US1200893A - Steam-engine. - Google Patents

Description

F. SHUMAN.

STEAM ENGINE.

APPLICATION FILED JAN-'9, I914.

1,200,893. Patented Oct. 10,1916.

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'F. SHUMAN.

STEAM ENGINE.

APPLICATION FILED JAN. 9, I914.

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Patented Oct. 10, 1916.

F. SHUMAN.

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APPLICATION FILED JAN-9,1914. 1,2UQ893. Patented Oct. 10,1916.

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F. SHUMAN.

STEAM ENGINE.

APPLICATION FILED IAN. 9, 1914.

Patented Oct. 10, 1916.

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F. SHUMAN; STEAM ENGINE.

APPLICATION FILED JAN. 9. I914. Patented Oct. 10

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FRANK SHUMAN, 0F PHILADELPHIA, PENNSYLVANIA.

STEAM-ENGINE.

Specification of Letters Patent.

Patented Oct. 10, 1916.

Application filed January 9, 1914. Serial No. 811,119.

To all whom it may concern:

Be it known that I, FRANK SHUMAN, citizen of the United States, and resident of Philadelphia county of Philadelphia and State of Pennsylvania, have invented an Improvement in Steam-Engines, of which the following is a specification.

My invention has reference to steam engines and consists of certain improvements which are fully set forth in the following specification and shown in the accompanying drawings which form a part thereof.

The object of my invention is to provide a construction of steam engine in which the steam is used expansively and under the control of the mechanical construction of the engine in such a manner as to reduce or eliminate much of the heat losses heretofore due to the cooling of the inside of the cylinder walls during the normal operation of the engine. More particularly, my object is to provide certain constructions of the cylinder and piston which shall eliminate the above referred to heat losses, and also to provide special forms of valve mechanism for controlling the admission of live steam and the escape of exhaust steam whereby a high efficiency may be secured in the operation of the engine.

My invention consists of certain improvements which are fully described hereinafter in connection with the drawings, and particularly defined in the claims. These various improvements will be better understood by special reference to the drawings, in which:

Figure 1 is a plan view of a steam engine embodying my improvements; Fig. 2 is a side elevation of the same; Fig. 3 is a vertical sectional elevation of the end of the cylinder and its connections adjacent to the main housing of the engine. said section being taken on line a2-az of Fig. 4:; Fig. 4 is an end view of the cylinder head with a portion in section and showing the exhaust chamber and also the exhaust valves and means for operating them; Fig. 5 is an enlarged view of a portion of Fig. 3 showing the manner of insulating the cylinder head from the cylinder proper; Fig. 6 is an end elevation of the cylinder separated from the housing and as if viewed from the righthand end of Fig. 3; Figs. 7 and 8 are respectively longitudinal and transverse sections illustrating the parts of the valve operating rock shafts; Fig. 9 is a cross section of the engine cylinder without the outside lagging but taken on the plane of the inlet ports and showing the construction of the inlet valve; Fig. 10 is an elevation of a portion of one of the inlet valves shown in Fig. 9; Fig. 11 is a general sectional elevation of the engine cylinder and pistons; Fig. 12 is a side elevation with portions broken away illustrating the rocker cams and operating parts therefor, employed for operating the valves; Fig. 13 is a sectional elevation illustrating the automatic governor which may be employed for the supply valves; and Fig. 14 is a diagram illustrating the position of the pistons within the cylinder and the expansion of the steam.

2 is the cylinder and has at each end cylinder heads which provide exhaust cliambers 29 which communicate with the exhaust pipe by a trunk 29. The cylinder is bolted to one end of the housing 3 which is provided with cross head guides and main bearing, as is customary in steam engines.

4 is the piston rod, 5 is the crank shaft, and 6 is the connecting rod by which the reciprocating motions of the piston are imparted to the crank shaft.

7 is the eccentric for operating the steam supply valves and may be provided with any suitable form of governor for automatically varying the point of cut-off, as is customary in steam engines to maintain a uniform speed, and one form of such mechanism is illustrated in Fig. 13.

