ISO 2758:2014 pdf download

ISO 2758:2014 pdf download.Paper — Determination of bursting strength
5.1 Clamping system, for clamping the test piece firmly and uniformly between two annular, plane, parallel surfaces which shall be smooth (but not polished) and grooved as described in Annex A, which also gives the dimensions of the clamping system. One clamping plate shall be held in a swivel joint or similar device so as to ensure that the clamping pressure is distributed evenly. Under the load used for testing, the circular openings in the two clamping faces shall be concentric to within 0,25 mm and the clamping surfaces shall be flat and parallel. The method of checking the clamps is given in Annex B. The clamping system shall be capable of applying a known clamping pressure up to 1 200 kPa and shall be constructed in such a way that repeatable clamping pressures can be obtained in use (see Annex C). In calculating the clamping pressure, the reduction in area due to the grooves shall be ignored. Any clamping-pressure-indicating device fitted should preferably be scaled to indicate the actual clamping pressure, not the pressure in the clamping system itself. The clamping pressure may be calculated from clamping-force and clamp-area information.
5.2 Diaphragm, circular, of natural or synthetic rubber, free from filler or loading and 0,86 mm ± 0,06 mm thick, clamped securely with its outer surface, when at rest, recessed about 3,5 mm relative to the outer plane of the diaphragm-mounting plate. The material and construction of the diaphragm shall be such that the pressure required to bulge the diaphragm 9,00 mm ± 0,2 mm outside the outer plane of the diaphragm plate is 30 kPa ± 5 kPa. Diaphragms in use shall be regularly checked and changed if the bulge-height requirement is no longer met.
5.3 Hydraulic system, to apply an increasing hydraulic pressure to the inside of the diaphragm until the test piece bursts. The pressure shall be generated by a motor-driven piston forcing a suitable liquid (e.g. pure glycerol, low viscosity silicone oil, ethylene glycol containing corrosion inhibitor) which is compatible with the diaphragm material against the inner surface of the diaphragm. The hydraulic system and the fluid used shall be free from air bubbles. The pumping rate shall be 95 ml/min ± 5 ml/min.
5.4 Pressure-measuring system, to measure bursting strength.
It may employ any principle which produces a measurement and display accuracy equal to ± 10 kPa or ± 3 % of the measurement, whichever is the greater. The rate of response to the rising hydraulic pressure shall be such that the indicated maximum pressure is within ± 3 % of the true peak pressure as determined by a calibration system of the type described in Annex D.