US2418477A - Steam power plant - Google Patents

Description

April 8, 1947. R. M. OSTERMANN 2,418,477

' STEAM POWER PLANT Filed Jan. 10, 1941 3 Sheets-Sheet 1 nccunummn AUTOMA TIC- THRWTLING VAL V5 INVENTOR= April 8, 1947- R. M. OSTERMANN 2,418,477

STEAM POWER PLANT Filed Jan. 10, 1941 3 Sheets-$heet 2 BOIL EA 6c ACCUMULA T0? THRBINE OQQQ QQZZ.

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April 8, 1947.

OSTERMANN 2,418,477

STEAM POWER PLANT Filed Jan. 10, 1941 3 Sheets-Sheet 3 jrza enfor fiadaif'ji. Oszerrkqreii .Marzrg? Patented Apr. 8, 1947 STEAM POWER PLANT Rudolf M. Ostermann, Kenilworth, Ill., assignor to The Superheater Company, New York,

Application January 10, 1941, Serial No. 373,883

10 Claims.

The invention relates to a steam power plant. The object is to provide a variable speed power drive with torque-speed characteristics, such as are useful for the propulsion of locomotives and other rail vehicles, as well as for steam hoists, rolling mills, and similar uses, all of which require substantial accelerating torques throughout their speed range. A particular object of this invention is, moreover, to provide such a variable speed power drive as will make it practicable to utilize extremely high steam pressures, thereby reducing the steam consumption per horse-power all possible. 1

An incidental object of this invention is t provide simple automatic steam generating means, particularly useful for this variable speed drive.

The highest possible steam economy of such drives is of great valuefor instance, when applying them to locomotives, since it tends to decrease the size, cost. and weight of the entire machine. It is also of substantially increased steam economy which makes the condensation of the operating steam and its re-use as boiler feed a practical possibility, in moving power lants, like locomotives, which has not been possible of attainment heretobefore, in the absence of a drive which combines both the requisite torque speed characteristics and high steam economy.

The invention is not limited specifically to the above mentioned objects.

The invention is illustrated more or less diagrammatically in the accompanying drawings, wherein:

Figure 1 is a flow diagram illustrating the flow of steam through the apparatus of the present invention;

Figure 2 is a diagrammatic showing in more detail of an apparatus suitable for carrying out the present invention and suitable for carrying out the method which will be described below after the description of the parts illustrated.

Figure 3 is a diagrammatic showing with parts in section and parts in elevation of the boiler, turbine, engine and boiler firing means of Figure 2;

Figure 4 is a section taken on an enlarged scale at line 44 of Figure 3;

Figure 5 is an automatic controlling valve of a type used in the assembly of Figures 2 and 3;

Figure 6 is a sectional view on an enlarged scale of the valve assembly or Servo motor for the steam engine, which assembly appears generally in Figure 3; and

Figure 7 is an automatic control valve of a type used in the arrangement of Figure 2.

Like parts are designated by like characters throughout the specification and the drawings.

In the particular form here shown the mechanism of the present invention comprises a primary prime mover which may be one or more steam turbines i. The primary expansion of the steam is accomplished in the turbine or turbines. 2 is a piston displacement steam engine which may be of many different types. The secondary expansion of the steam occurs in the steam engine 2. 3 is a variable speed shaft to which the turbine or turbines and the secondary steam engine are attached. 4 is a steam receiver connecting the exhaust of the turbine i with the valve chest Id of the engine 2 and carried by a pipe 4a to the engine 2. A pipe 2a leads from the engine 2. 5 is a boiler and G is a steam accumulator which is shown to act also as a Waste heat boiler since the boiler gases flow through it to a stack l5; into this accumulator the steam is discharged through a steam-charging pipe 55. Steam may enter the accumulator from the receiver 4 by means of a pipe 41). Steam may also enter the accumulator from the boiler by means of a pipe 5a. Water may pass from the boiler to the accumulator by means of a pipe 6b. Steam may pass from the accumulator to the receiver by means of a pipe 60. A pipe 5b leads from the boiler to the turbine I. Valves 49 are positioned one in the pipe 5b and one in the pipe 60. They are connected to operate together. The operating means will be described below. The description above applies primarily to the diagram of Figure 1. The same parts bearing the same numbers occur in the more detailed diagrams of Figures 2 and 3. Figure 1 shows merely the main units of the assembly without many of the operating parts.

