BS EN ISO 7590:2001 pdf – Steel cord conveyor belts Ð Methods for the determination of total thickness and cover thickness.
1 Scope This European Standard specifies two methods of measuring the total thickness and the cover thickness of steel cord conveyor belts. Method A ,( Micrometer method) can be used for all steel cord conveyor belts for measurement of both total thickness and cover thickness. Method B ( Optical method) is recommended for the measurement of cover thicknesses only. It is not suitable if there is a textile or metal weft , or if the ends of the steel cords become twisted when cut . 2 Terms and definitions For the purposes of this European standard the following terms and definitions apply. 2.1 breaker reinforcement included in the cover 2.2 weft transverse layer or layers included to reinforce the carcass of the belt and not regarded as part of the cover layer 3 Principle The total thickness is measured by micrometer at a number of specified points according to the belt width. The cover thicknesses can be determined either: a) by removing the covers, taking further measurements at the same specified points and calculating each of the cover thicknesses by subtraction, or, b) by direct measurement using an optical instrument. 4 Apparatus 4.1 Method A: Dial gauge micrometer, graduated every 0,1 mm. with flat feet, a circular foot of 10 mm in diameter and exerting a pressure of (22 ± 5) kPa on the specimen. 4.2 Method B: Optical measuring instrument. The measuring instrument is a hand-held magnifying glass with a scale divided in 0,1 mm steps. The magnification shall be at least 8 times.
5 Procedure 5.1 Test pieces Cut a rectangular test piece across the full belt width at 90? to the belt edge, with the following dimensions; 5.1.1 For method A1, the test piece shall be approximately 150 mm long. Cut three or five specimens at the measurement points as described in 5.2. Each specimen shall be two cord pitches wide, i.e.- width: equal to the width comprising two cords (see Figure 1) length : approximately 150 mm;
Key 1 Measurement point 2 Specimen Figure 1 – Test pieces taken at measurement points cut from full width belt sample 5.1.2 For method A2, the test piece shall be not less than 50 mm long , i.e. a) length: approximately 50 mm; b) width: equal to total belt width. Mark on the test piece the measurement points as described in 5.2. 5.1.3 For method B, the test piece shall be not less than 50 mm long , or the test may be performed in situ on the end of a conveyor belt. In either case it is essential that the cut edge of the test piece is at 90? to the surface of the belt and that the cords are clearly visible and free of contamination. If necessary, clean the cord ends. Mark the measurement points as described in 5.2.
126.96.36.199 Results Calculate the arithmetic mean of 3 (or 5) thicknesses , for d , e 1 , and e 2 , as determined in 188.8.131.52, 184.108.40.206 and 220.127.116.11. Express the results in millimetres. 5.3.3 Method B 18.104.22.168 Measurement of top and bottom cover thicknesses Measure the distance between the top edge of the cord and the surface of the belt using the optical measuring instrument (4.2) at each of the points defined in 5.2. e 1 = top cover e 2 = bottom cover Ensure that the measuring scale is in physical contact with the belt. 22.214.171.124 Results Calculate the arithmetic mean value of 3 (or 5) thicknesses, e 1 and e 2 , as determined in 126.96.36.199. Express the results in millimetres. 6 Test report The test report shall contain the following information: a) Reference to this European Standard; b) The method used: methods A1, A2 or method B; c) Identification of the conveyor belt tested; d) Number of measurement points; e) Test results as given in : 188.8.131.52 for method A1, or 184.108.40.206.for method A2, or 220.127.116.11 for method B f) Date of test.