Device and method for measuring relative concentration changes in gas stream components

Claim 1

The galvanic cell device for detecting and measuring fluctuations in the concentration level, in a flowing gas stream, of a gaseous component selected from the group consisting of oxygen, chlorine, bromine, iodine, sulfur dioxide, sulfur trioxide, hydrogen sulfide and carbon monoxide and a mixture thereof which comprises: measuring means and sensing means for an autogeneously generated potential difference; the sensing means consisting essentially of a substantially enclosed cell adapted to permit passage of the gas stream therethrough and containing an aqueous electrolyte solution in addition to first and second electrodes each formed of the same metal the electrodes being connected (1) electrically, via the potential difference measuring means and (2) electrolytically, via the aqueous electrolyte solution and the cell being without means for impressing a potential across the electrodes; said first electrode being a sample electrode having a foraminous structure and said electrode having a surface adapted to be exposed to said flowing gas stream and to have zones in which gas stream, electrolyte solution and metal surface meet to form a three-phase boundary; said second electrode being a reference electrode adapted to be in contact with an unchanging environment with respect to the gas stream component to be detected and measured; said aqueous electrolyte solution containing a mobile soluble ion and being not destructively reactive with the electrode metal under test conditions; and means for bringing the flowing gas stream to and from the sample electrode.

Claim 18

The method of detecting the fluctuations in the concentration level, in a flowing gas stream, of a gaseous component selected from the group consisting of oxygen, chlorine, bromine, iodine, sulfur dioxide, sulfur trioxide, hydrogen sulfide and carbon dioxide and a mixture thereof which comprises: providing a sample electrode and a reference electrode of substantially the same metal, a porous membrane, and a reservoir containing an aqueous electrolyte solution, the electrodes being separated by and each in contact with the porous membrane, the membrane extending into and being wetted by and haVing wicking action toward the electrolyte solution and the electrolyte solution being taken up substantiaLly throughout the extent of the membrane, said electrolyte solution containing a mobile soluble ion and being not destructively reactive with the electrodes, both electrodes being electrically connected via potential difference measuring means, conducting said gas stream over the sample electrode without contacting the reference electrode or the electrolyte solution in the reservoir, and measuring changes in potential difference between the electrodes as a consequence of said fluctuations without impressing a potential across the electrodes.