US194198A - Improvement in reciprocating steam-engines - Google Patents

Description

- z sheetssheeu. W. WALKER. RECIPROGATING STEAM-ENGINES.

No. 194,198. Patented Aug.14,1877.

' z'sheets-sheetz. W. WALKER. REGIPROCATING STEAM-ENGINES.

` No) 194,198. Patent'a Aug.14,1s77..

` luveuum Y nvf ATTuaNEvs.

l of modified construction.

PATENT QFrroa.

WILLIAM WALKER, OF BURY, GREAT BRITAIN, ASSIGNOR OF ONE-HALF HIS RIGHT TO EDWARD'BE'ITS AND ALFRED BEITS, OF WILMINGTON,V

DELAWARE.

IMPROVEMENT IN RECIPROCATING STEAM-ENGINES.

Specification formingK part of Letters Patent No. [94,198, dated August i4, 1877; application filed April 20, 1877.

To all whom it may concern Be-itknown that I, WILLIAM WALKER, of Bury, inthe county of Lancaster, in the Kingdom of Great Britain, have invented certain Improvements in Steam-Engines, of which the followingis adescription.:

My invention relatesto multiple cylinder-engines. I arrange the cylinders in a group` and form each piston with a shank, which slides in a bored passage, and acts as a valve to effectand control the admission and exhaust of steam to and from an adjoining cylinder in the group.

In the accompanying drawings, Figure 1 is a vertical section of the engine. 2 represents a horizontal sectionon theline B` in Fig. l. Fig. 3 is a sectional elevation of an engi-ne Figs. 4 and 5 arecross-sections of Fig. 13on lines C` and D, respectively. Fig. 5' is a vertical section on the line indicated in Fig. 6. Fig. 6iis a plan view of theenginewith the cap ll:y removed. Figs.\7 and18-are sectional views, illustrating the twopositions of the reversing-valve.

The three cylinders C, D, and Eiare formed in one casting, and are arrangedi in a group, with their axes equidistant; but, if-preferred, the cylinders may be arranged in line. The crank-shaft F passes 'through a chamber, G, into which the exhaust isidischarged from the cylinders. The crank-shaft passes between the axes of two cylinders, and the. third axis in a direction parallel with the two axes. A piston is' tted to slide Within each cylinder. Each piston is connected by-a connecting-rod, b, with one of the crank-pinsof the crank-shaft. The crank-pins are equidistanton the described circle. One end of each rod is jointed bymeans of a pin, c, to the piston. The other end is provided with a single brass or step, which bears upon the crank-pin, and is kept in place by a cotter. `Each piston is cast or provided with a hollow shank, d, which is fitted to slide within a bored passage, which is formed in an extension, c, of the casting in which the cylinders are formed. Each passage is concentric with one of the cylinders. The upper part of each A hollow passage,

f, is formed in each shank, and communicates A* with a port formed in the side of the shank.

The steam-ports g, h, and 'i areformed in the portion e. Each port leads from one oi' the bored passages of one cylinder to the steamspace of an adjoining cylinder. The upper ends of the Shanks d serve to cover and uncover these ports. The upper ends oi' the bored passages open into a space formed by a bonnet, k, which is bolted to the end ofthe extension c. The steam-supply pipe is attached to this bonnet, and supplies steam to all the three bored passages. Y

The crank-shaft is Iarranged to revolve in bearings l and m, which are provided with glands or stuffing-boxes to prevent the escape of steam. Ii such escape will not be objecl tionable in any case, these stuffing-boxes may wheel is not shown in the drawing.

