WeRead Powered by ReaderPub
History of electric light cover

History of electric light

Chapter 17: GRENET BATTERY
By Henry Schroeder
Open in WeRead

Explore more books like this:

Engineering & TechnologyHistory - Modern (1750+)

About This Book

A chronological, technical survey of electric lighting traces developments from early experiments with friction machines, Leyden jars and voltaic piles through advances in batteries, electromagnetic discoveries and the invention of the dynamo. It follows the parallel evolution of arc and incandescent illumination, outlining experimental filament and arc-control methods and the move to commercial installations and distribution schemes such as series, multiple and three‑wire systems. Later sections review later lamp technologies—Nernst, mercury‑vapor, gas‑filled and tungsten types—together with transformers, rectifiers, standardized voltages and sockets. The book is illustrated and includes a chronology, cost and usage statistics, and a selected bibliography.

GRENET BATTERY

It was discovered that chromic anhydride gives up oxygen easier than nitric acid and consequently if used would give a higher voltage than Grove’s nitric acid battery. It also has the advantage of a lesser tendency to attack zinc directly if it happens to come in contact with it. Grenet developed a cell having a liquid consisting of a mixture of potassium bichromate (K2Cr2O7) and sulphuric acid. A porous cell was therefore not used to keep the two liquids apart. This had the advantage of reducing the internal resistance. The chemical reaction was:

K_{2}Cr_{2}O_{7} (potassium bichromate) + 7H_{2}SO_{4} (sulphuric acid) + 3Zn (zinc) = 3ZnSO4 (zinc sulphate) + K2SO4 (potassium sulphate) + Cr2 (SO4)3 (chromium sulphate) + 7H2O (water).

In order to prevent the useless consumption of zinc on open circuit, the zinc was attached to a sliding rod and could be drawn up into the neck of the bottle-shaped jar containing the liquid.

Grove’s Incandescent Lamp, 1840.

Grove made an experimental lamp, using platinum for the burner which was protected from draughts of air by a glass tumbler.