US591485A - moore - Google Patents

Description

(No ModeL); 5 Sheets-Sheet 1.

M. R. MOORE.

STEAM ENGINE.

No. 591,485. Patented Oct. 12, 1897.

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M. R. MOORE, STEAM ENGINE.

Patented Oct. 12,1897.

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M. R. MOORE. STEAM ENGINE.

No. 591,485. Patented Oct. '12, 1897.

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M; E. MOORE. STEAM ENGINE. No. 591,485. Patented Oct. 12, 1897.

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(No Model.)

5 Sheets-Sheet 5.

M. R. MOORE STEAM ENGINE.

Patented Oct. 12,1897.-

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UNITED STATES:

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MATTHEW ROBERT MOORE, OF INDIANAPOLIS, INDIANA.

STEAM-ENGINE.

srn orricarroiv forming part of Letters Patent No. 591,485, dated October 12, 1897.

L Application filed May 12, 1886. Serial No. 591,270. (No model.) i

To all whom it mag concern.-

Be it known that I, MATTHEW ROBERT MOORE, acitizen of theUnited States, residing in Indianapolis, Marion county, in the State of Indiana, have invented a certain new and useful Improvement in Steam-Engines, of which the following is a specification.

The object of the invention is to securea quicker and more "complete opening anda more prompt closing of the valves than is ob tainable byiany of the direct mechanicallyconnected or releasing valve-gear now in use,

resulting in a better distribution of the steam and a saving in the power required to operate the valves.

My improvement is especially adapted for high speed engines. In all ordinarycut-offvalve gears the extent of valve-opening varies with the point of out-off whether the mechanism be operated by an eccentric of variable throw, a pair of eccentrics'with a shifting link, an adjustable cam, or any other means known to me of holdingthe valve in permanent mechanical connection with the means of operating it. The same difficulty is met with if the engine be of the Corliss class, operated by a releasing-gear, where the valve-stem is periodically caught, pulled open, and released andclosed by some form of drop motion. When cutting off early, the amount of opening is small, resulting in a cramping of the current of steam and producing the evil known as wiredrawing. This is especially serious in quick-moving engines, causing a great reduction of pressure in the cylinder and a consequent loss of power. My invention is designed to completely'avoid this objection, giving at every degree of cut-off a full opening of the valve, whichis maintained until the proper point of stroke is reached, When practically instant closure follows.

The accompanying drawings form a part of this specification, and represent what I consider the best meansof carrying out the invention.

Figure 1 is a side elevation, on a small scale, I

representation of my improved valve-gear, merely illustrating its mode of action as applied to a four-valved engine. The enginevalves (not shown) may be any form of slidepiston or puppet-valve, driven by the reciprocating motionof the valve-piston. Fig. 3 is a vertical section of a portion showing the parts in the correct position. Fig. at is a corresponding .side elevation partly in vertical section. Fig. 5 shows in side elevation anapplication of the invention to a four-valved engine having grid slide-valve moving transversely to the main cylinder. Fig. 6 is a corresponding plan view partly in horizontal section. Fig. 7 is a side elevation showing the'application of my invention to an engine having Corliss valves. Fig. 8 is a corresponding plan view of'a portion, and Fig. 9

a peculiardouble section on a larger scale. It shows a part of two vertical sections taken on the lines 8 8 and 9 9, respectively, in Fig. 8. The center of this figure is a section through the action-valve and its adjuncts on the line 8 8, and the parts of the figure surrounding such section show a section on the line 9 9. i I have shown the style of governor and shiftin-g eccentric set forth in the patent to me dated May 26, 1885, No. 318,782, and prefer to use such.

Similar letters of reference indicate corresponding parts in all the figures where they appear. Parts which are closely related take the Same letter, distinguished by supernumerals. For convenience of description I will use the word steam to denote any vapor or gas working mechanically by its pressure. Iwill use the terms engine steam-valve and engine exhaust-valve to designate, respectively, the ordinary valves which admit the operating fluid to the cylinder of an engine and permit its escapetherefrom. I will use the term trunk-piston to indicate a piston having two diameters and the term trunkcylinder to denote a corresponding cylinder of two diameters and proper length, in which the trunk-piston works. I will use the terms steam action-valve and exhaust actionvalve to designate the small supplementary valves which are worked by the engine and distribute the steam to the trunk-pistons which operate the en gines steam and exhaust valves, respectively.

