US2193822A

US2193822A - Multiple expansion engine

Info

Publication number: US2193822A
Application number: US250623A
Authority: US
Inventors: Knox Samuel Lippincot Griswold
Original assignee: Individual
Current assignee: Individual
Priority date: 1939-01-12
Filing date: 1939-01-12
Publication date: 1940-03-19
Anticipated expiration: 1957-03-19

Description

S. L. G. KNOX MULTIPLE EXPANS I ON EN GI N E March 19, 1940.

Filed Jan. 12, 1939 4 Sheets-Sheet 1 V41. v: "a

Q m E n R I I I I gwue rvbo o $.l-G. KNOX March 19, 1940.

S. L. G. KNOX MULTIPLE EXPANSION ENGINE Filed Jan. 12, 1939 4 Sheets-Sheet 2 March 19, 1940. s, O 2,193,822

MULTIPLE EXPANSION ENGINE Filed Jan. 12, 1939 4 Sheets-Sheet 3 March 19, 1940.- s. l..- e. KNOX 2,193,822

MULTIPLE EXPANSION ENGINE Filed Jan. 12, 1959 4 Sheets-Sheet 4 the present invention provides a system of steam distribution including a distributing valve by Patented Mar. 19, 1940 UNITED STATES PATENT. OFFICE Application January 12, 1939, Serial No. 250,623

14 Claims.

This invention relates to multiple expansion engines which are operated by the pressure of elastic fluids such as steam and in its more specific aspects to a system of steam distribution and auxiliary relief for compound engines of the steam reverse, type.

As conducive to a clearer understanding of the instant invention, reference is had to my prior Patent 1,845,288, granted February 16, 1932, which discloses a simple steam reverse engine designed to permit early cut-off. In such an engine a plurality of cylinders and a like number of valves are proposed, three cylinders and three valves being illustrated. As distinguished from older types of steam reverse engines in which each valve worked in conjunction with a particular cylinder, each valve works in conjunction with two sets of ports, of which one set admits steam to one cylinder and anotherset admits steam to a different cylinder. Thus for a three-cylinder engine, cut-off can be accomplished at approximately one-third of the stroke. For such a simple steam-reverse engine distribution of the steam maybe efiected in simple manner, as by the use of a double throttle or two throttle valves, steam being supplied by one throttle to those ends of all three valves which cause forward rotation, and by the other throttle to those ends of all three valves which cause reverse rotation. One such throttle valve arrangement is described and claimed in my prior Patent 1,850,209, dated March 22, 1932,

With a compound steam reverse engine incorporating the principles of early cut-off, as above discussed, complexities in distribution arise due to the fact that steam is admitted to the high pressure cylinder, from there passes to.

the receiver, and from the receiver goes to two low pressure cylinders so that the relativelyi simple distribution means of my above referred to patent is not feasible in a compound engine of the reversing type.

The present invention contemplates the provision of a novel system of steam distribution for a compound reversing engine having three cylinders and three valves by which steam is sent to those ends of all three valves and related ports which cause forward rotation, and to the same valves and ports, but with a difierent grouping thereof, for reverse rotation. More specifically,

which a compound engine of the type under discussion may be reversed, the steam exhausting from the high pressure cylinder into the receiver being carried back. to the distributing valve and passing through it, being directed through one set of canals leading from the distributing valve for one direction of rotation and through another set of canals from the distributing valve for the 5 other direction of rotation.

In. a compound engine of the character under consideration, all cylinders are usually provided with unifiow exhaust ports. The high pressure cylinder exhausts through these uniflow ports l0 intothe the receiver; the low pressure cylinders exhaust through their uniflow ports either to the atmosphere or to a condenser. However, if such were the only means of exhausting steam from the; cylinders, a low weight elliciency from the 1:5 engine would be obtained, because as soon as the piston on its return stroke closes the uniflow ports, steam will be trapped in the cylinder -;and thereupon compressed far above the admission point, unless excessive clearance is provided, 20 thereby increasing the stresses on the engine and pumping steam back into the main feedline with no advantage. For thisreason, ordinary' unifiow engines are frequently provided with additional exhaust ports which remain open much longer than the unifiow ports, eccentrics or cams and other mechanism of complicated nature being provided for their operation.

The present invention contemplatesfla system of auxiliary relief which does away with the requirement of eccentrics and like mechanism and, instead, uses the valves in conjunction with the one set of ports which do not control the direction in which the engine is running at the moment to provide auxiliary relief for that direction of rotation. Thus the desirable auxiliary relief is obtained with no extra parts Whatever.

