Delta P instrument for oxidation measurement.
An apparatus for measuring DELTA P in coal is described which comprises: (a) a plurality of closed metallic coal sample cups; (b) a gas manifold flow connected to each of said sample cups by way of a separate electric valve and said manifold being connected to a source of methane by way of electric valve means and connectable to a source of vacuum by way of electric valve means; (c) a pressure transducer connected to said manifold and adapted to measure absolute gas pressure in the manifold, and (d) processing means adapted to actuate said valves to sequentially (1) introduce vacuum to evacuate the manifold and one or more sample cups; (2) introduce methane gas to the manifold and saturate one or more coal samples therewith; (3) close sample cup valves and evacuate the manifold; and (4) selectively open individual sample cup valves. The processing means is also adapted to measure and record pressure in the manifold at short time intervals to indicate the pressure rise in the manifold with passage of time, thereby obtaining the DELTA P index fore the coal sample.