As 5 Wn more in detail in the large diagram of Fig e 2, one form of the apparatus of this invention includes many additional parts. There is thus a condenser I which is connected to the engine 2 by the pipe 2a. 8 is a cooler, 9 is a pump driven by gearing H! from the shaft 3. H is a fan arranged to force air to the cooler 8 and driven by a gear 12 from the shaft 3. The pump shaft 9a carries a governor 13 which is arranged to control a valv within the steam inlet I4 from which the pipe to leads to the receiver 4.

A stack i5 is associated with the accumulator, and an exhaust fan I6 is mounted in the stack I5 and arranged to be driven in a manner which will be desribed below. I! is a condensate pump to which condensate moves from the condenser by a-pipe Ia. i8 is a second pump, The pumps I1 and i8 are driven by a turbine l 9. The pumps l1 and IB and the turbine i9 are mounted on a mulator 6.

operate together and are connected to a rod 22' which is itself operated and moved by a governor 23 driven from the shaft 3 by gearing 24. Auxiliary fan 25 may be mountedon the shaft I9a. As a means for heating the boiler a series of burners 26 are provided. Automatic control ,is preferably arranged for these, as will be described below. A burner 21, which is not ordinarily automatically controlled, is also provided for the boiler. 28 is a condensing steam turbine driving a fan 28a. 29 is a damper, preferably hand-adjusted and arranged to control the passage 29a and its branches, which communicate with the burners 26. 30 is a second damper arranged to control a, passage 30a. 3| is a governor connected by means of a rod assembly 3Ia with the damper 30. The governor is carried by the shaft 32 which is itself driven by a regulating turbine 33. 34 is an automatic pressure regulating valve. 35 are shafts arranged one for each of the burners 26. These shafts actuate fuel distributors 35. 35, which may feed fuel from a tank 31 through a pipe 31a to the burners 25. Each of the'shafts 35' is preferably provided with a clutch 38. These clutches are operated by push rods 39, each of which is connected to a damper 40, there'being preferably one damper for each of the burners 26. An inclined cam M is moved by a centrifugal governor 42 which is effective to move the cam against the spring 43 by means of a rod 44. The governor 42 is mounted to be rotated by a shaft 45 which is geared to the shaft 3 by gearing 46. A clutch 41 is-provided for the shaft 45 and is operated by a lever 48. A spring 48a is effective to move the lever in the clutch engaging direction. The throttlevalves 49 above mentioned in the particular description of Figure 1 are connected together as shown by a handle bar49a. f

50 designates an automatic throttling valve for the steam which operatesthe. exhaust fan turbine 52, and which valve is made responsive to the discharged through pipe 6d to a steam water separator 65 located within a separating drum 68 outside the boiler setting. The steam separated pressure in the furnace of boiler 5. being connected by a pipe 5Ia to an orifice 5| opening into said furnace. 52 is a turbine arranged to rotate the exhaust fan I6 by means of a shaft 52a. 53 is a one-way check valve positioned in the pipe 86 which connects the receiver 4 with the accu- 54 is a second one-way check valve positioned in the pipe 4b which connects the receiver 4 with the accumulator 3 through the steam-charging pipe 55. The pipe may hav cir. culating nozzles 56. if desired. 51 is an auto 'atic charging valve positioned in the pipe 5a which connects the boiler 5 with the steam-charging pipe 55 of the accumulator 6. 58 is a safety valve blowing excess pressure steam from the boiler 5 to the accumulator 6. 59 designates a fitting on the steam dome of the accumulator where its steam is taken for the control of valve 51. 60 is a safety valve positioned in a pipe 60a which communicates with the steam space of the accumulator 6, and which blows oil, as shown in Fig. 2, through pipe 60a to the condenser I, M is a hand-operated valve positioned in a passage tla which bypasses the automatic pressure re ulating valve 34'. iris aiboiier feed check valve which controls the flow of water through the pipe I'm into the accumulator. 63 is a suction intak for pump I8 sucking through the pipe 1811. In

within said separator flows through pipe 55a to a super-heater b and thereafter through pipes 5a and 5b to the'accumulator or to the throttle valve 49a. respectively. The water separated at 85 drops within drum 66 by gravity. An overflow pipe 61 within said separating drum, and

open at its upper end. may be provided, and the water getting into said pipe maybe drained off to the water space of the accumulator at boiler check 64 through a pipe 6b and through a water flow restricting means 68, so designed with torque passages that the overflow pipe 61 is slowly drained to the accumulator and not vehemently blown clear of water by the very much higher pressure which may prevail in the boiler as compared with the one in the accumulator.