fixed framing and casing. 13 is a valve-rod operated by the variable eccentric 0, controlled by the governor l3, and D is an actionvalve moved by the valve-rod B to varying extents. These parts operate in the long-approved manner of automatic speed-governors, diminishing the throw and increasing the advance of the eccentric with respect to the engines crank as the speed increases, holding constant the point of valve-opening with reference to the stroke, but by changing the valve travel causing the admission of the steam to be cut off earlier as the engine tends to run faster, and vice versa. The actionvalve may be very small as compared with the necessary size of the engines valves, and the governor and all the connecting parts may be correspondingly light and easily moved, as the work required of them is of small amount.

Fig. 2 represents the steam and exhaust valves for the out end of a four-valved engine-cylinder, the crank-shaft being supposed to be toward the right hand. The parts, as before mentioned, are drawn somewhat out of position to permit their action to be more clearly shown.

A A is a small trunk-cylinder occupying a position with respect to the engines cylinder similar to the valve-bonnet through which projects the valve-stem in a Corliss engine. The bore A is of abouthalf the cross-sectional area'of the bore A G H is a trunk-piston fitting the two diam smaller bore of the trunk-cylinder A opening,

directly into the steam-chest V the pressure therein is constantly exerted against the Smaller face of the trunk-piston G, thereby holding the steam-valve M normally in the closed position. A passage w connects the steam-chest with the waist of the action-valve D. This action-valve is a small piston-valve, having a length about twice its diameter, the middle part being of a smaller diameter, so as to leave an annular space 10' surrounding the valve, into which the steam flows through the passage 10. The action-valve has a longitudinal reciprocating motion in a suitable cylindrical valve chamber containing. ports which are covered or uncovered by the motion of the valve.

In the diagram Fig. 2 the parts are shown in the neutral position just before the engines piston completes its stroke toward the left. \Vhen the action-valve D has moved a little farther toward the left,it will uncover the port and passage 10 thus openingwa way through the passage 20, w, and 10 for the steam to enter the larger end of the trunk-cylinderA and press against the larger face of the trunkpiston. The passage 10 leading back from the larger end of the trunk-cylinder to the action-valve case being closed by the valve when in the position described the steam admitted to A cannot escape.

The annular space X around the trunk-pistoncommunicates freely through the passage as with the action-valve case, and any steam contained therein can escape. The larger end of the trunk-piston H having about twice the area of the smaller end and both being new pressed upon by steam of the same pressure, motion will ensue and the engines steamvalve will beopened. To prevent the trunkpiston as it completes its stroke violently striking the bottom of the trunk-cylinder, the port w opens a little above the bottom of the annular space X, so that-it is closed by the trunk-piston just before reaching the end 'of its stroke, and the piston cushions on the imprisoned steam and, comes gentlyto rest.

The valve M having been opened, as described, will remain fully open until the action-valve D completes its stroke toward the left and returns to the position shown, closing the inlet-passage 10 leading to the larger part of the trunk-cylinder A Then a slight further movement toward the right opens the passage 10 The steam now escaping, the constant force of steam of full pressure on the smaller end of the trunk-piston G is opposed only by a much smaller back pressure on the larger end and is assistedby the like back pressure on the shoulder of the trunkpiston in the annular space X. Motion again ensues and the engine steam-valve M is suddenly closed. To prevent the trunk-piston strikingat the end of its outer stroke, a similar-steam-cushion is formed by making the port 10 to open a little within the outer end of the trunk-cylinder A, so that the trunkpiston overruns and closes it before reaching the end of its stroke, and the passage 10 bein g now closed by the action-valve D the remnant of steam in A cannot escape and so cushions the trunk-piston. These movements for opening. and closing. the engines steamvalve occur regularly, as described, at periods determined by the motion of the action-valve D, which, as before mentioned, receives its motion from an eccentric under the control of a governor, which causes the opening movement to occur constantly at the beginning of the engines stroke, and to close at any point when steam enough has been admitted to the cylinder to carry the engines load and maintain the speed determined upon. It will be observed that the action-valve D in its relation to the ports 10 and 10 has practically no lap or only just enough to enable it to cover both ports when in the center of its travel. The slightest movement in either direction will open one or the other, keeping the remaining one closed. At no point of-the valve travel can both be open to the same or connecting chambers. In consequence of this provision the position of the engines steamvalve is instantly changed whenever the action-valve D passes its central position.