8 is a crank performing the same functions as an eccentric.

Referring to the connection between the eccentric 7 and the means for operating the steam supply valves, I have shown this as conveniently made in the form of a rocker 10 which is connected with the eccentric by the eccentric rod 9 and also with a rocker 13 at the forward end of the cylinder by a link 11.- This rocker 13 is connected to a similar rocker at the rear end of the cylinder by a link 12, so that both rockers are operated from the same eccentric. The constructi n of alve operating means at each end of the cylinder being the same, it will suiiice to describe the details of one of these mechanisms by more particular reference to Figs. 6 and 12. The rocker 13 is secured to a rock shaft 15 journaled in a suitable frame and is provided with an adjustable cam portion 14. This cam portion 14.- works against the face of h r cker arm 16 which is clamped upon a rock shaft 17 The rocker arm 16 is preferably maintained in contact with the cam 14 by springs 18 (Fig. 2). The rock shaft 17 extends through a sleeve 30 and is provided on its inner end (in vertical alineinent with the center of the cylinder) with a hub 34 having a lateral projection, said hub being keyed to the shaft 17 and also preferably pinned thereto by a pin 36 (Figs. 7 and 8). The sleeve 30 through which the shaft 17 extends also acts as a rock shaft and is provided with an arm 19 which is connected at the bottom with the valve rod 20 which extends through a stufling-box 21 in the end of the cylinder head, said valve rod extending inward and connecting with the annular steam valve 39, as indicated in Fig. 9. There is also another and similar tubular rock shaft30 extending in the opposite direction from the center of the cylinder and in alinement with the first mentioned rock shaft, and this similarly is provided with the operating arm 19 which in turn operates another of the valve rods 20 which is connected to the same steam valve before referred to. The adjacent ends of the two tubular rock shafts 30 are firmly secured to a coupling head 31 by suitable keys 32 and clamps 33, as more fully shown in Figs. 7 and 3. The head 31 is provided with oppositely directed abutment screws 35 which are screwed up tightly against the laterally projecting portion of the hub 34 of the rock shaft 17, so that said rock shaft 17 and the two tubular rock shafts or sleeves 30 all rock as a unit, and by means of the arms 19 and valve rods 20, reciprocate the annular valve 39. Particular attention is directed to the fact that the power which is applied to the coupled rock shaft portions 30 is applied directly through the parts 34 and 35 in a vertical plane through the center of the piston and cylinder, and so that the torsional strain between the point of application of the power and its delivery to the two valve rods 20 shall be exactly equal, and in this way cause the large annular valve to be moved uniformly at each side and thereby pre ent any binding or defective positioning of the valve which would otherwise occur if the point of application of the power were near one of the valve rods and at a great distance from the other. By reference to Figs. 7 and 8, it will be observed that the adjusting abutment screws 35 will permit adjustment of the valve as a whole with respect to the rock shaft 17, whereas the arms 19 are adjustably clamped upon the two tubular rock shafts 30 to properly position them when assembling the engine. The pin 36 extends through the slots 37 in the head 31, so that when desired it can be removed when dismantling the operating parts for repairs or otherwise.

The mechanism for operating the exhaust valves is in all material res ects the same as that for operating the steam valves, except that it is operated from a crank 8 instead of from an eccentric provided with a governor, and consequently, the same illustrations of Figs. 6, and 12 will equally apply to the exhaust valve mechanism, and the description thereof may be taken as the description of the same as applied to the exhaust valves. In this case, however, the crank 8 operates a pitman 8 which rocks a rocker 8 and which rocker in turn reciprocates a rod 8" which connects with the rocker lever 13 (Figs. 6 and 12). In the case of the operation of the exhaust valves, the mechanism of which is shown at the righthand end of Fig. 6, the rock lever 13" operates the adjustable rocker cam 14, which in turn operates the rocker arm 16 which is secured to the rock shaft 61 which operates the exhaust valves. The parts 13, 14 and 16 correspond in shape and construction to the parts 13, 1% and 16, and therefor no further description of this valve operating mechanism will be necessary. It is to be understood, however, that while I prefer particular means shown for operating the rock shafts 17 and 61, by which the steam supply and exhaust valves are to be respectively controlled, other modified means adapted to the purpose may be employed.

