US3759141A

US3759141A - Steam engine

Info

Publication number: US3759141A
Application number: US00212564A
Authority: US
Inventors: J Zibrun
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-12-27
Filing date: 1971-12-27
Publication date: 1973-09-18
Anticipated expiration: 1990-09-18

Abstract

A novel multi-cycle compound steam engine having novel means for providing a double use of steam and wherein the steam on opposite sides of a reciprocating piston having recti-linear movements in a cylinder may be pressure equalized and wherein the maximum amount of high pressure steam may be efficiently employed. Said piston having separate connected terminal heads with a close fitting working engagement with the cylinder wall, and wherein the body of the piston is of less diameter than the heads so that the steam chamber is provided between the heads and between the cylinder wall and the piston body, so that the steam chamber is divided into two separate compartments; and having steam compartments within the cylinder between the ends thereof and the adjacent heads of the piston; said engine being optionally usable as a double engine, or as a simple engine, and which has novel valve means as described.

Description

United States Patent [191 Zibrun 1 [451 Sept. 18,1973

1 1 STEAM ENGINE [76] Inventor: Joseph Zibrun, 1741 W. 33rd St.,

Chicago, 111.

(22] Filed: Dec. 27, 1971 [21] Appl. No.: 212,564

[52] U.S.Cl ..9l/20,91/164,91/23l Primary ExaminerPaulE. Maslousky Attorney-John F. Brezina et a1.

[57} ABSTRACT A novel multi-cycle compound steam engine having novel means for providing a double useof steam and wherein the steam on opposite sides of a reciprocating piston having recti-linear movements in a cylinder may be pressure equalized and wherein the maximum amount of high pressure steam may be efficiently employed. Said piston having separate connected terminal heads with a close fitting working engagement with the cylinder wall, and wherein the body of the pistonis of less diameter than the heads so that the steam chamber is provided between the heads and between the cylinder wall and the piston body, so that the steam chamber is divided into two separate compartments; and having steam compartments within the cylinder between the ends thereof and the adjacent heads of the piston; said engine being optionally usable as a double engine, or as a simple engine, and which has novel valve means as described.

4 Claims, 16 Drawing Figures PATENTEDSEH ems $759,141

' sum 1 or 7 SHEET 2 [IF 7 PATENTEB SEN 8l975 .1 STEAM ENGINE This invention relates to improvements in steam engines and more particularly to those of the simple engine type. One object is to provide a simple engine type having many of the advantages of the compound engine, such as triple expansion and other multiple expansion engines, without having most of the disadvantages inherent in such multiple expansion types.

Among the specific advantages present in the instant engine are. the economical use of fuel, low maintenance, saving of steam, economical cost of manufacture, accessibility of structural parts for repair or replacement, and a high degree of efficiency generally, and the provision of an engine adapted for operation at high or low speed and equally well operable under light, medium, or heavy load. A further object is to provide a simple steam engine wherein a double use of the steam may be effected, one wherein the steam upon opposite sides of the piston withinthe cylinder may be pressure equalized, and one wherein for extra power and maximum load the maximum amount of high pressure steam may be employed, the provisions herein enumerated being manually selective by the operator and dependent upon the nature of the work in hand.

A still further object is to provide a simple steam engine having a cylinder provided with a piston having rectilinear movement therein, said piston provided with terminal heads having close fitting working engagement with the cylinder wall, the body of the piston being of materially less diameter than the heads so that a steam chamber is formed between the cylinder wall and piston body between said heads, piston rings being provided within the cylinder about the piston body which divide this steam chamber into two separate compartments, these compartments receiving and exhausting steam during the normal operation of the piston, steam compartments being also fonned within the cylinder between the ends thereof and the adjacent heads of the piston.

Other advantages and ob jects of my engine are:

a. to provide a novel, multi-cycle compact compound steam engine which is unique in design inwhich the moving partsare relatively easily accessible for repairs or servicing; which can beused either as a simple ene. and which includes two steam control valves, and only one of which valves may be used at one time depending on the requirements of the work.

