Taken from the series Cars and How To Drive Them- No. XVI. The White by Colonel R.E. Crompton, R.E, January 7, 1903.
The excellent results obtained by this car during the Reliability Trials of the Automobile Club have drawn the attention to probably the most interesting development of the application of steam to motor-car work that has been brought forward since Serpollet introduced the instantaneous steam generator, usually called the flash boiler. Mr. R. White, of the White Sewing Machine Company, Cleveland, Ohio, has for some years been working on the problem of fitting a boiler of a modified flash type to a steam car, which would be free from all the troubles that generally attend the introduction of a steam boiler into a motor car.
Mr. White evolved principles of construction differing so widely from those introduced by Serpollet that they practically constitute a new departure. Instead of supplying a boiler which evaporates from water into superheated steam just the quantity required for each stroke of the engine, Mr White provides a boiler consisting of a continuous coil so arranged that the boiler does not empty itself at each stroke of the engine, but the small quantity of water contained in it constitutes a sufficient reserve to enable the car to run a few hundred yards, even when the water supply to the boiler is not maintained. In order to do this it was necessary to provide an automatic means by which the portion of the coil of tubes which contain only superheated steam should be prevented from being overheated to a dangerous temperature, and it was also necessary to provide an automatic means of supplying the feedwater in the precise quantity required to suit the ever-varying demands of a car travelling on a road.
This twofold duty is accomplished by very simple means, and the results that have been obtained there from are extraordinarily satisfactory. To those accustomed to the Serpollet boiler on the one hand, and to the fire-tube boiler used in steam cars of the usual type on the other, the absence of attention that is required by the driver of a White Car to either his fuel supply or water supply is very astonishing, and the entire immunity from trouble caused by dirty water or by the entrance of oil into the boiler is truly remarkable, and was demonstrated very clearly by the marvellous freedom from stoppages of any kind shown by the two cars entered for the Automobile Club's Reliability Trials. The simplest way of describing the White car is to say that as regards general arrangement it does not differ very widely from the ordinary type of American built steam car, so far as the position of the machinery is concerned.
The boiler or generator is placed in a central position just behind and below the driver's seat, has a water tank immediately behind it, and supplies steam to a vertical engine placed in front of it; this is pivoted at its upper end, so that the crankshaft or lower end is free to swing, and so adjusts itself to maintain a constant distance between the crankshaft and the driving axle, and thus to maintain an approximately equal driving tension on the driving chain. The petrol tank extends across the vehicle under the footboard, and a condenser is fitted right across the front of the vehicle. The usual Ackerman steering gear, actuated by a lever, is employed. The boiler is fired by a burner which, in principle, does not differ in any important respects from the class of burner employed by the Locomobile and other American cars. So far it will be thus seen that, in the general arrangement of parts, there is no great difference between the White car and the type of American steam car with which we are so familiar, except in the very important particular that in nearly every respect the various parts are of increased size, strength, and solidity. It is when we come to the details of the boiler and of the automatic devices which control the fuel and water supply, in the condenser, and in the feed water filtering appliances, that we find striking differences.
Taking these in order-the boiler consists of twelve flat coils, each of them consisting of a flat spiral with the inner and outer ends turned up at right angles to the plane of the spiral. The turned up portion of each coil is of sufficient length so that it extends to the top of the boiler, which consists of a group of twelve of these coils superposed one on the other. It follows that, as the boiler is about 13" diameter and 14" high, each of the coils is about 13" diameter, and the upright tubes of the lower coil are about 14" long, while those of the upper coil are only about 2" long. These twelve coils are connected at the top by cross connections, so that they form one continuous tube, having a total length of about 360ft. These connections are by screwed joints and are at the top, i.e., the coolest part of the boiler, and all of them are very accessible.
The water coming in from the feed pump enters at the top coil. After filling it, it has to pass up through the short length of vertical pipe which connects it with the next coil, and so on with each coil in turn. It follows that when all the coils are filled, any number of the lower tubes can be blown off in turn, whilst those above them cannot empty themselves, as the water is trapped in the coils by these vertical lengths of pipe. At first starting, the boiler requires to be filled by a hand pump, but afterwards, every time the boiler cools down, it automatically fills itself from the tank, so that it is always ready for use whenever it is required to get up steam.
