There have been extensive revisions to ASTM standard E11, “Specification for Wire Cloth and Sieves for Testing Purposes.” Gilson is leading the way in educating our customers about the new specification and making these new products available. The new specification affects all test sieves, screen trays, and wire cloth, and changes the way the mesh openings are evaluated by looking at the statistical distribution of aperture sizes, rather than just the average opening sizes.
Verification of opening sizes for new Screen Trays assures optimal conformance to the latest ASTM E11 or ISO 565/3310 specifications. All new Screen Trays are supplied with a Certificate of Manufacturing Conformance and meet Compliance grade specifications for ASTM or ISO requirements.
In the Verification process for Inspection or Calibration Grades, wire cloth openings are measured using a computerized optical comparator traceable to NIST. The system automatically scans the mesh and provides statistical analysis and documentation of aperture size and wire diameters.
Inspection Grade has a confidence level of 99% that the standard deviation of openings is within the maximum allowed by ASTM or ISO. This grade is ideal for applications requiring added accuracy and verification. Each Inspection Grade Screen Tray consists of a standard Screen Tray with added Inspection Grade Verification service.
Calibration Grade measures twice as many openings with a NIST traceable optical comparator as Inspection Grade, increasing the standard deviation confidence level to 99.73%. This grade should be used where the highest degree of accuracy is required. Each Calibration Grade Screen Tray consists of a standard Screen Tray with added Calibration Grade Verification service.
Compliance Grade has a sample of the bulk wire cloth measured prior to assembly and there is a 66% statistical confidence level of meeting opening tolerances. These trays are serial numbered, furnished with a conformance certificate, and can be used in applications where basic accuracy and repeatability are sufficient. All standard Screen Trays are supplied at this basic level of conformance.