HORIZONTAL ENGINE.] 



API LIED MECHANICS. 



865 



of very simple construction, and has no parts that are 

 unnecessary to the efficient working. 



The annexed plate represents a horizontal direct-act 

 ing non-condensing engine ; and as this form of engine 

 has of late years been very extensively used, we think 

 its details may be studied with great advantage. The 

 principal objects attained by adopting the horizonta 

 arrangement are these : 



The framing (marked V V on the plate) is of a very 

 simple character, and can generally be cast all in one piece. 

 The whole strain caused by the alternate pulling and 

 pushing of the piston in giving motion to the crank, is 

 tlirown rectilineally on the framing, which can be readily 

 made strong enough to bear it, and which, being sub- 

 jected to no racking strain, fa laid upon a bed oi 

 masonry, and secured in its place by a few bolts. 



The whole machinery of the engine being spread oul 

 as it .were under the eye, is visible and accessible in 

 every part for cleaning, oiling, and repairs, and is in 

 itself so simple that great economy of construction is 

 secured, along with efficiency and durability. 



The plate gives an external side elevation, in which 

 A is the cylinder surmounted by the slide jacket, B ; 

 C is the piston rod, which, attached at one end to the 

 piston inside the cylinder, passes through a stuffing-box, 

 O, in the cylinder cover, and terminates in a cross-head 

 and pin, D, on which is jointed the connecting rod, E, 

 by means of a strap-joint, as shown in the plate, or any 

 other of the joints already described, that may be found 

 most suitable. As the connecting rod, by its oblique 

 action on the crank, throws a considerable lateral strain 

 on the head of tlie piston-rod, tending to push it upwards 

 or downwards, out of its direct lino of action,* the 

 cross-head, D, of the piston is made to slide between 

 guides, N N, which are nicely smoothed and kept well 

 lubricated. 



F in the crank fixed on the main shaft, and to which 

 the connecting-rod, E, is jointed by a strap-joint. The 

 shaft revolves in bearings, one of which is fixed on the 

 engine frame, and i.s generally made oblique (as indi- 

 cated by the dotted lines on the plate), because the 

 action of the piston being in the horizontal line, if the 

 bearing were jointed horizontally, the strain would be 

 thrown on the joints of the bushes instead of their solid 

 bodies. The outer end of the shaft revolves in a bearing 

 or plummer-block, which is fixed on a wall or other suit- 

 able masonry at the side of the engine. The fly-wheel, 

 H, is fixed on the shaft, and revolves with it A .small 

 crank, I, is mounted on a small shaft, J, concentric with 

 the main shaft, in order to give motion to the governor- 

 Bpindle, G, and to the eccentric, K, which regulate the 

 supply of steam to the cylinder. 



The governor and eccentric gear are connected by an 

 ingenious arrangement, which we will endeavour to de- 

 scribe. From the eccentric, K, extends a rod, L, to the 

 joint, M, of a "lever, which vibrates on a pin, n. This 

 lever contains a slit (which is part of a circular arc), in 

 which slides a pin, s. A rod, < , extends from this pin 

 to the extremity of a lever, which vibrates on a spindle, 

 v, and which has its other extremity, w, connected by a 

 rod, to x, to the slide-rod. The slide-rod moves recti- 

 lineally through a guide, y, and through a stuffing-box, 

 z, and puts the slide into alternating motion withiu the 

 jacket, B, so as to admit steam to the opposite ends of 

 the cylinder, and permit its egress from these ends 

 successively. 



The governor, which is mounted on a vertical spindle, 

 G, is put ia motion through bevil gearing, driven by 

 the small spindle, J. The governor-balls, e e, are at- 

 tached to equal rods, which work on pins mounted on 

 the head of the governor-spindle, d. From these rods 

 two bent rods extend downwards, and are jointed to a 

 tubular boss, /, which slides upwards or downwards on 

 the governor-spindle, according as the balls fly out from 

 or fall in towards its axis. This boss, /, has a groove 

 cut into it, which receives the ends of a forked lever, g, 

 mounted on a fixed pin, h. A lever at right angles to 

 this, terminating in a pin, /,-, communicates motion by 



* See ante, p. 859. 

