AN APPARATUS FOR DETECTING SMALL CONCENTRATIONS OF ETHENE IN AIR

摘要

A reduced concentrations of ethene in air detection apparatus comprises a spherical glass vessel having a flat bottom with a window portion, a radiation detector positioned in front of said window and a radiation switch placed between the window and the detector. A gas mixing tube extends towards the center of the container, the side opposite the flat bottom. Near its outer end, said tube is provided with a narrowing to draw air that is to be controlled therein, and ozone produced in excess by a source of ozone, and mixing these flows gas. An exhaust connection is formed near the mixing tube in order to remove the gas by maintaining a small negative pressure differential within the container. The gas mixture is completed in the mixing tube, and a chemiluminescent reaction occurs between ozone and the air that is to be controlled in the container before the gas flows out of the container. The radiation produced by this reaction is reflected by a reflective coating to said window and is converted into a pulsating electric signal corrected in the detector dark current. The correction of the dark current can be improved by using a signal amplifier driven by a signal having the frequency of interruption of the radiation. The ozone is preferably produced by an ozonizer comprising coaxial tubes between which a discharge is maintained by corona.