The Elwell-Parker Accumulator

The Wolverhampton Electric Light, Power, Storage and Engineering Company is now manufacturing and selling a new storage battery, of which very little has yet been heard. This battery appears, as far as can be judged, to promise well.

We assume that our readers are familiar with the general theory of the storage battery, which has, indeed, been very fully set forth in our pages by Professor Oliver Lodge. It will suffice to add here that augmentation of surface in the lead plates is most desirable, and has been earnestly sought for by all recent inventors of, storage batteries.

Some time ago M. Planté made the remarkable discovery that lead will absorb nitric acid. It not merely attacks the outside of the plates, but penetrates their substance, and a lead plate, after immersion in nitric acid, and being subsequently apparently quite dried, will for hours give off nitrous acid fumes if placed before the fire. The effect of the acid is to render the lead porous, although no considerable increase in bulk is apparent; and in this way the effective surface of the plates is enormously increased.

About the same time that M. Planté made this discovery, Mr. Bedford. Elwell and Mr. Parker, of Wolverhampton, hit on nearly the same thing. They found that by immersing lead plates in a dilute mixture of nitric and sulphuric acid, very important advantages were secured. M. Planté and Messrs. Elwell and Parker patented their inventions about the same time, and now work together.

The method of making the Elwell-Parker secondary battery may be thus described: Strips of sheet lead 9 inches wide and any convenient length, weighing 2 lb. to the square foot; are passed through a machine which first punches holes entirely through them and then impresses them with indentations, which act as distance pieces to keep the layers of each plate apart. The holes secure a free circulation to the electrolyte. These strips are then rolled spirally into cylinders containing, in the small cells, three thicknesses of plate each, the joints being made secure by fusing with a soldering iron, and an anode of much thicker lead being fused on at the same time.

Each cell contains eight of these cylinders ¼ inch apart. The lead cylinders are first placed in a bath containing a dilute solution of nitric and sulphuric add, and left there for twenty-four hours. The effect of this bath is to minutely honeycomb the lead plates, putting them into the most favourable condition for “formation” by the electric current. There is also formed upon the surface of the plates a deposit of sulphate of lead, the greater part of which is subsequently reduced to peroxide, part of it being first washed off. The plates on being taken from the bath are washed, and then placed in the ordinary dilute sulphuric acid solution in the cell. They are then charged in one direction for six hours with a current of 12 amperes, discharged in about three hours through ten Swan 45 volt, 20-candle lamps. Twenty-two cells give 45 volts, and charged again in the reverse direction. They are then ready for use. There is then no sulphate visible, the peroxide plate being a rich, dark brown colour, of smooth, hard, crystalline appearance, and the negative plate presenting a clean surface of ordinary lead colour.

The accompanying engraving shows one cell and a portion of another, coupled by clamping the electrodes together. The plates or cylinders are retained in position by notched vulcanite frames underneath, and notched distance pieces of the same material on the top, thus leaving the entire apace between the plates and a space underneath them open for the free circulation of the electrolyte. The period occupied from the cutting-up of the lead strips to the complete charging of the battery ready to send out is only 48 hours. Earthenware cells are generally used, but the company manufacturing under the patent also uses wood cells, coated inside with a composition of gutta-percha., which are preferable where strength and lightness are required.

The quantity these cells will give out at an electromotive force of 2 volts, or rather more, same as the original Planté cell, is about 40 ampere hours when sent from the works, that is, supposing an accumulator is required to give a current at an electromotive force of 45 volts, twenty-two of these cells will give a current of 10 amperes for four hours before any of the cells “give out.” But the capacity of the cell may be greatly increased by occasionally reversing the charging current, as in the original Planté cell. The cells are packed in small cases of three cells, carpet being slipped between the plates. They seem to travel safely thus.

In Mr. Elwell's country house at Albrighton, near Wolverhampton, there are two sets of twenty-four cells each, placed in the corner of the cellar, and charged twice a week during the daytime by a Siemens dynamo SDI, worked direct by Elwell and Parker's 3 horsepower high-speed engine, giving 120 revolutions per minute at a steam pressure of 35 lb. About this curious engine we shall have more to say. The gardener attends to the fire, which requires stoking twice an hour, no other attention being required, as the engine is self oiling, and the boiler is fed by a regulated injector.

