US373323A - Steam-engine - Google Patents

Description

' (No Model.) 2 Sheets-Sheet 1,

H. H. WESTINGHOUSE. STEAM ENGINB.

No.373',323. Patented-NoV.15,1887.

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STE AM ENGI NE.

No. 37332 3. Patented Nov. 15, 1887.

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A TTORNEY u UNIT D STATES PATE T OFFICE,

H. HERMAN WESTINGHOUSE, OF NEW YORK, N. Y., ASSIGNOR TO THE WEST- INGHOUSE MACHINE COMPANY, OF PITTSBURG, PENNSYLVANIA.

STEAM-ENGINE.

SPECIFICATION forming part of Letters Patent No. 373323, date& November 15, 1887.

Application filedAugust 20, 1885. Serial No? 174.878. (No model.)

To all whom, it may conccrn:

Be it known that I H. HERMAN WESTING- HOUSE, residing at New York, in the County of New York' and State of New York, a citizen of the United States, have invented or discovered certain new and useful Improvements in Ste-am-Eugines, of which improvenents the following is a specification.

In the accompanying drawings, which make Io part of this specifieation, Figure 1 is a vertical longitudinal section through a st'eam-en gine embodying my invention at the line w x of Fig. 3; Fig. 2, a vertical transverse section through the 'same at the line y y of Fig. 1, and

Fig. 3 a horizontal section atthe line z z of i Fig. 1.

My invention relates to single-acting steamengines of the class in which two or more' cylinders are located in parallel planes at right angles to a common crank-shaft, the pistons of the-several cylinders being connected, independently one ofthe' other, to separate crankpins on said shaft, an instance of which is ex'- emplified in Reissued Letters Patent of the United States No. lO,603, granted and issued to The Westinglouse Machine Company, as

my assignee, May 26, 1885. i

The object of my invention is to provide an engine of such general type of simple and'comparatively inexpensive construction, adapted to the effective utilization of steam upon the compound principle in which 'close and accurate regulation of speed, as well as economy of steam, may be insured by the employment of automatic cut-off mechanism governing the distribution of both the high and the low pressure cylinders.

To this end my invention, geuerally stated, consists in the combination of a high-pressure 0 and a low-pressure single-acting cylinder, a steamchest common to both cylinders, and ports so located as to cause the maximum of clearance to be between the valve and the high-pressure cylinder and 'to reduce to a 5 minimum the clearance between the valve and low-pressure cylinder; also, in the conbnation of a high-pressure and a low-pressure sngle-acting cylinder and a valve and ports adapted to first admit stean from the 'boiler to the high-pressure cylinder around the eX- terior of the valve, then to admit the exhaust of the high-pressure cylinder to the low-press'- ure cylinder through the interior of the valve, and finally to discharge the eXhaust of the lowpressure 'cylinder to the atmosphere, or to a eondenser at one end of the valve; also, in the combination of a high-pressure singleacting cylinder having a valve chest or chambercast integral therewith, and a low-pressure singleacting cylinder secured to the valve chest through the port or steam-entrance of the lowpressure cylinder.

The improvemenis claimed are hereinafter fully set forth. v

In the practice of my iuvention I provide a high-pressure cylinder, 1, having a valve chest or chamber, 3, cast upon its side, and a lowpres sure cylinder, 2, of larger diameter,which is secured to the high-pressure cylinder and val ve-ohamber by bolts passing through fianges 18 on the valve-chamber and lowpressnre cylinder, the plane of connection passing through the steam-port 14 of the low-pressure cylinder. The cylinders and interposed valvechanber, which are thus located as closely together as practicable and connected with a singlejoint, which can readily be made without expensive fitting, are secured upon the top of a closed crank-case, 2, which constitutes the bed or support of the engine and likewise.

'pins set oppositely, or at an augle of one hundred and eighty degrees, upon a pair of double eranks, 10 10, formed upon a crank-shaft, 4, having journals 50, mounted in bearings 41 in the ends of the crank-case 5, and carrying one or more balance-wheels, 4:2, and a belt-pulley, 43. A balancing-piston, 44, is formed upon or secured to the low-pressure piston 8, on the upper or steam side thereof, said balancing- -piston Working in a cylinder, 45, secured to the'head 48 of the low-pressure cylinder. The

IOO

cylinder 45 is closed at top by a head, 46, and comnunicates with the boiler or main steanpipe by a steani-supply pi pe, 47.

