US377463A - Steam-engine - Google Patents

Description

(No Model.) 2 Sheets-Sheet 1.

M.v N. 8 B. P. LYNN.

7 STEAM ENGINE. No. 877,488. 8888118881875. 7, 1888.

N, PETERS Pholblilhogrlphsf. Wnshnghm. ILC..

'(No Mom.) l I 2 sheets-sheer. 2.

f' M. N.,& E. P. LYNN.

STEAM ENGINE.

No. 377.463. Patented Feb.I 71888.'

NIT-ED STATES PATENT OFFICE. 'i

MIRABEAU N, LYNN AND ELMoien r. LYNN, or RISING s`1IN,INDIANv..LI,Wy

AssIGNons To THE LYNN ENGINE COMPANY, or DAYTON, VonIo..l

STEAM-ENGINE.

SPCIFICATIO-N forming part O'f Letters4 Patent NO. 377,463, datedFebIuary 7, 1888.

-Application filed July 20, 1886. Renewed June 22, 1887. Serial No. 242,152. (No model.) p

' Io of this specification', and to the figures and letters of reference marked thereon.

In an application filed simultaneously herewith,and numbered 208, 54.9,we have described Vand claimed an improved forni and construcv tion of engine wherein the inlet and exhaust ports and a valve co-operating therewith are located in the piston, the said valve mechanism being drivenby the piston and moving in unison therewith, while the piston operates as n* 2o a cut-off to regulate the admission of steam to the cylinder;` but as in said enginethe move# ments of the valve to alternately open the ex' haust and inlet ports take place at the terminal tion of thestroke ofthe piston in opposite direc- 25. tions as the crank passes the center, thevalve cannot be given whatis known as lap and lead77 without interfering with the action of the exhaust, forthe reason that, the movement of the valve in opposite directions being equal,

3o the exhaust is closed as .the inlet isopened, and vice versa, and if theinlet were opened in advance to take steam before the crank reached 'the center the exhaust would either remain open, permitting steam to'blow through, or if so placed as to close'in advance it would be retarded in opening the exhaust at the opposite end ofthe stroke.

The object of our present invention is to provide such an engine as described in the 40 application referred to with a supplemental exhaust at or near the end of the stroke of the piston in one direction, whereby we are enabled to give the valve the `necessary lap and lead to open theinlet before the piston has completed the back-stroke, and at the same time provide an escape for steam inthe cylinder during the interval between the closingof the inlet and opening of the direct exhaust at the end of the stroke in the opposite' direction.

' 55o Oursaid invention consists, therefore, in the novelcombinations and arrangements of parts for effecting this result, as hereinafter more fully described, and pointed out in the claims.

In the accompanying drawings, Figure lis A a longitudinal section of ,a cylinder, piston,

and valve mechanism, showing the application of our vpresent invention. Fig. 2 is a'longitudinal sectional view of said cylinder and piston, taken on aline at right angles to Fig. l.

Fig. 3is a sectional view illustrating a modil 69 l,

fied form of valve. Fig. 4. is a view in. perspective of our improved-valve, the section being shown separated. Fig. 5 is a diagrammatic view showing the positionof the inlet 4and exhaust vports near thetermination of the 65 forward and return strokes of the piston.

l Similar letters of reference in the several figures indicate the same parts.

necessary to av full understanding of our pres- Y ent invention, it being understood that any ap-` proved form :and construction of frame and other necessary parts and connections may be employed-fsuchjfor example, as shown in our vbefore-mentioned application. Y 8o Inthe drawings, l'is the cylinder, 2 the piston, and 3 thepitman connecting the piston and'crank. 1

The cylinder 1 is furnished with a series `of I steam passages or ports,- 4, leading from the jacket or supply-pipe through the series and into the interior of the cylinder.

The piston 2, preferably of the trunk class, is provided midway of its endswith a steam-` chamber, 5, which'may belformed by reduc` 9oy ing the ypiston at that point, the endsy 6 7 of the piston,'both above and `below the said l steam-chamber, being'provided with packingrings, thusforming practically'a 'double piston. Within the piston is .formed atransverse` valve-chamber, 8, in communication Awith steam-chamber 5, said valve-chamber being provided with inlet-ports 9 and exhaust-ports 10, opening through .thekwall of thevalvr-` Y chamber and intothe cylinder abovel the -pis-l rooA Asour invention 'relates solely to the con-if ton.