In case the boiler be forgotten, and the steam goes down, there is a simple self-acting arrangement in the circuit, by means of which the current is cut off the battery and shunted through a resistance coil. As soon as the steam rises again the current is shunted back again. This also acts in case the engine be stopped without first breaking the circuit. Five hours work of the engine twice a week, once a week at this time of the year, is sufficient for the lighting of the whole house on ordinary occasions, and a single lamp is often kept on all night. There are about sixty 20 candle lamps wired, and, when required, the whole sixty can be kept up for two or three hours at once by means of engine, and accumulators working together, but, as a rule, five or six 20 candle lamps suffice. The working expenses of this installation cannot exceed 4 shillings a week, common slack being used in the boiler, and the wear and tear is extremely small. As far as can be ascertained after six months use of the cells, there seems to be very little doubt but that they will last as long as the original Planté cells, many of which have been in use for twenty years or more without any visible deterioration.

On Saturday week we had an opportunity of seeing a complete installation at work lighting a private house at Bush Hill Park, between Edmonton and Enfield, about nine miles from Liverpool Street. This park has been built upon most judiciously by Mr. Tayler Smith, and is one of the most beautiful places near London. Mr. Smith determined that the place should be made to retain its rural character as much as possible, and no gas is laid on, the intention being to ultimately light the whole by electricity. There is a private waterworks, with a pumping station about three quarters of a mile from Mr. Smith's house. The pumping engines are sufficiently powerful to pump, in a couple of days, a week’s supply of water, and it has been determined to utilise these engines in lighting all the houses in the park.

As a preliminary, an Edison D machine was put down at the waterworks, and Messrs. Edison fitted up Mr. Smith's house with wires; but it was quickly found that the fluctuations in the current were so great, owing to the irregular action of the engines when pumping, that the lights rose and fell, and it became evident that some kind of storage must be used, if for no other purpose than as a regulator. As an experiment Mr. Smith has fitted his house with an installation of fifty-four Elwell-Parker cells.

These are arranged on shelves in a species of small pantry opening into the garden. This pantry is about 8ft. long, 6ft. wide, and 8ft. high. One side and the end opposite the door are fitted with shelves. On the remaining wall is placed a switchboard, controlling the flow of electricity from the waterworks, and from the battery into the dwelling house. By the aid of a multiple switch any number of cells may be used as required, from half a dozen up to the whole fifty-four.

A cell was taken to pieces for our inspection, and we found the lead plates presenting clear, clean smooth surfaces, while the “made” plates, as we may call them, were, as we have stated, coated with a thick brown deposit of peroxide of lead strongly adherent and showing no tendency to fall off. The arrangement of the battery is very workmanlike and convenient. A cell can be taken to pieces and put together again in about two minutes, and the way in which the cylinders are put together gives great stiffness and prevents deflection or bending, while the plates being free to expand or contract can do so without loosing their shape, which is much more than can be said of some other batteries. Tests showed that the electromotive force is rather in excess of 2 volts per cell. The lamps used for us by Mr. Smith are 110 volts Edison, but he has also 8-candle Edison, and many kinds of Swan lamps in his house.

Mr. Tayler Smith has devised a virtually new system of lighting, and the fittings which he uses are extremely ingenious. At another time we shall describe them more minutely. It must suffice for the present to say that they are all movable, and that various points of attachment are provided throughout the house. In this way the difficulty of knowing what to charge the consumer is got over. A safety cut out under lock and key is provided by the company supplying the current. The consumer is supplied with a certain number of lights, say twenty, and he pays so much a year per light, but there may be as many as a hundred points of attachment provided, and the twenty lights can be distributed at will. Thus, for example, let us suppose that eight lights are used in the dining and drawing room. One light in each room is a fixture. The remaining six may all be hung up in the dining room during dinner, and removed to the drawing room subsequently.

When the family retire for the night, each takes a lamp with him, and striking a match when he reaches his room, he finds the place whereon to hang his lamp, and he has immediately a light of twenty, sixteen, or eight candles, as the case may be. Each lamp is provided with the usual thumb spring, so that it may be extinguished without taking it off the wall. Should a dishonest householder attempt to use more than the legitimate number of lights, he will fuse the safety-plug under lock and key, and defeat his own object. We need scarcely say that we have done no more than give an inadequate idea of the system; the success of it depends on details, and these have all been worked out in a way which is full of promise. The whole principle is excellent.

We have thus a complete installation, suitable for lighting a house of any dimensions from a central station, within easy distance of London. We have had, of course no opportunity of testing the Elwell-Parker battery for months, but we have reason to doubt the strict accuracy of the statements which have been made to us concerning it, and what we saw has very favourably impressed us.

That the system has the approbation of the veteran electrician M. Planté, is of course a strong point in its favour. As to the cost of the battery and rate of production, we may say that the company is at present turning out not more than 100 cells weekly, but is preparing its works for making three or four times this quantity. The company is trying some cells upon a very large scale with suspended plates, taking care, of course, that the weight is not sufficient to cause the plates to stretch. These plates it is proposed to place in brick cisterns, lined with the same composition used in coating the wood cells which the company lately discovered to be very valuable for the purpose.