US678806A

US678806A - Compound pressure-engine.

Info

Publication number: US678806A
Application number: US4341399A
Authority: US
Inventors: Marcy L Whitfield
Original assignee: WHITFIELD Co
Current assignee: WHITFIELD Co
Priority date: 1899-04-15
Filing date: 1899-04-15
Publication date: 1901-07-16
Anticipated expiration: 1918-07-16

Description

v Patented luly I6, I90]. W L. WHITFIELD.

CUIW'IPOUND PRESSURE ENGINE.

(Application filed Apr. 15, 1899. Renewed Jan. 15, 1901.)

5 Sheets8heet L (No Mudal No. 678,806. Patented July n e, I901].

m. L. ll-ll'll'fl-BELD.

COMPOUND PRESSURE ENGINE.

I (Application filed Apr. 16, 1899. Renewed Jan..15, 1901.) Modem 5 Sheets-Sheet 2.

Pa'tentadl lluly i6, I905. M. IL. WHBTHEIL'D. COMPUUND PRESSURE EMGIW. (Application filed Apr. 15, 1899. Renewed Jan. 15, 1901.

5 Shaets$heet 3.

(No Model.)

, Patented fluly as, won. M. L. WHITFIELD.

BOMPUUND PRESSURE ENGINE.

(Application filed Apr. 16, 1899. Renewed Jan. 15, 1901.)

5 shem shmm- (No Model.)

a e o 0 M W m: Nonms PETERS co moraumu. WASHINGTON a. c

No. 678,806. Patented July 16, neon m. L. WHITFIELD.

COMPOUND PRESSURE ENGINE,

(Application filed Apr. 15, 1899. Renewed Jan. 15, 1901.) (No Model.)

5 ShaetsSheet 5.

"ma NoRms wcrzns my, Movoumo" wnumovon, n. c.

IUNTTEE STaTEs PATENT EETEE.

MARCY L. WHITFIELD, OF MEMPHIS, TENNESSEE, ASSIGNOR TO THE WHITFIELD COMPANY, OF SAME PLACE.

COMPOUND PRESSURE-ENGINE.

SPECIFICATION forming part of Letters Patent N 0. 678,806, dated July 16, 1901. Application filed April 15, 1899, Renewed January 15, 1901. Serial No. 43,413. (No model.)

To all whom it may concern.-

Be it known thatI, MAROY L. WHITFIELD, a citizen of the United States, residing at Memphis, Shelby county, Tennessee, have invented certain new and useful Improvements in Compound Pressure-Engines, of which the following is a specification.

My invention relates to improvements in compound steam-engines, and more particularly to that class of engines known as telescopic, and comprising a stationary lowpressure cylinder, a stationary piston-abutment, and a high-pressure piston-cylinder working on said abutment and in said stationary cylinder, respectively; and my said invention has for its primary objects, first, to provide means whereby the power of the engine is automatically increased either in starting, whereby the engine will accommodate itself to a maximum starting load, or in the event of a sudden overload being imposed thereon while in operation to accommodate itself to the increased load; second, to dispense with all stuffing-boxes, thereby decreasing leakage and lessening the friction, and, third, to simplify the general construction of the engine, whereby its cost and weight may be reduced.

In accordance with the first object of my invention I control the main or distributing valve by a governor, preferably a centrifugal governor, so that in starting or when a sudden load is imposed upon the engine live steam will be admitted through the highpressure piston-cylinder directly into the lowpressure cylinder on the low-pressure stroke, and owing to the increased area of the lowpressure cylinder the admission thereto of live steam will result in a very great increase of power on the low-pressure stroke, enabling the engine to overcome the load thereon in starting or to overcome a load greater than the normal load when imposed on the engine during its operation, the engine in such cases working as a semicompound engine.

I attain the second object of my invention by connecting the driving-rod with arms secured to or formed integral with the highpressure piston-cylinder. Steam working at all times on the cylinder side of the stationary abutment, there is no necessity for packing the connections between said piston-cylinder and the power-shaft.

