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| The Development of a Standard Humidity Generator with Large Temperature Range and Adjustable Chamber Pressure |
| ZHANG Wen-dong,ZHANG Yong |
| Shanghai Institute of Measurement and Testing Technology, Shanghai 201203, China |
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Abstract With two-temperature and two-pressure principle,a standard humidity generator with large temperature range and test chamber pressure adjustable is developed.It can generate the whole range relative humidity in the temperature range of -50～90 ℃ and the relative pressure range of -50～0 kPa with the estimated expanded uncertainty of 0.3%RH～0.8%RH(k=2).The inner size of the test chamber is 150 mm×400 mm.The flow rate of the sample gas is 5～30 L/min.Automatic operation in the generator has been realized by using the working and control mode in which the industrial control computer and PLC is combined and by designing the device which can control the saturator pressure and sample gas flow accurately.The test results of cool mirror dew-point hygrometers and a gravimetric hygrometer proved its uncertainty.
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2012, Vol. 33 