The steam which has done work in operating the engines steam-valve, as described, though much weakened in pressure by condensation and expansion into chambers of larger volume, still retains strength enough to operate the engines exhaust-valvesp To avail of this, the two ends of the steam-action-valve chamber and 00 are connected by the passage 00 the coupled pipes 00 and passage 00 with the chamber of the exhaust action-valve O. This action-valve and its case are exactly like the steam action-valve D, except that the left or working end of valve 0 is a little longer, so as to afford considerable lap over the two ports y and M, which the valve controls, the purpose of which will be described hereinafter. The engines exhaust-valve N is provided with a bonnet bored out to form a trunk-cylinder containing a trunk-piston connected by a valve-stem with the exhaust-valve, in all respects like the devices just described for operating the en gines steam-valves, except that the valve-stem, it must be understood, is attached on the exhaust side of the valve, so

that whatever style of valve be employed the the case of the exhaust action-valve 0. Steam released from the steam trunk-cylinder A flows freely down through the exhaust-actionvalve case and passages 50 to'the annular space 00 where it presses constantly against the shoulder of the exhaust trunk-piston and holds, by means of the valve-stem N, the engine exhaust-valve .in the closed position. The diagram Fig. 2 shows the position of the parts just before the completion of the engines piston stroke toward the left. The exhaust-valve has closed and compression of the steam remaining in the engine-cylinder is taking place. The action-valve O is now moving toward the left, and being driven by the same eccentric that operates the steam action-valve D will move in like manner to the end of its travel and return presently to the position shown. On account of the slightly-greater lap of the valve 0, however, the port y will not be uncovered when the steam action-valve D uncovers the port to shut the steam-valve.

uncovering the port g allows steam to flow The engine exhaust- 1 valve will therefore remain closed until near through the passage against the larger end of the exhaust trunk-piston S, forcing it to move and open the engines exhaust-valve N. The action-valve O, completing its travel toward the right, returns, again covering the port y and holding the en gines exhaust-valve open by the imprisoned steam until at the completion of a revolution of the engine it again reaches the position shown, uncovering the port y and permitting the steam in the trunkcylinder A to escape to the waist of the action-valve O. This waist-chamber is always in communication, through the passage 2 with. the exhaust-space Z of the engine-exhaust, so the steam can freely escape, and the trunk-piston R S, impelled by the pressure of the steam in the annular chamber at once moves outward and closes the exhaust-valve N. Provision is made for cushioning the movements of the trunk-piston R S by the position of the ports connecting the passages y and x with the trunk-cylinder A which act in the same manner as the like provisions for cushioning the steam-valve trunk-piston G H.

In view of the fact that there is steam of a working pressure constantly acting on the pistons it may not be necessary to make any ICO other provision for the return of the pistons;

but to cover any possible default I provide the passages p 11 connecting the bottoms of the annular chambers m 50 with the actionvalve cases arranged as shown, so that the several passages 19 19 will be closed each by the corresponding action-valve D or 0 before steam is admitted to the larger ends of the trunk-pistons. 7 I thus prevent the escape of the cushioning steam, but the passages are uncovered again to permit steam to enter when the valves uncover the exhaust-ports w 1J2. The effect ofv these extra passages 19' p is the same as the doubled connection to the larger ends of the trunk-pistons,the steam entering through one passage and being discharged through the other. It will, of course, be understood that the passage 19 has no connection with the passage 10 In recapitulation the spaces V, w, and w are constantly filled with steam of full pressure, which, for the purpose of illustration, may be assumed to be one hundred pounds per square inch. The spaces X, or, sci-w 00 00 as, 00 m 339, and a are filled with steam that has done work in moving the trunk-piston G H, and by reason of expansion and cooling has fallen to some lower pressure, which may be assumed as fifty pounds per square inch. The spaces g and Z being constantly open to the engines exhaust-chamber can never contain anything more than a slight back pressure, which in a simple non-condensing engine may be placed at two pounds per square inch above the atmospheric. The areas of the smaller ends of the trunk-pistons Gand It and the shoulders X and X may be assumed to be six square inches and the areas of the larger ends H and S may be taken as twelve inches. Any other dimensions might be assumed, and the dimensions will, in practice, depend on the size of the engine. There will, therefore, be, when the valve-gear is in the position shown in Fig. 2, a force of X 6-50 X 6) (50 X 12) 300 pounds, tending to close and hold shut the steam-valve M. When the action-valve has moved a little toward the left and uncovered the port 10 there will then be a force of (100 X 12) (100 X (350 X 6) 3OO pounds, tending to open the steam-valve. Similarly the exhaust-valve Nwill be held closed by a force of (50 X 6-2 X 6) (2 X 12) 2S8 pounds until the action-valve O uncovers the port 3 when the exhaust-valve will be opened by a force of (50X 12) (50 X 6- 2 X 6) -2S8 pounds.

