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Sieves and Sieve Calibration |
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FAQ |
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If you have a question, please complete & submit the form at the bottom of the page. |
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| Why use seamless frames? | |||||||||||
| The main body of the sieve is spun to give you a seamless frame. This makes an Impact sieve stronger than those from other manufacturers where the frame is curved and welded to form a circle. | |||||||||||
| Why do sieves bear individual serial numbers? | |||||||||||
| The use of serial numbers provides traceability for quality assurance systems. It also enables us to identify when a sieve was manufactured and the materials used. | |||||||||||
| How do grain sieves differ from test sieves? | |||||||||||
| Grain sieves conform to the specifications laid down in ISO 5223 and have long rounded apertures. One sieve, used for separating broken grains from maize, has rounded 4.5mm diameter holes | |||||||||||
| What is the difference between a certificate of conformity & a UKAS calibration certificate? | |||||||||||
A certificate of conformity is issued with all Impact test sieves. Our customers can be confident that the sieve has been manufactured to the specified standard. A UKAS calibration certificate is issued when the individual sieve has been examined under test conditions, the results of which are detailed on the certificate. Once a sieve is calibrated it is an accurate and traceable measuring device. |
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| How does a wet washing kit work? | |||||||||||
| Water enters through a special top lid, which sprays the sample. The water then washes through the other sieves in the stack and is then drained through an outlet on the receiving pan. | |||||||||||
| What is the difference between the BS Kitemark & UKAS certification? | |||||||||||
| The BS Kitemark is licensed by the BSI to cover the overall manufacturing system, rather than individual sieves. A UKAS calibration certificate is issued for each sieve that has been examined under specific test conditions, the results of which are detailed on the certificate. | |||||||||||
| What is meant by American standard? | |||||||||||
| ASTM standard (American Society for Testing Materials) is the standard most widely used in North America. Frame sizes are specified in inches and the aperture tolerances differ slightly from ISO standards. | |||||||||||
| What is meant by European standard? | |||||||||||
| We use this term to differentiate from the American standard (see above). European standards refer to the ISO (International Standards Organization) specifications. In fact the ISO standards have not only been adopted throughout Europe but also in many other countries worldwide. | |||||||||||
| What is the difference between mesh & perforated plate? | |||||||||||
Mesh, or metal wire cloth, is a woven wire sheet. Impact uses mesh manufactured from stainless steel. Perforated plate is either a mild steel or stainless steel plate with square, round or slotted holes punched out to form the sieving area. |
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| How are sieves calibrated? | |||||||||||
| Impact uses a optical projector capable of magnifying the sieve aperture by a factor of 100. Only optical projection, coordinate measuring machines or similar equipment can achieve true calibration | |||||||||||
| What does 40 mesh mean? | |||||||||||
| 40 mesh is a term used most frequently in America, 425 micron mesh is classed as a No. 40 | |||||||||||
| Conversion table of ASTM to ISO unit conversion for particle sizes | |||||||||||
If you look at the top of this page you will see the Sieve Selector. Using the drop-down box, select American 8 and 12 inch sieves and you will see a table which shows the ISO (left) and ASTM (right) sizes for each sieve. - e.g. 20uµm – No.635 |
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