I will now refer more specifically to the construction of the engine cylinder, pistons, supply valves and exhaust valves.

The engine cylinder 2 is approximately twice as long as the stroke of the engine, and preferably a little more than twice the length of the stroke, and is provided at each end with the cylinder heads 45 having attached to them. by bolts 60, the exhaust chambers 29. This cylinder is furthermore surround ed by a steam chamber 24, into which the steam is delivered by the supply pipe nozzle The outside of the cylinder and its annular steam chamber is preferably covered with a non-conductor of heat, as indicated at 25, any suitable lagging being employed for the final finish. It will be observed that the cylinder proper is thus in'closed by an annular live steam chamber 21, which maintains a high temperature to the cylinder walls and hence a minimum tendency to produce water of condensation within the cylinder and consequent loss of heat units thereby. The steam inlet ports are arranged between tlie cylinder and the annular chamber at each end and are arranged annularly, as indicated at 23. The steam valves for controlling the admission of steam through these steam ports 23 are annular-shaped and surround the cylinder and are preferably formed as indicated in Figs. 3, 9 and 10. More particularly these valves comprise an annular carrier 39 which is suspended upon springs 4L3 from the outer body of the annular steam space around the cylinder, and access to them may be had through removable doors or plates 41-4. The annular carrier 39 is preferably of girder-shape in cross section, as shown in Fig. 3, and is formed with a plurality of inwardly directed lugs 40 arranged at each side and between which the valve pieces 22 are arranged, so that when the carrier is reciprocated by the valve rods 20, the valve pieces 22 are simultaneously moved. These valve pieces 22 are curved to the curvature of the annular valve seat about the cylinder 2, and the ends thereof 22 are parallel, so that the valve pieces may be moved radially while at the same time maintaining a reasonably close fit against the V- shaped guides 42 on the inner wall of the annular carrier 39. Suitable springs 41 are arranged between the valve pieces 22 and the carrier 39, as clearly indicated in Fig. 9, so that said valve pieces are constantly pressed upon the valve seat during the reciprocation of the carrier; and the adjustability of the valve pieces upon the carrier will allow them to compensate for all wear. These guide pieces 42 and the ends 22 of the valve pieces will, in the assembling of the engine, come over bridging portions of the cylinder between the port apertures 23, as will be readily understood from an examination of Fig. 9. By the employment of the counterbalancing springs 43, with the capacity for adjustment as indicated, the carrier 39 may be suspended about the cylinder without putting objectionable strain upon the valve rods 20; but if these valve rods are made sufliciently heavy, these supporting springs 43 may be dispensed. with.

The piston rod 4 is provided with two pistons 27 and 28 arranged at such a distance apart that when one of these pistons is close to one end of the cylinder, the other is approximately at the middle of the cylinder. By constructing the piston double in this manner, an important result is obtained. No steam is ever positi ely or intentionally admitted into the space between the two pistons, therefore while the steam is exhausting from one end of the cylinder and live steam is entering and expanding in the other end of the cylinder, the large portion of the cylinder wall. between the two pistons is being heated from the outside by the live steam in the jacket-chamber 2% to a high temperature. A much higher tempera ture of the cylinder walls can be attained by constructing the cylinder and pistons in the manner shown, instead of in the ordinary way. because in the space between the two pistons there is never any steam expanding or being exhausted; therefore the cylinder walls are not being cooled from the inside as is the case in the ordinary construction of engines. An engine cylinder of this construction is twice as long inside,

for a given stroke, as one constructed in the usual manner, thus giving twice the area per stroke for the transmission of heat from the live steam in the acket.