From the well-known action of a pistonvalve driven bya shifting eccentric under the control of a shaft-governor it will be readily understood that the action-valve D may be so adjusted as to always uncover the port 211 and cause the opening of the steam-valve M at the beginning of the engines stroke toward the right. It will also be understood that when the engine has made exactly half a revolution the steam action-valve at the right end of the cylinder, Figs. 5 and 6, driven by the same eccentric, will admit steam to open the steam-valve at that end to begin the return stroke. These two points are constant, however the throw of the eccentric, the valve travel, and the consequent point of cut-off may vary. Now since the exhaust actionvalves are also driven by the same eccentric it will be seen that the valve 0 may be so adjusted as to uncover the port just a little in advance of the uncovering of the port to by valve D, thus causing the engine exhaustvalve N to close a little before the end of the leftward stroke of the engines piston, producing the required compression to fill the engines clearance-spaces and enable it to pass the center smoothly. It will also be seen that so much lap may be given the valve 0 that the port y will not be uncovered until the engine has made about half a revolution, the uncovering taking place just before the completion of the engines stroke toward the right, thus opening the exhaust-valve N and releasing the steam a little in advance of the opening of the right-end steam-valve by the action-valve at that end. Thus the left or releasing corner of the exhaust action-valve 0 stands in about the same relation to the righthand steam action-valve that its inner or compression corner does to the left-hand steam action-valve D. Therefore the steam admissionpoints being constant the release and compression points must be likewise constant.

changing the length of the steam-action-valve rod. Figs. 3 and 4 show, partly in section, the same valves, &c., which are represented in Fig. 2. The ports and passages are here somewhat difiicult to trace, but their proper relations will be understood from the description already given.

Modifications may be made without departing from the principle or sacrificing any of the advantages of my invention. In Figs. 7

v and 8 is shown an engine-cylinder having the well-known rocking or Corliss valves, to

which my invention is applied in a modified form. The valves are operated through the medium of cranks and rods connecting them' with trunk-pistons moving in four cylinders joined in a single casting, which occupies the position of the wrist-plate in the ordinary Corliss valve-gear. The steam distribution to these pistons is effected by a single-action valve, which alternately admits live steam to and exhausts it from the larger ends of the trunk-pistons at proper times respectively to give outward motion to the pistons and the valves attached thereto, the return motion being produced by a constant pressure of steam upon the shoulders of the trunk-pistons, which have about half the area of the larger ends. The construction and arrangement of these parts are more clearly shown in the sectional diagram Fig. 9. The four cylinders are bushings inserted in a hollow castin g, the annular spaces surrounding the bushings being in communication through a passage a with the live-steam passage of the engine-cylinder, so that the valve-moving cylinders are surrounded with steam and are certain to be quickly and thoroughly heated up to the working temperature. In each cylinder is a trunk-piston, the trunks passing out through a suitable packing, so that each piston presents two unequal faces to the pressure of steam admitted to its cylinder. Through a port I) in the lower side of each cylinder the steam passes freely and bears with a constant pressure against the shoulder of the trunk-piston. The effect of such pressure is normally to drive the trunk-pistons to the bottoms of their cylinders and to hold the engines steam-valves closed and its exhaustvalves open. Ports and passages for steam These passages are doubled for the purpose of cushioning the motion of the trunk-pistons, steam being admitted through the inner passage of each pair and exhausted through the outer one, which is so placed that the trunk-piston overruns and closes it before it can strike the bottom of the cylinder. For the like reason the ports b b are placed at a little distance inward from the outer ends of the, cylinders. A passage leading from the bottom of the hollow casting containing the cylinders enters the action-valve case and admits steam through its central port 0. By taking this passage from the bottom of the casting, the passage a entering the top, circulation is promoted and the spaces prevented from filling up with water of condensation.

