US2311074A - Steam engine - Google Patents

Description

Feb. 16, 1943. W NEWCOMB 2,311,074

STEAM ENGINE ATTORNEYv l Feb. 16, 1943. W NEWCOMB 2,311,074

STEAM ENGINEV Filed May 24,v 1940 2 Sheets-Sheet 2 I8 24' l5 23' l 44 4346 4/0 4344 l y 8 3 4 4l/ .a7 '32' 03a 4J P S f .f4-.; 5 5 a ATTORNEY l Patented Feb. 16, 1943 UNETED STTES PATENT. OFFICE lSTEAM ENGrNE William Newcomb, Brooklyn, N. Y.

Application May 24, 1940, Serial No. 336,917

6 Claims.

T his invention relates to steam engines of the reciprocating type;and particularly to a method andr apparatus for electing the admission of Ysteam to the power cylinder of the engine, its expansion in said cylinder, and its final exhaustion and release therefrom.

In general the chief object of my invention is to provide a steam engine which will perform a given amount of work with a smaller consumption of steam and fuel than has previouslyrbeen required. n

A further object of this invention is to provide a steam engine into Which the flow of steam is substantially free and almost entirely unobstructed so that a relatively great amount of steam can 4be admitted in a comparatively short space of time.

Another object of the invention is to provide a steam engine in which the steam is retained and allowed to expand over substantially the full extent of the travel of the piston, thus developing the maximum thrust or power, before the steam is discharged from the engine.

This invention has for a further object the Vconstruction of an improved piston engine having a controlling valve with adjustable lap members for engaging over the inlet and outlet ports for controlling steam consumption, efficiency and operation of the engine.

Another object resides in so arranging the lap members that they may be adjusted from the outside of the engine.

Still further the invention proposes a construction which permits the adjustable lap members to be adapted to single acting piston engines or double acting piston engines, or other types.

These and other objects cf the invention will be apparent from the following description, taken with the accompanying drawings, and the novel characteristics of the invention are pointed out in the appended claims. But this disclosure is illustrative only and I may vary the construcvieW of a double acting reciprocating steam enthese passages communicates through a port with tion and manner of proceeding to the full extent o double-acting reciprocating steam engine, accordtion of this invention.

- Fig. 6 is an enlarged longitudinal sectional view of a portion of Fig. 5 showing in particular one of the valves thereof.

Fig. '7 is a fragmentary vertical sectional view taken on the line 'I-'I of Fig. 6.

Fig. 8 is' a vertical sectional view taken on the line 8-8 of Fig. 6.

The same numerals identify the same parts throughout. Y

In the drawings, the numeral I0 indicates the -cylinder of the steam engine With heads II and I2; Adjacent the cylinder is the valve :chest I3 connected with the interior of the cylinder through passages I4 and I5. One end of each of the valve chest I3, and the opposite ends of each of lthese passages communicates through a port with the interior of the cylinder Ill. For the sake Yof example; the passage I4 is shown as communicating with one extremity of the interior of the `cylinder l'and the passage I5 communicates ,With the opposite extremity thereof.

At I6 is shown a supply pipe through which steam ows j into the interior of `chest I3, and I'I and I8 indipiston valve with heads 23 and 24 connected together so that these heads move in unison. One

of the heads 23 controls the passage I5, and the other `controls the 'passage I4, and each of these heads may be, of course, consideredI as a separate valve for the end of the cylinder and steam chest with which it is associated. As the-engine is a double-acting engine there must be two of'these valves, one for each of the passages I4 and I5, and these valves must move together. The particular construction of the cylinder and the valve chest need not behere described at greater length forthe reason that my invention is capable of Yuse with virtually every type of steam engine,

and it relates more particularly to the manner in which the valves 23 and 25: control the operation f the piston I9.

lt is well known that in ordinary steam engines the admission of steam to force the piston to make its working stroke usually takes place at one side of the piston before the piston has reached its dead point position. The exhaust begins on the other side of the piston when the piston has traveled about three-quarters of its full stroke, a little before admission has begun on the first mentioned side. This principle is favored by many engineers but it has the disadvantage that part of the stroke of the piston is made against the cushion of live steam on one side, while on the other side, the exhaust beginning when only about three-quarters of the piston travel has been completed, the maximum energy of the expanding steam is not obtained; and during the last quarter of the stroke the steam that, has begun to escape from the cylinder imparts no further power t the engine and only the momentum of the fly-wheel keeps the engine from slowing down greatly and perhaps coming to a stand-still. In contrast to this method of operation I have devised an entirely new system which is much more advantageous and desirable.

