US592824A - Compound engine - Google Patents

Description

(No Model.) 4 Sheets-Sheet 1.

A. J. PITKIN & J.- E. SAGUE.

COMPOUND ENGINE.

Patented Nov. 2, 1897.

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(No Model.) 4 Sheets-Sheet 2. A. J. PITKIN & J. E. SAGUE.

COMPOUND ENGINE.

Patented Nov. 2, 1897.

M il (No Model.) 4 Sheets-Sheet 3, A. J. PITKIN 86 J. E. SAGUE.

COMPOUND ENGINE.

fiaywe W UNrTED STATES I PATENT rrrcn.

ALBERT J. PITKIN AND JAMES E. SAGUE, OF SCHENEOTADY, NEWV YORK.

COSMPOUND ENGINE.

SPECIFICATION forming part of Letters Patent No. 592,824, dated November 2, 1897.

Application filed May 21, 1897. Serial No. 637,592. (No model.)

T0 at whom it may concern.-

Be it known that we, ALBERT J. PITKIN and JAMES E. SAGUE, citizens of the United States, residing at Schenectady, in the county of Schenectady and State of New York, have invented certain new and useful Improvements in Compound Engines, of which the following is a specification.

Our invention relates to the class of compound engines which are organized to start with live steam in both the high and low pressure cylinders and automatically change to operate with live steam in the high-pressure cylinder and exhaust-steam in the low-pressure cylinder and which have provisions whereby the engine may be run by live or high-pressure steam in both cylinders whenever desired and for any desired length of time. I

Locomotive-engines organized to operate in this way are most eflicient, and there is much economy in the expense of operation. The use of live steam in both cylinders at start ing insures the immediate operation of the mechanism to set the locomotive in motion, which can then under ordinary conditions run compound, and thus economize in the use of steam. When extraordinary service is required, as when ascending grades, it is desirable to operate with increased power, and hence live steam is used in both cylinders. It is important that the mechanism shall be so constructed and organized that the changes from simple to compound or from compound to simple may be quick, accurate, and automatic.

The object of our invention is to provide simple, positive, and automatic mechanism for starting compound locomotives of this class, reliably-acting means for automatically changing from-simple to compound after the engine is started, and improved mechanism for changing from compound to simple working or to cause the engine to run as a simple engine for any desired length of time.

WVe employ an intercepting-valve which opens or closes the steam-passage from the high-pressure cylinder to the low-pressure cylinder and which also governs the admission of live steam direct to the low-pressure cylinder when communication between the high-pressure cylinder and low-pressure cylinder is cut off. \Ve employ an exhaustvalve of an improved construction whereby the exhaust-steam from the higlrpressure cylinder may pass to the atmosphere when both cylinders are receiving live steam and the engine is running continuously as a simple engine.

We do not wish it understood that we claim,

broadly, a supplemental exhaust-Valve in a compound engine involving the use of an automatic intercepting-valve, nor do we claim as our invention, broadly, an engine organized to work at will as a compound engine or as a simple engine, but we claim to have made certain improvements in the details of construction and in the operation of the valves whereby the engine is made to workmore smoothly and with greater efficiency.

In the accompanying drawings, Figure 1 is a vertical transverse section through the smoke-box of a locomotive and the cylinders and cylinder-saddles, the intercepting-valve chamber being shown on the low-pressure side of the engine. Fig. 2 shows a vertical longitudinal section on the line 2 2 of Fig. 1 and illustrates particularly the steam-admission pipes and the receiver-pipe. Fig. 3 is a longitudinal sectional view, on an enlarged scale, through the intercepting-valve, the auxiliary exhaust-valve, and their case, the parts being shown in the position they occupy when the engine is running simplethat is to say, when live steam is being admitted to both the highpressure and low-pressure cylinders. Fig. at is a similar View showing the parts in another position-via, that in which they are arranged when the engine is working compound. Fig. 5 shows a transverse section on the line 5 5 of Fig. 4. Fig. 6 shows a similar section on the line 6 6 of Fig. 4, and Fig. 7 shows a transverse section on the line 7 7 of Fig. 3.

' The high-pressure cylinder A and the lowpressure cylinder 13 are connected by a receiver-pipe O in the usual way. High-pressure or live steam enters through the pipe D and passes to the high pressure cylinder through pipe E and to the low-pressure cylinder through branch pipe F. The exhaust from the low-pressure cylinder passes out through the nozzle G.

The parts just described are all of wellknown construction and need no detailed description.