Stean is supplied to the valVe-ehamber 3 from the boiler by a stean-pipe, 11, seeured to a flange or nozzle'on the side of the Valvechamber, and is supplied to and exhausted froni the upper ends ot' the high and low pressure cylinders l 2 by a main or distribution valve, 12, performing the distribution functions ot' both eylinders and aetuated by an automatic cut-oti' mechanisin consisting of an eeeenlrie, 21, which is pivoted to the supporting disk or carrier 25 ot' a centrifugal governor or regulator fixed upon the erauk-shaft, and is provided with a slot fitting freely on the crank-shalt, so as to be adapted to be moved transversely to the crank-line by said governor in accordance with variutions ot' pressure or resistance, or both, and thereby to vary the traverse of the distribution-valve and correspondingly cut off stean from the high and low pressure cylinders at carlier or later periods in the strole. The eceentric 2L is connected to the distributionvalve 12 by an eccentric-rod, 19, seeured at one end to the eecentriestrap 20, and coupled at the other to a pin fixed in the lower end of the valve. The governor or regulator herein illustrated does not, per se, form part of my present invention, and being, noreover, fully set i'orth in Letters Patent No. 303,085, dated August 5, 1884, need not be herein at length described.

The main or steam-distribution valve 12, which fits aecnratcly in and is reeiproeated within a sleeve or bushing, 40. Secured in the valve-chamber 3, is coniposed of upper and lower main or steam-adnission pistons, 38 39, connected by an intermediate hollow or tubular body portion, a lower guide-pisten, l7, connectcd to the lower main pisten, 39, by bars, between which are formed a series ot' highpressure exhaust-ports, 65, an exhaust-piston, 66, connected to the upper main pisten, 38, by bars, between whieh are formed a series of lowpressure supply-ports, 67, and an upper balance-pisten, (32, connected by a rod or stern, 68, to the exhaust-piston GG. Steam is admitted to the interior of the bushing 40 from the steampipe ll and valve-chanber 3, through supplyports (39, so located as to be included between the main pistons 33 39 at all points of the traverse ot` the valve, and is exhausted froni the bushing through eXhaust-ports 70, located between the eXhaust-piston GG and balance-pisten (32, to the eXhaust-pipe 15, and thence to the atmosplere, or to a eondenser.

The adnission and exhaust of stean from the boiler to and from the high-pressure eylinder l are eti'eeted through a port or passage, 13, leading from the top of the high-pressure cylinder to a series of ports, 74, located in such position in the bushing 40 as to be alternately uncovered and covered by the lower steampisten, 39, of the valve, and the eXhaust-steain froni the higlrpressnre cylinder is admitted to and exhausted from thelQw-pressure cylinder 2 through a short straight port or passage, 14, I

leading from the top ot' the low-pressure eyll inder into the valve-chamber and communieating with a series of ports, 75, located in such position in the bushing as to be alternately uncovered and covercd by the exhaustpisten GG. It will thus be seen that the maximum elearance is between the valveand highpressure eylinder, the clearanee between the valve and low-p ressu re cylinder being red need to the minimum amount possible-to wit, the thickness of metal of the cylinder, valve-ehamber, and bnshing. The bushing 40, which is open at both ends, tits the valve-ehamber 3 tightly at and near each of its cnds. The top of the valve-chanber is closed by a t'ght head or eap, 64, and in order to prevent the escape of steani which may leak past the lower piston, 39, and guide-pisten 17 into the crank case an annular recess, 71, is fornied in the lower valveehamber, 3, around that portion of the bushing 40 in which the guide-pisten works, said recess communieating with the interior of the bushing by ports 72 therein, and being provided with a suitable diseharge-port, 73.

In operation steam froni the boiler is admitted from the steani-pipe 11 through the ports (39, between the main pistons 38 39, and around its central tubular body, and in the downward movement of the valve passes through the ports 74 and passage 13 to the upper end of the high-pressure cylinder l and effects the downward and working stroke ol' its pisten 7. In the upward movement oi' the valve the steam which has effeeted the downward sti-oke of the high pressnre pisten is exhausted through the passage 13, ports 74, tubular body of the valve, and upper ports, 67, thereof into the ports 75 and 14 and low-pressnre cylinder 2, efi ecting the downward stroke of its pisten S, its action being supplcmented by the pressure of stean froni the boiler upon the balancing-piston 44 of the low-pressure eylinder. In the succeeding downward traverse of the valve the exhaust-piston GG uneovers the porls 75, and thereby placing the port 14 in communication with the exhaust-ports 76 the steam which has effected the downward stroke of the low-pressure pisten is exhausted through the ports 14, 75, and to the cxhaust-pipe 15, and thence to the atmosphere,or toaeondenser, as the ease may be.