Referring now to the construction shown in Figs. 3, 4t and 5, and more particularly in respect to the cylinder heads and the ex haust valve mechanism, the cylinder head 45 is provided with a plurality of exhaust valve ports 46 which may be normally closed by valves 50, said valves being preferably of disk form and operated by reciprocating stems 51 guided in bearings 52. As shown, there are six of these exhaust valves 50 for each head, and the said head is provided with a hub portion 47 forming an annular guide bearing for a reciprocatable annular rame 53 to which the several stems 51 of the valves are connected. As shown, the stems 51 have cylindrical parts 54 extending through radial arms on the frame 53, and shouldered so that when the annular frame is reciprocated toward the cylinder, the valves are positively opened. These extensions 54 of the valve stems are provided at their other end with nuts and between said nuts and the arms of the annular frame 53 are arranged springs 55. These springs compensate for any movement of the frame 53 upon the parts 54: of the stems after the valves 50 seat themselves upon the exhaust ports. By the employment of these springs, the valves are insured being steam tight upon their seats and without any unequal strain being put upon them in seating. The annular reciprocatable frame 53 is reciprocated by the rocking arm 63 which is secured to the rock shaft 61 journaled in bearings 62 and leading to the rocker arm 16 of the valve gear mechanism, before referred to, and more particularly illustrated in Figs. 2 and 6. All of these valve operating devices for controlling the exhaust steam, except the part 16, are arranged within the exhaust chamber 29 which is bolted to the cylinder head and clearly illustrated in Fig. 3. In the construction of exhaust valves illustrated in Figs. 3 and 4, it will be seen that a very large area of opening in the end of the cylinder is provided, and said ports are so arranged that the exhaust steam may be driven from the cylinder by the advancing piston with great freedom since it passes directly through the end of the cylinder head into the large exhaust steam chamber or receiver. It will be further observed, that as the valves are flat and their inner ends correspond to the plane of the interior wall of the cylinder head, the clearance between the piston and the cylinder head may be reduced to a minimum. It will be understood. however, that in the operation. of the valve mechanism, the valves 50 would be so operated as to approach their seats as the piston nears the end of the rec stroke and will be fully seated when the piston reaches the position shown in Fig. 8, so that the cylinder is practically exhausted of steam with each stroke.

At the end of the cylinder which connects with the housing 3, (which end is particularly illustrated in Fig. 3), the central guide 47 through which the piston rod 4 passes is provided with a stuffing-box 48, said stuffing-box being of any suitable construction.

It is very desirable to insulate the cylinder itself from the cylinder head and also the exhaust chamber, and for accomplishing this purpose I have provided the construction which is clearly illustrated in Figs. 3, 4 and 5. The end of the cylinder head 45 is provided with an insulating coating 59 which may be of a dense asbestos fabric set in andfirmly attached to the head, which attachment may be by the employment of a fusible cement. The surfaces of the valves 50, which are presented toward the cylinder, are preferably provided also with an insulating covering 50 of the same character. The perimeter of the cylinder head is preferably slightly grooved and filled withan insulating layer 56 which in this case may be of asbestos material wrapped with a fine wire to hold it in position. The flange of the exhaust chamber 29 is bolted to the cylinder by bolts 58 and to the cylinder head by the bolts 60, preferably insulated from the cylinder by the packing 57, although this part of the insulation is not so impor tant as that comprised in the parts 56 and 59.

It will be understood that while I have illustrated my invention, even to the details of construction which I prefer in practice, the minor details of construction may be greatly varied to suit the particular design of the engine, and consequently I do not restrict myself to the details shown, but include within my invention all modifications of the same which do not depart from the spirit of the invention as defined in the claims.

In this application I make no claim to the specific construction of the cylinder and pistons, nor to the heat insulating joint between the cylinder head and cylinder, as these features are reserved for a divisional application.

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

1. In a steam engine, the combination of a cylinder head provided with an exhaust chamber and having a plurality of exhaust valve ports opening through the head into the cylinder and arranged about its axial line, a plurality of disk valves for the said ports, means within the exhaust chamber for simultaneously reciprocating the said plurality of valves in the direction of the length of the cylinder, and devices extending to the outside of the exhaust chamber for operating the said valve operating means.