With the engine running in one direction, instead of exhaust ceasing as soon as a piston returns a short distance from the exhaust end of its stroke and so cutting ofi' access of the steam trapped in the cylinder to the unifiow ports, the reverse ports from anothervalve connected with that same cylinder for operation of the engine in opposite direction open after the uniflow ports are closed and before there occurs objectionable compression of the steam trapped in the end of the cylinder into which the piston is moving. As the reverse ports for the high pressure cylinder are connected to the receiver through the valve of the distributing system, the invention provides that the auxiliary exhaust from the high pressure cylinder goes to the receiver, just as does the main exhaust, through the uniflow ports, and

that the auxiliary exhaust from the two low pressure cylinders goes to exhaust.

Other objects will be in part obvious and in part hereinafter pointed out in connection with the following analysis of this invention wherein is illustrated an embodiment of the invention in detail.

In the drawings Fig. 1 is a transverse section of a compound steam reverse engine in accordance with the invention, the section being taken through the port at the crank end of the engine which admits steam from one of the valves (valve a) to the high pressure cylinder;

Fig. 2 is a section generally along lines 2-2 of Fig. 1, the detail of the crank shaft, connecting rods, cross heads and the like being omitted as they form no part of the present invention;

Fig. 3 is a diagrammatic section view of the cylinders and valves illustrating the connections between the valves and cylinders for both directions of rotation;

Fig. 4 is a schematic diagram illustrating the path of steam distribution for one direction of rotation of the engine;

Fig. 5 is a schematic diagram illustrating the path of steam distribution for opposite rotation, or operation in reverse direction, of the engine;

Fig. 6 is a schematic diagram illustrating the distributing canals between the distributing valve and the cylinder valves;

Fig. 7 is an imaginary section through the cylinder valves and cylinders, being developed so that the center lines of the valves and cylinders lie in the same plane, and further illustrating, respectively, the relations of the pistons, valves, and eccentrics.

Referring now to the drawings wherein like reference characters designate like parts throughout the several views, the compound steam reverse engine in accordance with the present invention utilizes a high pressure cylinder conventionally arranged intermediate the low pressure cylinders A and B, the relative location of the cylinders being indicated in Fig. 1. Arranged in the cylinder block 5, and at a convenient location therein are the valve chests of the valves 0., b and 0 related to the cylinders as indicated, and also the valve chest of a distributing valve d, which latter is disposed sidewardly of the valve a. A cover plate I!) is suitably secured across the top of the cylinder block and forms therewith an enclosure providing a receiver space through which extends the chests of the valves a, b, c, d. The head ends of the valve chests for the valves :1, b and c is provided with suitable manifold caps or covers (not shown) which carries steam to the ends of valves a, b and c. As above indicated, Fig. 1 is a section taken through one of the ports at the crank end of the engine which connects the valve a and the high pressure cylinder C and through a transversely aligned port which connects either of the valves b, c with cylinder B. Due to difficulty in illustrating, the distributing canals between valve d and the cylinder valves (1, band 0 are not shown in Fig. 1, but are schematically shown in the succeeding figures to be referred to.

In Fig. 2 the distributing valve and the cylinder valve a, together with the chests in which they operate, are shown in section, the valve 2) being shown partly in elevation. Each cylinder is provided with uniflow exhaust ports intermediate its ends, of which the uniflow exhaust ports Ba: of cylinder 13 are shown.

The valves a, b and c are operated through valve stems 15 in conventional manner by eccentrics (not shown) which may either be mounted on the engine crank shaft or on a separate shaft driven by the crank shaft synchronously therewith. The piston rods ll of pistons PC, PB and PA drive the engine crank shaft in either forward or reverse direction, depending on the direction of rotation of the engine. As the cranks, connecting rods, cross heads, and like parts through which the valve stems and piston rods are connected to crank shaft and eccentric shaft, if separate eccentric shaft is used, may be regarded as conventional, no detailed description will be here given of such parts, it being understood, however, that the valve eccentrics (or cranks) are 120 apart, the cylinder cranks are 120 apart, and that each valve eccentric has suitable angular relationship with the crank of the cylinder which it operates for forward and reverse rotation, as typically illustrated in Fig. '7 to be referred to hereinafter.

The cylinder valves a, b, a may take various forms and may also partake of various motions. In the ilustrated embodiment, which may be taken as exemplary of one type of valve which provides satisfactory operation, the valves a, b and c are of tubular or sleeve-like form, open from end to end, and are given straight reciprocatory motion by the stems I secured to the valves adjacent their crank ends. The outer diameter of the intermediate portion of each valve is reduced, thereby to provide, in conjunction with its encircling sleeve 19, an annular steam space [8 of substantial length. The valves each operate in the sleeve H), the sleeves being pressfitted into bored holes in the walls which make up the cylinder block casting. The arrangement is such that steam admitted to an end of the valve may pass through the interior thereof to the other end, and that steam admitted to the annular space H! between the valve and its fixed sleeve l9 may pass the length of said space.