The valve which I prefer to use in the stationary piston-abutment for controlling the admission and cut off of steam to and from the high-pressure cylinder is preferably a piston-valve whose stem does not require to be packed. The valve which I prefer to use for controlling the admission of steam from the high to the low pressure cylinder and hereinafter referred to as the intermediate valve and located in the piston-head of the high-pressure cylinder is preferably of the semirotary type, its stem being splined to the exhaust-valve or otherwise constructed to rotate therewith, and as said stem Works at all times within the steam-space and has no connection with the atmosphere it also requires no packing. The exhaust-valve is also preferably oscillating and is operated directly by connections with the power-shaft, the only packing being that of the valve itself. Consequently in the construction of my engine no stuffing-boxes are necessary.

The third object of my invention follows as a matter of course from the construction of the engine.

That my invention may be fully understood I will describe the same in detail, reference being had to the accompanying drawings, in which- Figure 1 is a side elevation of a compound engine embodying my present improvements. Fig. 2 is a horizontal section of the same. Fig. 3 is a vertical longitudinal section. Fig. 4 is a cross-section on the line 4 4: of Fig. 3 looking in the direction of the arrow seen on the section-line. Fig. 5 is a cross-section on the line 5 5 of Fig. 3 looking in the direction of the arrow and illustrating partly the con struction of the exhaust-valve with its operating mechanism; and Figs. 6, 7, 8, and 9 are cross-sections on the lines 6 6, 7 7, 8 8, and 9 9, respectively, of Fig. 3.

In all of the above views corresponding parts are represented by the same numerals of reference.

1 is a suitable frame, to which is bolted the low-pressure cylinder 2. Mounted in bearings 3 is the power-shaft 4, carrying one or more fly-wheels 5, two being shown.

Shaft 4 is provided with a crank 6, driven from the connecting-rod 7. Mounted to reciprocate in the cylinder 2 is the high-pressure pistoncylinder 8, working in said low-pressure cylinder 2. The high-pressure piston-cylinder 8 is provided with two arms 9 9, working in guides 10, which'are cast to the low-pressure cylinder 2, and connecting said arms is a cross-head 11, (see Fig. 9,) having a wrist pin 12 therein, on which the driving-rod 7 is mounted.

13 is the stationary piston-abutment, having two arms 14 14, bolted or otherwise secured to the engine frame 1. The highpressure piston-cylinder 8 works on this stationary abutment, as shown. One of the arms 14 of the stationary abutment is provided with a live-steam passage 15, leading to a valve-chamber 16 therein. Mounted in said valve-chamberis the reciprocating main or distributing valve 17, the stem 18 of which is operated from a cross-head 19 by two arms 20 20. The arms 20 connect with two rockerarms 21 on a rock-shaft 22, mounted in the engine-frame. Keyed to the rock-shaft 22 is a lever 23, the upper end of which connects by an eccentric-rod 24 with an eccentric 25, whereby the operation of the eccentric will reciprocate the valve 17 in the valve-chamber in the stationary abutment, as shown. The live-steam passage '15 leads into the valve-chamber 16 by means of a port 26, which is at all times in connection with a pocket27in thedisiributing-valve17. Aport 28 leads through the stationary abutment, as shown,to permitlive steam to drive the pistoncylinder backward within the low-pressure cylinder 2, the steam expanding against the stationary abutment, as will be seen. The valve 17 is provided with a shoulder 29, adapted to close the port 28 when expansion is to be effected from the high to the low pressure cylinders when the engine is working compound. Said valve is also provided with a passage 30, which is adapted to connect the pocket 27 with the port 28 when the valve is moved to its forward limit in the valve-cham ber in the direction of the shaft 4. This movement is effected under the influence, preferably, of a cut-off governor 31 of any suitable type, which controls the throw of the eccentric 25 to determine the cut-off. WVhen the engine is stationary or working at a very slow speed, the pocket 27 will, through the passage 30, bein communication with the port 28 on the low-pressure stroke to permit steam to pass directly under boiler-pressure into the low-pressure cylinder; but as the speed increases the governor 31 will retard the cut-off, moving the valve 17 farther inward, so that the passage will not communicate with the port 28. The cylinder-head 32 of the pistoncylinder is preferably removable, as shown, and is provided with an intermediate valve 33 therein, preferably of the oscillating or semirotary type. Said valve is adapted to cover and uncover passages 34, which correspond, preferably, with passages 35 in the stationary abutment, the latter passages conmeeting with the steam-passage 28. The intermediate valve 33 is provided with pockets 36, which when they register with the passages 34 allow expansion to take place from the highpressure to the low-pressure cylinder. The stem 37 of the valve 33 is operated in any suitable way, but preferably from an exhaust-valve 38. The stem 37 of the intermediate valve 33 is provided with a keyway 39, (see Fig. 6,) in which a key (not shown) on the exhaust-valve 38 works, whereby stem 37 may move longitudinally with respect to the exhaust-valve, but will be oscillated by the movements of the latter.