The intercepting-valve His a slide-valve and is located in the saddle of the lo\vpressure cylinder,as in Pitkins patent No. 417,083, of December 10, 1889. The passage I, connecting the valve-chest of the low-pressure cylinder with the receiver, is bridged by a guide K for the intercepting-valve. This valve is hollow or chambered, being closed at its front end h, at which end it is provided with a forwardly-projeeting annular flange Z, having an opening Z for the passage of steam from the high-pressure cylinder, as hereinafter described. The portion 7b of the intercepting-valve is solid, and the portion ll in rear of the solid portion h is made hollow or chambered, but it has a web 7L2, provided with a perforated abutment 7L3 for the reducing-valve M The intercepting-valve is prov'ded with lateral openings N, which communicate with the hollow or chambered portion of the valve and at times communicate with openings a, leading to the steam-chest of the low-pressure cylinder or to a passage n", which communicates with said steanrchest. Packing-rings n are let into the outside of the intercept ing-valve on one side of the openings N, and a packing ring or groove 01 may be arranged on the opposite side of said openings N. This is to prevent the escape of live steam into the receiver when the engine is working on the compound principle. Preferably a bushing N is used around the interceptingvalve, as in Iitkins patent before referred to.

The rear portion of the valve II is reduced in diameter and works in a casin g or bushing N, which, when desired, maybe removed from the shell or casing N. The rear portion of the valve is provided with lateral openings at, communicating with the interior of the valve and also with the live-steam chamber N which is connected with the pipe F. (Indicated in Figs. 1 and 2.)

The reducing-valve M is arranged close to the openings n" and is arranged to slide in guides 0 and in a cylindrical boss 0, formed on an end piece 0, which is removably secured to the rear end of the intercepting-valve. The smaller end of the reducing-valve works back and forth in the cylindrical boss, and a piston 0 within the cylindrical boss extends into a cylindrical opening in the reducingvalve. This arrangement acts as a dash-pot to eushionthe movementof the reducingvalve, which would otherwise vibrate too rapidly and hammer badly. The rear end of the interceptirig-valve may be packed with metallie rings or other paekings 0 and it is provided with an escape-opening O in rear of the reducing-valve to permit the escape of steam or condensed vapor should there be any leakage. A drip-pipe 0 is also provided to carry elf condensed steam when necessary.

The opposite or larger end of the reducing valve when it is open abuts against the perforated abutment 7L3. .Vhen the reducingvalve is closed, as in Fig. hits larger end coincides or registers with an annular flange 0.

A dash-pot P, similar to that shown in Pitkins patent No. ll7,083, is employed to regulate the movement of the inLercepting-valve. The rod 1 is connected to the valve by a taper-joint and removable key 1). The pistonhead 17' is guided and prevented from turn ing by a feather-aml-groove connection p By this arrangement the intercepting-valve is also prevented from turning and the several steam-ports are kept in proper alinement. Ground joints are employed wherever required, and packing-rings are also employed at such places as would be apt to leak. The particular manner of packin the joints is not important. The dash-pot is removable from the end of the intercepting-valve casing, and the piston-rod 1 maybe readily detached, as may also the end of the intereepting-valve, so that the reducing-valve may be withdrawn for examination or repair.

The auxiliary exhaust-valve is arranged at the front end of the intereepting-valve. The casing Q is bored centrally in line with the interceptingvalve to receive a cage 1%, in which the auxiliary exhaust-valve is arranged to slide. The cage is flanged at v and removably secured to the casing Q. It has a front chamber 0', within which slides a piston-head 0- and a back chamber 0", which communt cates with a central opening 1', leading into the receiver, and with lateral openin r", connecting with a chamber or passage S, which leads to the main exhaust G. The larger member R of the valve has a ground seat 1" on the back end of the cage, and it is formed with guide-wings 0- which slide within the chamber f. The stem r of the valve member lt is hollow and extends back into the chamber 1'. The hollow or chambered portion is open at 0" and is provided with lateral openings 0' within the chamber r.

A valve member T of col'n mratively small area has a valve-seat t at the rear end of the chambered portion of the valve member lrt'-. It has a stem T extending through the chambered stem 4*, and the front end of the stem is connected with the piston-head r by a tapered joint and a nut r A spiral spring U surrounds the hollow valve-stem r and bears against the flange or partition 1/ between the front and back chambers 0" an d 0* and against the piston-head 9' This spring is put in place under considerable initial. pressure and holds both valves closed when there is no con 11- teracting pressure. There is a space between the piston-head 2- and the end 0- of the hollow stem r so that the valve T may move for a short distance independently of the valve member B A chamber V is formed in the front of the piston-head w, and with this chamber communicates a steam-pipe c, which leads to the cab. By causing steam, air, or other fluid to pass through this pipe the piston may be moved rearwardly, first causing the valve member T to open and then opening the valve member R When this occurs, there will be a communication between the receiver and the exhaust-passage S.

