Patent GB-442403-A (GB)
Title: Apparatus for testing gases by chemical means
IPC: G01N7/08
Filed: 1935-05-20
Abstract: <PICT:0442403/III/1> <PICT:0442403/III/2> In gas-analysis apparatus of the type in which a predetermined volume of the gas mixture is subjected to chemical treatment to alter its initial physical state and which comprises a reaction chamber of constant volume, and a standard pressure chamber, each being connected to one end of a differential manometer and arranged also to communicate or not with the supply of gas to be tested, a supplementary reaction chamber is provided adapted to be connected either with the main reaction chamber or with the supply of gas to be tested and containing means whereby the chemical reactions are carried out.  As shown diagrammatically in Fig. 1, the pipe C, supplying the gas to be tested, is connected to a standard pressure chamber P, a reaction chamber V of constant volume, and, through an intermediate chamber G with the supplementary reaction chamber L.  The combination of chambers L and V which communicate via tap R constitutes the reaction space. The differential manometer M is connected between the chambers P and V, and taps R1, R2 and R3 isolate the different chambers from the pipe C.  The gas, after testing is exhausted through pipe E. The combined reaction chambers are shown in detail in Fig. 4; the chamber L consisting of a cylindrical container 11, closed at the top by a water-tight stop 13 and fitting tightly inside cylinder 14.  These cylinders both contain wide apertures 15 and 16 and a closed chamber 17 is mounted integral with the cylinder 14 round the opening 16 and forms the constant volume reaction chamber V. The inner chamber L is shown communicating with chamber V, and by rotation of handle 18 through 180 DEG  the connection is interrupted, and a perforation 30 in the wall of cylinder 11 is brought opposite pipe 10 whereby communication with chamber G and thence to the supply pipe C is established.  The various taps are preferably operated from a single control through gear trains. The chamber L contains a solid absorbent or a catalyst, preferably contained in a small cylindrical basket, and may also be filled with a gaseous reagent and contain a platinum wire for determination by rapid combustion.  The chamber G contains the same reagents &c. as chamber L.  The indicator M is preferably an inclined glass tube connected at its lower end with a liquid container, and may act either as a differential manometer or as a volume meter based on the displacement of a small liquid index in the tube, which in this case is a capillary tube.  The liquid is preferably gas-oil.  Provision is also made to isolate the indicator M from the remaining apparatus to avoid surges.  The whole apparatus is preferably constructed of metal, except the tube M, and is suspended in a constant temperature bath, preferably by means of a cardan joint.  The apparatus may be modified by connecting chamber V with two supplementary reaction chambers L, in which case a double chemical reaction may be used, e.g. a combustion followed by an absorption.  The indicator M may consist of any differential instrument and may be provided with a registration device, e.g. electric and based on the displacement of mercury which closes a circuit through which passes a current of constant voltage, the resistance of which varies according to the displacement.  The apparatus may also be made automatic, a constant flow of gas being provided in pipe C and the apparatus being actuated electrically, controlled by clockwork.  The device may be used, for example, for the determination of hydrogen, carbon dioxide, oxygen or humidity.