The distributing valve generally indicated at d operates in a sleeve 20 press-fitted into the cylinder block casting. Sleeve 20 is of substantial length and is provided along its length with a plurality of annular series of openings 2|, 22, 23, 24, 25, 25, 21. The central openings 24 register with the boiler-steam supply opening 30 into which a steam line from the boiler is adapted to be connected. Sleeve openings 2l23 inclusive and 252l inclusive register with annular channels in the valve chest forming a part of the cylinder block, of which

channels

22a and 26a communicate directly with the receiver space; channels 23a. and 25a communicate with canals running to valves a and 0, respectively; channel 2 la communicates with a canal running to valves 1) and c; and channel 27a communicates with a canal running to valves (1 and b, all as will be described hereinafter.

The valve proper consists of a plurality of pistons which, in the construction shown, are four in number, the pistons being suitably spaced from each other and being rigidly secured to a stem 29 which extends through the center of the pistons. The spacing between the valve pistons is such that in the mid or neutral position of the valve the adjacent faces of the intermediate valve pistons 3I, 32 provide a passage generally in alignment with steam inlet opening 30 and sleeve openings 24. The length of each of the pistons 3|, 32 is such that they cut olf communication between sleeve openings 24 and adjacent openings 23, 25, whereby no steam can flow to either of said openings. The left-end piston 33, when the valve is in its neutral posi tion, serves to cut off communication between the channel 22a going to the receiver and the channel Zia delivering to valves b and c. Similarly, the right-end piston 34 cuts off communication between the channel 26a going to the receiver and the channel Z'la delivering to valves (1 and b.

To the left-end piston 33 is secured ayoke 35, to which is connected one end of a link 35, the other end being secured as by a pin 31 to operating shaft 38, which can be rocked throughout a limited arc to either side of its mid or neutral position. The shaft 38 is adapted to be rocked by a handle (not shown) under the control of an operator, rocking movement in one direction causing movement of distributing valve d to the left for reverse rotation of the engine, with rocking movement in opposite direction actuating valve d to the right thereby to cause forward operation of the engine.

Considering now the arrangement of ports between valves a, b, c and cylinders A, C, B, the compound engine under description incorporates the principles disclosed in my prior Patent 1,845,288 in that it provides two sets of ports in conjunction with each valve, one set of ports admitting steam to one cylinder, and. the other set of ports admitting it to a different cylinder. Ap-

will be apparent from Fig. 3, such being a valve, cylinder and port diagram looking into the head end of the cylinders.

Valves a, b and c are arranged, respectively, above the cylinders A, C, and B, of which the high pressure cylinder C is arranged intermediate the low pressure cylinders A and B. For operation of the engine in one direction (reverse direction), valve a supplies steam tothe high pressure cylinder C through outside port aC; valve 17 supplies steam to low pressure cylinder A through the outside port 17A; and valve 0 sup a plies steam to low pressure cylinder B through outside port 03.

From the aforesaid designation of ports as outside ports, it is to be understood that for the particular engine under description steam is plied to the cylinders for forward operation. 60'

During forward operation, the outside ports aC, bA and 03 act as auxiliary relief ports. The features of auxiliary relief of the cylinders A, G and B through inside ports aA, 12B and c0, during reverse rotation, and of auxiliary relief of the cylinders through outside ports :10, bA and 0B during forward operation will be discussed hereinafter.

Reference has been made previously to the fact that in a simple engine-as disclosed in my Patent 1,845,288, it is only necessary to employ a double throttle valve, or two throttle valves, for distributing the steam to those ends of all three valves which cause forward rotation or to those ends of all three valves which cause reverse rotation. In a compound engine, however, due to the fact that the high pressure cylinder exhausts to the receiver and that receiver steam is sup-' plied to the low pressure cylinders, such an arrangement is not feasible and accordingly a distributing valve, such as the valve at, above referred to, is utilized in conjunction with a system of steam canals to obtain the desired reversal of operation. Such a system of distribution for reverse engine operation is diagram matically illustrated in Fig. 4, wherein dis the distributing valve which directs boiler steam through canal 2 to valve 01. which supplies cylinder C through outside port a0. Cylinder C exhausts through unifiow exhaust ports to receiver R, from whence the steam passes through canal 3 back to distributing valve d, which directs it through canal 4 to valve b, and also through canal 15 to valve 0. From valve 2) steam passes to low pressure cylinder A through outside port 19A, and from Valve 0 steam passes to cylinder'B through outside port cB.