The exhaust-valve is provided with ports 40, adapted to register with ports 41, connected with an exhaust-space 42, (see Fig. 5,) from which leads an exhaust-pipe 43. The exhaustvalve may be operated in any suitable way. I illustrate it as being provided with an arm 44, which may be moved up and down to oscillate the valve, said arm being operated from a link 45, connected to a power-crank 46, the latter being operated by a link 47 from the lower end of the lever 23. Preferably the arm 14 of the stationary abutment opposite to the one containing the live-steam passages 15 is provided with a receiving-chamber 48, the purpose of which is to allow for a sufficient steam-space in the engine for the accumulation of steam therein, so that on running light and with the cut-off operating quickly the piston-cylinder will not be required to move against a vacuum. Receivers for this purpose are common in compound engines, although I am not aware that they have ever been placed so as to constitute an integral part of the device.

The operation of the engine is as follows: In starting, whether the high-pressure pistoncylinder is on the instroke or the outstroke, live steam passes from steam pipe 15 and through port 26 into pocket 27 of the distributing-valve 17, thence through port 28 and passages 35 into the high-pressure cylinder, the intermediate valve 33 being closed and the exhaust-valve open, causing pistoncylinder 8 to make its instroke. As said piston-cylinder is about to reach the limit of its instroke, the connections between the exhaust-valve 38 and the eccentric 25 will cause said valve to close, and as said valve controls the intermediate valve 33 the latter will open, allowing steam from the high-pressure piston-cylinder to expand into the low-pressure cylinder. Owing, however, to the lagging of the cut-off the steam-passage 30 will be in communication with port 35. Hence live steam will flow through the high-pressure cylinder directly intothe low-pressure cylinder from pipe 15, through port 25, passage 30, port 28, and passage 35,. thence through ports 34 and the pockets 36 in intermediate valve to said low-pressure cylinder, the outstroke being effected under live-steam pressure, and ow- IIO ing to the greater area of the low-pressure cylinder and its piston relatively to the area of the piston-abutment the power of the engine will be greatly increased. As the highpressure piston-cylinder 8 reaches or is about to reach the limit of its outstroke the intermediate valve closes and the exhaust-valve opens, while the main or distributing valve again admits live steam to the high-pressure piston-cylinder 8, the engine Working semicompound. This operation continues until the engine is running at the required speed, when themoment of cut-off is accelerated so that the passage 30 does not register with the port 35, the shoulder 29 of the valve cutting off said port on the low-pressure stroke, live steam being admitted to the high-pressure piston-cylinder 8, as before, to etfect the instroke; but on the outstroke the distributing-valve cuts oif the live steam at the port 35,the intermediate valve 33 opens, and steam from the high-pressure piston-cylinder eX- pands into the low-pressure cylinder, thus effecting the outstroke. As the high-pressure piston-cylinder reaches or is about to reach the limit of its outstroke, the intermediate valve closes and the exhaust-valve opens to exhaust steam from the low-pressure cylinder, while the distributing-valve will now again be in a position to admit live steam to the high-pressure cylinder, and so on, the engine working compound.