 VOL. 1. 



the rod, I, to the extremity of another lever, m, which 

 is mounted on the same pin, H, with the slotted lever, M, 

 already described. From each side of the central pin, 

 n, arms extend to o and p, the one suspending a weight, 

 q, balancing the rod, t u, which is suspended at r, by a 

 small vertical rod from the other extremity, p, of the 

 double-ended lever. In order to understand the action 

 of this apparatus in governing the engine, we shall first 

 suppose that it is going at its proper speed, so that the 

 governor-balls, e e, maintain their mean distance from 

 the axis, G, neither flying out from it, as they would do 

 if they revolved too fast, nor falling into it if they re- 

 volved too slowly. Under these circumstances, the 

 eccentric-rod, M, works directly on the pin, *, and 

 through it, and the rod, <, and lever, uvw, on tho 

 slide-rod, x, giving the slide its mean amount of stroke 

 backwards and forwards, so as alternately to uncover the 

 steam ports to the extent necessary for the admission of 

 such a quantity of steam into the cylinder as is required 

 for working the engine at the speed to which it is timed. 

 Let us now suppose that some additional work is thrown 

 on the engine, more than the steam allowed to it is 

 capable of performing. The first and immediate result 

 of this is a reduction of speed. 



The governor-balls, e e, no longer maintained in their 

 position by their former centrifugal force, sink inwards 

 towards the axis G ; the tubular boss, /, is thus caused 

 to slide down the axis, the bell crank lever, g h k, pushes 

 the rod, I, towards the cylinder, and thereby throws the 

 double-ended lever, mop, into the position represented 

 on the diagram (Fig. 2). The effect of this movement, 

 by dropping the point r, is to let the pin, s, slide down 

 the circular slot of the lever to a point farther from its 

 centre, . As the eccentric-rod, L, maintains the same 

 amount of stroke as before, the pin, s, being removed 

 farther from the fulcrum, n, of the lever, receives a 

 more extensive vibration, which it gives to the slide-lever 

 and rod, and the slide itself is thus caused to move over 

 a larger extent of the facings within the jacket, B, and 

 so to open the steam ports more widely, and admit iiito 

 the cylinder the increased amount of steam required for 

 the increased work thrown on the engine. If, on the 

 other hand, work were tlirown off the engine, the speed 

 would increase, the governor-balls would fly outwards, 

 their operation on the slotted lever would be reversed (as 

 marked by the dotted lines in Fig. 2), and the stroke of 

 the slide and supply of steam would be proportionally 

 diminished, to suit the reduced work which the engine 

 might have to perform. 



P is the steam-pipe leading from the boiler to the 

 cylinder ; R the shut-off valve for stopping the passage 

 of the steam, or regulating the quantity supplied ; S a 

 short piece of connecting-pipe, which may be removed 

 ay undoing the bolts, by which it is connected to the 

 valve and to the slide-jacket, so that room may be 

 afforded for lifting the slide-jacket itself off the cylinder 

 without disturbing the steam-pipes, when it may be 

 necessary to repair the slide or adjust the facings on 

 which it works. The eduction passage is carried by a 

 mbular jacket! round the cylinder to a convenient place, 

 U, below the framing, whence the waste steam may be 

 conducted away. The feed-pump X is placed in an 

 excavation made to receive the lower portion of the 

 ly-wheeL It is worked by an eccentric from the main 

 shaft acting through the rod W, and draws by the pipe 

 Z its supply of water, which, after passing through 

 valves situated in the lower part of the pump X, is 

 "orced through the pipe Y to the boiler, and supplies the 

 eed required for the generation of steam to work the 

 engine. 



Figs. 196 and 197 are views of what is called a table- 

 ingine. The cylinder is elevated on a table ; the piston- 

 rod terminates in a cross-head, having a roller at each 

 end working in a guide, and a connecting-rod descending 

 in each side of the cylinder to a shaft made with tw o 

 xauks below, working in bearings, and carrying a fly- 

 wheel and eccentrics for the slide and feed-pump. The 

 governor is driven by bevil gearing from the crank- 

 haft. 



6s 



