306 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL 



I October, 



all the screw propellers hitherto in use ; but 

 it promises to be more especially advantageous 

 in the case of vessels {roiiig long voyages, with 

 small store of fuel, and employing steam as an 

 auxiliary power only, when the wind is not fair 

 for the use of sails. AV'ith a propeller of this 

 description, not a minute need be lost in changing 

 from sailing to steaming, or from steaming to 

 sailing, and consequently, not a pound more of 

 fuel need be expended than is absolutely re- 

 quired. 



2. The peculiar feature of Mr. Maudslay's new 

 furnace consists in the employment of rotating 

 tubular screw bars, and hence tlie the name 

 (" Archimedian") by whicli we (not Mr. Mauds- 

 lay) have ventured to distinguish it. Fig. 5 is a 

 longitudinal section of the furnace ; and fig. 6 a 



front view. 



H H, are the fire-bars, which, instead of being 

 as usual solid fixtures, consist of a series of tubes 



which are free to revolve in their bearings, are 



open from end to end, screw-threaded on the out- 

 side, and perforated with numerous air-holes. On 



the front end of each bar there is a broad flange 



or shoulder f^ which projects beyond the general 



line of the furnace, and has a worm-wheel W, 



formed upon it. An endless screw-shaft K, 



which passes across the front of the furnace, and 



is worked from the engine through the medium 



of the bevil-wheels N, O, takes into the whole 



series of worm-wheels AV, and causes thereby 



the constant rotation of the fire-bars. L is a 



throttle-^•alve hopper by which the coals are sup- 

 plied to the furnace. As the coals drop from the 



hopper they fall upon an inclined shoot M, 



which projects them upon the front end of the 



furnace bars, whence they are carried gradually 



forward to the back, by tlie rotation of the bars and the action of their screwed surfaces on the mass of fuel. 



In consequence of the bars being in this constant state of rotation it is almost impossible that either clinkers or ashes should accumulAte 



upon them. 



LOCOMOTIVE ENGINES. 



Charles Ritchie, of Aberdeen, Scotland, engineer, for " certain 

 Improvements in locomotive enyines." — Granted March 2 ; Enrolled 

 September 2, 1848. [Reported in the Mining Journal.'] 



This invention consists in, and has reference to, certain im- 

 provements in locomotive and other engines, carried into practical 

 eflfect by the means, or through the agency, of certain new or 

 improved mechanical combinations and arrangements, having for 

 their object the simplification of the construction, and the augmen- 

 tation of the efficiency, of such engines. 



The first part consists in the application of a cylinder, or 

 cylinders, with two distinct and separate pistons in each cylinder, 

 to which are affixed piston-rods, for imparting motion to the 

 cranked-axles and driving-wheels fixed thereon, whereby the rock- 

 ing, or oscillating, motion attending locomotive engines as hitherto 

 constructed, is considerably diminished, and greater steadiness 

 of motion obtained, as, by this arrangement, the momentum of 

 one piston, together with its cranks, and other connections, is 

 at all times exactly balanced, or nearly so, by that of the other, 

 in consequence of the approaching or receding of the pistons to 

 and from each other being always simultaneous. The second part 

 relates to an improved mode of working the slide-valves of loco- 

 motive and other engines, by rendering the eccentric, which 

 imparts motion thereto, available for the purpose of reversing the 

 engine. The third ])art relates to an improved valve for regulating 

 the admission of steam, or other motive power, to the working 

 cylinders of locomotive and other engines, and to improvements 

 in safety-valves, to be applied to the boilers of engines, or other 

 reservoirs of power. The fourth part relates to an improved 

 anti-primer, or steam-collector, to be applied to the boilers of steam- 

 engines. The fifth part relates to an improved self-acting feeding 

 apparatus, for supplying water to the boilers of steam-engines. 

 And the sixth and last part consists in the application to the 

 wheels of locomotive engines of an improved guai-d, or safety- 

 break. 



The drawing exhibits a side elevation of a locomotive engine, 

 constructed according to this invention. A marks the boiler of 

 the engine ; B, the driving-wheels fixed upon the crank-axles, C ; 

 the boss, or nave, D, of each of such wheels serving as the crank, 



to which one end of the connecting-rod E, is attached by a crank- 

 pin, or stud, «, secured to the said nave, and the opposite end of 

 the rod E, is connected to the piston-rod F, in the usual way of 

 forming such connections. G, G, two pistons, to which are' at- 

 tached the rods F, F — the said pistons working steam-tight in the 

 cylinder H, by means of metallic, or other packing. The cylin- 

 ders are fixed to each side of the boiler. Instead of haviiiii' the 

 fixed cylinder and connecting-rods, as above described, oscillaUng- 

 cylinders may be used, with their piston-rods connected directly 

 with the crank-axle ; or where fixed cylinders are used, and space 

 is an object, the connecting-rods E, E, may be dispensed with, by 

 attaching to the piston-rods a cross frame, in whicli there is a slot 

 formed, into which a crank-pin, or stud, takes. The outer end 

 of the frame works through a guide-hole, fixed to the side of the 

 engine, and thus the rectilinear motion of the piston-rods imparts 

 rotary motion to the crank-axle and driving-wheels fixed thereon. 

 The steam may be admitted through the ports, into the cylinder, 

 by a common slide, in the following manner: — Upon the hinder- 

 most driving-axle is fixed an eccentric, upon whicli is a cam, of the 

 following peculiar construction : — Two rods are fixed to, or formed 

 upon, the said cam ; or it may be composed of one double-gabbed 

 rod, one gab being employed for effecting the backward, and the 

 other the forward, motion of the slide-valve, through the inter- 

 vention of a double lever, which has its fulcrum upon a stud, fixed 

 to the side of the boiler, as shown by the drawing, and this lever 

 is connected to the slide-valve by a rod c. The length of this 

 lever, as also the angle of inclination of the parts O, O, should be 

 in accordance with the lead of the valve — the one or other of the 

 inclined parts O, being caused to act upon the lever by a hand 

 lever, connected to the said cam in any convenient manner, so as 

 to enable the engine-driver to start, reverse, and stop the engine 

 readily, by the same eccentric which gives motion to the slide- 

 valve. By making the end of the vahe-rod mo\eable, as in a slot 

 in the lever P, the steam may be worked expansively at pleasure. 

 Improved spring safety-valves are exhibited by other drawings at- 

 tached to tliis specification, from which it will appear there are 

 two forms of construction, showing a valve with a conical-shaped 

 seat, being a flat-valve, and constructed with a flange, which the 

 inventor terms a compensation flange — such flange being let into 

 the seat vertically, about one-sixth of the diameter of the steam- 