It will be seen that the objcction which ohtains in prevailing constructions of conpound engines of the \Voolf typeto wit., that of expansion between the cylinders without performance of work-is substantially removed, as but a small fraetion of clcarance is apportioned to the low-pressure eylinder, and the steam from the high-pressure cylinder is exhausted directly thereinto from the valve. The steam is not wholly exhausted at each stroke from the passage leading froni the highpressure to the low-pressure cylinder-that is, froni the interior of the tubular body of the valvc--but is entrapped therein under a pressure equal to the pressure in the lowpressure cylinder at the point of cut-off, and is surronnded on the outside of the valve by the live steam from the boiler, which eXerts a reheating action, tending to vaporize any Water of condensation in the steam exhausted from the high-pressure cylinder which may be due to expanson or other causes. The coincident variation of the point of cut-offin both cylinders in correspondence with variations of speed and resistance effected by the action of an automatic cut-off mechanism upon a distribution-valve common to both cylinders insures a close degree of regulation and thereby a substantially constant speed and economical Consumption ofsteam. Undue upward pressure upon the loW-pressure piston on its upward stroke, due to the action ofatmospheric pressure in the crank case against a vacuum or partial vacuum on the npper side of the piston,

is prevented by the pressure on the balancingpiston 44; and such pressure acts, together with the pressure on the main piston 8, to effect the downward stroke.

A special advantage of the balancing cylinder and piston is developed in its employment in connection with automatic cut-off nechanism, as it is possible for the latter to' effect so early a cut-off in the high-pressure cylinder as to give an insufficient terminal in the low-pressure cylinder to start the piston of the latter on its downward stroke. The avoidance of such objection is iudispensable to the proper working of asingle-aeting engine, and as the balancing-piston-is constantly subject to the pressure of steam from the boiler it will be seen that under the above Construction a sufficiency of initial pressure upon the low-pressnre piston is insu red at the shortest cut-off that can be effected.

I disclaim herein a compound engine having a single valve governing the distribution of both its cylinders and aetuated by an eccentric which is movable transversely to the crank-line and is coupled to a governor, as the same. forms the subject-matter of my Letters Patent N o. 340,02l, dated April 13, 1886.

I claim herein as my inventionl. The conbiuation of a high-pressure single acting cylinder, a low-pressure single-acting cylinder of larger diameter, pistons fitting said cylinders and coupled to crank-pins upon a. common crank-shaft, a single main or distribution valve working in a valve-chamber between saidcylinders and governing the sup- 4 i ply and eXhaust of steam to and from the same, a steam-port extending from the steamsupply end of the high-pressure cylinder to a point in the valve-chamber below said end, and a steam-port extending directly or substantially in right line from the steam-Supply end of the loW-pressure cylinder to the Valvechamber and of a length practically equal to* the thickness of metal of the low-pressure cylinder and VaIVechamber, substantially as set forth.

2. The combination ofa high-pressure single-acting cylinder, a low-pressure single-acting cylinder of larger diameter pistons fitting said cylinders and coupled to crank-pins upon a common crank-shaft, and a single main or distribution valve working in a valvecham: ber having delivery, supply, and exhaust ports and governing the supply and exhaust of steam to and from both of said cylinde's, said valve having two main pistons connected by a tubular body and an exhaustpiston adjacent to one of its ends and separated therefrom by a series of ports. and being adapted to first admit steam from the boiler around its body to the high-pressure cylinder, then to admit steam exhausted from the high-pressure cylinder through its body and below its exhaustpiston to the low-pressure cylinder, and finally to deliver the eXhaust-steam of the low pressure cylinder above its exhaust-piston to an eX- haust-pipe, substantially as set forth.

3. The combination of a high-pressure single-acting cylinder, a low-pressure single-acting cylinder of larger diameter, a single main or distribution valve gove'ning the supply and exhaust of steam to and from both ofsaid cylinders and working within a valvechamber interposed between the cylinders, and a fixed sleeve or bushing inclosing said Valve and having ports communicating with au annular recess in the Valve-chamber adapted to receive leakage from the interior of the bushing, substantially as set forth.

4. The combination of a high-pressure sin gle-acting cylinder having a valve-chamber cast integral therewith, and a steam-port eX- tending from one of its ends to said chamber, and a low-pressure single-acting cylinder of larger diameter having a port extending from one of its ends directly to its shell and Secured IOO to the high-pressure cylinder by bolts passing

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