Patent GB-190103058-A (GB)
Title: Improvements in Mechanical Stoking Apparatus.
Inventor: WHEATLEY WILLIAM HUMPHREY
Filed: 1901-02-12
Granted: 1901-03-16
Abstract: 3058. Wheatley, W. H., [Kincaid, J. W.]. Feb. 12. Valves and valve gear.-Relates to steam-actuated mechanical stokers. Coal is fed above the grate of a locomotive firebox or other furnace by a steam-actuated piston b<1> working in a trough b below a hopper A. The hopper has two feeding screws, one on each side, one only being shown. The supply of steam to the cylinder B to operate a piston therein connected to the piston b<1> is so regulated that successive strokes of the pistons are of different velocities, recurring in cycles of three or four strokes. The feeding screws are slowly rotated at a constant velocity by ratchet gear worked by a steamactuated piston in a second cylinder C, the supply of steam to which is controlled by the movement of its own pistonrod. One of the screw shafts a operates valves for distributing the steam to the cylinder B. Two special arrangements of valves and valve gear for this purpose are described, and also an arrangement of valves and valve gear for the cylinder C. According to one arrangement, shown in sectional plan to a larger scale in Fig. 5, the admission of steam to the rear end of the cylinder B to effect the forward strokes of the piston b<1> is controlled by three slide valves b<26> within the valve chest B<2>, Figs. 1 and 5, which are moved successively by onefingered cams on one of the feeding-screw shafts a. The ports are of different areas, so that a successively greater amount of steam is admitted to the cylinder for the second and third strokes, which are thus proportionately quicker than the first. The return strokes are produced by steam admitted to the front end of the cylinder by a fourth slide valve b<28>, which also controls the exhaust from the rear end of the cylinder. This valve is operated by a three-fingered cam on the feeding-screw shaft. The return strokes of all the valves are produced by springs. The steamadmission passages to the rear end of the cylinder B, and also the exhaust passage from the front end, are fitted with regulating plugs. The admission passages open into the cylinder at some distance from the ends, as well as by smaller openings near the ends, cushioning of the piston being thus effected. In the second arrangement, shown in Figs. 12, 14, and 15, a single rotary valve e' on a spindle geared to one of the feeding-screw shafts controls the supply to the cylinder B for all the strokes of each cycle. This valve, which is shown separately by Fig. 14, has four admission ports e<4>, e<5>, e<6>, e<7>, successively increasing in diameter, and a cross-shaped exhaust cavity e<8> ; it works on a port face shown separately by Fig. 15. The admission ports and passage leading to the forward end of the cylinder are of a diameter equal to the smallest port in the valve, so that the return strokes are all effected at the same velocity, but the forward strokes vary in velocity in accordance with the quantity of steam admitted by the different ports in the valve. The distribution of steam to the cylinder C is effected by a slide valve c<23>, Fig. 9, worked by steam pistons in a subsidiary cylinder c<9> to which steam is distributed by a circular slide valve c<11> (shown separately in Fig.10), reciprocated vertically in a valve chest c<2>. The valve c<11> is operated by a tappet c<13>, Fig. 1, on the piston-rod c acting on collars on the valve spindle c<12>.