Other objects, novel features and advantages of ar rangement, construction and design comprehended by the invention are hereinafter more fully pointed out or made apparent from the following description of a preferred embodiment as illustrated in the accompanying drawings wherein like reference characters denote corresponding parts throughout.

DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a side view of a steam engine, with parts broken away, embodying the features of the instant invention.

FIG. 2 is a top plan view of the engine of FIG. 1.

FIG. 3 is a longitudinal vertical central sectional view through FIG. 2 on the line 3-3.

FIG. 4 is a horizontal cross sectional view through FIG. 3 on the line 4-4.

' FIG. 5 is a vertical cross sectional view through FIG. 3 on the line 5-5.

FIG. 6 is'a view similar to FIG. 5 but on the line 66 of FIG. 3.

FIGS. 7, 8, and 9 are vertical cross sectional views taken respectively on the line 7--7, 8-8, and 9-9 of FIG. 3.

FIG. 10 is a view in side elevation of the slide valve employed.

FIGS. 11 and 12 are views similar to FIG. 3 but with certain parts in altered positions.

gine or a double engine using only one piston and one I cylinder; and which includes a novel and modified piston valve;

b. which is selectively changeable so as to change of operation from one single engine to a double engine according to work requirements; Y

c. to provide a novel engine which has structural means whereby the steam enters at the approximate center of the cylinder and may be exhausted at either end of the cylinder, and in which the piston mounted in the cylinder provides two separate and independent steam chambers, each working independently to supply steam to the same piston which has four power impulses to each revolution as a double engine or as a compound engine, and in which there are two power impulses when operated as a normal engine,

d. which includes 6 manually operated valves mounted to open and close their respective steam passages, said valves being manually selectively operable depending on the requirements of the work being performed,

FIG. 13 is a view in elevation of a valve casing employed.

FIG. 14 is an enlarged view in section of the cylinder, without the piston, and the steam by-pass structure associated therewith.

FIG. 15 is a view similar to FIG. 14 but with the valves in an altered or open position, and,

FIG. 16 is a longitudinal central sectional view, partly broken away, on the line l616 of FIG. 14.

As disclosed in the drawings the reference numeral 1 denotes the oblong steam chest having a cover plate 2, front end plate 4 and rear end plate 5, said steam chest having atop its cover plate and approximately centrally thereof the relatively small steam dome 6 having a base flange 7 secured to said cover plate by screw bolts 8, thedome in its crown receiving the nut 9 securing the steam pipe 10 connected by valved coupling 11 to the steam pipe 12 leading to the boiler (not shown). The valved coupling 11 is provided with a handle 13 for controlling the admission of live steam from the pipe 12 to pipe 10 which communicates with the dome.

Communicating with a port 14 in the steam chest cover 2 is the pipe 15 connected by elbow 16 to a pipe 17 connected by elbow 18 with steam pipe 19 that is connected by three-way coupling 20 to

steam pipes

21, 22, the pipe 21 connected by T-coupling 23 connected to, pipe 24 that registers with the port 25 in cover 2, the

pipes

15, 24 arranged upon opposite sides of the steam dome and adjacent opposite ends of the steam chest, the pipe 22 being provided with a control valve 26 and leading to the boiler. Also received atop the cover plate 2.at the front and rear ends thereof respectively are the

sills

27, 28, each secured in place by bolts 29, each receiving a steam discharge pipe 30 registering with a port 31 in registry with a terminal port 32 at each end of the steam chest, each pipe 30 being connected by an elbow 33 conneced a steam pipe 34, one at each end of the cover plate 2, to a steam condenser, if desired (not shown), or communicating with the atmosphere.