Referring now to Fig. 5, such being a diagrammatic representation of the steam distribution with the engine operating in forward direction, boiler steam is sent by distributing valve (1 to valve 0 through canal 6, and from valve 0 passes to high pressure cylinder C through inside port cC. Exhaust from cylinder C passes to receiver R, from whence it returns to distributing valve at through canal 1, valve 03 then directing the steam through canal 8 to valve a and through canal 9 to valve b. Steam from valve a passes to cylinder A through inside port aA, with steam from valve 27 passing to cylinder B through inside port 1113.

It will be appreciated from the foregoing that there is provided a system of distribution whereby steam exhausting into the receiver from the high pressure cylinder is returned to and through the distributing valve, with the distributing valve thereupon directing steam through one set of ports to the cylinders for operation of the engine in one direction and through another set of ports for operation of the engine in the reverse direction. 1

Referring to Fig. 6 wherein is illustrated a typical system of canaling between the distributing valve d, as illustrated in Fig. 1, and the cylinder valves (1, b and c, the distributing valve d is shown in its left position which, in the con struction illustrated, will cause the engine to operate in reverse direction. Valve piston 35 is in position to establish communication between steam inlet 30 and channel 230,, into which opens one end of canal 2 referred to in Fig. 4, the other end of the canal opening into the end of valve a and supplying high pressure steam thereto. Similarly, valve piston 33 has established communication between the channel 22a which opens to receiver (line 3 in Fig. 4 indicates this connec-' tion) and channel 2 la into which opens one end of the combined canals 4, 5, the other or branched ends thereof delivering to the outer ends of both valves 1) and 0, whereby receiver steam may be supplied to valves b and 0. Valve piston 32 is in position closing communication between boiler steam opening 3!! and channel 25c with which canal 6 to the inside of valve 0 connects, and, similarly, valve piston 3 is in position closing communication between channel 26a which opens full line arrows in Fig. 6.

- valves for forward operation of the engine.

Full movement of distributing valve d to the right results in operation of the engine in forward direction, by supplying boiler steam through canal 6 and inside of valve 0 to the high pressure cylinder C, and by supplying low pressure cylinders A and B with steam from the receiver through canals B and 9, to the inside of valves (1 and b, respectively. The path of steam flow for forward rotation is indicated by the dot-dash arrows,

Referring now to Fig. 7, such being a schematic layout of the valves, pistons, and their connecting rods and eccentrics developed to illustrate the relation of piston and valve position to port location, the piston PA of the low pressure cylinder A is moving to the left, the eccentrics moving anti-clockwise for reverse direction, as indicated by the full line arrows related to each of the connecting rods. As will be seen from the position of valve b which supplies steam to cylinder A for reverse rotation, right-hand admission is taking place through righthand outside port bA, the valve 1) closing righthand inside port b3 and lefthand outside port bA. Valve 2), however. has opened lefthand inside port bB leading to cylinder B, as will be referred to hereinafter.

Piston PC is moving to the right, its valve a for reverse rotation moving to the left, and having just cut off lefthand admission through lefthand outside port aC. Righthand outside admission port (LC is closed, but righthand inside port 00 will open shortly as valve 0 is moving towards the right.

Piston PB is moving towards the left with its valve 0 for reverse rotation moving to the right. Piston PB is approaching the end of its stroke, the righthand and lefthand outside admission ports cB being both closed by valve 0. Since piston PB has closed the uniflow exhaust ports, it would normally compress the steam trapped between its working face and the head end of the cylinder, but the auxiliary relief to be described functions to prevent this condition.

The Fig. '7 illustration also provides basis for describing the forward operation of the engine, for which the eccentrics move clockwise as indicated by the dotted line arrows related to the associated connecting rods.

Piston PA moving to the right is substantially at the end of its exhaust stroke, with admission about to take place through the righthand inside port aA, with its valve a for forward rotation moving to the right. All other ports are losed.

Piston PC of the high pressure cylinder C is moving to the left toward the exhaust end of its stroke, its valve 0 for forward rotation, which is moving to the left, having cutoff admission through righthand inside port 0C. Righthand outside port :10 is closed by valve a, left-hand inside port 0C is closed by valve 0, and lefthand outside port a0 is closed by valve a but will open shortly as valve a is moving to the right.

Piston PB of the low pressure cylinder B is moving to the right and is still receiving steam through the lefthand inside port bB, its valve 1) for forward rotation moving towards the right and about to cut off admission. All other inside and outside ports are closed.

By further reference to Fig. 7, it will be seen that the canals leading from and to the distributing valve d (not shown in this figure) have been indicated in their approximate position so as to supply steam to the ends of the valves a, b and c for reverse operation, and to the inside of said Thus canal 2 delivers to the end of valve a, with canals 4, 5 delivering to the ends of valves 1) and 0, respectively, as in Figs. 4 and 6. In like manner, canal 6 is shown as delivering steam to the inside of valve 0 (space I8), canal 8 is delivering to the inside of valve a, and canal 9 to the inside of valve b, all as indicated in Figs. 5 and 6.

