| 46 |
|---|
Rev. Professor Michael T. Casey
St. Patrick's College, Maynooth
Dr. James J. Drumm, inventor of the "Drumm" Traction Battery was born in 1897 at Dundrum, Co. Down. He received his primary education at the National School where his mother taught, and his secondary education at St. Macartan's College, Monaghan, where he won a County Council Scholarship. In 1914 he entered the Chemistry School of University College, Dublin under the late Professor Hugh Ryan, and graduated with an Honours B.Sc. Degree in 1917. In the following year he obtained the M.Sc. degree by research. He then spent three years with the "Continuous Reaction Company" in England and returned to Dublin in 1922 to work as a research and production chemist with "Fine Chemicals Ltd." at 40 Mary Street, originally the premises of the Apothecary's Hall. Later he worked with James Crean & Co., soap manufacturers, for whom he produced a very fine toilet soap which was marketed under the trade name "Dromona". He also acted as consultant chemist for various firms and was engaged in some academic research funded by an 1851 Scholarship.
In conjunction with the late Professor James Bayley-Butler of U.C.D., Drumm carried out work on the canning of peas with the idea of preserving their green colour. Up to that time canned peas lost their fresh colour and looked rather uninviting. Drumm's work laid the foundation of modern methods of processing. Drumm's best known researches were concerned with the electric storage battery which bears his name. The origin of his interest in batteries is little known and came about in the following way. In 1925 the writer of this article gave the inaugural lecture to the Chemical Society of U.C.D. The subject was "Hydrogen ions", a common-place subject nowadays, but sixty years ago not so well known. During this lecture the quinhydrone electrode was discussed. On our way back in the tram to our lodgings that evening Drumm suggested that the quinhydrone electrode could be used in a cell to produce current.
I agreed but pointed out that the amount of current would be very small, as proved to be the case when, on the following day, we set up a quinhydrone cell. Drumm became characteristically enthusiastic and decided to experiment further. I pointed out that quinhydrone being an organic substance - and not a very stable one at that - would produce tarry decomposition products during charging and discharging of the cell. Not daunted, however, Drumm experimented with various substituted quinhydrones and found that, though the cell could be charged and discharged rapidly, its life was short because of the intractable tars produced by the oxidation of the quinhydrone. Drumm then abandoned this type of cell and turned his attention to the alkaline cell. He was working in the Experimental Physics Laboratory under the late Professor John J. Nolan, Head of the Department and also adviser to the Ministry of Industry and Commerce with regard to Drumm's researches.
The government at that time had invested heavily in the Shannon Hydroelectric Scheme developed by the late Dr. Thomas J. McLaughlin. It was capable of supplying abundant electrical power and to offset the taunt of "white elephant" from the opposition party, the government was anxious to get customers for the surplus supply. Industries capable of utilising electricity were not numerous and so electrification of the railways seemed to offer a solution to the problem. However, the relatively small bulk of traffic and the scattered population would have made it impossible to justify the initial cost of a "live third rail" or an overhead cable system. Consequently a suitable battery system would be ideal.
Incidentally, nearly a hundred years previously the Rev. Dr. Nicholas Callan - inventor of the induction coil and of the Maynooth Battery - worked on the idea of a battery-powered engine to haul a train from Dublin to Dun Laoghaire but found that the economics of a laboratory-scale experiment did not always apply to the large industrial scale. Callan was dealing with primary batteries, the only available source of electricity at that time since the dynamo had not been invented, although Callan himself had discovered the principle of the self-induced dynamo but did not follow it up.
At the time Drumm was working the only available storage batteries were the lead/lead dioxide/sulphuric acid accumulator and the Edison nickel/iron alkaline battery. The former had several disadvantages:
A commercially successful storage battery must have a long life, must be mechanically robust and must have a low upkeep cost. In addition, a battery for traction purposes must have low weight in relation to its output, for obviously the battery forms part of the haulage load. It is also of prime importance that the battery should be capable of giving rapid acceleration. This involves rapid discharge.
Now a battery capable of rapid discharge can also be rapidly charged, for the changes involved in discharge are roughly the reverse of those involved in charging. To construct such a commercially viable cell was the problem which Drumm undertook and solved so brilliantly. From 1926 to 1931 he worked unremittingly at his research which eventually produced the Drumm Traction Battery and in that year -1931- he was awarded the Degree of D.Sc. by the National University of Ireland for his researches.
Familiar with all the snags of the quinhydrone cell and the lead accumulator, Drumm now turned his attention to the construction of a new alkaline cell. At that time possibly the most commonly used alkaline cell was that devised by Edison. It was a nickel-iron cell with potassium hydroxide solution as electrolyte. the reactions in the cell may be written:
The E.M.F. of this cell is 1.34 volts. The iron anode tends to become passive and also the rates of charge and discharge are rather low. Drumm got the idea of using a zinc negative electrode and after much experimenting used an electrolyte containing zinc oxide dissolved in potassium hydroxide solution, in effect, potassium zincate solution.
The Drumm Cell, which has been the subject of patent rights in all the principal countries of the world, is an alkaline cell and the only metals which enter into its construction are stainless steel and pure nickel. Its mechanical strength is therefore quite satisfactory. The positive-plate system consists of the hydroxides of nickel mixed with nickel flakes. This electrode was first developed by Edison. The negative plate is a grid of nickel gauze and the electrolyte is a solution of zinc oxide in potassium hydroxide (potassium zincate).