Should in starting the high-pressure piston-cylinder S be at any point of its outstroke, the same operation as described will take place, live steam being admitted to the high-pressure piston-cylinder.

Should during the normal operation of the engine an overload be imposed thereon, its speed will be reduced, so that on the outstroke of the high-pressu re piston-cylinder immediately following such reduction of speed live steam will be admitted to the low-pressure cylinder through said high-pressure piston-cylinder, owing to the lagging of the cut off, exactly as in starting, whereby the available power of the engine is increased to overcome the increase in the load thereon, the engine working semicompound until it has again acquired its normal or regular speed.

Having thus described my invention, what I claim as new therein, and desire to secure by Letters Patent, is

1. In a compound engine, the combination with the high and low pressure cylinders, of means operating automatically under certain conditions and at a certain point of the stroke to establish direct communication between the source of live-steam supply and the lowpressure cylinder through the high-pressure cylinder to change the operation of the engine from compound to semicompound, for the purpose set forth.

2. In a compound engine comprising a low pressure cylinder, a piston-abutment and a hi gh-pressure piston-cylinder workin g on said abutment and in said low-pressure cylinder respectively; means operating automatically for establishing under certain conditions and at a certain point of the stroke, direct commu nication between the source of live-steam supply and the low-pressu re cylinder through the high-pressure cylinder, to change the normal operation of the engine from compound to semicompound, for the purpose set forth.

In a compound engine comprising a lowpressure cylinder, a piston-abutment and a high-pressure piston-cylinderworking on said abutment and in said low-pressure cylinder respectively; means operating automatically for establishingat a certain point of the stroke of the high-pressure cylinder in starting, direct communication between the source of live-steam supply and the low-pressure cylinder through said high-pressure cylinder, to change the normal operation of the engine from compound to semicom pound, for the purpose set forth.

4. In a compound engine comprising a lowpressure cylinder, a piston-abutment .and a high-pressure piston-cylinder working on said abutment and in said low-pressure cylinder respectively; means operating automatically for establishing under certain conditions and at a certain point of the stroke during the normal operation of the engine, direct communicat-ion between the source of live-steainsupply and the low-pressu re cylinder through the high-pressure cylinder to change said operation from compound to semicompound,for the purpose set forth.

5. In a compound engine, the combination with the high and low pressure cylinders, a valve mechanism,and suitable steam passages and ports controlled thereby and operating to cause the engine to normally work compound; of means automatically changing the operation of the valve mechanism to establish, under certain conditions and at a certainpoint of the stroke, direct communication between the source of live-steam supply and the low pressure cylinder through the high-pressure cylinder to change said normal operation from compound to semicompound, for the purpose set forth.

6. In a compound engine comprising high and low pressure cylinders, a valve controlling the flow of live steam to the high-pressure cylinder, a valve controlling a passage or passages leading from said high-pressure cylinder into said low-pressure cylinder, and an exhaust-valve controlling the flow of steam from the low-pressure cylinder; at valve-gear operating the valves to cause the engine to normallywork compound and means operat ing automatically for changing the operation of the valve-gear and valves so as to establish, under certain conditions and at a certain point of the stroke, direct communication between the source of live-steam supply and the low-pressure cylinder through the high-pressure cylinder to change the normal operation of the engine from compound to semicompound, for the purpose set forth.

IIO

7. In a compound engine comprising a lowpressure cylinder, a piston-abutment, a highpressure piston cylinder working on said abutment and in said low-pressure cylinder the purpose set forth.

8. In a compound engine comprising a lowpressure cylinder, a piston-abutment, a highpressure piston cylinder working on said abutment and in said low-pressure cylinder respectively a valve controlling the flow of live steam to the high-pressure cylinder, a valve controlling a passage or passages leading from the high-pressure cylinder into the low-pressure cylinder, and an exhaust-valve for the latter cylinder; avalve-gear operating said valves to cause the engine to normally work compound, and means automatically changing the operation of said valvegear and valves to establish, under certain conditions and at a certain pointof the stroke, direct communication between the source of live-steam supply and the low-pressure cylinder through the high-pressure cylinder, to change the normal operation of the engine from compound to semicompound, for the purpose set forth.

