Patent GB-190418403-A (GB)
Title: An Improved Electrolytic Process, and Apparatus therefor.
Inventor: TOWNSEND CLINTON PAUL
Filed: 1904-08-25
Granted: 1904-12-08
Abstract: 18,403. Townsend, C. P. Aug. 25. Chlorine; hydrogen.-Relates to a process and apparatus for electrolysing solutions, especially aqueous solutions of alkali-metal salts. Fig. 1 is a side elevation, with parts broken away, of a preferred form of cell, and Fig. 2 a vertical section of the lower part cf the cell. The cell consists of a bottom and ends 1 of artificial stone or slate, a cover 2 of slate, and sides 3 of metal, held in place by clamps 4 against a packing 5. It is provided with apertured lugs 6 for removal &c. by a travelling crane, and with a cathode conductor 7. Each side plate has marginal portions 8, 9 and a central raised portion 10 forming a cathode chamber. The cathode 11 is an iron wire mesh facing the part 10, and is secured above by a bar 12 and bolts 13, and below by a semicircular bar 15 and screws 16 within a horizontal groove 14. The cathodes are supported by a series of vertical tubular springs 17, each spring consisting of several right and left hand interwoven spirals of thin spring steel wire. The springs are carried by a heavy iron wire netting 18, against which are pressed vertical U-shaped bars 22 riveted to an iron or steel plate or dam 19, adjustably pressed forwards by screws 21 and resting upon cross-ribs 20. The bottom of each cathode chamber inclines to the centre, where there is a trap 23 into which can be screwed more or less by a hand-wheel 27 the lower end of a tube 24 having a notch 25 at its lowest part and an aperture 26 near its upper end. The temperature of the liquid is regulated by heating or cooling pipes 28. The anodes are vertical bars 28, preferably of "Acheson" graphite, resting on blocks 39, and having inclined active faces 30 provided with narrow vertical grooves 33 in which strips 34 of a non-conducting material, such as glass, rest, the strips being bevelled on top and bottom. Their outer edges bear against hard-rubber facings 36 perforated at the parts 37 opposite the anodes. Current is carried to the anodes by a conductor 31, and by graphite or aluminium or other metallic bars 32. These bars are protected from the action of the electrolyte. Between the facings 36 and the cathodes 11 are diaphragms 35, formed of fibrous material of animal or mineral origin, such as two or more sheets of thin asbestos paper, with the fibres of adjacent sheets at angles to one another, or of paper or cloth. Additional rubber sheets are provided at the upper part between the diaphragm and cathode. A central space 40 left between the two anodes has a central sedimentdepositing channel 44, and a vertical tube 41 is held in the position shown by packing 42. Brine is continuously charged into the anode compartment through the tube 43, and, when the cell is in action, escapes along with the chlorine through the tube 41. The brine also circulates up the active face of each anode, over the latter, down the other side, under each ptate, and up again, the circulation being rapidly effected, at a current density of 100 to 150 amperes per square foot of anode surface, by the chlorine generated. This circulation prevents any insoluble matter from accumulating on the diaphragm. The cathode compartments are charged above the plates 19 with a liquid which is substantially immiscible with and inert towards the caustic alkali &c. formed, a non-saponifying or mineral oil being given as an example. In consequence of the hydrogen generated in the cathode compartments, this oil circulates up, down, and around the plate 19, while the caustic alkali, which is never exposed to the air, flows downwards and is removed by means of the trap 23. Other means for circulating the oil may be provided. By the raising or lowering of the oil level, the rate of flow of the electrolyte through the diaphragm may be regulated. The cell may also be constructed with but a single cathode compartment, a solid back replacing the second.