The Weight Treatment of Extraction Thimbles

The extraction thimbles should be treated before doing the experiments of gravimetric monitoring for particulate matter, asphalt fume, and other matters.

The fiber extraction thimbles contain a small number of flammable substances and Easy-to-dissolve ashing substances. The extraction thimbles will lose weight during the high-temperature sampling of smoke and dust. The data suggest that the weight of the extraction thimbles will lose about 5 mg when heated at 400℃ for one hour, which makes the monitoring results lower than the actual results.

Consequently, to avoid errors, the extraction thimbles must be treated at high temperatures before sampling when the temperature is not certain. The temperature of the flue gas generally does not exceed 400℃ in the actual monitoring, which means that as long as the extraction thimbles are heated at 500℃ for one hour, the weight loss treatment can meet the monitoring requirements.

And then select the qualified extraction thimbles, number the sample, put them into the oven, and dry them at the prescribed temperature to constant weight. The extraction thimbles after the above operations can be used for sampling monitoring.

For smoke and dust sampling filtering, the extraction thimbles need to be dried at 105℃ to 110℃ for 2 hours at a constant temperature.