ln the operation of the steam engine according to my invention, the steam is not admitted until the piston has reached the farthest point of its travel in one direction and then has begun its return stroke. For example; in Fig. 1, assuming the direction of rotation of the shaft 2l to be clock-wise, and the crank and eccentric 22 to have the same direction of motion, one can see that the piston I9 has already started on its stroke toward the crank end of the cylinder to. The vertical dotted line between the piston I9 and head II of the cylinder represents the farthest point of the travel of the piston toward the head i I. When the surface of the piston adjacent the head II lies in the transverse plane of this dotted line, the valve or head 23 has not quite opened the passage I5, and the valve 2t has just begun to open the other passage IA. But when the piston I9 moves from this dotted line to the position -it actually occupies in Fig. l, the piston valve with the heads 23 and 24 in the valve chest I3 moves a little farther to the right thus fully 'opening both passages ill and I5. As a result live steam flows into the end ci the cylinder which is closed by the head II. At about the same time, the interior of the cylinder I0 between the piston yI9 and opposite head I2 is open for exhaust. The out stroke of the piston toward the shaft 2I is now free to commence.

As the rotation of the shaft ZI, crank 20 and eccentric 22 continues and the piston moves to the left, the two connected valves 23 and 24 continue to move farther to the right to extreme positions, indicated by broken linein Fig. 1, when the ports leading into the passages I4 and I5 are opened fully. When however, the crank 20 has moved through said 90 of rotation, and the piston i9 has made about of its stroke or is near its mid-position, the two heads or valves 23 and 2d close the ports 'leading to the passages I4 and I5, as indicated in Fig. A2,\th e passage` I5 being closed simultaneously with the passage I4. The steam being admitted to the cylinder I0 between the piston I9 and head `II is now sealed in this space and expands therein and acts upon the piston for practically the entire remaining portion" lof 'the' piston stroke; 'While 'the 'steam which is in the space between piston and the head I2 is trapped and forms a cushion; which does not entail any great loss of power in the operation of the engine, but merely prevents the vibration and hammering vas the piston reaches the end of the stroke, comes to a stop, and starts on the reverse stroke. No great loss of power takes place because the steam trapped between the piston I9 and head I2 is exhaust steam and not live steam and thus no great risk of lowering the eniciency of the engine is incurred. In view of the fact that exhaust steam has no direct connection with the steam boiler or other generator it does not have the pressure behind it that live steam does, and therefore is more easily compressed when the piston moves to the end of its stroke.

The next step in the cycle of the engine is indicated by the position of the parts in Fig. 3. Here the piston has completed its out-stroke and has started on the return stroke toward head II. As before the vertical dotted line, between the piston and the head I2, indicates the limit of movement of the piston toward the head I2, and the piston in Fig. 3 together with the piston valve is just about 180 distant from the positions occupied in Figure l. Before live steam can be admitted between piston and head I2 and cylinder Il), the return stroke of the piston must have actually commenced. As the piston starts to move toward the head II, the head or valve 24 moves to uncover the port leading to the passage iii, and at the same time or perhaps a little sooner the head or valve 23 moves to uncover the port leading to the passage I5. The live steam flowing in between the piston and head I2 forces the piston toward the head II and as the exhaust through the passage I5 into the valve chest and out through the exhaust-opening II has already started, the full force of the in-owing live steam takes elfect to force the piston to move back toward the position it is shown as occupying in Figure 1.

When the parts of the engine have moved from the position shown in Figure 3 to those shown in Figure 4, the crank and eccentric have both moved through about "Y more in rotation and the piston has completed about of its stroke or is somewhere near its mid-position on its way toward head II. The valve or head 24 has now moved to cut off the iniim of live steam through the passage I4 and about this time, the head or valve 23 closes the port leading to the passage I5. Hence the piston travels over the remainder of its stroke toward the head II with part of the exhaust trapped between it and the head II, but with the live steam continuing to expand between it and the head I2. When the piston reaches the limit of its travel toward its head Ii, the head or valve 24 again overruns the port leading to the passage I5 so that the steam between the piston and the head I2 lof the cylinder can then exhaust; and as soon as the Vpiston has started again back toward the head I2, or in other words, when it reaches its position shown by the dotted line in Figure '1, and has receded l, is retained in thevcylinder andy is allowed to 'expand until the piston reaches the end of its stroke Vtoward thehead l2, and the head. 23 has overrun inthe reverse direction the port leading to 'the passage l5 so as to open this passage Ato the exhaust port l1. Thus the steam is retained in the cylinder and expands during the latter portion of the entire travel of the piston. I therefore obtain a greater mean effect-ive pressure during piston stroke.

