Patent GB-833926-A (GB)
Title: Improvements in or relating to the continuous determination of the quantity of liquid-soluble gas in a gas mixture
IPC: G01N7/04
Filed: 1957-11-22
Abstract: <PICT:0833926/III/1> A gas absorption apparatus with continuous determination of a quantity of liquid soluble gases in a gas mixture, and similar in type to Specification 714,898, comprises a gas vessel having an inlet and an outlet for a continuous passage of absorption liquid, a first pump arranged to introduce the gas mixture into the vessel below the liquid level therein and a second pump arranged to extract gas not absorbed by the liquid from the top of the vessel through a conduit connected to pressureindicating means for indicating the gas pressure in the conduit, means for supplying the absorbed liquid at substantially constant super atmospheric pressure a restricted outlet for liquid passing from the vessel to maintain the pressure in the vessel and a restricted outlet passage from the vessel to the conduit at the top of the vessel whereby substantially only gas escapes through the conduit and the pressure therein is substantially independent of the pressure in the vessel.  An absorption vessel has two compartments 2 and 3 communicating with each other through a pipe 4.  A conduit 5 for the supply of liquid (usually water) to the vessel under pressure is provided in the wall of the bottle 2.  A reduction valve 6 for setting a desired super-atmospheric pressure, preferably about 1 atmosphere above atmospheric pressure, may be inserted in the conduit 5 or, instead, the conduit 5 may be drawn from a container which is placed on appropriate higher level and in which the liquid level is kept constant.  The gas to be analysed is supplied through a conduit 7 passing through the wall of the bottle 2 and connected to the suction side of a gear pump 8 mounted within the bottle.  At the pressure side of the pump a constant amount of gas is discharged per unit of time in the form of finely-divided bubbles which will rise toward the mouth of the bottle.  The lower end of the tube 10 contains a nozzle 11 by which the gas bubbles are still more finely divided.  The cylinder 3 has a narrower top portion 12 which may be of a transparent material to render observation possible.  The conduit 13 extends downwards along the outer side of the cylinder 3, passes through the wall of a bottle 15 of approximately the same size as the bottle 2, and ends at the suction side of a gear pump 16.  The pumps are preferably of equal size and may be driven by a common motor so that no difference in speed occurs.  The conduit 13 passes axially through a cylindrical container 17, the upper end of which is connected to a mercury manometer 18.  A hole 19 is provided in the wall of the conduit 13 slightly above the bottom of the container 17, so that the manometer 18 is subjected to the pressure prevailing in the conduit 13.  The purpose of the container 17 is to dampen possible pressure shocks and to collect drops of liquid carried by the gas in the conduit 13.  It is convenient to graduate the mercury manometer in such a way that the percentage of gas absorbed may be read directly.  Instead of a mercury manometer it is, of course, possible to use any kind of pressure indicating apparatus which gives a sufficiently exact reading.  The lower part of the cylinder 3 communicates with the bottle 15 through a conduit 20. Further, an outlet conduit 22 has its inlet end placed within a cup-shaped top portion of the bottle 15.  The conduit 22 has a slightly restricted inlet end 23, the inner diameter of which is for example about 2 mm. The conduit 22 passes through the bottom of the bottle and ends closely thereunder.  The water or other liquid delivered by the conduit 22 flows out through an outlet 24 provided in the bottom of the casing 1.  The two pumps 8 and 16 may also be mounted outside the vessels 2 and 15 respectively, in which case the restricted passage 23 may instead be provided in the conduit 20 and the vessel 15 may be entirely dispensed with.  Although not shown in the Figure, the bottles must of course be provided with removable bottoms or the like if the pumps are to be mounted therein.  For instance, the cylinder 3 need not be located above the bottle 2 but may be on the same level, and the pipe coil 4 may very well be provided outside the cylinder 3, although the compact construction shown is generally to be preferred in view of the desirability of maintaining a constant temperature in the whole absorption system.