What are the steps to calibrate and confirm sieve mesh size?
To check the size of the openings in a sieve, you can use a few different methods, such as the microscope method, densometer method, or special calibration beads. It’s pretty simple—you’ll usually count the number of holes per inch with a magnifying glass or some other tool. Or, you can use calibration beads that are already measured, shake them through the sieve, and see how many stay behind to compare with a handy chart that tells you the exact size
Here is a comprehensive overview of the calibration procedure:
- Preparations:
– Cleanliness: Ensure that the sieve is thoroughly cleaned prior to calibration.
– Labelling: Attach a label indicating “Under Calibration” to the sieve.
- Counting Mesh Openings (Microscope Method):
– Marking: Use a calibrated ruler to draw a square inch on a sheet of paper.
– Counting: Position the paper beneath the sieve and count the number of openings in the designated area, both horizontally and vertically, utilizing a magnifying glass.
– Multiple Locations: Conduct the counting at various points on the sieve to obtain an average.
– Tools: Alternatively, a densimeter or a combined eyeglass can be employed to count the openings.
- Sieve Calibration Beads Method:
– Weigh the sieve: Place the sieve on a balance and tare it.
– Add calibration beads: Introduce a predetermined quantity of calibration beads, which have a known size distribution, onto the sieve.
– Shake the sieve: Shake the sieve for a specified period.
– Weigh retained beads: Weigh the sieve along with any beads that have been retained.
– Calculate percentage passing: Determine the percentage of beads that passed through the sieve.
– Compare to calibration graph: Utilize the percentage passing in conjunction with the calibration graph provided with the beads to ascertain the mean aperture size of the sieve.
- Verification:
– Visual Inspection: Conduct a visual examination of the sieve cloth for any imperfections such as punctures, creases, or oversized openings.
– Comparison with Standards: Compare the mesh size of the sieve against established standards such as ASTM E11 or ISO 565.
– Repeatability: Confirm that the calibration process is both repeatable and consistent.
By adhering to these steps, you can effectively calibrate and verify the mesh size of your sieve, ensuring its dependability across various applications.
Sieve Calibration Methods
- To check mesh size above 40# and up to 150#: Hold the sieve against the light on sieve inspection board.
- Take the appropriate scale of Denso meter.
- Hold the Denso meter over a sieve. …
- Check with Denso meter at five different positions.
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