THE WHITE CLOUD ENGINE.

Wellington Independent, Volume XXVI, Issue 3182, 25 April 1871, Page 3

THE WHITE CLOUD ENGINE.

(From the Mechancs' Magazine.) By R. M. Mabchant.

"When reviewing the principal scientific and engineering events of the past year — which we did at the commencement of the present one — we referred to the circumstance that some very nai progress had been made during 1870 in promoting the economy of the steam engine. We noticed all the recent examples, except one, of engines designed upon special principles with a view to this valuable result. Our reasons for withholding information respecting this one engine were twofold. In the first place, it is one which is designed upon such a perfectly new principle as to demand a special and separate notice at our hands, and in the second place we wished before writing about it to inspect it for ourselves, and, moreover, to illustrate it in our journal, so that its constructfbn and working might be rendered perfectly intelligible to our readers. This engine is known as the " White Cloud" engine. The name would seem to be of North American Indian origin, and would at first sight appear to have been bestowed upon it at the caprice of the inventor, just as a shipowner names his vessel. But it is not so in reality ; the name " White Cloud" indicates the molivc power used in this engine just as the prefix of steam, air, or water in other cases indicates the power employed to drive the engine to which it is applied. In brief, the engine under notice is literally driven by a white cloud, and hence its name. The inventor and patentee of this engine is Mr R. M. ' iVJarchant, of 41, Kirby street, Hatton [ Garden, on whose premises we recently inspected this singular apparatus. The principle of the engine depends upon the compression of air in stages and the passing of it at each stage through water, by which means it becomes saturated with moisture. The heat given out by

compression is so completely absorbed by the water that under no circum- | stances do the pumps become heated. This combination produces the white cloud which gives a distinctive name to ■ the engine, and which passes into a coil enclosed in a .heating chamber, from whence it passes in a highly expanded condition to the cylinder, where it is utilised for the production of power with very marked economy in fuel. Such in general terms is the principle of the White Cloud engine. Before, however, proceeding to describe the details of construction, we would offer a few remarks on the economical production of motive power, as indicative of the mental process by which Mr Marchant arrived at the results embodied in this engine. In the first place, he sought to develop into practice the principle of using an existing gas to the utmost practicable extent, and in the most effective manner, and by this means to realise a saving in that fuel which is necessarily expended in the manufacture of unygas for subsequent use. Steam is the gas of water, and in every state of freedom from condensation it represents a specific quantity of water in combination with a specific expenditure of heat, being, in fact, so much heat into so much water. The quantity of fuel expended for the conversion of water into steam becomes startling when thoroughly realised. We have it on authority that of 600 tons of coal expended by a steam vessel in crossing the Atlantic, 570 tons are required for the conversion of water into steam. The remaining 30 tons, therefore, represent the proportion expended in adding that pressure to the steam so manufactured, which pressure so added constitutes the motive power. In other words, we have 570 tons of coal expended in manufacturing the gas, and 30 tons used in raising it to a pressure exceeding that of the atmosphere. Now, if the steam already existed as gas, and did not have to be manufactured, it follows that the proper application of 30 tons of fuel to the gas would effect the work now requiring 000 tons of fuel ! The actual saving then would clearly be 570 tons of coal in every 000 tons, which would give an immense additional space for Cargo or passengers. These are the main considerations that have influenced the various attempts to substitute air for steam as a motive power, and have also promoted the improve mimt of the steam engine itself.

We will now proceed to explain in detail the means by wln'ch the difficulties attending the utmost practicable uso of the gas of creation have been surmounted. In the engine illustrated herewith, and which can be seen at work in Kirby street, as already. mentioned, air is drawn in through the first of a series of pumps, the chamber of which is seen on the left of the engine, and is passed through water as a supply to ihe succeeding one, which is so arranged as to limit that pressure on the first pump, at which pressure the second pump is supplied. A repetition of this arrangement in the third pump limits the further attained pressure at which the third pump is supplied from the second, and so on for any number of stages of pumping to any determined compression. In practice, the air is compressed in the first pump from 1 to 3 atmospheres, iv the second from 3 to 6, in the third from 6 to VI, and in the fourth from 12 to 24 atmospheres. From the fourth pump it is conducted to a chamber or reservoir, from which it passGS in a thoroughly saturated condition to the coil in the heating chamber. At this stage we have the resulting product — the white cloud — which consists of the compressed air, of the steam expressed by the saturation of this air when under further compression at each stage of pumping, and of the saturation not so already expressed by steam.

The white cloud enters the heated coil at a determined pressure, and here the remaining saturation is converted into gas, and expansion is given to the already compressed gas. From this coil the cylinder of the engine is supplied wiih its motive power, the exhaust being carried off by means of the chimney. By this process the pressure is attainable to and determined limit, and the little experimental engine we are now describing has, in this way, stored a pressure of 1,2001 b per square inch. This is the first engine that has been constructed with the view of proving the principle, and in future engines some slight alterations will be made in the details. This, however, in no way affects the principle, which has been thoroughly and practically demonstrated in the present engine. Although we have called it a little engine, we by no means intend to imply that it is a toy or a model. We use the term relatively, its size being small in proportion to the power developed. The cylinder is 4 3-Bths in. in diameter, with a 6 in. stroke, and the effective power developed over and above that required to work the pumps is 4-horse power. The pumps themselves absorb 4-horse power, so that the total represents 8 horse power, as has been proved by the inventor with proper brake apparatus. The cylinder is neither lflgged nor jacketted, and there is no piiming with the engine. The amount of fuel consumed, as shown by a register kept for that purpose which we inspected, is 2^}h per hour for the effective power of four horses. These results compare well with those of the best engine at the Oxford Show last year. This was one of Messrs Clayton and Shuttle worth's engines, in which the consumption wns 3-721 b per hour per horse power. The engine was a 4-horse and had a 7in cylinder with a 12in. stroke. These facts speak for themselves, and need no comment at our hands.

Upon a consideration of the general principles of this engine, it will be seen that tUeic application increases power with speed. In this fact alone it is a striking advance upon the existing application of steam for all locomotive purposes, for, as at present applied, the greater the speed the less the effective power attainable from the steam used. This will be clearly comprehended from

the consideration, that every revolution of Mr Marchant's engine represents a stroke of every pump, and consequently a completed charge forward to the coil and thence to the cylinder. Hence as at 100 revolutions per minute 100 charges are stored, each of which repre. sents a surplus for effective power, so at 200 revolutions there is twice such surplus ; at 400 revolutions 400 charges and four times such surplus. Whan charged the engine is ready for operation. The charging is effected by any determined number of revolutions of the engine, according to the storage space provided and the pressure required. The charging is effected by pumping a sufficient quantify of water into the coil of the heating chamber to manufacture the steam required for the necessary number of revolutions, and to shut off the coil from the pressure supply, until the pressure gauge shows that by such use of the steam manufactured in the coil the charge is effected. The cock is then opened on the coil, and the whole operation to full running is effected in about a quarter of an hour from lighting the fire. Jt is candidly admitted by the inventor that the present apparatus is defective in some of its proportions, but notwithstanding this we have seen what excellent results of working have been obtained from it. Looking at these results and bearing these defects in mind, and bearing in mind also that this is the first engine made, and only an experimental one, we may sufely predict for the White Cloud engine a wide sphere of application in the future. We congratulate the inventor upon having effected one of the most ingenious and novel improvements known in the present day, and we look forward to the full development of the system to effect a revolution in steam engineering.