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How to test the conveyor belt gas permeability

Mar 14, 2019

The specific operation method is mainly for the ventilating chamber that we need to keep at a constant temperature. It is divided into a high-pressure side and a low-pressure side by a circular sample, and the high-pressure side is connected to a gas reservoir capable of maintaining a constant pressure, and the gas penetrates into the low-pressure side. Since the low-pressure side volume is small and is the same, the gas permeability meter is composed of a gas permeable chamber, a measuring device and a thermostat device; the gas permeable chamber is a device capable of clamping the periphery of the sample in an airtight state, and is connected at the upper portion of the high pressure side. The high-precision barometer has a hard and extremely permeable microporous hard rubber picture on the low-pressure side, and a sintered microporous stainless steel disk to fill the space to keep the internal volume to a minimum and support the sample. Deformation, the low-pressure side is connected to the capillary through a detachable connector with a small-diameter tube. The total volume of the cavity between the reference marks should not exceed the specified size. In the thermostat, a constant temperature bath can be used or the temperature of the plenum can be used. The device shall be kept at a temperature within ±0.5 °C from the test. The standard test temperature is 23 °C. If the test conditions are required to be close to the service temperature, the following temperatures are generally selected: 40 55, 70, 85, 100, 125, 150, 175, 200, 225 and 250 ° C, for any given test or comparative test, the allowable deviation of temperature is within ± 0.5 ° C, then can be directly from vulcanization If the film or rubber product is cut, if there is an annular groove in the ventilating chamber, the upper and lower edges of the molded sample shall have annular ribs so as to be fixed into the corresponding annular groove in the ventilating chamber, and the planar sample taken can be properly sized. The butyl rubber "O" pattern, the sample is clamped in the middle, fixed in the gas permeable chamber to maintain its airtightness, in order to ensure airtightness, a small amount of vacuum grease is allowed to be applied on the clamping surface of the gas permeable chamber, However, there shall be no oil on the effective surface of the sample. The thickness of the sample shall be measured on the effective surface of the sample by taking six different points, accurate to 0.02 mm, and the arithmetic mean of the six measurement points shall be taken as a test. The thickness value of each sample should not exceed 10% of the average thickness value. When using a vertical installation of the gas permeability meter, first inject a proper amount of liquid into the capillary, then shake the handle to adjust the height of the liquid storage bottle to make the liquid level Located in capillary reference Close the bypass above the tick mark. When the meniscus crosses the reference mark, the recording time and the corresponding distance of the meniscus movement are started. During the test, the height of the liquid bottle should be adjusted at any time to keep the sides of the capillary. The liquid level balance, when the gas permeation reaches a steady state, the corresponding distance of the meniscus movement recorded about every 2 minutes is generally recorded 5-6 times, the test duration is 10 hours, and the meniscus moving distance is after the test is over. An accurate relationship between the gas permeability of the rubber conveyor belt can be obtained on the coordinate paper with the time parameter.