2. In a steam engine, the combination of a cylinder head provided with an exhaust chamber and having a plurality of exhaust valve ports opening through the head into the cylinder and arranged about its axial line and also having a central guide portion having an aperture for the piston rod and providing a stufiing-box therefor, a plurality of disk valves for the said ports, means within the exhaust chamber and surrounding and guided upon the central guide portion also within the exhaust chamber for simultaneously reciprocating the said plurality of valves to control the ports opening through the cylinder head, and devices extending to the outside of the exhaust chamber for operating the said valve operating means.

3. In a steam engine, the combination of a cylinder head provided with an exhaust chamber and in which the cylinder head is also provided with a plurality of circular valve ports and seats arranged about the axis of the cylinder head, a plurality of disk-shaped valves for said ports and seats and each having a stem extending into the exhaust chamber and guided in the cylinder head, a reciprocating frame within the exhaust chamber for simultaneously reciprocating all of the valve stems and their valves and providing connections between the reciprocating frame and the valve stems for moving the valves from their valve seats and also for closing the said valves upon their valve seats and compensating for any seating of any valve slightly before the others, and means extending to the outside of the exhaust chamber for operating said reciprocating frame.

4. In a steam engine, the combination of a cylinder head provided with an exhaust chamber and in which the cylinder head is also provided with a plurality of circular valve ports and seats arranged about the axis of the cylinder head, a plurality of disk-shaped valves for said ports and seats and each having a stem extending into the exhaust chamber and guided in the cylinder head, a reciprocating frame within the exhaust chamber for simultaneously reciprocating all of the valve stems and their valves and providing connections between the reciprocating frame and the valve stems for moving the valves from their valve seats and also for closing the said valves upon their valve seats the connection between the valve stems and the reciprocating frame each comprising a shouldered part of the stem extending through the reciprocating frame and held thereto by spring devices said means positively opening the valves against any pressure within the cylinder and'compensating for any seating of one valve before another, and means extending to the outside of the exhaust chamber for operating said reciprocating frame.

5. In a steam engine, the cylinder having an annular steam space and valve chamber and provided with inlet ports arranged annularly about the cylinder and opening into the annular chamber, in combination with valve devices comprising an annular valve surrounding the cylinder and the ports said annular valve having extensions at widely separated places in its circumference for directly imparting motion to it and a rocking arm having separate connections with each of the rods of the valve whereby both rods are accurately moved in unison under all conditions, and mechanism under the control of the engine for operating the valve devices.

6. In a steam engine, a cylinder head provided with an exhaust chamber and in which the cylinder head is also provided with valve ports, in combination with valve devices comprising valves for said valve ports and each having a stem extending into the exhaust chamber, a reciprocating frame within the exhaust chamber to which the valve stems are connected and by which the valves are simultaneously moved and spring devices arranged to permit the valves and their stems to have slight movement upon the reciprocating frame, and means extending to the outside of the exhaust chamber for operating the valve devices.

7 In a steam engine, the cylinder having an annular steam space and valve chamber and provided with inlet ports arranged annularly about the cylinder and opening into the annular chamber, in combination with an annular valve surrounding the cylinder and comprising an annular carrier, means for reciprocating the carrier in the direction of the length of the cylinder, a plurality of valve sections arranged withinthe carrier and about the cylinder so as to be reciprocated with the carrier, and springs between the carrier and valve sections whereby said valve sections are moved radially under spring action into close contact with the surface of the cylinder to control the passage of steam through the ports.

8. In a steam engine, the cylinder having an annular steam space and valve chamber and provided with inlet ports arranged annularly about the cylinder and opening into the annular chamber, in combination with an annular valve surrounding the cylinder and comprising an annular carrier, means for reciprocating the carrier in the direction of the length of the cylinder, a plurality of valve sections arranged within the carrier and about the cylinder so as to be reciprocated with the carrier, springs between the space for sustaining carrier and valve sections. whereby said valve sections are moved radially under spring action into close contact with the surface of the cylinder to control the passage of steam through the ports, and suspending devices within the annular steam the weight of the annular carrier consisting of springs arranged at opposite sides of the carrier and having one end connected with the cylinder body and the other end with the carrier, and means to adjust the tensionof the springs.