7 9. In a compound engine comprising a lowpressure cylinder, a piston-abutment, ahighpressure piston cylinder working on said abutment and in said low-pressure cylinder respectively, a valve controlling the flow of live steam to the high-pressu re cylinder, a valve controlling a :passage or passages leading from the high-pressure cylinder into the low-pressure cylinder, andan exhaust-valve for the latter cylinder; a valve-gear operating said valves to cause the engine normally to work compound, and means operating antomatically for changing the operation of said valve-gear and valves to establish, at a certain point of the stroke of the high-pressure cylinder in starting, direct communication between the source of live-steam supply and the low-pressure cylinder through the highpressure cylinder, to change the normal operation of the engine from compound to semicompound, for the purpose set forth.

10. In a compound engine comprising alowpressure cylinder, a piston-abutment, a highpressure piston cylinder working on said abutment and in said low-pressure cylinder respectively, a valve controlling the flow of live steam to the high-pressure cylinder, a valve controlling a passage or passages leading from the high-pressure cylinder into the a rests low-pressure cylinder and an exhaust-valve for the latter cylinder; a valve-gear operating said valves to cause the engine normally to work compound, and means operating antomatically for changing the operation of the valve-gear and valves to establish during the normal operation of the engine and at a certain point of the stroke of the high-pressure cylinder, direct communication between the source of live-steam supply and the lowpressure cylinder through the high-pressure cylinder, to change the normal operation of the engine fromcompound to semicompound, for the purpose set forth.

11. In a compound engine comprising a lowpressure cylinder, a piston-abutment, a highpressure piston cylinder working on said abutment and in said low-pressure cylinder, respectively, a valve controlling the supply of live steam to the high-pressure cylinder, a valve controlling passages leading from the high-pressure cylinder into the low-pressure cylinder, and an exhaust-valve for the latter cylinder; in combination with a valve-gear operated from a moving element of the engine and actuating the valves to cause the engine to normally work compound, and

means operating automatically for changing the operation of said valve-gear and valves so as to establish, under certain conditions and at a certain point of the stroke, direct communication between the source of livesteam supply'and the low-pressure cylinder through the high-pressure cylinder, to change the normal operationof the engine from compound to semicomponnd, for the purpose set forth.

12. In a compoundengine comprising a lowpressure cylinder, a piston-abutment,a highpressure piston -cylinder working on said abutment and in said low-pressure cylinder respectively, a valve controlling the supply of live steam to the high-pressure cylinder, a valve controlling passages leading from the high-pressure cylinder into the low-pressure cylinder, and an exhaust-valve for the latter cylinder; a valve-gear operated from a mov-- ing element of the engine and actuatingthe valves to cause the engine to normally work compound, a governor influencing the operation of said valve-gear and valves so as to establish, under certain conditions and at a certain point of the stroke, direct communication between the source of live-steam supply and the low-pressure cylinder through the high-pressure cylinder, to change the normal operation of the engine from compound to semicompound, for the purpose set forth.

13. In a compound engine comprisinga lowpressure cylinder, a piston-abutment, a highpressure piston cylinder working on said abutment and in said low-pressure cylinder respectively; a valve controlling the supply of live steam to the high-pressure cylinder, a valve controlling a port or ports leading from said high-pressure cylinder into said lowpressure cylinder, an exhaust-valve for the latter cylinder, a valve gear for operating said valves to cause the engine to normally work compound, and a governor influencing the valve-gear and valves so as to establish, a certain point of the stroke of the high-pressure cylinder in overcoming inertia or when the speed of the engine drops below a normal speed, direct communication between the source of live-steam supply and the lo W-pressure cylinder through the high-pressure cylinder to change said normal operation from compound to semicompound, for the purpose set forth.

