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I_.X-FL011V The XIGATM Concept and Operation Manual <br /> -.—� <br /> Membrane Integrity Testing <br /> Membrane Integrity Test: <br /> Membrane integrity is a crucial factor in the membrane filtration process. To determine the integrity of a membrane <br /> system air is used to locate a defect. The test is based on a natural phenomenon that air will not pass through <br /> wetted membrane pores without a certain pressure. These pressures are related to the size of a membrane pore. <br /> When applying an air pressure of 1 bar on a wetted membrane element, the integer element will hold this pressure <br /> (pressure hold test). This test could also be achieved by implying a vacuum on the element. <br /> v_ <br /> Membrane elements made for the XIGATM -Concept have a central � <br /> permeate tube. To perform the membrane integrity test these central '• <br /> permeate tubes are closed with special test-adapters. A compressor or a <br /> vacuum pump with a pressure indicator and a valve is hooked on the test <br /> adapter. <br /> Pressure hold test: IR` <br /> Before applying a pressure on the element, the test adapters have to be <br /> secured. This can be done by using two metal end plates connected with <br /> each other by two chains. <br /> Connect a compressor with a pressure indicator and a valve on the test <br /> adapter and slowly increase the pressure to 1 bar. Maintain the pressure <br /> for at least 2 minutes (all remaining water will be pushed out of the <br /> permeate side of the element). Close the valve and check the pressure <br /> drop over 1 minute. The maximum pressure drop over 1 minute is 0.05 <br /> bar. To locate the defect membrane capillary repeat the procedure under <br /> water with an air pressure of 0.2-0.3 bar. A leaking capillary will cause <br /> a regular stream of air. <br /> Vacuum test: <br /> Before applying a vacuum on the element drain all water out of the <br /> element by placing the element in a vertical position for 2 minutes. <br /> Connect a vacuum pump with a pressure indicator and a valve on the test <br /> adapter and slowly increase the vacuum to 200 mbar abs. Close the valve ` <br /> and check the decrease of vacuum drop over 1 minute. The maximum <br /> decrease of vacuum over 1 minute is 20 mbar. <br /> Online integrity monitoring i — <br /> - & +�. <br /> The integrity of a membrane system can be tested on-line by analysing – <br /> the permeate quality, using turbidity meters or particle counters. Turbidity <br /> meters can only be used with dirty feedwater. On relatively clean waterIna <br /> particle counters are used. C: <br /> s <br /> CAPF-XIGA-0143 <br />