Although there is shown an operative form of the device, it will be understood that many changes in the form, shape and arrangement of parts might be made without departing from the spirit of.this invention, and it is wished that the showing be taken as, in a sense, diagrammatic. The automatic control valve shown in detail in Figure 7 illustrates one type of such a valve. which may be inserted at 50in Figure 2. As shown in Figure 7 steam flows through the pipe 15. which is connected to pipe 50 into the valve the furnace 5 are effective upon the bellows 8|,

and through the linkage shown they are effective to move the valve member within the valve housing 50. When the pressure rises in the furnace it opens the valve 50 and operates the turbine 52 and the blower I8.

The material of Figure 3, which repeats on a. larger scale and more in detail the showing of portions of Figure 2, need not be redescribed. Identical numerals are applied to corresponding parts in both figures.

The engine of Figure 3 is illustrated merely as a typical piston displacement engine which can be embodied in the structure of the invention. The engine and turbine are geared together through the shaft 3 upon which a worm 9I is secured. This meshes with a worm gear 92 on a shaft 93. A crank 94 is fixed to the shaft, and a connecting rod 95 is joined to a piston rod 95 of a piston 91.

A second crank arm 98 is also joined to the shaft 93 and is connected by means of a link 99 to a slotted, pivoted link I00. A member IOI is' connected to a cross head I02 in suitable bearings I03. The member I M is also connected to a connecting member I04 which is joined to a conventional valve I05, which moves in the valve chest I4.

Fixed on the shaft 93 is a sprocket I06 about which a 'chain I0! is engaged. The chain also meshes with the sprocket I03 on a shaft I09.

Fixed to the shaft I09 is a bevel gear I I0 which meshes with a bevel gear III on the shaft I I2 upon which a governor II 3 is mounted. A con- The valve member is itself moved necting rod H4 is joined to the collar of the governor and to a cross head H5 of thescrvo motor assembly. Pivoted to the cross head 5 is a member IIS which has a rack II'I formed at one end.- The rack meshes with a hollow and preferably cylindrical valve member IIB of the servo motor. As shown a portion of the member H8 is provided with teeth II9 which mesh with the teeth of the portion I I1,

A pair of outlet openings I20 and I2I is formed in the cylindrical member H8. Steam pipes I22 and I23 are connected to the housing I24within which the valve member H8 is mounted and which is arranged to communicate with the interior of the valve member. A shaft I25 passes through the valve member II8. Fixed on the shaft I25 is a valve member I26 which as shown is of relatively triangular cross section and is provided with two offset arms or portions which are spaced apart from each other approximately the same distance as the openings I20 and I2I of the valve member I I8.

Fixed to the shaft I25 is a lever arm I21 to which is connected a link I28. The latter is connected to the piston rod I29 of the servo motor. On the rod I29 is mounted a piston I30.

The housing I24 is provided with passages I3I and I32, which communicate with ports I33 and I34, respectively. These ports communicate with the interior of the cylinder I35 in which the piston I30 is mounted and arranged to move. A second piston rod I36 is connected to the piston I30 and is joined to a cross head I31. Secured to the cross head is a lever I38 which is connected to the pivoted link I00, which cooperates with the link IOI which is itself connected to the cross head I02, as above mentioned.

a The valves indicated diagrammatically at 34 and 51 in Figures 2 and 3 are illustrated in greater detail in Figure 5. The numeral 51 is applied generally to the valve. As shown, a housing which may be unitary or formed of several members is provided with connection openings, for example, to the pipe 5a, It is also connected to the pipe 59a, which is the connection for the control of the operation of the valve. 'As here shown steam flows through the valve housing in the direction of the arrow when the passage is open. The valve comprises duplicate valve parts I 38' which are connected to a member I39.

The valve is mounted on a shaft I40 which at one end projects into the cavity I4l formed in an enlargement I42 of the valve housing. At its opposite end the shaft I40 extends into a chamber formed within the housing portion, I43. chamber is not open to the interior of the main housing but is in communication at its upper end with the pipe 59a. Fixed on that portion of the shaft I40 which lies within the chamber I43 is a second piston member I44. A spring I45 located beneath the piston and bearing upon the end housing is biased to raise the valve to the open position.