9. In a steam engine, the cylinder having an annular steam space and valve chamber and provided with inlet ports arranged annularly about the cylinder and opening into the annular chamber, in combination with an annular valve surrounding the cylinder and comprising an annular carrier, means for reciprocating the carrier in the direction of the length of the cylinder, a plurality of valve sections arranged within the carrier and about the cylinder so as to be reciprocated with the carrier and in which the opposite ends of each of the valve sections are madewith parallel surfaces and guided between parallel guiding surfaces on the annular carrier whereby said valve sections may freely adjust themselves in a radial direction with respect to the carrier to compensate for wear, and springs between the carrier and valve sections whereby said valve sections are moved radially under spring action into close contact with the surface of the cylinder to control the passage of steam through the ports.

10. In a steam engine, the cylinder having an annular steam space and valve chamber and provided with inlet ports arranged annularly about the cylinder and opening into the annular chamber, in combination with an annular steam inlet valve surrounding the cylinder and within the annular steam chamber, valve rods connected with the annular valve and extending through the end of the cylinder, two rock shafts having arms connected with the valve rods, a third rock shaft mechanically connected with the two first mentioned rock shafts at a point intermediate of their arms and arranged to rock said rock shafts simultaneously in the same direction, whereby the same amount of torsion comes upon each rock shaft, and valve operating mechanisms under the control of the engine for rocking the last mentioned rock shaft.

11. In a steam engine, the cylinder having an annular steam space and valve chamber and provided with inlet ports arranged annularly about the cylinder and opening into the annular chamber, in combination with an annular steam inlet valve surrounding the cylinder and within the annular steam chamber, valve rods connected with the annular valve and extending through the end of the cylinder, two rock shafts having arms connected with the valve rods, a third rock shaft mechanically connected with the two first mentioned rock shafts at a point intermediate of their arms and arranged to rock said rock shafts simultaneously in the same direction said connection comprising a sleeve in which the two rock shafts having the arms are rigidly secured, a short arm secured to the third rock shaft and projecting slightly to one side of its axis, and adjustable screw connections between the opposite sides of said arm and the sleeve, the construction being such that while the two rock shafts operate their valve stems in identi cally the same manner they may be adjusted as to the position of their throw by the adjusta'oility of the mechanical connection between them and the third rock shaft, and valve operating mechanisms under the control of the engine for rocking the last mentioned rock shaft.

12 In a steam engine, the cylinder having an annular steam space and valve cham her and provided with inlet ports arrangedannularly about the cylinder and opening into the annular chamber, in combination with an annular valve, two valve stems on opposite sides of the cylinder for operating the valve, a tubular rock shaft structure journaled on the cylinder and having at each end an arm connecting with one of the valve stems, a rock shaft extending throughthe Copies of this patent may be obtained for five cents eacl}, by addressing the tubular rock shaft structure and positively connected therewith at a point intermediate of the two arms thereof, and valve operating mechanism for rocking the rock shaft.

13. In a steam engine, the cylinder having an annular steam space and valve chamher and provided with inlet ports arranged annularly about the cylinder and opening into the annular chamber, in combination with an annular valve, two valve stems on opposite sides ofthe cylinder for operating the valve, a tubular rock shaft structure journaled on the cylinder and having at each end an arm connecting with one of the valve stems, a rock shaft extending through the tubular rock shaft structure and positively connected therewith at a point intermediate of the two arms thereof said connection comprising a part on the rock shaft extending laterally through the tubular rock shaft structure, and oppositely directed abutment screws carried by the rock shaft structure and pressing upon the laterally projecting part onthe rock shaft in opposite directions, and valve operating mechanism for rocking the rock shaft.

In testimony of which invention, I hereunto set my hand.

FRANK SHUMAN.

"Commissioner of Patents,

Washington, D. Q.

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