The valve in the cab is so arranged that it can be turned either to admit the operating fluid to the chamber V or to permit the exhaust of fluid therefrom. Such valves are of well-known construction and need no further description. There is, however, a liability of these valves leaking, and in order to prevent any accidental accumulation of pressure in front of the piston r we provide a leakage groove :12 in the chamber 9". This groove is made large enough to relieve any pressure due to such leakage, but it is not large enough to prevent the piston r from being operated when the valve in the cab is opened wide. The groove is especially essential when the auxiliary exhaust-valve is operated by steam, as without it a slight leakage of the valve in the cab would cause the chamber V or r to be filled with condensed steam. As shown in Fig. 4, the groove x is longer than the piston T and there is a free passage from one end of the piston to the other when the auxiliary exhaust-valve is closed. Any leakage past the piston escapes through an opening 00. In order to protect the parts at the front of the apparatus,we provide a shell or casing W, which may be attached, as indicated, to the flange 'r and to the end piece R of the cage. The flange Z on the interceptingvalve is adapted to be seated,when this valve is closed, in an annular seat 1.

In starting the engine the position of the intercepting-valve and the auxiliary exhau stvalve will be as indicated in Fig. 4. Live steam from the main throttle-valve is admitted into the high-pressure cylinder through the main steam-pipe E, and at the same time through the,pipe F to the back of the intercepting-valve chamber. The live steam enters the chamber N passes through the openings N, and moves the intercepting-valve forward into the position shown in Fig. 3, (the auxiliary exhaust-valve, however, being closed).

When the intercepting-valve has almost reached its point of full forward travel, it opens the ports n in the bushing N and steam passes through the reducing-valve M and openingsn into the chamber n, and thence to the steam-chest of the low-pressure cylinder. The high-pressure steam, acting upon the opposite ends of the reducingvalve, which have different areas, moves the valve forward and opens the passages, as shown. The live steam after passing the reducingvalve exerts its reduced pressure on the full area of the large piston of the reducing-valve, tending to move this valve back and throttle the admission of steam. The sizes of the opposite ends of the reducing-valve are so proportioned that the difference of the areas against which the high-pressure steam acts is about one-half of the area of the large piston which is acted upon by the reduced pressure. The steam supplied to the low-pressure cylinder is thus reduced in the ratio required to suit the relative areas of the high and low pressure cylinders and enable them to exert equal power when running simple. Highpressure steam thus being supplied to the high -pressure cylinder through the main steam-pipe and steam at reduced pressure to the low-pressure cylinder through the interc'eptin g and reducing valves, the engine starts with the intercepting-valve closed, the communication between the low-pressure cylinder and the receiver being cut off.

The high-pressure cylinder exhausts into the receiver and accumulates pressure upon the front end h of the intercepting-valve. The area of this end h of the interceptingvalve is so proportioned in relation to the difference of areas at the back of the intercepting-valve that the intercepting-valve is moved by receiver-pressure when this pressure has accumulated sufficiently to give the full required power to the low-pressure piston. This occurs after one or two exhausts from the high-pressure cylinder. After the intercepting-valve is started the flange Zis moved from its seat Z and then the valve slides quickly back to its extreme rear position, as pressure is then exerted upon the full area of the front of the valve, including the the flange Z. i/Vhen the intercepting-valve is thus moved, the supply of live steam to the low-pressure cylinder is cut off, communication is opened between the receiver and the steam-chest of the low-pressure cylinder, and the latter is then supplied with steam from the receiver. The locomotive will then run as a compound engine. When thus operated, the pressure equalizes around the larger piston of the reducing-valve, pressing it firmly against its seat at the back, and all leakage is practically prevented. The intercepting-valve is also held back firmly by receiver-pressure, and the joints and packing are such as to prevent escape of steam.

The auxiliary exhaust-valve is not used in ordinary starting and remains closed, as shown in Fig. 4. The engine maybe repeatedly started and stopped without bringing into operation the auxiliary exhaust-valve; but in case it is desired to run the engine simple steam or air is admitted from a threeway valve in the cab through the pipe 1) to 1- soaesa the intercepting-valve forces this valve for ward against its seat Z and communication between the receiver and the low-pressure cylinder is out off. The low-pressure cylinder is then supplied with steam at reduced pressure through the intercepting and reducing valves, as previously described, for automatic starting, and the engine runs simple, with the valves in the position shown in Fig. 3, as long as desired.