Considering now the exhaust features of a compound engine as described, each of the cylinders is provided with uniflow exhaust ports (see Fig. '7) exhaust ports Cx from the high pressure cylinder C leading directly into the receiver space, and unifiow exhaust ports A1: and Bar from the low pressure cylinders A and B going to atmosphere or condenser. As pistons PC, PA and PB move toward the exhaust end of their respective strokes, they cover their unifiow exhaust ports so that if such ports were the only means provided to exhaust steam from the cylinders, steam would be trapped in that portion of the cylinders into which the pistons are moving. Usually, uniflow engines of the character under consideration are provided with additional exhaust ports which remain open much longer than the uniflow ports, the additional exhaust ports requiring eccentrics and other mechanism for their operation.

The present invention provides auxiliary relief of cylinders A, B and C by the same means which effect steam distribution as aforesaid. Thus, valves a, b and c act in conjunction with the one set of the ports and canals through which steam is not being admitted to the cylinder for a given direction of operation as auxiliary relief means for that direction of engine operation. For example, if the engine is running in reverse, steam being accordingly supplied by valves a, b and c to cylinders C, A and B, respectively, through outside ports aC, DA and 0B, the arrangement is such that auxiliary relief is provided through the valves, canals and the inside ports which constitute the distributing means to the cylinders for forward operation. Similarly, if the engine is operating in forward, auxiliary relief is provided through the valves, canals and outside ports through which the steam is distributed for re verse operation.

The arrangement will be understood from an analysis of the Fig. 6 diagram, where it will be remembered valve d is in its lefthand position for reverse operation of the engine, in which positlon valve a supplies steam to cylinder C through outside port aC; valve 1) supplies steam to low pressure cylinder A through outside port DA; and valve 0 supplies steam to low pressure cylinder B through outside port cB. Under this condition of operation, auxiliary relief for the cylinders is obtained as follows:

Auxiliary relief for the high pressure cylinder C is obtained through inside port cC, valve 0 and thence to the receiver through canal B, distributing valve d, and channel 26a which opens to receiver, as indicated by the dotted line arrows. Auxiliary relief for low pressure cylinder A is provided through inside port aA, valve 11, canals 8, 9, and distributing valve d whose right end opens to exhaust. Auxiliary relief for low pressure cylinder B is provided through port 123, valve 1), canals 8, 9, distributing valve d, and similarly to exhaust. The paths of auxiliary relief from cylinders A and B are also indicated with dotted line arrows.

With the valve d in its righthand position for forward operation, auxiliary relief for high pressure cylinder C is provided through outside port (10, valve a, canal 2, distributing valve d to the B, valve 0, canals 5, and similarly to exhaust through distributing valve (1. The path of steam liow for auxiliary relief of the cylinders when the engine is operating in forward direction is inch-- cated by the dash X arrows appearing in Fig. 6.

The manner in which valves a, b and c operate in conjunction with the inside and outside ports to provide such auxiliary relief will be further realized from a consideration. of '7. Referringto Fig. '7, it will be seen that for reverse operation piston PC is moving to the right and has covered the unifiow exhaust ports 09:, with valve 0, which would control admission to cylinder C if the engine were operating in forward direction, moving to the right. valve 0 in that direction will uncover righthand inside port cC, the arrangement being such that the said inside port cC will be uncovered upon piston PC completing about two-thirds of its stroke. When so uncovered, auxiliary relief is provided through the inside of valve 0, canal E and to r ceiver.

in Fig. '7 piston PB, which is moving to the left towards the exhaust end of its stroke, would normally compress steam in the head end of the cylinder following closing of the uniflow exhaust ports Br. However, valve b, which controls admission of steam to cylinder B for forward operation, has uncovered leithand inside port DB, so that auxiliary relief of cylinder B is taking place through said inside port 1313, valve 1), canals 8, 9, valve d. to exhaust (see Fig. 6).

While cylinder A is obtaining no auxiliaryreliei in the Fig. 7 diagram, it will be understood that as piston PA nears the end of its leftwise movement, valve a will uncover the lefthand inside port (LA, to provide auxiliary relief through said inside port on, valve a, canals 8, 9, distributing valve d, to exhaust. v

For forward operation and with the piston PC ofthe high pressure cylinder C moving to the left, and nearing the end of its exhaust stroke, cylinder C is about to receive auxiliary relief, as valve a, which is moving to the right, is about to uncover lefthand outside port aC, so thatthe cylinder may exhaust through canal 2 to the receiver. In like manner cylinder B will .obtain auxiliary relief when its valve 0 for forward rotation, which is moving to the left, uncovers the righthand outside port 0B. Cylinder A is obtaining auxiliary relief in its position as shown through rghthand outside port bA, the valve b moving it the right shortly to cut oif this auxiliary' relief.

