Patent GB-180120-A (GB)
Title: Improvements in and relating to electric primary cells
IPC: H01M6/24
Filed: 1921-03-16
Abstract: 180,120. Darimont, L. March 16, 1921. Electrolytes; electrodes; arrangement; absorbents; diaphragms; carbon electrodes, making; gas exits; connections.-A two-fluid cell having an exciting- solution consisting of a non-acid chloride and a depolarizing solution containing ferric chloride is provided in the exciting solution with calcium carbonate o r phosphate, barium carbonate, dolomite, lime, or other substance capable of precipitating ferric compounds and forming a semipermeable membrane preventing diffusion. The electrodes consist of a carbon rod 4 and a zinc cylinder 10 having a lead or other metallic connection 11. The zinc is immersed in the exciting- solution, to which an agglutinant is also added. In one example, the excitant consists of 125 grms. of sodium chloride, 300 grms. of calcium carbonate, 60 grms. of cornflour, and 500 grms. of water, the whole being mixed together and boiled. Another mixture consists of 600 grms. of sodium chloride, 1,200 grms. of calcium carbonate, 25 grms. of bone gelatine, 200 grms. of cornflour, 200 grms. of kaolin, a small quantity of formol, and two litres of water. Antiseptic substances other than formol may be used. Another mixture consists of 500 grms. of sodium chloride, 125 grms. of calcium carbonate or phosphate, 75 grms. of flax flour, 200 grms. of kaolin, 2 litres of water, and an antiseptic substance. The depolarizing-solution consists of a mixture of ferric chloride, sodium chloride and chromic acid or a salt of chromium with or without hydrochloric or other acid. In an example, the mixture consists of 380 grms. of ferric chloride, 25 grms. of sodium chloride, 2 grms. of chromic acid, 4 grms, of hydrochloric acid and 360 c.c. of water. The mixture mav be further diluted with salt water. The sodium chloride may be replaced by other substances capable of precipitating any oxides and hydrates of iron which may occur in the depolarizing solution. The hydrochloric or other acid is for the purpose of dissolving any excess of insulating salts deposited in the carbon electrode and in the walls of the porous vessel 3. An agglutinant may also be added, such as dextrin, invert sugar, and flour. The agglutinant in the exciting solution may consist of starch, fecula. flour of cereals or flax, molasses, agar-agar, gelatine of bones or skin &c. Gelatinous silicates or cellulose paste may also be used. and oxide of aluminium, kaolin, or other hydrophile substance may be added. The bottom of the porous vessel 3 is made convex to prevent the accumulation of gas, and the upper part of the vessel is made impervious either by immersing it in glue or molten paraffin or by immersing it before the furnace baking in molten lead oleate &c. with or without the addition of metallic soaps such as those of iron or manganese. The upper part of the carbon electrode 4 is also made impervious bv immersion in molten paraffin. The porous vessel is sealed with pitch or wax &c. 8 which is poured while molten on to the surface of sand with which the vessel is nearly filled. A tube 6 surrounded by a wire 7 or having a roughened surface is fixed in the seal 8, the sand being poured out through this tube after the sealing operation. A slit or perforated stopper 9 serves as a gas exit. The vessel 3 is held in the outer jar 1 by a cork ring 12. During transport of the battery the ring 12 may be used in conjunction with a cardboard disc and sheet of parchment as a temporary stopper.