This paper proposes a measurement method to compensate temperature change for the Isothermal Discharge Method, which determines flow-rate characteristics of pneumatic components by just measuring the pressure response in a tank when air is discharged. The tank is filled with isothermal material such as thin copper wire to make temperature change small. However, less material and small tank preferable for low cost make isothermal performance worse. A compensation term for temperature change in an exponential expression is proposed to be added to the flow rate equation based on the mathematical model of the air discharge process and heat transfer for a quasi-isothermal tank. The compensated flow rate is in satisfactory agreement with that measured by the ISO Exhaust-to-atmosphere method. There are very little errors between the flow rate characteristics of sonic conductance C and critical pressure ratio b calculated by the proposed equation and the results measured by the ISO Exhaust-to-atmosphere method.

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Many industrial instruments use rubber; NBR(Nitrile Butadiene Rubber) is especially used for the packing attached to pneumatic equipment. Recently, with the spread of dry pneumatic pumps, the deterioration of NBR by ozone has become a serious problem. However, the process of the ozone degradation of NBR has not been sufficiently clarified. When examining the ozone degradation of NBR, it is very important to control the ozone concentration. In general, it is difficult to get a low ozone concentration using an ozonizer with an ultraviolet ray lamp. Therefore, we attempted the optimum control of the ozone concentration with dilution by adjusting the air flow rate through the ozonizer using the flow proportional valve. As a result, the ozone concentration in the testing chamber is controlled with greater accuracy than the method based on supplying voltage to the ozonizer.

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