Steam flows through the pipe or conduit 59a, enters the chamber formed in the member I43 and exerts pressure upon the piston I44 to move it and the valve members I38 to the closing or seating position. Thus this valve operates to open and to close in response to pressure variations within the accumulator.

A similar valve which is marked 34 in Figures 2 and 3 is connected similarly to the pipe 6Ia.

The use and operation of this invention are as follows:

If the apparatus as shown in the drawings be This 6 considered as mounted on any suitable support, preferably a locomotive, and it then is desired to put it into operation from a cold start, the boiler and accumulator are filled preferably with scalefree water which is heated by the condensation of steam from an auxiliary boiler until that pressure is established both in the boiler and accumulator which it is intended to maintain in the accumulator under operating loads. Steam from the accumulator is then admitted from the handoperated valve GI to the turbine 33. The blower turbine 28 is also started by opening the valve 69 in pipe 69a. Primary and secondary air of manually adjusted pressure and a fixed amount of fuel from the fuel tank 31 are then admitted, preferably under manual control, to the burner 21 and the lighter is lighted by hand. The capacity of this burner is preferably such that it can maintain the pressure in the accumulator. under proper conditions to supply steam to all the auxiliary turbines. All of these turbines are started into operation after the lighting of the auxiliary burner. 1 When this condition has been reached the hand-operated valve BI is closed and the plant is ready for automatic operation,

When the high and low pressure throttles 49 are opened simultaneously, steam will flow from the boiler and accumulator to the main turbine I and engine 2 as indicated by the arrows in Figure 1, and this steam is suflicient to start revolution of the shaft 3. the engine increases, the relatively small steam storage capacity of the boiler as compared with that of the accumulator causes the steam delivery from the boiler to lag behind the delivery of the latter, and there is a tendency for pressure in the accumulator to drop. The governor 42, however, is so designed that before a substantial drop in the accumulator pressure occurs, a small number of revolutions of the shaft 3 is sufficient to shift the cam 4| and thus to operate the push rod 39 of one of the burners 26, thus coupling the clutch 38 and starting one of the fuel distributors 36 and also at the same time opening the corresponding air damper 40, thus-placing the particular burner affected in position to be lighted by the flame of the pilot burner 21 which is already lighted. Pressure in the boiler: will rise rapidly as a result of the operation just described and as the valve 51 will also have opened the accumulator will be recharged from the boiler to its original steam pressure.

While this occurs steam of higher pressure will also flow to the main turbine I and if the rise in boiler pressure caused by this operation has taken place before the turbine-has attained a speed sufficient to expand the steam to the fixed accumulator pressure, steam will also flow from the receiver 4 into the accumulator sufliciently raising pressure within the accumulator to the point where the valve 34 reduces the speed of the firing control turbine 33' and thereby reduces the air and fuel supply to the newly lighted main burner. This sequence of operations will eventually establish the boiler pressure at a sufllciently lower level to stop the reverse flow of steam from the receiver to the accumulator and to cause all of the steam coming to the turbine from the boiler to expand through the engine to the exhaust or condenser pressure.

As the shaft 3 speeds up the governor I3 acts to reduce the engine cutoff and therewith its average torque. At the same time, due to the automatic firing and steam flow control" conditions just described above, the boiler generating steam As the steam demand of of progressively higher and higher pressures causes greater weights of steam to pass through the turbine and the latter, as a result of this, will yield higher and higher torques, thus increasingly supplementing the decreasing engine torques.

In order to obtain increasing'steam generating capacities in the boiler with the increasing speeds and consequent increasing horsepower requirements of shaft 3, the governor 42 responds to the speed of the shaft 3 and will at certain speed intervals and in conformity with the variations of the engine cutoff caused by the governor I3 cause burner after burner to be lighted. The control turbine 33 will respond to the pressure variations in the accumulator and will cooperate in the fire control of the several burners to cause them to maintain a constant accumulator pressure. The charging valve 51 cooperates in this control.

As a result of the operations above described, the total expansion range of steamand thereby the ability of each pound of steam to do mechanical work are steadily and automatically increased as the power output of shaft 3 increases. From that follows that the amount of heat per effective horse power which must be carried off from the condenser or which must be wasted, at the exhaust, under maximum load conditions is kept at a minimum.

