Patent GB-282487-A (GB)
Title: Improvements relating to apparatus for automatically determining the amount of gas existing in water and to the automatic control of chemical operations
IPC: G01N33/18
Filed: 1926-09-20
Abstract: 282,487. Hatfield, H. S. Sept. 20, 1926. Testing and estimating; gas analysis. - In an apparatus for automatically determining the the amount of gas contained in successive quantities of water and thus the temporary hardness, the gas is liberated by physical means without the addition of a reagent, as by boiling, the gases evolved being passed to an automatic measuring or recording device which may be used to control chemical operations such as the operation of a water softening plant. In the form shown, the mixed gases are collected in an arcuate bell carried on an arm secured to one exterior member of a differential gear and after a predetermined period are passed through an absorption tube, to remove carbon dioxide, to a second bell carried by the other external member of the differential, an arm on the third member moving over electrical contacts to operate the measuring device. Water from the main feed is forced by a pump 1 through a boiler 5, the steam being condensed by a condenser 7. The evolved gases pass through the tube 8 of the condenser, a drying tube 10 and a tube 12 to a curved bell 13 carried by a weighted arm 14 secured to one exterior member of a differential gear 15. After a predetermined period, the gases are passed, by the operation of a piston valve 11, through an absorption tube 20, to remove carbon dioxide, to a second bell 17 carried by an arm 18 secured to the other exterior member of the differential. When the bells 13, 17 are in their lowest position, an arm 24, carried on the shaft of the third member of the differential, is situated at the right hand end of a series of contacts 25, and upward movement of the bell 17 moves the arm 24 counter-clockwise. The period during which water is supplied to the boiler is determined by a cam 33 driven counter-clockwise from the shaft of the pump 1 and operating, through levers 35, 39, the valves 11, 22 controlling the bells 13, 17. While the levers are in the lowered position, the tube 8 is in communication with the tube 12 and a tube 19 leading to the absorption tube 20 is closed. The lever 39 is first rocked and a tube 23 leading to the bell 17 is brought by the movement of the valve 22 into communication with an aspirator 42 which exhausts the gases contained in the bell 17. The lever 39 is then released, thus restoring the parts to the position shown, and the lever 35 is raised to cause the valve 11 to put the tube 12, through the absorption tube 20 and the tube 23 into communication with the bell 17, the bell 13 being lowered to force out the contained gas by the weighted arm 14. Entrance of the gases raises the bell 17 and moves the arm 24 above the contacts 25 to an amount corresponding to the gas contained therein. During the time the lever 35 is being acted on by the cam 33, the drying tube 10 is brought by the valve 11 into communication' with the atmosphere through a tube 21, the parts being restored to the position shown as the cam leaves the roller. Movement of the arm 24 in the clockwise direction over the contacts 25 operates, through a, magnet 27 and a lever 28, a ratchet wheel 30 serving to operate the measuring-device and also being connected to a member controlling the water softening plant described in Specification 282,168. A pair of contacts 45 is closed by a cam 44 to allow this to be done. Thus at each subsequent movement of the bell 13, the wheel 30 is moved an amount corresponding to the dissolved gases less the amount of gas contained in the bell 17 at the previous operation. To prevent the magnet 27 from being energized except during upward movement of the bell 13, the cam plate 44 on the cam 33 opens a switch 43 and breaks the circuit of the magnet during the time the cam 33 is raising the levers 39, 35, the switch being released as soon as the cam leaves the lever 35. Zeroization of the wheel 30 to return the mechanism controlling the water softening plant to its original position is effected by the cam 33 closing contacts 46 to energize a magnet 47 as soon as the contacts 45 are released by the cam 44. Energization of the mamet 47 rocks a lever to raise the holding and actuating pawls 49, 50 of the wheel 30. In a modification, the evolved gases, alter the steam has been condensed, are passed in succession through two small gas meters, the carbon dioxide being removed between the meters, which may be connected by a differential gear operating in the manner described. In a second modification, the evolved gases are continuously mixed with a quantity of air or other gas which bears a, definite ratio to the quantity of water boiled. According to the Provisional Specification instead of an evolution of gas, an absorption may take place in the case of water which has been treated with an excess of slaked lime, the arrangement being that carbon dioxide alone or mixed with another gas may be passed through the water and the amount absorbed automatically measured and recorded.