Measurements of time-variant gas pressure in porous media

Authors: M. Gawor, J. Rysz

This article presents a critical analysis of a commonly-used method of time-variant gas pressure measurements in the pores of coal briquettes.

In case of transient-state measurements a considerable reduction of the sensitive volume of the transducer is neccesary.

Some results of dynamical response of various sensitive volume transducers are presented.

An apprcciable reduction of the sensitive volume in sensors allows the time variations of gas pressure in the pores during the stage of briquettc decompression to be monitored, that is about 2 ms before a crack should appear.

A sensor with a sensitive volume of less than 0.5 mm sup 3 registers very distinct pressure changes throughout this time interval.

Measurements of gas pressure in the cracks, following the briquette breaking, can be taken with pressure sensors with a the sensitive volume of up to several cubic millimetres.