The method of feeding the condensate to the accumulator and from it to the boiler by the means described which means are controlled in a positive mechanical manner, instead of by the use of intermittently acting water level control devices, has great advantages, both in the accuracy of their operation and in the certainty and ease of their maintenance.

The throttles 49 may be closed while the shaft 3 rotates; for example, when coasting a locomotive down grade or bringing its train to a stop. When that is done the lever 48 is actuated and disengages clutch 41. The governor 42 then comes to a stop and the spring 43 is free to shift the cam 4| into the starting position in which it will cut off progressively the air and fuel supply from all of the burners 26 leaving, of course, only the pilot burner 21 lighted. This automatic operation, following upon the closing of the valves 49, prevents steam blowoff from the boiler to the accumulator and from thelatter to the condenser while the engine is coasting without admission of steam to the propelling means.

The boiler draft regulation of the plant is entirely automatic since the valve 50 always admits enough steam to the turbin 52 to maintain constant furnace pressure at 5 I.

I claim:

1. In combination in a steam power plant, primary expansion turbines and, compounded therewith, secondary expansion piston engines, a drive shaft, said turbines and engines mechanically coupled to the said drive shaft, a boiler for the supply of superheated steam to the primary expansion stage of said turbines, means for firing said boiler, a receiver and an accumulator of steam of lower than boiler pressure connected to the receiver between the two expansion stages of said turbines and engines, means responsive to the shaft speed for adjusting the cutoffs of the secondary expansion engines in relation to the shaft speed, means for varyin the firing rate in the boiler furnace, automatic means responsive to the accumulator pressure, and supplementary to the aforementioned means for varying the firing rate, which reduces the firing whenever the accumulator pressure rises above a predetermined, amount, and automatic means for causing a discharge of superheated steam from the boiler into the accumulator when the latters pressure de creases below a predetermined level, means for unrestrictedly discharging the steam from the boilers safety valve into the accumulator, and means responsive to shaft speed for controlling the water feedv to the accumulator, as well as for pumping the identical amount from the accumulator into the boiler.

2. In combination in a steam power plant, a primary expansion turbine and, compounded therewith, a secondary expansion piston engine, a common drive shaft, both turbine and engine being coupled to the said drive shaft, a boiler for the supply of superheated steam to the primary expansion stage, means for firing said boiler, a receiver, an accumulator of steam of lower than boiler pressure connected to said receiver between the two expansion stages, means responsive to the shaft speed for adjusting the cutoff of the secondary expansion engine in relation'to the shaft speed, means for varying the firing rate in the boiler furnace, automaticmeans responsive to the accumulator pressure, and supplementary to the aforementioned means for varying the firing rate, which reduces the firing whenever the accumulator .pressure rises above a predetermined amount, automatic means for causing a, discharge of superheated steam from the boiler into the accumulator when the latters pressure decreases below a predetermined level, said boiler having a safety valve. there being means for unrestrictedly discharging the steam from the boilerssafety valve into the accumulator, a condenser for condensing the steam exhausted by the engines, combined with shaft speed responsive means for control ling the cooling capacity of the condenser, means responsive to the shaft speed for pumping the condensate into the accumulator and for pumping an identical amount of water from the accumulator into the boiler.

3. In combination with a variable speed power shaft, a primary expansion steam turbine mechanically coupled thereto, in conjunction with a secondary expansion piston displacement engine, means adapted automatically to decrease and increase the cutoff of said engine with increasing and decreasing shaft speeds, a boiler adapted to generate superheated steam, means for feeding steam from said boiler to said turbine, receiver interposed between the exhaust of said turbine and the admission of said engine, a steam accumulator with charging inlets connected to said boiler and to said receiver, means responsive to the pressure in said accumulator, and means responsive to the shaft speed adapted to co-act with said means responsive to the pressure in said accumulator, said second mentioned means correlating the shaft speed and the fuel input, said first mentioned means functioning to modify the correlation between shaft speed and fuel input established by the second mentioned means.

4. In combination with a variable speed shaft, multiple expansion steam propulsion means for driving said shaft, said means including a turbine, a steam engine in series therewith and having a variable cut off, a boiler, a steam accumulator and means for maintaining substantially constant pressure in said accumulator by means of varying heat charges derived from said boiler,

means responsive to the pressure in said accu-' mulator, and means responsive to the shaft speed in coaction with said means responsive to excess pressure in said accumulator for increasing the pressure of steam generation within said boiler in proportion to increasing shaft speeds and for decreasing said boilers steam-generating pressure in proportion to decreasing shaft speeds.