By reference to Figs. 3 and 7, it will be understood that each set of outside and inside ports at the ends of the valves has a common opening through the cylinder wall. From this common opening, the outside ports each branch outwardly toward the outer end of the valve, and the inside ports each branch inwardly towards the inside of the valve. Means other than a common opening for the related sets of ports may be utilized, such as individual openings but with the ports of a set connected intermediate their ends.

With the above arrangement, auxiliary or additicnal relief beyond that provided by the uniflow exhaust ports is provided so that no ob- Someiurther movement of the cylinders into which the pistons are moving can occur, and the valves, ports, and canals which provide inthe first instance the means for distributing steam to the cylinders for either forward or reverse operation of the engine also have the additional function of providing for auxiliary exhaust. ficiency of the engine (weight per horse power) is increased, the requirement for extra ports, parts or other mechanism to effect auxiliary relief is obviated, and simple and certain operation is assured.

While in the foregoing analysis of the invention, the relief of the. cylinders obtained through the sets of ports and canals through which steam is not being supplied to the cylinders for a given Accordingly the weight efdirection of engine operationhas been referredv to and designated as auxiliary to the main or principal exhaust obtained through the uniflow exhaust ports, the sets of ports and canals as aforesaid may and can be utilized as the sole means of exhausting the cylinders, as in engines designed 'for' specialized purposes where high speed is not Of importance, and the claims are to be interpreted accordingly. It will also be expressly understood that'the engine as described can be operated by, the pressure of elastic fluids other than steam, and that where the word steani is used throughout the specification and in the claims, such use is made for convenience and is intended to designate and embrace all formsof elastic fiuids'ca'pable of operating engines of the character herein described.

As many changes could be made in carrying out the above construction without departing from the scope of the invention, it is intended that all matter contained or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

1. A compound steam reverse engine comprising a high pressure cylinder, a receiver into which the high pressure cylinder exhausts, a plurality of low pressure cylinders adapted to receive steam from the receiver, control valves each connected to the cylinders by two sets of ports, of which oneset connects a valve to one cylinder and the other set connects the same valve to a different cylinder, each valve being so related to-the ports'connecting it with the cylinders as aforesaid as to supply steam to the cylinders through one set of ports only for one direction of engine operation and thru the other set of ports only for the opposite direction of engine operation, and distributing means operative to direct high pressuresteam to the one of the two valveszcontrolling the high pressure cylinder and receiver steam to the one of the two valves controlling each low pressure cylinder for" the given direction of engine operation.

2. A compound steam reverse engine compris--- through one set of ports onlyfor one direction ofengine operation and thru the other set of ports only for the opposite direction of engine operation, and distributing means operative to directl high pressure steam to the one of the two valves controlling the high pressure cylinder and receiver steam to the one of the two valves controlling each low pressure cylinder for the given direction of engine operation.

3. A compound steam reverse engine comprising a high pressure cylinder, a receiver into which the high pressure cylinder exhausts, a plurality of low pressure cylinders adapted to receive steam from the receiver, control valves each connected to the cylinders by two sets of ports, of which one set connects a valve to one cylinder and the other set connects the same valve to a different cylinder, each valve being so related to the ports connecting it with the cylinders as aforesaid as to supply steam to the cylinders through one set of ports only for one direction of engine operation and through the other set of ports only for the opposite direction of engine operation, and means includinga distributing valve operative to direct high pressure steam to the one of the two valves controlling the high pressure cylinder and receiver steam to the one of the two valves controlling each low pressure cylinder for the given direction of engine operation.

4. A compound steam reverse engine comprising a high pressure cylinder, a receiver into which the high pressure cylinder exhausts, a plurality of low pressure cylinders adapted to receive steam from the receiver, control valves each connected to the cylinders by sets of outside and inside ports, of which the outside ports connect a valve to one cylinder and the inside ports connect the same valve to a diiierent cylinder, each valve being so related to the ports connecting it with the cylinders as to supply steam to the cylinders through one set of ports only for one direction of engine operation and through the other set of ports only for the opposite direction of engine operation, and means including a distributing valve operative to direct high pressure steam to the one of the two valves controlling the high pressure cylinder and receiver steam to the one of the two valves controlling each low pressure cylinder for the given direction of engine operation,

