US1712497A - Apparatus for regulating the working of steam-generating plants - Google Patents

Description

y 9- o. H; HAR TMANN ET'AL 1,712,497

' APPARATUS FOR REGULATING THE WORKING'OF STEAM GENERATING PLANTS Filed March 16, 1925 e Sheets-Sheet 1 y 14, 1929- o. H. HARTMANN ET AL APPARATUS FOR REGULATI NG THE WORKING OF STEAM GENERATING PLANTS Filed March 16, 1925 6 Sheets-Sheet W/NESS y 14, 1929- o. H. HARTMANN ETAL 1,712,497

APPARATUS FOR REGULATING THE WORKING OF STEAM GENERATING PLANTS Filed March 16, 1925 6 Sheets-Sheet 3 imam/c WEMPE 4 14, 1929- o. H; HARTMANN ET AL 1,712,497

APPARATUS FOR REGULATING THE WORKING- 0F STEAM GENERATING PLANTS Filed March 16, 1925 6 Sheets-Sheet 4 v Q 4 73 6.9 m

W/T/VESS INVENTORS orra M f/flRTMflNA/ g. raga/arc M/EMPE A TTOR/YEVS May. 14, 1929.

o. H. HARTMANN ET AL Filed March 16, 1925 APPARATUS FOR REGULATING THE WORKING OF STEAM GENERATING PLANTS 6 Sheets-Sheet 8, 560 0/ z acomar/n 61M or 80/4 [Rs llY STE/9M .Su

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APPARATUS FQR REGULATING THE WORKING OF STEAM GENERATING PLANTS Filed March 16, 1925 6 Sheets-Sheet 6 0 rra M ///m TM/l/V/V f'R/EUR/Cl/ WEMPE Rue/71b6,

Patented May 14, 1929.

UNITED STATES 1,712,497 PATENT OFFICE.

-OTTO H. HARTMANN AND FRIEDRICH WEMPE, OF GASSEL-WILHELMSHOHE, GER- MANY, ASSIGNORS TO SCHMIDTSCHE HEISSDAMPF-GESELLSCHAFT, M. .B. IL, 01 CASSEL-WILHELMSHOHE, GERMANY,'A CORPORATION OF GERMANY.

APPARATUS FOR REGULATING THE WORKING OF STEAM-GENERATING IPLANTS.

Application filed March 16, 1925, Serial No. 16,075, and in Germany March 28, 1924.

The invention relates to apparatus for regulating the working of steam-generating plants, especially in locomotives, which generate steam of different pressures in several steam generators.

The object of the invention is, in multipressure steam-generating plants, which are frequently subject to violent and irregular variations in the generation of steam or in the demand for steam, to provide an arrangement which renders it possible to vary in the simplest manner the distribution of the steam from the individual steam generators working at different pressures and also in addition to vary thepower developed by the engine.

According to the present invention, this object is secured by adjusting the steam valves of the different steam generators by a common adjusting arrangement.

The adjustment in question can be effected either by hand or automatically. In the latter case, preferably the alterations of pressure in one of the steam generators, or the alterations in the ratio of the pressures of two steam generators, are utilized for actuating the mechanism controlling the steam.

valves.

As a third possibility, hand adjustment and automatic adjustment may be simultaneously utilized.

The invention can be applied to all steamgenerating plants in which the above-dcscribed variations of pressure occur and is thus especially applicable to locomotives though similar pressure variations may occur in marine installations and other plants.

For the purposes of explaining the invention, the application of thedevice will be described, by way of example, with reference to a locomotive operating with steam at two different pressures generated in separate boilers having a common furnace, the highpressure steam being supplied to the highpressure stage and the low-pressure steam to the low-pressure stage of the engine or in some cases being added to the exhaust steam of the high-pressure stage.

In locomotives, the application of the present invention is especially advantageous because the engineer is no longer under the necessity of attending to a number of different regulating arrangements; on the contrary, the invention renders it possible for Fig. 1 is a top plan view of the same, with I the outer casing removed and the inner casings in section.

Figure 2 being a section through the lowpressure regulator and parts actuating it;

- Figure 3 is a similar section through the hi h-pressure regulator;

igure' t shows dia raminatically in plan the position of the di erent parts of the apparatus and the two regulators of the 1000- motive; I

Figure 5 is a development of the profiles of the two cams forming part of the regulating apparatus;

Figure 6 is a development of the profiles of cams of a modified form;

Figure 7 is a perspective view of an arrangement in which adjustment of the valves is effected both by hand and automatically,

Figure 8 being a section to an enlarged scale on the line 88 of Figure 7, and

Figure 9 a modified form of a detail shown in Figure 7;

Figures 10 and 11 show. diagrammatic view of a further modification of the invention.

Figures 12 and 13 are diagrams illustrating the varying relation between certain factors during the operation of the locomotive.