The advantage of employing the smaller valve member T is that it affords a means of reducing the receiver-pressure gradually in case the receiver is filled with steam at the normal pressure, thus avoiding a violent exhaust and permitting the large valve mem ber R to be opened more easily than it could be against full receiver-pressure.

When it is desired to resume compound working, the position of the valve in the cab is changed, allowing the air or steam to exhaust from the front chambers 1" and V, and the spring U will force the valve members back to their seats. Receiver-pressure then accumulates, opens the intercepting-valve, and shuts oil the independent supply of live steam to the low-pressure cylinder, as in automatic starting. During compound working the valve members R and T are held iirmly against their seats by receiver-pressure, as well as by the spring U.

A collar p on the valvestem T guides the stem, and forward movement of the pistonhead is limited by an annular shoulder y in the chamber 1', and the flange l serves not only to shut off communication between the receiver and the steam-chest of the low-pres sure cylinder, but also to direct the passage of exhaust-steam from the receiver to the auxiliary exhaust.

The auxiliary exhaust-valve, it will be observed, comprises two parts or members R and T. Both coact to effect the same result, but the independent actuation of the smaller member T modifies the action, as above explained. The amount of independent movement of the valve member T is regulated by the distance between the head 7' and the end of the valve-stem 0' when the valves are closed.

o claim as our invention 1. In a compound engine the combination of the high and low pressure cylinders, a receiver-pipe connecting them, an intercepting valve interposed between the two cylinders, a red uein g-valve within the intercepting-valve, an auxiliary exhaust-valve composed of two independently-movable parts, and means for actuating one part to partially open the auxiliary exhaust-passage, and for subsequently actuatingthc other part to further open said passage.

2. In a compound engine, the combination of the high and low pressure cylinders, the receiver-pipe connecting them, a chambered intercepting-valve interposed between the two cylinders and formed with ports for the entrance and exit of live steam and provided with a removable end piece having a chambered boss for guiding a reducing-valve, a reducing-valve within the chambered intercepting-valve, an abutment within said chamkey for attaching the rod to the end of the intercepting-valve, packings to prevent the passage of steam, drip-apertures and escapepipes, and an auxiliary exhaust-valve for the exhaust from the high-pressure cylinder.

In a compound engine, the combination of the high and low pressure cylinders, a receivenpipe connecting them, an intercepting valve, means for operating it automatically, and an auxiliary exhaust-valve consisting ol' two in dependeutly-movable parts, the smaller one of which is adapted to be opened before the larger, to reduce the receiver-pressure gradually and avoid a violent exhaust, sub stantially as described.

t. The combination of the interceptingvalve, and the auxiliary exhaust-valve comprising the larger member having a hollow stem, the smaller member-having a stem moving within the hollow stem of the larger n1ember, a piston-head to which the stem of the smaller member is connected, and a spring for closing both members.

5. The combination of the cage of the auxiliary exhaust, the larger member of the ex.- haust-valve, its hollowstem having a rear opening and one or more lateral openings, the smaller member having a stem arrz'mgod within the hollow stem of the larger member, a piston-head secured to the stem of the smaller member, and a spring under pressure interposed between the piston-head and the cage and a port for the admission of fluidpressure to the front end of the piston.

O. In a compound engine the combimition of the high and low pressure cylinders, a receiver-pipe connecting them, an interceptingvalve interposed between the high and low pressure cylinders, a flange Z projecting lorwardly from the intercepting-valve and having an edge of reduced area fitting a closed or steam-tight seat 1, said flange being also provided with a lateral opening through which steam passes from the receiver to an auxiliary exhaust, and haviuga closed portion closing a passage between the receiver and the low-pressure cylinder.

7. In a compound engine, the combination of the intercepting-valve, the cage for the auxiliary exhaust-valve provided with front and back chambers, the larger member of the auxiliary valve having a hollow stem and provided with guide-wings sliding in the back chamber of the cage, the smaller member of In testimony whereof we have hereunto the auxiliary exhaust-valve having a stem arsubscribed our names.

ranged Within the hollow stem of the larger ALBERT J. PITKIN. member, a piston-head secured tothe stem of JAMES E. SAGUE. the smaller member and arranged in the front Witnesses chamber of the cage and a spring for closing W. S. HUNTER,

both members of the Valve. H. W. DENNINGTON.

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