5. A compound steam reverse engine comprising a high pressure cylinder, a receiver into which the high pressure cylinder exhausts, a plurality of low pressure cylinders adapted to receive steam from the receiver, control valves each connected to the cylinders by two sets of ports, of which one set connects a valve to one cylinder and the other set connects the same valve to a different cylinder, each valve being so related to the ports connecting it with the cylinders as aforesaid as to supply steam to the cylinders through one set of ports only for one direction of engine operation and through the other set of ports only for the opposite direction of engine operation, and means for distributing steam to the cylinders including a distributing valve and two sets of steam passages extending therefrom to the control valves, of which one set of passages connects the distributing valve with the one of the two valves controlling the high pressure cylinder and the receiver with the one of the two valves controlling each low pressure cylinder for a given direction of engine operation, the other set of passages connecting the distributing valve with the other of the two valves controlling the high pressure cylinder and the receiver with the other of the two valves controlling each low pressure cylinder for the opposite direction of engine operation.

6. A compound steam reverse engine comprising a high pressure cylinder, a receiver into which the high pressure cylinder exhausts, a plurality of low pressure cylinders adapted to receive steam from the receiver, control valves each connected to the cylinders by sets of outside and inside ports, of which the outside ports connect a valve to one cylinder and the inside ports connect the same valve to a different cylinder, each valve being so related to the ports connecting it with the cylinders as to supply steam to the cylinder through one set of ports only for one direction of engine operation and through the other set of ports only for the opposite direction of engine operation, and means for distributing steam to the cylinders including a distributing valve and two sets of steam passages extending therefrom to the control valves, of which one set of passages connects the distributing valve with the one of the two valves controlling the high pressure cylinder and the receiver with the one of the two valves controlling each low pressure cylinder for a given direction of engine operation, the other set of passages connecting the distributing valve with the other of the two valves controlling the high pressure cylinder and the receiver with the other of the two valves controlling each low pressure cylinder for the opposite direction of engine operation.

7. A compound steam reverse engine comprising a high pressure cylinder, a receiver into which the high pressure cylinder exhausts, a plurality of low pressure cylinders adapted to receive steam from the receiver, control valves each connected to the cylinders by two sets of ports, of which one set connects a valve to one cylinder and the other set connects the same valve to a difi'erent cylinder, each valve being so related to the ports connecting it with the cylinders as aforesaid as to supply steam to the cylinders through one set of ports only for one direction of engine operation and through the other set of ports only for the opposite direction of engine operation, and means for distributing steam to the cylinders, including a distributing valve, means for actuating the valve to one of two positions, and two sets of steam passages extending from the distributing valve to the control valves, the distributing valve in one position directing through one set of passages high pressure steam to one of the two valves controlling the high pressure cylinder and receiver steam to the one of the two valves controlling each low pressure cylinder for a given direction of engine operation, the distributing valve in its other position directing through the other set of passages high pressure steam to the other of the two valves controlling the high pressure cylinder and receiver steam to the other of the two valves controlling each low pressure cylinder for the opposite direction of engine operation.

8. A compound steam reverse engine comprising a high pressure cylinder, a receiver into which the high pressure cylinder exhausts, a plurality of low pressure cylinders adapted to receive steam from the receiver, control valves each connected to the cylinders by sets of outside and inside ports, of which the outside ports connect a valve to one cylinder and the inside ports connect the same valve to a different cylinder, each valve being so related to the ports connecting it with the cylinders as to supply steam to the cylinders through one set of ports only for one direction of engine operation and through the other set of ports for the opposite direction of engine operation, and means for distributing steam to the cylinders including a distributing valve, means for actuating the valve to one of two positions,

- and two sets of steam passages extending from v the distributing valve to the control valves, the

distributing valve in one position directing through one set of passages high pressure steam to one of the two valves controlling the high pressure cylinder and receiver steam tothe one of the two valves controlling each low pressure cylinder for a given direction of engine operation,

the distributing valve in its other position directing through the other set of passages high pressure steam to the other of the two valves controlling the high pressure cylinder and receiver steam to the other of the two valves controlling each low pressure cylinder for the opposite direction of engine operation.

9. A compound steam reverse engine comprising a high pressure cylinder, a receiver into which the high, pressurecylinder exhausts, a plurality of low pressure cylinders adapted to receive steam from the receiver, the cylinders being each provided with unifiow exhaust ports, pistons operating in the cylinders, control valves each 'connected to the cylinders by two sets of ports, of which one set connects a valve to one cylinder and the other set connects the same valve to a different cylinder, each valve being operative to supply steam to the cylinders which it controls through only one set of ports for a given direction of engine operation and through only the other set of ports for the opposite direction of engine operation, the arrangement being such that the sets of ports through which steam is not being supplied to the cylinders for the given direction of engine operation function as auxiliary relief ports for the cylinders, and distributing means operative to distribute steam to the cylinders through said control valves andthe one set of ports connecting each valve to a cylinder for the given direction of engine operation, said. distributing means being also operative to connect the cylinders to a lower pressure stage through said ports when the latter function as auxiliary relief ports.