Within this valve-chamber is located a reciprocating valve, 11, having ports 12, opening into the valve-chamber and co-operating with inlet-ports 9, and ports 13, cooperating with exhaust-ports 10 and opening into a passage or passages, 14, which latter communicate with an opening or openings, 15, in the lower head of the piston. The valve 11 may be eithercylindrical, as shown in Fig. 1, or flat, as shown in Fig. 3; but the former is preferred. It is constructed in two sections, 16 and 17, each formed with a hollow cylindrical portion, 18, fitting the one within the other, and provided with packing-rings to prevent the passage of steam between them. The cylindrical portion 18 of the valve-sections does not 0ccupy the whole area of the proximate surfaces, suiicient space being left for the steam in the valve-chest to act upon the sections and force them apart and hold them firmly seated upon the valve-seats.

The outer end of the pitman 3 is screwthreaded or otherwise securely fastened to the upper section, 1G, of the'valve, as by a crosspiece, 19, in its cylindrical portion 18, so that the valve itself will form the pivot and point of attachment of the pitman and piston.

If it is deemed expedient to employ a flatfaced valve, the arrangement shown in Fig. 3 may be adopted; but in such case the pitman is to be pivoted directly in the piston, as at 20, while the valve is driven through a connection, 21, secured to the head of the pitman and pivoted in ablock, 22, working in a guide, 23, in the upper section of the valve, this arrangement being substantially the same as is described in our before-mentioned application No. 208,549.

Referring to the valve shown in Fig. lmit will be observed that it constitutes a practically-balanced valve, the overbalancing by the pressure of steam upon the proximate faces of the valve-sections being only sufficient to overcome the inertia of the parts and hold the sections pressed against their seats in the piston, and by attaching the pitman directly to the upper section of the valve the pressure lof the piston and thrust of the crank are borne by said section, thereby relieving the lower section, which operates merely to permit the escape of steam from the valve -chamber through the opening in the piston in which the pitman works.

ith the exception of the novel cylindrical balanced valve and the arrangement of the inlet and exhaust ports, the combination of devices as thus far described is arranged to operate substantially in the manner set forth in our application No. 208,549-that is to say, steam is admited through passages 4 into the steam -chamber 5 between the ends of the double piston, from whence it passes through the valvechamber and inlet-port into the cylinder above the piston. As the piston descends, the upper section or head closes the passagesa in the cylinder, cutting off the supply of steam and permitting that contained in the cylinder to act expansively. At the end of the stroke, and as the crank passes the center, the valve is shifted to open the exhaust and close the inlet. Instead, however, of simultaneously opening the inlet and closing the exhaust as the crank crosses the center at the end of the back-stroke, we so arrange the valve with relation'to the inlet and exhaust ports that the exhaust-port shall close and the inlet begin to open just before the piston reaches the end of its back-stroke, and before the crank passes the center at the top. As the valve reciprocates in unison with the pitman, its movement is reversed when the crank is at right angles, and it travels in the opposite direction during a half-revolution, and as this movement is the same, but in an opposite direction as that which effected the closing of the exhaustand opening of the inlet-ports, it follows that the opening of the exhaust and closing of the inlet will take place at relatively the same point during the return movement of the piston-that is to say, the inlet-port will not be closed nor the exhaust opened at the beginning of the back-stroke of the piston;

but the closing of the one and the opening of the other will be delayed at the beginning of the back-stroke in the same degree that the closing of the exhaust and opening of the inlet areadvanced at the end of the back-stroke.

The supply of steam to the valve-chest hav ing been interrupted by the closing of the ports 4 by the piston (or by the action of any approved cut-off mechanism) near thc end of the stroke of the piston, the steam contained in the valve-chest and cylinder acts expansively upon the piston, and inasmuch as the communication between the interior of the cylinder and the valve-chest remains open and the exhaust-port closed at the beginning of the baclestroke, it becomes necessary to provide an auxiliary or supplemental exhaust to relieve the pressure in the cylinder and bridge over the interval which elapses before the direct exhaust is opened. Otherwise the piston would be brought to a standstill. Such exhaust or relief is provided for in the following manner: Vithin the cylinder are formed al series of ports or channels, 24, so located and arranged relative to the stroke of the piston that their upper ends shall be uncovered by the lower head of the piston just before it reaches the end of its stroke, thereby opening a free passage for the escape of steam contained in the valvechamber, as well as of so much of the steam in the cylinder as can escape through the inletport and before the direct exhaust opens.

