PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 607 



to have a door, or valve, over it, of common construction, which may be 

 opened or closed, by a handle from the outside of the box, or case, h, or 

 may be made to operate of itself, the handle working through a stuffing 

 box in H. 



I have described this part of my invention as being made of tubes, or 

 pipes, chiefly, but it is obvious that other forms may be substituted, as 

 sheets of metal, coils of pipe, &c., and the operation of it is as follows: — 

 The engine being started in the usual manner, the exhaust steam flows 

 through the pipe, si , into the cap, p, and thence into the cluster of tubes, n. 

 At the same time, a jet of cold water is admitted through the injection 

 cock, 0, on to the perforated plate, m, from which it falls in a shower, upon 

 the tubes, n, and thus, by a well known law, at once condenses the steam, 

 the water resulting, being collected in the bottom of the tubes and caps. 

 The large pump, l, removes the condensing water as fast as it accumu- 

 lates from the box, h, and also maintains a vacuum therein The smaller 

 pump, u, removes the water resulting from the condensed steam, in like 

 manner, at the same time maintaining a vacuum within the tubes. The 

 condensing water is allowed to flow off", as fast as discharged from the 

 pump, L, but the water taken from the tubes is discharged into a suitable 

 reservoir, to be used as feed to the boilers. The aperture, w, is for the 

 pui'pose of insuring the maintenance of an equal pressure on each side of 

 the^tubes, or rather to prevent them from being subjected to any pressure, 

 either internal or external. This can be made "apparent, as follows: — Sup- 

 posing the orifice, w, closed, and the cold w&ter admitted in quantity suffi- 

 cient to condense a part of the steam only, it will be evident that the 

 vacuum within the case, h, will be better than that in the tubes, and the differ- 

 ence will be as the volume of uncondensed steam; now if we open the 

 door or valve, over the aperture, w, a portion of the steam in the tubes 

 will at once rush through, and extend itself throughout the case, h, until 

 an equilibrium is produced. So long as the steam is fully condensed, and 

 the operation of the pumps, l and u, is also equal, so long, of course, 

 the surface condenser, n, will be subjected to the same pressure, both ex- 

 ternally and internally, or rather will not be subjected to any, even if the 

 orifice, w, be kept closed. The use of the opening, w, therefore, is to 

 insure the preservation of the equilibrium, in cases where the steam is not 

 fully condensed, or where the pumps fail to work equally, the atmospheric 

 pressure being in all cases sustained by the case, h, whether the vacuum 

 is maintained within the tubes, or not. The peculiar feature of an alter- 

 native will now be seen, for so long as the various joints of the surface 

 condenser remain tight, and it is otherwise in good order, the operation 

 will go on as in the old kinds of condensers. Should a fracture occur, 

 from any cause, as by some of the tubes wearing out, the box or case will 

 at once come into play, as a jet condenser, to condense so much of the 

 steam as shall escape through the defective tube, or tubes, and the occur- 

 rence of such a defect would still further serve to illustrate the advantage 

 of my said improvement; for whereas, in the old surface condenser, a 

 comparatively small leak would at once destroy its operation; in mine, 

 that only involves the loss of so much of the fresh water as can escape in 

 the form of steam through the defective aperture. 