let. In a compound engine comprising a power-shaft, a low-pressure cylinder, a piston-abutment, a high-pressure piston-cylinder connected with said power shaft and working on said abutment and in said lowpressure cylinder respectively, a valve controlling the supply of live steam to the high pressure cylinder, a valve controlling ports leading from said high-pressure cylinder into the low-pressure cylinder, and an exhaustvalve for the latter cylinder; a valve-gear, an eccentric on the power-shaft operating said valve-gear to cause the engine to normally work compound, and a governor influencing the aforesaid eccentric to change, under cert-ain conditions and a certain point of the stroke, the operation of the valve-gear and valves so as to establish direct communication between the source of live-steam supply and the low-pressure cylinder through the high-pressure cylinder to change the normal operation of the engine from compound to semicompound, for the purpose set forth.

15. In a compound engine comprisinga lowpressure cylinder, a piston-abutment, a highpressure piston cylinder working on said abutment and in said low-pressure cylinder respectively, a valve in the head of the abutment controlling the supply of live steam to the high-pressure cylinder, a valve in the head of the latter cylinder controlling ports leading therefrom into the low-pressure cylinder, and an exhaust-valve in the head of said low-pressure cylinder controlling a passage or port leading therefrom; a valve-gear operating the aforesaid valves to cause the engine to normally work compound and means operating automatically for changing the operation of the valve-gear and valves to establish, under certain conditions and at a certain point of the stroke, direct communication between the source of live-steam supply and the low-pressure cylinder through the high-pressure cylinder to change said normal operation of the engine from compound to semicompound, for the purpose set forth.

16. In a compound engine comprisinga lowpressure cylinder, a piston-abutment, a highpressure piston cylinder working on said abutment and in said low-pressure cylinder respectively, a distributing-valve in the head of said abutment controlling a supply of live steam to the high-pressure cylinder, an oscillating intermediate valve in the head of the latter cylinder controlling a port or ports leading therefrom into the low-pressure cylinder, a rocking exhaust-valve in the head of said low-pressure cylinder and means for oscillating the intermediate valve through the exhaust-valve; a rock-shaft, connections between the same and the distributing and exhaust valves and means for rocking said shaft, for the purposes set forth.

17. In a compound engine comprising a power-shaft, a low-pressure cylinder, a piston-abutment, a high-pressure piston-cylinder working on said abutment and in said low-pressure cylinder respectively, a distrib uting-valve in the head of said abutment controlling the supply of live steam to the highpressure cylinder, an oscillating intermediate valve in the head of the latter cylinder controlling a port or ports leading therefrom into the low-pressure cylinder; a rocking exhaustvalve in the head of said low-pressure cylinder and means for oscillating the intermcdiate valve through the exhaust-valve; a roclc shaft, connections between the same and the distributing and exhaust valves, an eccentric on the power-shaft connected with said rockshaft and operating the valves to cause the engine to normally work compound, and a governor influencing the eccentric under certain conditions to change the amplitude of the rocking movements of the rock-shaft and therethrough the operation of the distributing-valve to establish direct communication between the source of live-steam supply and the low-pressure cylinder at a certain point of the stroke of the high-pressure cylinder to change the said normal operation of the engine from compound to semicompound, for the purposes set forth.

18. In a compound engine comprising alowpressure cylinder, a piston-abutment, a highpressnre piston cylinder working on said abutment and in said low-pressure cylinder, a cylindrical endwise-movable distributingvalve in the head of the abutment and controlling the supply of live steam to the highpressure cylinder, a discoidal oscillating intermediate valve in the head of said highpressure cylinder controlling a port or ports leading therefrom into the low-pressure cylinder, a cylindrical rocking exhaust-valve in the head of the low-pressure cylinder and means for oscillating the intermediate valve through the exhaust-valve; a rock-shaft and suitable connections between the same and the distributing and exhaust valves for imparting the described movements thereto, substantially as set forth.