The steam chest 1 includes the base plate 35 integral with the

sides

36, 37, said plate and sides secured to the front and rear plates by the bolts 38'.- Spaced from the

sides

36, 37, integral with the base 35 and rising therefrom to the cover plate 2 and extending from the front to the

rear plates

4, 5 is the core 340 formed longitudinally in its lower approximately central portion with a cylindrical bore 38a extending from end to end of a diameter substantially two-fifths that of the core in which is snugly received the cylindrical valve chamber 39, the ends of which abut the

end plates

4, 5 and are closed by said plates, said valve chamber being formed at each end with longitudinally extending

duplicate terminal ports

40, 40a and inwardly from each set of terminal ports with a plurality of

duplicate ports

41, 41a somewhat smaller than the

ports

40, 40a, and arranged in a circle and preferably in staggered relation to

ports

40, 40a, and inwardly from

ports

41, 41a with a plurality of duplicate ports 42, 42 a similar to

ports

41, 41a in size and arrangement, and inwardly from each ring of ports 42, 420 with a relatively large imperforate portion 43 and inwardly from each with twin spaced rings of duplicate oppositely disposed

ports

44, 44a.

Between the sets of twin rings is a central ring of somewhat elongated ports 45. The core 34a is spaced from the end plates to form duplicate front and

rear ports

46, 47 that register with the smaller ports 32 in the cover plate and that extend around and slightly below the valve chamber 39 and register with the

terminal ports

40, 40a of said chamber and spaced inwardly from

said ports

46, 47 with forward and

rear ports

48, 49 that extend through the base 35 and about and slightly above the valve chamber but not through the core top face but that register with the

valve chamber ports

41, 41a disposed near opposite ends of that chamber. Separated from the closed upper terminals of the

ports

48, 49 and spaced inwardly from the front and

rear core ports

46, 47 are the large

steam chamber portions

50, 51 much larger than and that register respectively with the cover plate ports .25, 14, said

chamber portions

50, 51 being formed respectively with contracted

portions

52, 53 that extend to and about and slightly below the valve chamber 39 and that register with the ports 42, 42a thereof, the ports 52 registering with the valve chamber ports 42 and the ports 53 registering with the valve chamber ports 42a.

Spaced inwardly from the large

steam chamber portions

50, 51 are the

medium size ports

54, 55 that extend from the top face of the core to and about the valve chamber and slightly therebelow and which

ports

54, 55 register respectively with the rings of

valve chamber ports

44a, 44, said

ports

54, 55 also registering respectively with the

cover plate ports

56, 57 that open into the steam dome 6. Spaced inwardly from the

ports

54, 55 are the

core ports

58, 59 of medium size, the inner closed terminals thereof disposed slightly above the valve chamber, the ports extending about the adjacent rings of

valve chamber ports

44a, 44 and registering therewith, the lower ends of

said ports

58, 59 being inclined toward each other as they pass through the base 35. Disposed inwardly of the

ports

54, 55 and slightly above the inner ends of the

ports

58, 59 is the centrally disposed steam chamber portion 60 closed by the cover plate 2.

Steam chamber portion is formed with a contracted extension 61, the juncture of the

portions

60, 61 defining the seat of the check valve 62, the stem 63 of which is formed with a steam passageway 64, said stem operatively received in the guide sleeve 65 operatively supported in the cover plate 2, said stem 63 withinsleeve 65 being received upon one end of the expansion coil spring 66. Operatively received within the valve chamber 39 is the valve 67 shown per se in FIG.

10 and comprising a stem 68 of somewhat greater length than the chamber and extending through the front steam chest wall 4 and through the stuffing box 69 and connected by the crosshead 71 and pin 72 to the connecting rod 73 connected to eccentric 75 connected to the shaft 76 of the fly wheel 77 operatively arranged upon the supports 78. Fast upon or integral with the valve stem 68 are the spaced valve units of a common diameter and of predetermined thicknesses and spacings upon the valve stem for effective cooperation in closing and opening the several rings of ports in the valve chamber in predetermined manner, the terminal valve units 80, 800 being of a common thickness and and adapted to open, partially open and close the

terminal ports

40, 40a and

adjacent ports

41, 41a, 42, 42a, the duplicate valve units 81, 81a of a lesser common thickness adapted for like service in connection with the rings of ports 44a, and the innermost or

adjacent valve units

82, 82a for cooperation with the more closely associated rings of ports 44 and with the central ports 45, as the valve is moved axially within the valve chamber.

