surface

Sieves don't need to be sent away for calibration

WHICH STANDARD SHOULD I USE?

The aperture size of every sieve manufactured from 20 to 3350 microns can be certified to NIST traceability.
Our standards are named after the 30 most popular sieves (R40/3) but can also be used for the 30 intermediate sizes.
If you are unsure of the standard you should be using just check the table below, the ‘primary’ sieve size is highlighted in bold, the sieve on either side can also be calibrated using the same Sieve Standard.

INSTRUCTIONAL ANIMATION
on a 30 second loop

INSTRUCTIONS

SIEVE CALIBRATION BY THE GLASS MICROSPHERE METHOD

 
Instructions
Place the 200mm or 8 inch sieve to be calibrated with the collecting pan on a 0.01g resolution balance and tare. Select the appropriate calibration standard for the sieve and a pour on a single-shot bottle. Record the initial weight of the microspheres. Shake the standard over the surface of the sieve using one of the generic methods shown above until the end-point is reached - see below. When complete, tap the frame a few times to dislodge near mesh beads and empty the undersize fraction from the pan into a collecting vessel. (These microspheres can be kept for future analysis by microscope if the maximum aperture size of the sieve needs to be determined). Reassemble the sieve and pan and tap a few more times by hand. If beads still fall through the mesh, the shaking time needs to be increased because the end-point has not been reached. Empty the pan again if necessary. Without resetting the tare on the balance, re-weigh the sieve and pan together with the retained microspheres. Record the weight. From the retained weight, calculate the percentage of microspheres passing the sieve and use the calibration graph supplied with the test certificate to determine the mean aperture size.

Use a vigorous swirling action to disperse the standard over the sieve surface. 2–3 cycles per second for 1 minute is recommended.

Shaking times may vary from 1 to 3 minutes depending on the sieve shaker. Empty and check the pan each minute to determine the end -point.

A vacuum of 2000–2200Pa for 3 minutes is adequate for most sizes above 30 um. The end- point is when the retained fraction is constant.

Run time typically 1 minute. An amplitude of 30 is sufficient to fluidize most standards but increase if necessary.

Notes:
(a) For sieves below 100um a 5% difference in weight passing usually only corresponds to a 1um difference in aperture size, which makes this method one of the most accurate ways of calibrating a sieve.
(b) To clean the sieve, lightly brush the underside with a soft bristle bush or use an ultrasonic bath. Never use a wire brush or sharp object to remove trapped beads.
(c) For 300 and 450mm sieves, use 2 to 5 bottles (see library).

A calibration graph from a 63mm sieve standard

Tolerances and Recommended Aperture Sizes in the Calibration of 200mm Diameter Test Sieves by Microscopy 
- from BS 410-1:2000, ISO 3310-1:2000

Recommended Count for Microscopy