5. In combination, a variable speed shaft, a

steam turbine of constant through flow areas, and a displacement engine, both connected to said shaft to drive it and arranged in series with each other. the turbine being ahead of the engine,

a boiler, means for conveying steam from said boiler to said turbine without throttling, adjustable means for firing said boiler, additional .means being thereby operated in response to variations in the speed of rotation of said'shaft.

6. In combination, a variable speed shaft, a steam turbine of constant through fiow areas, and a displacement engine, both connected to said shaft to drive it and arranged in series with each other, the turbine being ahead of the engine, a boiler, means for conveying steam from said boiler to said turbine without throttling, adjustable means for firing said boiler, additional means responsive to the speed of rotation of said shaft, for varying the. degree of firing of said boiler, means for maintaining the pressure of steam which is delivered from the turbine to the engine below a pre-determined maximum pressure without throttling, and valve means for varying the quantity of steam passing from said turbine to said engine. said last-mentioned varying means including a governor driven from said shaft, said varying means being thereby operated in response to variations in the speed of rotation of said shaft.

7. In combination, a variable speed shaft, a'

steam turbine of constant through flow areas, and a displacement engine, both connected to said shaft to drive it and arranged in series with each other, the turbine being ahead of the engine, a boiler, means for conveying steam' from said boiler to said turbine without throttlingrand an accu mulator in communication with the steam line between the turbine and the engine, adjustable means for firing said boiler, additional means responsive to the speed of rotation of said shaft, for Varying the degree or firing of said boiler, means for maintaining the pressure of steam which is delivered from the turbine to the engine below a pre-determined maximum pressure, and valve means for varying the quantity of steam passingv from said turbine to said engine.

said last-mentioned varying means including a governor driven from said shaft, said varying means being thereby operated in response to variations in the speed of rotation of said shaft.

8. In" combination. a variable speed shaft, a

and a displacement engine, both connected to line between the turbine and the engine, adjustable means for firing said boiler, additional means responsive to the speed of rotation of said shaft, for varying the degree of firing of said boiler, means for maintaining the pressure of steam which is delivered from the turbine to the engine below a pre-determined maximum pressure without throttling, and valvemeans for varying the quantity of steam passing from said-turbine to said engine, said last-mentioned varying means including a governor driven from said shaft, said varying means being thereby operated in response 'to variations in the speed of rotation of said shaft.

9. In combination, a variable speed shaft, a steam turbine of constant through flow areas and a piston displacement engine, both connected to said shaft to drive it and arranged in series with each other, the turbine being ahead of the engine. a boiler. means for conveying steam from said boiler to said turbine without throttling, manually adjustable means for firing said boiler, additional automatic means responsive to the speed of rotation of said shaft. for varying the degree of firing of said boiler, means for maintaining the pressure of steam which is delivered from the turbine to the engine below a predetermined maximum pressure, and means for varying the quantity of steam passing from said turbineto said engine, and means operated in response to variations in the speed of rotation of said shaft which is connected and adapted to operate said means for varying the quantity of steam passing from said turbine to said engine.

10. In combination, a. variable speed shaft. a steam turbine of constant through flow areas, and a piston displacement engine, both connected to said shaft to drive it and arranged in series with each other, the turbine being ahead of the engine. a boiler. means for conveying steam from said boiler to said turbine without throttling. manually adjustable means for firing said boiler, additional automatic means responsive to the speed of rotation of said shaft, for varying the degree of firing or said boiler, co-acting means for modifying the firing eifect of said shaft speed responsive firing means, so as to maintain the pressure of steam which is delivered to the engine steam turbine of constant through flow areas,

said shaft to drive it and arranged in series with each other, the turbine being ahead of the engine, a boiler, means for conveying steam from said boiler to said turbine without throttling, and an accumulator in communication with the steam below a predetermined maximum pressure, and valve means for varying the quantity of steam passing from said turbine to said engine, and governor means operated in response to variations in the speed of rotation of said shaft, which latter means is connected and adapted to operate said valve means for varying the quantity of steam passing from said turbine to said engine.

R. M. OSTERMANN.

REFERENCES orrsn I The following references are of record in the file of this patent:

UNITED STATES PATENTS

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