Referring again to the base plate 35, same is flush with and received upon the top wall of the cylinder 83 arranged upon the hollow base 84 supported upon the floor or base plate 85, the cylinder having an exterior substantially square in cross section and having secured to opposite lateral faces the

rectangular plates

86, 87, the top edges or faces of which are flush with the top outer face of the cylinder, said plates extending longitudinally of the cylinder from end to end and of a depth substantially one-half that of the cylinder, the cylinder bore closed at one end by the front head 88 having a central perforation 89 and by a rear head 90 formed with a centrally disposed inner face clearance recess 91.

Substantially the forward half of the cylinder wall is recessed upon its inner face to receive the sleeve 92 the wall of which is of the same thickness as the depth of said recess and coextensive therewith, the juncture of the recessed and non-recessed portions of the cylinder wall inner face defined by an annular rib 93 integral with the cylinder wall and disposed inwardly slightly extending completely thereabout. Contiguous to the rib 93 and fast to the inner face of the sleeve 92 is the band 94 that carries the

twin piston rings

95, 96 in contiguity, the thickness of a piston ring and the band being equal to the depth of the ring 93 inside the cylinder bore, the diameter of the cylinder bore upon opposite sides of the rib and piston rings, with band 94 being the same.

Received within the cylinder is the piston 97 having

terminal heads

98, 99, the body of the piston being of materially smaller diameter than the cylinder bore and extending through the piston rings and rib and having a close fitting steam-tight operative engagement therewith,'the heads of the piston having a like operative engagement with the cylinder wall in conventional manner, the piston having the piston rod 100 extending throughout and secured thereto at one end by the nut 101 that, as the piston'operates, moves into and out of the clearance 91, the piston rod 100 passing through the plate perforation 89 and connected by crosshead 102 to the connecting rod 103 by pin 104, the connecting rod secured by pin 104a to the crank 105. The

plates

86, 87 are each formed with

passageways

107, 108 tangential to the cylinder wall and each extending from points adjacent the cylinder ends to points beyond the center of the cylinder, the passageway 107 adapted to register with

ports

109, 110, in the cylinder wall adjacent one end and the center of the cylinder, said ports and passageway being connected respectively by

valves

111, 112, valve 111 being provided with handle 113 and valve 112 provided with handle 114, the several valve handles being supported in projections 114a of the steam chest side walls. The

plates

86, 87 are formed further with

ports

121, 122 arranged upon opposite sides of the piston rings and adapted to be opened and closed by the

said valves

112, 118.

In FIG. 14 the valve 112 is in position to close one end of the passageway 107 and the valve 111 is in posi tion to close the opposite end of the said passageway, the valve 112 opening the port 121 to port 110 in the cylinder. In this figure the

valves

117, 118 are in position to close the ends of the passageway 108 and the port 115. The valve 118 also opens the port 116 in the cylinder to port 122 in the plate 87. The

ports

121, 122 respectively receive

elbows

123, 124, the latter connected by pipe 125 to elbow 126 connected to pipe 127 which is connected by elbow 128 connected to pipe 129 which is engaged by elbow 123.

