Patent GB-338410-A (GB)
Title: Improvements in and relating to eudiometric apparatus especially to those for measuring firedamp
IPC: G01N7/06
Filed: 1929-12-21
Abstract: 338,410. Daloz, J. G. June 20, 1929, [Convention date]. Gas analysis.-In eudiometric apparatus, particularly for the measurement of firedamp, the eudiometric chamber consists of two parts which can be brought together to form a closed chamber, or separated to admit the gas to be tested. In the apparatus shown in Fig. 1, the chamber consists of a bell k, preferably containing a loose lining k<1> with openings k<2>, fitting in a groove f in a plate e in which is also fixed the upper end of a transparent tube c constituting the manometer, and the whole being mounted in a socket d fitted with windows d<1>. This socket is frictionally held in an outer casing h, provided with windows h<1> coinciding with the windows d<1>, and havings openings h<3> at its upper end. This portion of the caGing h is surrounded by a further casing h<4> which can be rotated to bring openings h<5> into coincidence with the openings h<3> to allow of communication with the surrounding atmosphere. Two pipe connections h<6> on the outer casing are arranged to open into the casing h when the latter is closed from the atmosphere, thus enabling the instrument to be calibrated by the introduction of a known mixture of firedamp and air. The bell k is held gas-tight by a screw j<2>. The wires g<1>, and g<2> from the heating coil g<3> are connected to pole plates l (only one is shown in the drawings) carried by the socket d, while contacts m, connected to a battery &c. are carried by the casing h. These are arranged to coincide only when the spring i, bearing on the respective bases of d and h, is in compression. In operating, e.g. in an atmosphere of firedamp, the bell is released, put into connection with the outer air, and agitated till equilibrium is attained. The screw j<2> is then tightened, closing the bell and compressing spring i. The mixture in h is then ignited, and the contraction measured by the rise of liquid in c. The following modifications are described :-(1) The base a<1> of the manometer is wholly rigid, or may be deformable as shown in Fig. 1, which allows the liquid c to be brought to the zero of the scale used. (2) The manometer consists of a single tube p, Fig. 2, which is arranged similarly to the tube c at its upper end, but, at the lower end has an elastic pocket p<1> by which the level of liquid in the tube p may be altered. (3) The bell k is divided into two equal chambers q and q<2> by a partition r, Fig. 3, which may carry fins r<1> to facilitate the transmission of heat between the two chambers, and the apparatus is so arranged that when the bell is closed, each of the above chambers q and q<2> communicates with a branch of a U-shaped manometer tube. Equilibrium of temperature in the two chambers may be attained by providing a heating resistance in q which evolves the same amount of heat in a given time as the filament g<3> while remaining below the ignition temperature. (4) In the . case of apparatus, for measuring firedamp, the apparatus may be mounted on a miner's lamp, so that the manometer is illuminated through the windows d<1> and h' (see Fig. 1).