A process for the preparation of a platinum metal - aluminum oxide - catalyst for the reforming of hydrocarbons

摘要

834,633. Photo-electric fluid analysis. TECHNICON INTERNATIONAL Ltd. May 21, 1958 [June 7, 1957], No. 16313/58. Class 40 (3). In apparatus for obtaining a quantitative indication of the concentration of a substance in a liquid the voltage produced in a photo-cell by the light transmitted through the cell containing the liquid under test is compared with that produced by light transmitted through a standard cell in a self-balancing potentiometer circuit arranged to give a linear relationship between indication and substance concentration. Light from the source 12 transmitted through the flow or test cell 38, Fig. 1, is converted to a voltage across potentiometer 46 by the photo-cell 40. Similarly, photo-cell 30 produces a voltage across potentiometer 44 from the light through the standard cell 28. The voltage between potentiometer taps 68 and 72 is applied via the converter stage 54 and amplifier 58 to the winding 60 of the two-phase motor 62 which drives the tap 68 on potentiometer 44 to balance the system. The voltage across potentiometer 46 bears a logarithimic relationship to the substance concentration, by shunting the slide wire of potentiometer 44 by the resistors 78 a logarithmic law is obtained between the voltage at tap 68 and its position along the slide wire, hence the position of the tap repeated by the pointer 74, on scale 76 is linearly related to substance concentration. A second self-balancing potentiometer circuit is driven by the voltage between tap 88 of potentiometer 86 (mechanically positioned by shaft 70 to the position of the tap 68) and tap 96 on potentiometer 90 which is applied via the converter and amplifier 94 to the two-phase motor 100. This drives the counter 114 to a figure indicative of the concentration. This figure can be printed by the unit 122 to provide a record of concentrations in a series of liquids. Circuit 124 (Fig. 2, not shown), ensures that the figure is not printed until each reading of concentration has reached a maximum value.