It will be noted that the

steam pipes

12 and 22 both lead to the steam boiler. Pipe 12 is provided with steam valve 13, while steam pipe 22 is provided with control valve 26 so that steam from either

pipe

12 or 22 may be received in the steam chest. Under a medium load the valve 26 is opened, admitting steam from the boiler through the pipe 22, T-coupling 23, pipe 24 into the steam chest compartment 50, through the contracted portion 52 about the valve chamber 39 and through ports 42 thereof and between the

valve units

80, 81, where it temporarily remains. As the valve 26 is open the steam also passes through steam pipe 19, pipe 17, pipe into the steam chest compartment 51, through port 53, through valve ports 42a, between the valve units 80a, 81a where it remains temporarily. The steam chest is now full of high pressure steam. Referring now to FIG. 14 the

valves

112, 118 are open setting up equalized pressure upon both sides of the piston rings 7 within the cylinder. As shown in FIG. 3 the valve 67 is in neutral position with the

terminal ports

48, 49 in the steam chest closed by the terminal valve .

units

80, 80a within the valve chamber, and the central

steam chest ports

58, 59 also closed by the

valve units

82, 82a. The fly wheel 77 is now moved manually to cause the valve 67 to move about five-eighths inches to the extreme end of its inner stroke causing the valve unit 80a to uncover ports 41a in the valve chamber and admit steam therethrough and through terminal port 49 into the space between the rear piston head 99 and the rear cylinder head. The piston is now in position to be acted upon by this steam which in expanding forces the piston to the right.

When the piston, FIG. 3, has moved to the right to dotted line position, the valve 67 has moved to the right sufficiently to close terminal port 49 cutting off the steam supply. The piston continues in this direction to complete its stroke to the right which is a position contiguous to the rib 93. During this piston movement the valve has moved to the right uncovering valve chamber ports 41a permitting this steam to exhaust from between .the piston head 99 and rear cylinder head, the exhaust steam passing through chamber ports 41a and a and ports 47 and out through steam pipe 30 into the atmosphere or to a condenser. As the piston reaches the limit of its outward movement the valve is still moving to the right or outwardly uncovering steam chest port 48 admitting steam into the cylinder against the outer face of the piston head 98 causing the piston to travel to the left again, and by the time the said head 98 has travelled again to dotted line position, FIG. 3, the valve 67 has moved to the left sufficiently to again close the port 48 cutting off the live steam intake; the piston continues to the left with the steam accelerating its movement through expansion until the stroke is complete.

The following is the follow through for a light to a medium load: Live steam from the boiler flows through pipe 12 when valve 11 is open (pipe 22 being closed) into the steam dome 6 and out through steam

chest cover ports

56, 57 into the steam chest and through the open remote valve chamber ports 44, 440 into the valve chamber and around and below same, the steam filling the spaces or chambers between the

valves

81, 82, 81a, 82a and being. therein temporarily confined, the valve 67 being in neutral position, FIG. 3. When the fly wheel is manually moved as previously described the valve 67 moves five-eighths inches to the left, the piston moving slightly to the right from FIG. 3 position, causing valve 82 to uncover port 59 registering with port 130 in sleeve 92, said port 130 registering with the space 131 between the piston body and the inner periphery of the sleeve 92. The steam in space 131 exerts pressure upon the left side of the piston head 98 causing the piston to move to the right, the space 131 increasing in extent as the piston moves forwardly.

The valve 67 is now moving to the right with the piston, the valve having started this movement almost simultaneously with the piston. When the piston has traveled to the right hand dotted line position, the valve 67, unit 82, has moved sufficiently to the right to close the port 59 and no more steam is then admitted to the space 131. the

The steam expansion in space 131 forces the piston to complete its right hand stroke, the valve 67 continuing to the right almost to its farthest right hand position also. This valve movement causes valve unit 82 to uncover port 59 and one ring of ports 44 permittingthe steam in space 131 to exhaust through

ports

59, 44 into the valve chamber between

units

82, 82a. From this chamber it passes'through valve chamber ports 45 opening check valve 62 and passing into steam chamber 60 and through the open spaces about the core into the

steam chambers

50, 51, the

steam chambers

50, 51, 60 having plate 2 as cover. These chambers are now filled with exhaust steam.