10. A compound steam reverse engine comprising a high pressure cylinder, a receiver into which the high pressure cylinder exhausts, a pluraiity of low pressure cylinders adapted to receive steam from the receiver, the cylinders being each provided with uniflow exhaust ports, v

operative to supply steam to the cylinders which it controls through only one set of ports for a given direction of engine operation and through only the other set of ports for the opposite direc tion of engine operation, the arrangement being such that the sets of ports through which steam is. not being supplied to the cylinders for the given direction of engine operation function as auxiliary relief ports for the cylinders, means operative to direct high pressure steam to the one of the two valves controlling the high pressure cylinder and receiver steam to the one of the two valves controlling each low pressure cylinder for the given direction of engine operation, said means being also operative to connect said cylinders to a lower pressure stage through said ports when the latter function as auxiliary relief ports.

11. A compoundsteam reverse engine comprising a high pressure cylinder, a receiver into which the high pressure cylinder exhausts, a plurality of low pressure cylinders adapted to receive steam from the receiver, the cylinders being each provided with uniflow exhaust ports,

pistons operating in the cylinders, control valves each connected to the cylinders by twosets of ports, of which one set connects a valve to one cylinder and the other set connects the same valve to a different cylinder, each valve being operative to supply steam to the cylinders which it controls through only one set of ports for one direction of engine operation and through only the other set of ports for the opposite direction of engine operation, the arrangement being such that the sets of ports through which steam is not being supplied to the cylinders for the given direction of engine operation function as auxiliary relief ports for the cylinders, distributing means operative to distribute steam to the control valves, said means including a distributing valve movable to one of two positions and two sets of canals connecting the distributing valve and said control valves, the distributing valve in one position being operative to direct through one set of canals high pressure steam to the one of the two valves controlling the high pressure cylinder and receiver steam to the one of the two valves controlling each low pressure cylinder for the given direction of engine operation,

the distributing valve in its other position be ing operative to direct through the other set of canals steam to the other of said valves controlling the cylinders for the opposite direction of engine operation, said distributing valve being rality of low pressure cylinders adapted to receive steam from the receiver, pistons operating in the cylinders, control valves each connected to the cylinders by two sets of ports, of which one set connects a valve to one cylinder and the other set connects the same valve to a different cylinder, each valve being operative to supply steam to the cylinders which it controls through only one set of ports for one direction of engine operation and through only the other set of ports for operation in opposite direction, the arrangement being such that the sets of ports through which steam is not being supplied to the cylinders for a given direction of engine operation function as exhaust ports for the cylinders, and'means operative to direct high pressure steam to the one of the two valves controlling the high pressure cylinder and receivers'team to the one of the two valves controlling each low pres sure cylinder for the given direction of engine operation, said'means being also operative to connect the cylinders to a lower pressure stage through said ports when the latter function as exhaust ports.

13. A compound steam reverse engine comprising a high pressure cylinder, a receiver into which the high pressure cylinder exhausts, a plurality of low pressure cylinders adapted to receive steam from the receiver, pistons operating in the cylinders, control valves each connected to the cylinders by two sets of ports, of which one set connects a valve to one cylinder and the other set connects the same valve to a different cylinder, each valve being operative to supply steam to the cylinder which it controls through only one set of ports for one direction of engine operation and through only the other set of ports for operation in opposite direction, the arrangement being such that the sets of ports through which steam is not being supplied to the cylinders for a given direction of engine operation function as exhaust ports for the cylinders, and means operative to direct high pressure cylinder and receiver steam to the one of the two valves controlling each low pressure cylinder for the given direction of engine operation, said means being also operative to open the high pressure cylinder to the receiver and the low pressure cylinders to exhaust through said ports when the latter function as exhaust ports.

14. A compound steam reverse engine comprising a high pressure cylinder, a receiver into which the high pressure cylinder exhausts, a plurality of low pressure cylinders adapted to receive steam from the receiver, pistons operating in the cylinders, control valves each connected to the cylinders by two sets of ports, of which one set connects a valve to one cylinder and the other set connects the same valve to a difierent cylinder, each valve being operative to supply steam to the cylinder which it controls through only one set of ports for one direction of engine operation and through only the other set of ports for operation in opposite direction, the arrangement being such that the sets of ports through which steam is not being supplied to the cylinders for a given direction of engine operation function as exhaust ports for the cylinders, and means for distributing steam to the valves and thence to the cylinders.

SAMUEL LIPPINCOTT GRISWOLD KNOX.