By the employment of a supplemental exhaust of this character not only is the steam in the steam and valve chambers of the piston allowed to escape at each inward stroke of the piston, but it renders practicable the employment in the piston of a valve adjusted to have lap and lead, as before described.

What we claim as new is 1. In a steam engine such as described,

IOO

IIO

IIS

wherein steam is admitted and exhausted in the cylinder above the pistongandthrough ports in thelatter, and in combination with said cylinder and piston, a valve controlling the inlet and exhaust ports in the piston, a cut-off independent of said valve, and a supplemental or auxiliary exhaust, alsoindependyent of the valve, substantially as described.

2. In a steam engine such as described, wherein the piston is provided with a steamchamber vintermediate its ends co-operating f with steam-openings in the side of the cylinder, while the head 4of the piston-serves as a cut-off, and in combination with said piston and cylinder, a reciprocating valve located in the piston and adjusted to have lap and lead withA respect to the inlet and exhaust ports, and a supplemental or auxiliary exhaust-passage opened at or near the end of the stroke of the piston to relieve the pressure in the cylinderv before the direct exhaust opens, substantially as described.

3.- In combination with the cylinder and its steam-openings, the double piston having steam-chamber communicating with said openings in the cylinder, a vcut-off for regulating e the'admission of steam to lthe said steamchamber during the stroke of the piston, a

l valve carried by the`piston and reciprocating -in unison with its pitman to open and close the inlet and exhaust ports, and a supplemental or auxiliary exhaust independent of said valve and its exhaust-ports co-operating with the .piston to. relieve the pressure in the cylinder near thel end of tially as described;

4. In an engine such as described, wherein the stroke, substansteam is admitted through the side of the cylinder into a chamber in the piston and'is conducted through inlet-openings into the cylinder above the piston, and in combination with said cylinder andpiston, a cut-od, a reciprocating valve carried, by the piston and connected to the pitman to vibrate in unison therewith, said valve being adjustedto open the inlet before the completion of the return or back stroke of the piston, a direct exhaust j controlled by said valve, andV a supplemental and lead, of a cylinder provided with steamports and exhaust-passages Vat or near one end, one end of the said piston cooperating scribed. s

7. In .combination with the cylinder and with the steam-ports in the cylinder to cut ofi" i n of the stroke, andthe other end co-operating with tle exhaust-passages to relieve the pressure in the cylinder at the end of the stroke, substantially as and for the purpose'set forth.

6. In an enginepsuch as described, and'in combination with the piston and cylinderl thereof, the cylindrical valve controlling the inlet and exhaust ports and located in the sections fitted to move the one upon the other, and the pitman secured directly to the upper section of said valve, ksubstantially as dethe supply of steam during'the latter portion double piston having steam-chamber and f cylindrical valve-chamber, the balanced cylindrical valve constructedin two sections moving one within the other, the upper, section, containing inlet and exhaust ports, being attached directly to the head of .the pitlnan, Y

substantially as described.

8. In combination with the cylinderhavin'g steam-ports in the side and supplemental exhaust-ports at or near the end, the double piston provided` with the steam -chamber and valve-chamber, and the cylindrical valve made in two sections fitted to move one withinthe a other, and the pitman secured directly to one of the sections of the valve, substantiallyas described.

9. In a steam-engine such as -described y wherein steam is admitted kand exhausted vin the' cylinder through 'a valve in the piston, and in which a cut-off is'v employed for limiting the admission-of the steam to the valve.- chamber, and in combinationwith saidcylinder, piston,and valve, the latterdrivenfrom the pitman andadjusted to have lap and lead,

the supplemental or auxiliary exhaust opened. '1 by the movement of the piston before the crank IOO reaches the center, substantially as 4and for thev l purpose set forth.

10. In an engine such as described, and in combination with' thepiston thereof containing a valve-chamber, the cylindrical valve` constructed in two sections, the outer section of said valve containing theinlet and exhaust ports and means whereby it can-,be firmly secured to the vhead of the pitman, and the-iuner section moving uponthe other section and?` closing the opening for the pitman in the lower head of the piston, substantially as described.

.-MIRABEAU- N. LYNN.

ELMovaE P. LYNN.

' 'Witnessesr O. M. GoTTsoHALL, WILLIAM H.' RUssELL.

I rov 70 piston, said valve being constructed in two

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