Just before the valve 67 reaches its extreme right hand position, the valve unit 82a uncovers the port 58 and permits high pressure steam to pass from the dome 6 through port 56, port 54, outer ring Ma of ports in chamber 39, all around the valve chamber and out through the inner ring 44a of valve chamber ports,

through port 58, through port 132 in the cylinder wall contiguous to the said rib 93, said port 132 opening into a steam space 133 between the piston body 97 and the cylinder wall and abutting the rib 93 and cylinder head 99. The high pressure steam entering the space 133 forces the piston to the left and at the same time the exhaust steam stored in

chambers

50, 51, 60 passes through port 54, through valve chamber ports 42, through ports 41, through port 48 in register with port 134 in the cylinder wall, through port 135 in sleeve 92 and into the cylinder between the head 88 and the piston head 98 and acts against the latter, thus at the same time the high pressure steam is acting against the piston head 99 in steam space 133 thus providing two forces acting simultaneously upon the piston in a common direction. This continues until the piston reaches the dotted line position in FIG. 3. The valve 67 has now travelled far enough to the left to cover the

ports

58, 48. No more steam now enters the cylinder between the piston head 98 and the cylinder head 88 nor the steam space 133. The steam in both spaces continues to expand forcing the piston to complete its stroke to the left. At this time the valve 67 has moved to the left sufficiently to uncover port 58 and permit the exhaust to pass through the innermost left ring 440 of valve chamber ports into the ring 45 of ports, raising the check valve 62 and passing into the

chambers

50, 51, 60 where it again temporarily remains. Valve unit 80 has now moved to the left to uncover port 48,

ports

40, 46, 32 and out through pipe 30 to the atmosphere or to a condenser. The valve 67 has now moved almost to the end ofits left stroke into a position to permit high pressure steam from the dome 6 to pass through the steam passageways, in a manner as previously described, into the steam space 131 forcing the piston to the right.

At the same time the steam in

chambers

50, 51, 60 is passing through port 53,

valve chamber ports

42a, 41a, 49, cylinder port 136 into the space 136a between the cylinder head 90 and the piston head 99 cooperating to force the piston to the right. As the piston travels to the dotted line position, FIG. 3, the valve 67 has moved sufficiently to the right to shut off more steam from entering the cylinder from the steam chest and steam dome, the steam expanding in the cylinder causing the piston to complete its stroke to the right. As the piston completes this stroke, the valve following, the valve uncovers the ring 41a of valve chamber ports permitting the steam in the cylinder to exhaust to and through the pipe 30 into the atmosphere or condenser. With the engine under heavy to extra heavy load the operation is as follows: In this case the mechanism disclosed in FIGS. 14 and 15 is brought into play. The mechanism is shown in FIG. 15 in open or operative position. High pressure steam, valve 26, FIG. 3 being closed, flows from pipe 12 into the steam dome and the operation is that described with reference to the description for light to medium load previously recited. As shown in FIG. 15, the valve 118 permits steam to pass from the cylinder through port 116 into passageway 108, and valve 117 permits the steam to continue through port 115 into the cylinder upon the opposite side of the piston ring. This steam now passes into the steam space 1360 between the left face of piston head 99 and the cylinder head 90 forcing the piston to the right, some of the steam through the port 136, through port 49, through ring of ports 41a, 42a, through port 53 into the steam chest intercommunicating chambers 50,

51, 60 where it temporarily remains. A portion of the steam also moves the piston to the dotted line position, FIG. 3. Valve 67 has now moved sufficiently to the right from extreme left position to close port 59 so that high pressure steam may not continue to be supplied from the steam dome through the steam chest into the cylinder. Expansion steam within the cylinder to the left of the piston head 99 and steam within the cylinder to the left of piston head 98 will cause the piston to complete its stroke to the right. The valve will now have opened

passageways

136a, 136, 49 to exhaust the steam and through valve chamber ports 40a, passageways 47, 32 and pipe 30 into the atmosphere or condenser.

