Patent GB-1068661-A (GB)
Title: Electrical gas analysis equipment
IPC: A61B5/083
Filed: 1963-10-14
Abstract: 1,068,661. Determining physical properties. L. ESCHWEILER [trading as L. ESCHWEILER & CO. ]. Oct.14, 1963 [Oct. 13, 1962; Oct. 24,  1962; Nov. 23, 1962; May 28, 1963; June 4, 1963; June 10, 1963], No.40525/63. Heading G1N. In an electrical gas analysis equipment for example, determining polarographically the oxygen pressure and/or the carbon dioxide content by pH measurement, in small liquid or gas samples wherein an analysis chamber has inlet and outlet capillaries and at least one aperture for the insertion of an electrode, a hermetic joint is ensured between a region of the electrode adjacent to and around the top, and the aperture. Chamber (1), Fig. 1 (not shown) is sealed top and bottom by glass electrodes (2) and (5), the former being immersed in a bicarbonate solution (3), and serving to determine the carbon dioxide content of a sample in chamber (1) in conjunction with a reference electrode (4), also in the solution, whilst the latter in conjunction with a further electrode (7) in the inlet tube (6) is used for measuring pH. Reference is made to a test on blood in which a second pair of readings is taken on a sample of changed carbon dioxide content achieved by blowing a gas through the sample. The tests are made whilst the apparatus is immersed in a temperature controlled bath. In a modification described with reference to Fig. 2 (not shown) an electrode which comprises a glass body with a central platinum wire is sealed in a ground conical boss and the underside of the chamber is sealed by a flat plate. The end of the electrode wire in the chamber is hemispherical, and a cock is provided in one capillary to provide for sucking in a sample, or connecting to a calibrating fluid. The capillaries are inclined to the base plate so that the whole may be immersed in a temperature controlled fluid. The spherical end of a glass bar (307) Fig. 3 (not shown), is seated in a ground spherical recess (303) in a straight capillary (302) and the samples are caused to flow or reciprocate by a compressible obturating device such as a rubber tube which may be periodically pinched by a motor driven eccentric wheel (315). The measuring area of the capillary is enclosed in a glass casing (313) which, in use, contains temperature controlled water. The electrode may be a glass electrode for pH measurement, and there may be more than one electrode in the measuring area. An injection tubule may be attached to the end (302) of the capillary so that the apparatus itself may be used directly to extract a blood sample. In a further modification, Fig. 4 (not shown) the electrode is fitted to the aperture by a rubber seal and the apparatus includes a reference electrode. An arrangement for testing the lungs comprises a capillary test apparatus through which an oxygen nitrogen mixture is drawn by the patient, used in conjunction with a further equipment for progressively extracting and analyzing blood samples. A measurement of the changes in partial pressures taking place when biological organisms use oxygen may be determined in an apparatus comprising a reaction chamber (603), Figs. 13, 14 (not shown) and a measuring chamber (602) interconnected by a pair of grooves (606). The measuring chamber includes a magnetic stirrer (609) and is sealed by an electrode (604) and a plug (605) above chamber (603) may be rotated to seal off the chamber. The plug (605) may be replaced by a further electrode, and the CO 2  content may be determined by measuring conductivity.