Again since the admission of live steam to either-end'of the cylinder is entirely free and unobstructed, a greater amount of live steam can be admitted in the shorter space of time which elapses between the instant when the piston is at the point shown inv Figure 1 and the point shown in Figure 2 for instance. I do not mean to say that moresteam lisadmitted into an engineaccording to my invention than into an ordinary engine, but only that a relatively i larger amount of steam can'be taken in for the time during which such admission actually continues. Hence nota greater quantity of steam is consumed, but in fact a much smaller quantity of steam is expended for performing the same or greater amount of work; and a proportionately greater quantity is Iadmitted during a relatively shorter period of time between the beginning of vthe admission of steam and the cut-off.

My invention can beutilized with Virtually any kind `of steam engine consisting of valves merely by increasing the thickness of these valves or heads. This increase of thickness is obtained by attaching to both heads or valves 23 and 24 rings or discs to provide what is known as added laps on both faces of each of these heads 23 and 24. I can thus practice my invention in connection lwith virtually any engine now in use without radically changing the design and construction of same. All I am required to do is tov add-laps to the twosides of valves or heads 23 and 24 and in some cases adjust the eccentric 22. On automatically controlled engines, no change in the eccentric is required; however, with engines having a link motion, the eccentric is advanced but the valve travel always remains unchanged.

With a steam engine of ordinary type altered in accordance with my invention so that it will operate upon the principle of my invention, actual tests have shown an increase in piston speed of .6 per cent, while the horsepower may decrease as much as 5 per cent. Greater freedom of action in the cylinder is thus allowed and I can perform greater work with less energy and a correspondingly smaller expenditure of steam and fuel .and a much lower cost of operation, these gains and advantages being due as above stated to thefact that there is nonlive steam between the piston and head of the cylinder which it approaches vat the end of its stroke; the fact that the admission of steam does not begin until the piston has actually started on its stroke and the admission is allowed to take place without obstruction, so that the speed of admission can be greater and more steam admitted in a given yamount of time; the fact that when the piston starts on its working stroke the exhaust has already commenced on its opposite side, thus leaving'nothing but the load on the engine to resist the movement of the piston; the further fact, that the live steam is retained in the cylinder and caused to expand over nearly the full extent of the piston travel; and finally the fact that smoother running is obtained because the exhaust is stopped at about when the piston is adjacent its mid-position or slightly beyond same, so that the piston completes its stroke in each direction'against a soft cushion of exhaust ste-am only, which has no effect but to slowy up the piston in a manner that eliminates lhammer- -ing and vibration, without loss of power and undue retardationwhen the piston is reversed.

In the modiied form ofthe invention illus-- trated in Figs. 9-12 inclusive, the double acting .piston engine is shown to include a double head valve having cylindrical heads 23'V and 24. Each of these heads is provided with a lap member 33 which is `adjust/ably, mounted thereon arranged to cooperate with the ports of the engine, that is, with the po-rts leading to the passages I4 and l5. Each lap member 3D is longitudinally slidably mounted in a groove 3l formed in the side Wall of the valve head and adapted to project from one end thereof. Worm teeth 32 are formed on each lap member 30 which mesh with a worm wheel 33 Xedly mounted on la tube 31' which is 'turnably supported on the stem 35 of the valve.

Each valve head is of hollow construction to have an enclosed hollow space 35. The worm wheel 33 is disposed within this hollow space. Each valve head has a projecting tubular member 37 projecting from one end thereof and rotatively mounted on the tubular member 34.. This rotative mounting is accomplished by a flange 33 mounted on the tubular member 31 and engaging a perpiheral groove 39 formed in the tubular member 34. Each tubular member j led on pins to urge the pins inwards. The stem 35 is formed with a plurality of peripheral grooves i6 slightly spaced from each other and adapted to be engaged by the pins 43. The outer end of the tube 34 is formed with a flange 68 having a knurled periphery by which it may be conveniently gripped and turned.

Each lap member 30 may be extended or re- 'pins 43 and moving the tubes 34 towards or away from eachother and re-engaging the pins 43 in selective grooves 41.

