ISO-9090-1989.pdf
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1、INTERNATIONAL STANDARD IS0 9090 First edition 1989-04-15 Gas tightness of equipment for gas welding and allied processes b) 10 % of the maximum working pressure. 6.2.2 Routine tests All devices shall be tested at that pressure (of the two pressures specified in 6.2.1) which gave the most unfavourabl
2、e results during the type tests. 7 Maximum permissible leakage rates NOTE - The leakage rate for individual devices will be incorporated directly in the relevant standards for that device when they are revised. 7.1 Regulators Regulators shall not have a total leakage rate greater than 10 cm3/h. 1 Co
3、pyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/27/2007 04:47:15 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 9090: 1989 (El 7.2 Blowpipes 7.5 Devices with
4、 combined functions With the gas hose connected to one of the inlet connections, blowpipes shall be submitted to the following test: a) Close off the nozzle and the other inlet connection and half-open both the valves. Permissible leakage rate: 8 cm3/h g-egas b) Close off the nozzle and open the sec
5、ond inlet connec- tion; half-open valve 2 and close valve 1. Permissible leakage rate: 4 cm3/h c) Close off the second inlet connection and open the nozzle; close valve 2. Permissible leakage rate: 4 cm3/h NOTE - This test procedure enables total leakage and leakage through each valve to be tested.
6、7.3 Safety devices Safety devices shall not have a total leakage rate greater than 8 cm3/h. Devices with combined functions shall have a total leakage rate not exceeding the maximum rate applicable to any individual function. 7.6 Other equipment Other equipment which may be used on an installation f
7、or gas welding and allied processes shall not have an overall leakage rate greater than 8 cm3/h. 7.7 Hoses Hoses shall conform to the requirements laid down in IS0 3821 in terms of the leakage rate and/or gas permeability. 8 Measurement of the leakage rate The method described below is used to deter
8、mine the leakage rate of a device; it is a type test method which determines whether a device conforms to the requirements specified in clause 7. For routine purposes, manufacturers may use whatever method is most suited to their requirements. 8.1 Principle of the test method Immersion of the device
9、 to be tested in water, with the device connected to a gas source throughout the test; collection of the gas leaking from the device in a graduated cylinder initially full of water. Other test methods are permitted, provided that it can be shown that these give results as accurate as those available
10、 from the method given in this clause. 8.2 Test apparatus (see the figure) 8.2.1 Water-bath, having suitable dimensions for complete immersion of the device to be tested. 8.2.2 Gas supply, allowing pressurization of the device throughout the test. 8.2.3 Graduated cylinder, initially full of water, m
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