Abstract: A portable refrigeration gas analyzer employs infrared spectroscopy to detect adulterant refrigerant gases in existing R12 refrigeration systems. The analyzer can detect contaminants such as R134a, R22, and butane in concentration as low as 1% by volume. A rugged opto-acoustical infrared narrow band sensor is suitable for field use in the repair of refrigeration systems.

Abstract: A spring structure for a weight scale is described which is assembled from four extruded aluminum parts. The structure readily lends itself to the addition of a platform for placing weights and its deflection resulting from a weight is essentially invariant to the location of the weight on the platform. The sensor which converts deflection of the structure into an electrical signal includes two conducting plates, attached to the structure, which constitute a variable capacitor. The variable capacitor is part of a self-excited oscillator circuit which yields a frequency which is accurately related linearly to the value of the weight. Means are provided for distorting one of the capacitor plates to provide further improvement of invariance to weight location on the platform.

Abstract: A condition tester for a storage battery that monitors the effect of internal battery resistance without drawing large currents. A switched load periodically draws a small current across the battery terminals. An AC voltage is produced at the battery terminals resulting from the oscillating current and the internal battery resistance. That small oscillating voltage is amplified, rectified and filtered to produce a DC voltage which depends upon the AC component. This DC voltage is subtracted from the nominal battery voltage and the difference is indicated by an appropriate meter. As the battery deteriorates its internal resistance increases causing the meter reading to decrease, thereby reflecting battery condition.

Abstract: A method .[.is disclosed.]. of detecting gaseous impurities, particularly halogens, in an ambient atmosphere by repeatedly pulsing a pair of electrodes disposed in that atmosphere with a voltage sufficient to cause a corona discharge in the continuous corona region, and detecting the average (d.c.) current component of such discharge, changes in which correspond to changes in the concentration of such gaseous impurities. Apparatus .[.is disclosed.]. for detecting such impurities in concentrations as low as 1 ppm.