Within the action-valve case,'controlling the ports therein, is a piston-valve, which may be made in a single piece, similar to D and 0, Fig. 2, but the one shown in Fig. 9 is a modified form, with means for adjustment in length. This form of action-valve consists of twodisks, one of which is fastened firmly to the end of the valve-rod and the other is mounted on a hollow rod surrounding the valve rod proper and connected thereto by a pair of jam-nuts, so that the disks can be moved toward or from each other, as occasion may require, and firmly fastened in the desired position. The steam-ports in the upper side of the action-valve case are so arranged that the action-valve has no lap over the steam-ports and exhaust-ports leading to and from each steam-valve cylinder, so that the closing of one port is immediately succeeded by the opening of the other. The opening of the steam-ports in the lower side of the action-valve case, connecting with the exhaustvalve cylinders, are so arranged that the action-valve will open them just before opening the steam-valve ports for the corresponding end of the engine-cylinder, to the end that compression and release may precede admission, and the exhaust-ports are so placed as to give sufficient lap to serve the purpose before described. The steam which has done its work in moving the trunk-pistons and the attached engine-valves is discharged from,

the ends of the action valve case down through the passage cl into the exhaust-passage of the engine.

The modus operandi of the device will be readily understood from the drawings, in the light of the description already given.

The features which are common to these different forms of my steam-actuated valvegear and which constitute the gist of my invention are the valve-moving pistons having faces of different areas, with constant pressure upon their smaller faces tending to open or close and hold in such position the enginevalve connected therewith, in combination with action-valves actuated by the motion of the en-gine, under the control of a speed-governor, admitting and releasing the steampressure to and from the larger faces of the pistons through ports so arranged as to obtain constant lead opening and variable cutofi for the engines steam-valves, and for its exhaust-valves practically constant release and compression.

I claim as my invention 1. In a valve-motion for steam-engines, a trunk-cylinder and a trunk-piston, and connections from the latter to a main valve of the engine, in combination with passages for steam, admitting constant pressure to the smaller face of the trunk-piston, and means as an action-valve with ports and passages for alternately admitting and releasing the steam-pressure to and from the larger face of the trunk-piston to operate the main valve, together with variable mechanism operating the action-valve by the motion of the engine, substantially as herein specified.

2. In valve-actuating gear for steam-engines, a trunk-cylinder containing a trunkpiston adapted to be driven alternately in opposite directions by the pressure of steam on one of the end faces and on an annular area at the Waist, connected with a main valve and with an action-valve, and variable mechanism as a shifting eccentric G and with means as the governor B for variably operating' the action-valve by'the motion of the engine, all combined and arranged for joint operation as herein specified.

3. In a Valve-actuating gear for steam-engines, a trunk-cylinder containing a trunkpiston adapted to be driven alternately in opposite directions by the pressure of steam on one of the end faces" controlled by ports and passages and the action-valve D, the said trunk cylinder and piston forming at the waist an annular area, together with ports and passages 00 and p, communicating with said area, and with the action-valve, and adapted to be closed to enable the steam in the area to cushion the piston, substantially as herein specified.-

l. In valve-actuating gear for steam-en gines, a trunk-piston working in a trunk-cylinder having ports "w and a2, arranged to cushion the steam and cause such piston to be arrested gently at the end of its movement, the piston being connected with a corresponding main valve in combination with an action-valve, variable mechanism as a shifting eccentric C, and means as a governor B for variably operating the actionvalve by the motion of the engine arranged for joint operation as herein specified.

5. A valve-motion for steam-engines comprising two trunk-pistons working in corre-' sponding trunk-cylinders and connected to two main valves of the engine, and provisions as the shifting eccentric and governor and connections to thesteam'action-valve D, and exhaust action-valve O, and the requisit-e ports for operating one by the pressure of live steam and the other by the pressure relatively to such eccentric, all arranged for joint operation substantially as herein specified.

In testimony that I claim the invention above set forth I affiX my signature in pressenee of two witnesses.

MATTHEW' ROBERT MOORE.

Vitnesses:

ROLLIN DEFREES, R. M. COFFIN.

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