The action of the engine is as follows: To avoid repetition I will distinguish the pistons by the letters with which the cylinders are marked. When the piston E is moving downward or toward the crank-shaft, and is nearing vthe end of the stroke, the end of the shank d on the piston uncovers the port i, and steam is thereby admitted to the cylinder D. rIhe shank of the piston D in like manner causes steam to be admitted to the cylinder G, and the shank of the piston O regulates the admission of steam to the cylinder E. As the crank with which the piston .of the cylinder E is connected is one-third of a revolution ahead of the crank to which the piston D is coupled, the shank on the piston E is nearing the end of its upward stroke when the'piston D reaches the termination oi' its downward stroke. At this time the opening in the side of the shank on the piston E arrives opposite tothe end of the port t, and establishes a communication between the cylinder D and the chamber G, and

the exhaust-steam iiows through the port t and the passage f in the shank ou the piston E into the sai-d chamber. The shank on the piston D in like manner exhausts the cylinder U, and the shank on the piston() exhausts the cylinder E. The arrangement permits the passage for the supply of steam to each cylinder to remain open for about one-third of a revolution of the crank-shaft, or for a smaller period, according to the lap, and the exhaust to remain open for about one-third ot' a revolution. The exhaust steam is conveyed away from the chamber Gr by a suitable pipe attached to the chamber.

I do not confine myself to the casting of the cylinders together, as they may be formed in separate castings, and be bolted or fastened together.

As each piston is only single-acting, and in consequence Vot' the steam exerting a constant pressure in the same direction upon the ends of the Shanks d, the moving parts are kept in compression-that is to say, taking, 'or example, the vertical form of engine illustrated, the pressure upon the crank-pins is always exerted in a downward direction. Figs.3 to 8, inclusive, show the modied construction of the engine when areversing-valve, p, is employed for the purpose of changing the direction ot'motion ofthe crank-shaft. On each side of the bored passage in which the shank d slides is formed a vertical port, n, which communicates, at its lower end, with the space above the piston. The conical valve p is dtted to revolve within a correspondinglysh aped recess bored in the extension e in the center ofthe group ofcylinders. This valve is formed with three steam-passages.

When the valve isin the position represented in Fig. bgthe steam from E tiows through one of the two ports n into D, the steam from D into G, and the steam from Cinto E, as indicated by the arrows. When the valve is slightly turned on its axis into the position indicated in Figfl, the steam from E tlows through the other of the two ports n into O, the steam from C into D, and the steam from D into E, as indicated by the arrows", the direction ot' motion of the crank-shaft being reversed. A further rotation of the valve shuts oft' the How of steam and arrests the movements of the engine. 1

The steam finds access successively to the spaces above the respective pistons G D E by passing from the space beneath the cap k down successively through the bored passages as the shanks d recede therein, and thence through a part of the valve. For example, in Figs 3 and 5a the course of the live steam is shown by the arrow. It is just entering the space above piston D'through the port n (see Fig. 6,) on the right otits shank d. Thus, when the engine is running in one direction the live steam passes from a bored passage through the valvep to the port n, which is on the right ot' the contiguous left-hand bored passage, (see dotted lines, Figs. 6 and 7;) but when the engine is reversed the steam passes successively from each bored passage to the left of the contiguous right-hand bored passage. The exhaust takes place back through the same port n and valve p dow-n through the Shanks d, which latter cut off the live steam, and at the same time open an escape for the exhaust.

1tI will be understood the valve p is station-y ary when the engine is running, and is shifted only when it is desired to reverse the engine.

I do not coniine myself to the tri-cylinder arrangement, as, for example, four cylinders might be arranged in a group with the crankshaft midway between the two pairs ot' cylinders.

I do not claim a tri-cylinder engine such as is shown or described in Patent No. 176,823.

I claim- In a tri-cylinder engine, the combination of pistons G D E, each having a shank, d, with a bored exhaust-passage extending from a side opening down through both the shank and piston, the steam-passages leading from each bore in which the shanks work down through the casting or frame of the engine to the cylinders, and the steamchamber above the Shanks, all as shown and described, Whereby steam is admitted to the piston-cylinders in succession when the shanks d recede suftciently for their upper ends to uncover the port, and the exhaust takes place alternately with admission of live steam through the side ,opening in the shanks and the passage extending vertically through them and the pistons, as specified.

, W. -WALKER.

Witnesses:

EDWARD K. DUTToN, HUGH G. GRANT.

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