During charge zinc is plated on to the nickel grid, and during discharge this zinc dissolves readily in the potassium hydroxide. The reactions in the Drumm cell may thus be written:
Effectively then, the negative system is Zinc/Zinc hydroxide. The above reaction permits rapid charging and discharging rates - a great advantage over the Edison nickel-iron cell in which the ferric hydroxide in insoluble in potassium hydroxide. The E.M.F. of the Drumm cell is 1.85 volts and even at high discharge rates is some 40% higher than that of other alkaline cells of the Edison Ni/Fe type. Chiefly in consequence of its high voltage and low internal resistance this battery could be charged and discharged many times a day and at rates greatly in excess of those which had hitherto been accepted as st
ly at 0°C. Unlike the lead accumulator the amp-hour capacity of the Drumm cell is independent of the rate of discharge. Thus this cell will furnish 600 amps continuously for 1 hour, or 900 amps for 40 minutes or 200 amps for 3 hours. The standard rate of charging for a single traction cell of weight 112lb and allowing for all losses in efficiency, corresponds to an input of 0.134 effective watt-hour/lb/minute which is about four times the normal rate for alkaline cells. In practice the same cell is normally discharged at 400 amps and at an average voltage of 1.65 volts which is equivalent to about 0.1 watt-hour/lb/minute.
This figure is twice the highest discharge rate of other alkaline cells. But over and above this the current can, when required, be raised to 1000 amps for limited periods, corresponding to an energy delivery of about 0.22 watt-hour/lb/minute - a very high rate indeed. The Drumm cell deals with these loads quite comfortably and with no sign of deterioration. Another feature of the Drumm battery is that it cannot be damaged in any way by frequent over-charging or over-discharging. Neither can prolonged reversals of current through the battery when discharging, cause any harm. The maximum allowable cell-temperature for this battery is 45øC. The working life of the Drumm battery has been assessed as not less than ten years. Tests carried out on the nickel grid show that it can withstand hundreds of thousands of cathodic and anodic polarisations. The electrolyte is comparatively cheap and can be changed or renewed at very small cost.
The power of furnishing energy at these unprecedented rates makes it possible for a traction battery of Drumm cells to overcome the grave disadvantage inherent in the majority of such batteries, i.e. the impossibility of furnishing rapid accelerations. In February 1932 the Drumm battery train was charged at Inchicore and went on a test run to Portarlington and back - a total distance of 80 miles - on the single charge. This was repeated several times and a few days later the train went into regular service on the Dublin-Bray line and was operated for 180 to 230 miles per day. The battery was charged at Amiens Street Station (Connolly Station) and at Bray. The distance is about 14« miles. The weight of the train with passengers was about 85 tons. There was seating accommodation for 140 passengers.
The train could accelerate from standstill at about 1 m.p.h. per second and attain speeds of 40 to 50 m.p.h. with ease. The train was fitted with a successful system of regenerative braking, whereby an important fraction of the energy surge made available on a down-gradient or on de-accelerating at a station was returned to the battery. The Drumm Battery train operated successfully on the Dublin to Bray section of the line with occasional runs to Greystones some five miles farther on, from 1932 to 1948. One wonders why it was discontinued. Various suggestions have included vested interests and cheaper fuel oil.
Professor A.J. Allmand F.R.S., in a report stated "It is clear that Dr. Drumm has produced a cell of somewhat remarkable properties, and that, although primarily designed for transport purposes, these properties may lead to its utilisation in other fields". (Nature 12th March 1932).
Drumm's work on the traction battery - apart from his other contributions to industrial development - entitles him to a high place in the Honours List of Irish Scientists. Just over a century ago Callan's pioneer work was let slip into oblivion and were it not for the devoted researches of the late Monsignor J. McLaughlin - himself a successor of Callan in the Chair of Natural Philosophy at Maynooth - Callan would be totally forgotten today. Let us fervently hope that Drumm's work will not suffer a similar fate.
In conclusion, the writer would like to express his gratitude to The Very Rev. Patrick Drumm P.P., brother of Dr. Drumm and to Mr. John Drumm (son) and to Professor Eva M. Philbin for materials from which this article was completed.
Further details on the history and workings of the Drumm Train are given in an article in the Journal of the Irish Railway Record Society (1979a, Vol. 13, No. 80, pp 454-427), by T.A. Illingworth.
This article was first published in Irish Chemical News Spring 1988 and is reprinted by permission.
The main problems occur during charging when the zinc is redeposited from solution and may cause shorting out by forming dendritic growths, or may deposit unevenly. Prototype batteries have been tested by companies in the USA, Europe and Israel with energy densities of up to 90 Wh/kg, giving ranges of 100-230 km with small vehicles. It is interesting to see that Drumm's battery, used over 50 years ago to run railway cars in Ireland, has been resurrected for the 1990's drive towards clean energy. He was certainly ahead of his time and despite the limited state of battery technology at the time, Drumm's batteries were remarkably successful with a life of 10 years, with daily use.
Michael Baker commented in 1972: ".. the Drumm trains of the Great Southern were unique and it might have been that, but for the war and insufficent research funds, Ireland would by now be leading the world in this particularly clean and self-contained form of motive power."
Other refereneces to Drumm and his batteries are to be found in: Some People and Places in Irish Science and Technology ed. C.Mollan, W.Davis, B. Finucane RIA Irish Railways Since 1916 M.C.Baker Ian Allan 1972 (pp 100-103)
STOP PRESS: An illustrated booklet on "The Drumm Battery" has just been published. It was written by Brian Hogan, one of the team who helped to make the batteries. It is available at a cost of £4 from: Rick Cox, 10 Corbawn Court, Shankill, Dublin 8.