The steam of this boiler is uniformly superheated to a temperature of 800 degrees Fahr., and this is carried out in a very simple way. The Steam, on its way from the lowest coil to the engine, passes right across the centre of the fire through a thermostat, which, by the expansion of two metals when the temperature of the lower coil reaches 800 degrees Fahr., is arranged to press on and actuate the end of a lever which closes the petrol admission valve of the main burner. Thus, as soon as the temperature of the steam passing through the above-mentioned thermostat arrangement reaches 800 degrees, the fire is automatically shut off, and the sub-burner only continues to burn. On the other hand, a fresh demand for steam causing steam to be drawn in increased quantity through the thermostat again turns on the fire, and the temperature is thus maintained constant.
The water supply to the boiler is also automatic. It consists of a diaphragm regulating the supply, actuated by the steam pressure, and which can be adjusted in such a manner that so long as the steam pressure is below 220lb. the feed pump drives the whole of its water supply into the boiler. This full supply of feedwater causes additional coils to fill with water, and hence the steam pressure rises, but when the steam pressure reaches the above limit of 225lb. the diaphragm regulator opens the valve of the bypass, and the water no longer passes to the boiler, but is returned to the water tank.
It will be seen that this water regulator is positive in its action, does not depend on a mere weighted by-pass valve being lifted by the pump, but the steam pressure itself opens and continues to hold open the by-pass until the steam pressure again falls to the specified point at which it is desired to feed water into the boiler.
From this description it will be understood that the combination of the semi-flash boiler with the twofold regulation of the thermostat, maintaining the temperature constant at 800 degrees Fahr. with the water regulator, which only feeds the water when the steam pressure is below a fixed limit, is the chief feature of the White car, for from this combination arises the extraordinary fact that the steam engine is supplied at all pressures with steam at a constant temperature, so high as to prevent any cylinder condensation taking place.
Now it is well known to engineers that the chief cause why small steam engines are so uneconomical, and therefore compare so unfavourably in economy with the internal combustion engine, is that the cooling surface exposed by the small cylinders is so large in proportion to their cubic capacity that the initial condensation, which represents sheer waste of steam, is very large as compared with engines of greater size, where the surfaces exposed do not bear such a high proportion to the cubic capacity. But if the steam is superheated to a temperature at which we can make certain that no cylinder condensation takes place, it is possible not only to get high economy with the small engines used in motor-cars, but the complication of compound or triple-expansion engines becomes unnecessary, and very high economy of steam consumption is obtained in the simplest possible manner.
Mr. White claims that careful testing in America, when the cars have been jacked up and the engine has been used to drive dynamo machinery belted from the hind wheels, has shown that the engines use about half the steam that is used when steam is not superheated.
Putting it roughly for purposes of comparison, during recent American official trials the petrol consumption of the White steam cars was only 30 per cent. greater than that of the very best internal combustion cars, and was practically equal to that of average internal combustion cars.
Another fact arises from this small consumption of steam, that it is an easy matter to condense the whole of the steam produced by the White Car. All those who are familiar with the running of the White car know that it is very rare indeed that any exhaust steam is seen escaping from these cars; and, moreover, the water tank, which only contains fourteen gallons of water, is in most cases sufficient to run the car one hundred miles without a fresh supply of water, and in extreme cases as much as 140 miles.
Summarising, in the White steam car we have quiet running and freedom from the noise, vibration and smell which we generally associate with the best steam cars, but we have in addition the high economy and long radius of action, without refilling water or fuel, which we associate with internal combustion cars . The fact, also, that no exhaust of any kind is allowed to blow on the road, and that the car is built with considerable clearance from the ground, enables it to be run at a considerably higher speed than is possible with other cars without raising dust, so that it is probable that as regards freedom from dust raising it is almost the best car that the writer has yet seen.
The writer has driven one of these cars for 3,000 miles, and has found it not only remarkably free from troubles of any kind, but exceedingly pleasant to drive. The driving, moreover, as will be seen later, is easily learnt by unskilled persons.
(To be concluded.)
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