Patent GB-282168-A (GB)
Title: Improvements relating to apparatus for controlling chemical reactions
IPC: C02F1/68
Filed: 1926-09-18
Abstract: 282,168. Hatfield, H. S., and United Water Siofteners, Ltd. Sept. 18, 1926. Mixing fluids in flow.-Apparatus for controlling the amount of a chemical to be added during a chemical reaction, such as occurs in a water softening plant, consists of a combination of an analysing or testing plant, such as is described in Specification 264,237, with an apparatus arranged to control the quantity of reagent to be added in accordance with the results of the analysing tests. As described in relation to a water softening plant, hard water is supplied by a pipe 3 to a pivoted measuring-vessel 2, of the kind described in the Specification referred to, which, when released, discharges the water into a small tank 5 whence it is conveyed by a pipe 6 to a reaction vessel 7 pivoted at 17. Standard soap solution is fed drop by drop from a vessel 9 through a pipe 12 to the vessel 7 into which air is forced by a pipe 23. When the frothing stage is reached, the froth passes by a spout 25 on to the spoon 26 of a balanced lever 20 thus releasing a projection 19 on the lever from a catch 18 and allowing the vessel 7 to rotate in an anti-clockwise direction and discharge its contents into a sink 28. On the return of the tank 7, the end 21 strikes an horizontal extension of a wire 31, so depressing it and releasing a catch 32 which frees a rod 33 rigid with the shaft of the vessel 2, thus allowing it to tilt and discharge a fresh sample of the water to the testing vessel 7. The discharge movement causes a cam 34 on the pivots of the vessel 2 to close electric contacts 35 to energize a magnet 36. On the return of the vessel 32 the contacts 35 are broken. Control of the valve which feeds the softening material is effected as follows :-A rocking shaft 37, on which are carried buckets discharging measured quantities of water to a softening tank, has mounted thereon a cam 57 which rocks a lever 59 bearing a spring-depressed pawl 60 engaging a ratchet wheel 61 carried by a shaft 62 bearing a pinion engaging a toothed sector 54 loose on its shaft, the sector 54 thus being advanced a tooth for each rocking movement of the shaft 37. Each movement of the cam 57 feeds a drop of standard soap solution by means of a spring-controlled rod 64 which is secured to the lever 59 and closes contacts 67 of a magnet 68 in the testing apparatus 1. Energization of the magnet 68 rotates, through a pawl-bearing armature and an intermediate pinion 71, a wheel 14 the shaft of which carries an arcuate arm 10 dipping into a similarly curved part 9<a> of the soap tank 9, thus forcing out a drop of soap solution through the pipe 12. The wheel 61 is rotated step by step by the pawl 60 until the magnet 36 is energized by the closing of the contacts 35 by the cam 34 when the vessel 2 is discharged. Energization of the magnet 36 rocks its armature 73 and raises the pawl 60 and a detaining detent, thus freeing the sector 54 which returns to its starting position. Upward movement of the sector 54 controls the movement of a second similar sector 53, by the engagement of projections on the sectors. Tilting of the reaction chamber 7 closes, through the extension 21, contacts 29 of a magnet 30 which releases the sector 53 through a ratchet wheel 77 bearing a pinion engaging the sector. Movement of the sector 53 by the sector 54 rocks a wheel 81 on the shaft of the sector and this, through a chain 82 and crank 83, rocks a shaft 52 which, through a crank 51 and a connecting-rod 50, controls the movement of a piston 48, Fig. 4, in a valve 43 serving to supply the softening fluid. The valve 43 is mounted in a cylindrical extension 46<a> in the base 46 of the tank containing the softening fluid and is carried by a rod 42 secured to a bracket 40 moving in guides 44 and connected by links 38, 39 to the shaft 37. The arrangement is such that when the sector 53 is in its lowest position, the piston 48 is near the top of the valve and as the sector 53 is raised by the sector 54, the piston is lowered, thus enlarging the content of the valve. When the valve is raised by the shaft 37, softening fluid from the tank flows into the valve through ports 47 in the walls thereof and when the valve is lowered, this fluid flows out through ports 49 in the extension 46<a>. As the testing tank 7 moves before the measuring tank 2, the magnet 30 is energized before the magnet 36 and the sector 53 is thus released first and, if it has not been reached by the sector 54, moves down until the projections on the sectors engage. At the end of the operation, the wheel 71 is released when its actuating and detaining pawls are raised by the energization of a magnet 87, in series with the magnet 36, which, as the measuring-vessel tilts, attracts an armature 88 carrying pins releasing these pawls. The arm 10 thereupon returns to its zero position together with the recording arm 15. In a second form of apparatus, modified devices are described for ensuring a correct position of the toothed sector 53 together with a modified valve and operating means therefor. The sectors may also be controlled from the apparatus described in Specifications 282.170, and 282,487, [Class 1 (i), Chemical processes &c.].