19. In a compound engine comprising a power-shaft, alo w-pressure cylinder, apistonabutment, a high-pressure piston-cylinder working on said abutment and in said lowpressure cylinder, a cylindrical endwise-movable distributing-valve in the head of the abutment and controlling the supply of live steam to the high-pressure cylinder, a discoidal oscillating intermediate valve in the governor influencing the eccentric under certain conditions to vary the amplitude of the rocking motion of the rock-shaft and change the operation of the distributing-valve so as to establish at a certain point of the stroke of the high-pressure cylinder direct communication between the source of live-steam supply and the low-pressure cylinder to change said normal operation of the engine from compound to semicompound, substantially as and for the purposes set forth.

20. Ina compound engine comprisinga lowpressure cylinder, a piston-abutment, a highpressure cylinder working on said abutment and in said low-pressure cylinder respectively said abutment having formed therein a livesteam passage and two chambers one for the reception of the distributing-valve and the other serving as receiver, for the purpose set forth.

21. In a compound engine comprising alowpressure cylinder, a piston-abutment, a highpressure piston cylinder working on said abutment and in said low-pressure cylinder respectively, said abutment having formed therein a live-steam-supply passage and two concentric chambers of different areas, the outer chamber of greatest area acting as a receiver and the inner chamber of least area for the'reception of the steam-distributing valve, and means for draining the-receiving-cham- 'ber, substantially as and for the purpose set forth.

22. In a compound engine comprising a power-shaft, a low-pressure cylinder, a pistonabutment andahigh-pressure piston-cylinder working on said abutment; a pair of guideblocks in extension of the high-pressure cylinder, guides for guiding said blocks, a crosshead to which said guideblocks are connected, and a driving rod connecting the oross-head with a crank on the power-shaft, substantially as set forth.

23. In a compound engine comprising a power'shatt, a low-pressure cylinder, a pistonabutment, and a high-pressure piston-cylinder; guides carried by the low-pressure cylinder in extension thereof, a pair of guide-blocks carried by the high-pressure cylinder in extension thereof, a cross-head to which said guide-blocks are connected, and a drivingrod connecting said cross-head to a crank on the power-shaft, substantially as described.

24. In a compound steam-engine, a lowpressure cylinder, a piston-abutment, a highpressure piston-cylinder working on said abutment and in said low-pressure cylinder, said high-pressure piston-cylinder extended for connection with the crank-shaft beyond the steam area determined by the packing on said abutment; a self-packing distributingvalve working in a suitable chamber and having'its operating-stem located externally-of said chamber for connection with the valveoperati'ng device, an intermediate valve in the head of thehigh-pressure piston-cylinder, an exhaust-valve for the low-pressure cylinder and the valve-stem for said intermediate valve operated by said exhaust-valve located wholly within the steam area of the low-pres sure cylinder, said exhaust-valve having its stein externally of said steam area, substantially as set forth and for the purpose of dispensing with stu fling-boxes and glands for said parts.

25. In a compound steam-engine, a lowpressure cylinder, a piston-abutment, a highpressure piston cylinder working on said abutment and in said 1ow-pressure cylinder, said high-pressure piston-cylinder extended for connection with the crank-shaft beyond the steam area determined by the packing on said abutment; a self-packing distributingvalve working in a chamber and in the abutment, said valve having its operating-stem located externally of the valve-chamber and high-pressure piston-cylinder for connection with the valve-operatin g device, a semirotary expansion-valve in the head of the high-pressure piston-cylinder, a semirotary exhaustvalve for the low-pressure cylinder, and the valve-stem for the expansion-valve splined to said exhaust valve and located wholly within the steam area of the low-pressure cylinder, said exhaust-valve having its stem externally of said steam area, substantially as set forth and for the purpose of dispensing with stuffing-boxes and glands for said parts.

This specification signed and witnessed this 20th day of March, 1899.

MARGY L. WHITFIELD.

Witnesses:

J NO. R. TAYLOR, ARCHIBALD G. REEsE.