US301990A - Hebmalpr howaldt - Google Patents

Description

UNITED STATES PATENT ()FFICEQ HERMANN HOWALDT, or nrnrnicusnonr, NEAR KIEL, PRUssIA, GERMANY.

BALANCED SLIDE-VALVE.

a'PECIFIGATION forming part of Letters Patent No. 301,990, dated Jul 15, 1884.

- Application filed February 3, 1984. (No model.)

To all whom it new concern.-

Be it known. that I, HERMANN HOWALDT, of Dietrichsdorf, near Kiel, in the Kingdom of Prussia, German Empire, have invented certain new and useful Improvements in Balanced Slide-Valves for Steam-Engines; and I do hereby declare that the following is a full description thereof.

The object of the invention is to reduce by the peculiar construction of the slide-val ve for sider the best means of carrying out the invention.

The accompanying drawings form a part of this specification.

Figure l is a section through one of the valves and the adjacent portions. Fig. 2 is a section at right angles to Fig. 1.

- with the steam'chest cover removed. The two figures embraced in 3 are horizontal sections showing two arrangements of devices for holding the valve in position laterally. Fig. 4 is a horizontal section through the valve and the adjacent parts which discharge the steam from a first cylinder into a second in a compound .engine. Fig. 5 is a corresponding cross-section. Fig. 6 is a cross-section'showing a modification.

Similar letters of reference indicate corresponding parts in all the figures where they occur. 1

Figs. 1, 2, 3, and 3 represent a slide-valve, a, of the D-slide type of a steam-engine with one cylinder. This slide-valve a forms a prismatic body of rectangular cross-section, provided with the passage necessary for the steam, and which is worked by valve-gear (not'shown) to slide up and down or fore and aft, as the case maybe, upon the valve-face of the cylinder 0 and the inner face of the lid D of the steam-chest.

Supposing the face d of the slide-valve a to Fig. 3'is a' top view of the valve and the adjacent parts small pressure, with the tendency to lift the I 1 be uninterrupted and full, the fresh steam could not press at all upon the slide-valve a, while the under side a would endure only a slide-valvea from the face of the cylinder 0.

To counterbalance this pressure recesses extending lengthwise on the upper face, d,-of the slide-valve a and of proportionate width are provided, as shown in Figs. 1 and 2, adapted to allow the fresh steam to act upon this portion of the upper face, d. The same effect is attained by providing a communication between the exhaust-pipe or the condenser of the engines and an excavation on the upper face, d, of the slide-valve a. (See Fig. 1.)

To prevent the slide-valve a from being forced by the steam-pressure upon the broader side 7 too tightly between the convergent faces of the lid D and the cylinder-face C, it is set by an adjustable plate or strip, f, extending along its narrow side 9 in such a manto prevent the steam from entering between the working-faces. For greater security and for steadying the slide-valv a, an adj ustable strip or plate, f, similar to that above mentioned, is arran gedworkin g against the broader side h.

The adjustment of each set plate or strip f may be effected with some success by screws,

as represented on the right-hand side of Fig.

3; but I have devised a preferable construction in which the end is better attained by wedges f, manipulated by screws and nuts, as representedon the left-hand side of Fig. 3, on top of Fig 2, and in Fig. 3. The wear of the working-faces g 7b of the slide-valve a and of the plates f is. compensated by readjusting the wedges f. A screw-stud, m, is fitted tightly and permanently in each end of the wedge f, (see Fig. 3,)extendingl0osely through ahole in the end of the steam-chest,and serves thenceforward as a part off. M is a washer having its inner face accurately finished-and fitted steam tight against the corresponding surface of the steam-chest. M is a nut fitted tightly on the stud m. The same construction being at each end, and the nuts being screwed up tightly,

hold the wedges f. firmly and make steam 'When it is desired to shift the wedge f, the nut M at one end is slackened,

tight joints.

. nor that it works freely and with the minimum 7 "of friction, at the same time tightly enoughand the corresponding nut at the opposile end of the steam-chest is tightened.

In Figs. 4 and 5 are shown parts of the two cylinders of a compound engine with the new trapezoidal slide-valve a arranged between the slide-faces of the cylinders I and II, which faces are parallel in axial direction, but inclined or converging in the other, correspond ing to the converging faces of the slide-valve a. (See Fig. 5.) The steam-chest belongs jointly to both cylinders I and II. The slidevalve a is set by an adjustable strip or plate, f, working against the narrower side 7 of the slide-valve a. A collateral strip, 1, is provided against the broader side 71. The crosssections of the wedges, by means of which the set-platesf are adjusted, are indicated by f This form, which I will term the new trapezoidal slide-valve, is important for twineylinders of common \Voolt' or compound or other engines, as it works steanrtight upon the slide-faces of each of the two cylinders, and at the same time with the minimum of friction and capacity for perfect adjustment. \Vhere a second slide, a, for the cut-off is used on top of the slidevalve a for the distribution and expansive working of the steam, one of them may be of rectangular cross-section and the other of trapezoidal section, in which case the working-faces 0f the chestlid and of the cylinder, or those of two cylinders, should be converging; or the cross-section of both slide-valves a, and amay be a trapezoid, in which case the steam-chest is- After having described my invention and suitable means to carry it into effect, I clai1n The adjusting-stiuls m, steam-tight washers M, and nuts M, in combination with the adj usting-wed ge f and guidingstripf,arranged to serve relatively to each other and tothe slide-valve a of a steam-engine.

This specification signed by me this 21st day of December, 1883.

HERMANN HOWALDT. Vitnesses:

CLARUS KonNnoLi), Enxs'r BRUGKELMANN.

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