The adjustable valve heads and the adjustable lap members 30 make it possible to vary the instant of steam admission and exhaust to the cylinder of the engine. Thus the characteristics of the engine may be altered. Suitable pressurevolume diagrams may be taken to determine just where the points of admission and exhaust are desired. Any steam which enters the enclosed spaces 36 of the valve heads 23 and 24 will merely remain, and be of no benet nor cause any harm.

While I mention steam, of course, any other expansible medium can be employed in the same manner within the scope of my invention.

With my invention perfect governing is obtained and wear on the bearings practically eliminated.

While I have illustrated and described the preferred embodiments of my invention, it is to be understood that I do not limit myself to the `precise constructions herein disclosed and the right is .reserved to .-all changes and modifications 'comingfwi'thin'the scopec-orf,theinvention as defined inthle appended claims.'

Having thus described my invention, what I claim as new, and desire to secure-by United States Letters Patent is:

1. A piston engine having a controlling valve with adjustable lap members for engaging over the inlet and outlet ports for controlling the steam consumption, efficiency and operation of said engine, each lap member being longitudinally slidably mounted on the vperiphery` of said valve and having teeth, a Worm rotatively supported and engaging said teeth, a tubular member extending to the exterior and supporting said Worm by which the worm may -be turned.

2. A piston engine havingv a controlling valve with adjustable lap members vfor engaging over the inlet and outlet ports for controlling the steam consumption, efliciency and operation of said engine, said controlling valve being of cylindrical form and having a-lon'gitudinal groove on its periphery, said lap member beingslidable in said groove, a tubularmemberA coaxially'extending into said valve head` andhaving a Worm meshing with teeth onl'saidl'ap member for vex-r tending the same, said-walve head being provided with a stem and meansv for adjustably holding the valve head in various positions on the stem. i

, 3. In an engine, a valve chest,v a hollow valve Within said chest and engageable over an exhaust port for controlling the'passage of steam through said port as said valve isoscillated, a lamp member longitudinally' slidably `mounted on the periphery of said valve inan alignedl position with said port for controlling the operative width of said valve, rack teeth formed on said lap member, a rod having one end extended into the hollow of said valve and its other end extended to the exterior Yof said chest, and a Worm mounted on the end of said rodl extended Yinto the hollow of said valve and meshing with said teeth to cause said lap member to be extended and retracted as said rod is turned to CTI control the overall operative width of said valve.`

4. In an engine, a valve chesthaving spaced ports, a pair of spaced valve heads within said chest for controlling the passage of steam through said ports, a stem extended through said chest and centrally through said valve heads, said stem having its endsy extended from the end of said chest, projecting tubular members formed on opposite sides of said valve heads and encircling said stem and projected from the ends of said chest, and means on each of said tubular members for releasibly securing its respective valve head in position on said stem. whereby the position of said heads may be shifted along the length of said stem relative to each other.

5. In an engine, a valve chest having spaced ports, a pair of spaced Valve heads Within said chest for controlling the passage of steam through said ports, a stem extended through said chest and centrally through said valve heads, said stem having its ends extended from the end of said chest, projecting tubular members formed on opposite sides of said valve heads and encircling said stem and projected from the ends of said chest, and means on each of said tubular members for releasibly securing its respective valve head in position on said stem, whereby the position of said heads may be shifted along the length of said stem relative to each other, comprising a bracket mounted jon each of said tubular members, a pin slidably supported on each of said brackets and selectively engageable with one of a plurality of peripheral grooves formed in its adjacent end of said stem, and means for urging each of said pins tinto ka position in which they Will maintain their 'engagement with said grooves.

6*.In an engine, a valve chest having spaced ports, va pair of spaced valve heads Within said chest for .controlling the passage of steam through said ports, a stem extended through said chest and centrally through said valve heads, saidy stem having its ends extended from ythe end of said chest, projecting tubular meming its respective valve head in position on said stem, whereby the position of said heads may be shifted along the length of said stem relative to each other, .comprising a bracket mounted on each of said tubular members, a pin slidably supported on each of said brackets and selectively engageable with one of a plurality of peripheral grooves formed in its adjacent end of said stern, and Vmeans for urging each of said pins into a position in which they Will maintain their engagement with said grooves, comprising `a collar formed on an intermediate portion of said pin, and a spring coaxially mounted on `said pin and operating between the adjacent faces of said collar and a portion of said bracket.

WILLIAM NEWCOMB.

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