| 摘要 |
999, 909. Determining relative quantities of fluid mixture constituents. NATIONAL RESEARCH DEVELOPMENT CORPORATION. May 18, 1962, No. 19294/62. Heading G1N. An immersible oxygen detecting cell comprises a perforated electrode 2 of gold platinum or silver surrounding but spaced from a porous mass of metal 3 such as lead forming an inner electrode, the electrode 2 being covered by a membrane 15 permeable to gaseous or dissolved oxygen but not to liquids or dissolved ions. The membrane which may be polyethylene sheeting is secured around the electrode by rings 16,17 in grooves. The electrodes are secured by a perspex end cap 4 screwed on to the central spigot of a perspex body 1. The temperature of the liquid is measured by a thermistor 31 in the centre of the spigot so that temperature corrections can be made. The electrodes are separated by a fine mesh nylon gauze in an annular space 6 and are connected to terminals 7, 8 of silver and lead. The cell electrolyte comprises a saturated aqueous solution of potassium hydrogen carbonate which is introduced through inlet 18 in cap 4 by a syringe, injection and withdrawal being performed a number of times to remove bubbles. Dilute sulphuric acid is mentioned as an alternative electrolyte and rubber sheeting as an alternative membrane material. The effect of membrane thickness on sensitivity is discussed and dimension are exemplified. Cleaning of the cell and the regeneration of the lead electrode are described. |