At the same time the steam in the cylinder between the piston ring and piston head 98 will exhaust through port 116, passageway 108, port 115, FIG. 15 position, into passageway 136a and finally out through pipe 30 as just described. The piston is now at the extreme right hand end of its stroke. The valve 67 continues to the right to uncover port 58 to the left of the piston ring and permit steam from the steam dome to pass through

ports

56, 57, 54, 55, through remote rings of

valve chamber ports

44, 44a, through port 58 into the cylinder between the piston ring and the right face of piston head 99, the piston position now being about that shown in FIG. 11. At the same time, as in FIG. 15, the steam from the cylinder at the left of the piston ring passes through port into passageway 107 into port 109 and back into the cylinder to the right of the piston head 98. There is now high pressure steam effective upon the right hand side of both piston heads. This forces the piston to the left into dotted line position, FIG. 3. The valve 67 has now moved to the left to close port 58 allowing no more steam from the dome to enter the cylinder. This steam continues to expand thus forcing the piston to extreme left hand position.

The valve continues to the

left uncovering ports

134, 135, 110, passageway 107, port 109 into the cylinder between cylinder head 88 and piston head 98, the steam exhausting from the sleeve and

cylinder ports

135, 134 through port 48, ring of

valve chamber ports

41, 40, ports d6, 32, 31 and out through pipe 30. It will be noted that the check valve 62 normally remains closed so that with the engine running as just described, the steam from

chambers

50, 51, 60 will not escape through valve chamber ports 45 and out through other valve ports and finally through

ports

110, 116, 109, l 15 to the atmosphere.

While the foregoing specification sets forth the invention in specific terms, it is to be understood that numerous changes in the size of materials may be resorted to without departing from the spirit and scope of the invention as claimed hereinafter, and it is contemplated that various changes may be made in the embodiment of the invention herein specifically described.

I claim:

1. In a steam engine, cylinder means defining internal cylindrical surface means, piston means reciprocably movable in said cylinder means and including first and second end portions having external cylindrical surfaces of the same diameter in sealing engagement with said internal cylindrical surface means and including an intermediate reduced diameter portion between said first and second end portions and defining an external cylindrical surface in concentric relation to said cylindrical surface means, annular means projecting inwardly from a central portion of said cylinder means into sealing engagement with said external cylindrical surface of said intermediate reduced diameter portion of said piston means to define a first space between said first end portion of said piston means and said annular means and a second space between said second end portion of said piston means and said annular means, forward wall means closing one end of said cylinder means to define a third space between said forward wall means and said first end portion of said piston means, reciprocable valve means operable between first and second positions in synchronized relation to reciprocable movement of said piston means, said reciprocable valve means including first means operable in said first position of said reciprocable valve means for introducing high pressure steam into said first space to move said piston in a forward direction toward said forward wall means and including second means operable in said second position of said reciprocable valve means to introduce high pressure steam into said second space to move said piston in a reverse direction away from said wall means, and reverse direction compound action control valve means arranged to be opened for flow of steam from said second space to said third space when said reciprocable valve means is in said second position to obtain a compound action in said reverse direction.

2. In a steam engine as defined in claim 1, said reciprocable valve means further including third means for introducing high pressure steam into said third space in said second position of said reciprocable valve means to obtain a double action, reverse direction double action control valve means for controlling said introduction of high pressure steam through said third means of said reciprocable valve means, said reverse direction compound action control valve means being closed when said reverse direction double action control valve means is open.

3. In a steam engine as defined in claim 1, rearward wall means closing the opposite end of said cylinder means to define a fourth space between said rearward wall means and said second end portion of said piston means, and forward direction compound action control valve means arranged to be opened for flow of steam from said first space to said fourth space when said reciprocable valve means is in said first position to obtain a compound action in said forward direction.

4. In a steam engine as defined in claim 3, said reciprocable valve means further including fourth means for introducing high pressure steam into said fourth space in said first position of said reciprocable valve means to obtain a double action in said forward direction, and forward direction double action control valve means for controlling said introduction of high pressure steam through said fourth means of said reciprocable valve means, said forward direction compound action control valve means being closed when said forward direction double action control valve means is open.

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