Figures 14 and 15 are perspective views, partly in section, showing two constructions of a regulating device.

Fig. 16 is a detail of the cam adjusting means, and

.Fig. 17 is a diagrammatic View of a locomotive having the present invention applied thereto. 7

The locomotive shown in Fig. 17 corresponds, except for the regulating features, to U. S. application Serial No. 7 37 ,311, filed September 12, 1924, by Otto H. Hartmann. The steam generating system of this locomotive comprises a steam drum 6 in which high pressure steam is generated, and a low pressure boiler B which is constructed as a fire tube boiler, the general arrangement being known in the art. The high pressure steam generated in drum e is passed through a conduit 36 to the dome 80, whence it passes through a regulator 3 and a conduit 37 to a super-heater C, the tubes of which extend into the fire tubes of the boiler 13. The steam from the superheater 0 passes through a pipe n, to the high pressure cylinder of the locomotive, and the steam from the superheater D passes through a pipe m to the low pressure cylinder.

In Figures 1 to 3, the usual steam dome on the boiler is indicated by the numeral, 1, a regulator valve 2, in the present case, being arranged in this dome for controlling the delivery of low-pressure steam from the lon- .gitudinal boiler. Adjacent to the steam dome, 1, a second regulator, 3, is provided which similarly regulates the delivery of the high-pressure steam from the boiler generatmg it.

To serve as the low-pressure regulator, 2, a valve of the usual kind is shown by'way of example, having in one casing, 4, a main valve, 5, and an auxiliary valve, 6, constructed as a needle valve. Steam passes to this auxiliary valve through slots 4 in the casing and remains in the s ace above the main valve, 5, until the auxiliary valve, 6, is raised from its seat and thereby compels the main valve to rise from its seat likewise. Steam flows to the main valve from the inlet pocket, 7. After the main valve opens, steam passes through the pipe, 8, to the low-pressure cylinder, or if desired passes first to a superheater.

The high-pressure regulator is preferably constructed in a similar manner to the lowpressure regulator, 2, with a main valve, 9, and an auxiliary valve, 10, taking the form of a needle valve, by means of which the main valve is operated. The high-pressure steam passes to the casing of the main valve through the pipe, 11, and leaves the regulator through the pipe, 12. To initiate the movement of the main valve, the necessary steam can be led to the auxiliary valve, 10, through slots 10.

For the hand operation of the two regulators, the following arrangement is provided The regulator shaft, 13, which is provided in the cab of the locomotive with a hand lever, 14, carries two cam discs, 15 and 16, of which the disc, 15, serves for moving the'auxiliary valve, 6, of the low-pressure regulator, 2, while the disc, 16, performs a like function in relation to the auxiliary valve, 10, of the high-pressure regulator, 3. Inoperative association with the cam, 15, a forked lever, 17, is arranged carrying rollers, 18, and 19, this lever being mounted to rock on a spindle, 20, carried on the boiler. The lever, 17, is connected by the link, 21, and the lever, 22, with a spindle, 23, carried in bearings in the upper part of the dome, 1, the spindle, 23, also carrying a second lever, 24, which is operatively connected at its free end at 25, with the rod of the auxiliary valve, 6. By turning the regulator shaft, 13, by means of the hand lever, 14, so that the roller, 18, runs over the swell of the cam, 15, the auxiliary valve is raised by the mechanism described, thus causing the main valve, 5, to rise also and thereby increase the flow of steam through the pipe, 8, to the low-pressure cylinders. The greater the swell of the cam, 15, the greater the movement of the auxiliary valve, and consequently also of the main valve and the greater the flow of low-pressure steam to the low-pressure cylinders.

Rotation of the cam, 16, on operation of the regulator shaft, 13, actuates the auxiliary 35 valve, 10, of the high-pressure regulator, 3, in a similar manner. A forked lever, 26, with rollers, 27 and 28, is carried on the spindle, 20, and movement due to the swell of the cam, 16, is transmitted through the link, 29, and lever, 30, to the rocking spindle, 31, carrying the lever, 32, and thus to the rod of the auxiliary valve, 10, to which the lever, 32, is connected at 33. It will be understood that the lever 26 rocks on its axis independently of the lever 17.

The diagrammatic plan of Figure 4 shows how the high-pressure regulator is arranged near the dome for the low-pressure regulator and shows also the dome, 1, which contains the low-pressure regulator and the manner in which the usual sand-boxes, 34, are surround ed by a wall, 35. Between the dome, 1, and the sand-boxes, 34, the high-pressure regulator, 3, is arranged. The inlet and outlet pipes, 11 and 12, respectively are led to the wall, 35, to which a pipe, 36, coming from the high-pressure boiler, and a pipe, 37, leading to the high-pressure cylinder or to the ,superheater, are secured. The connection be- 11 tween the pipes, 11 and 36, and also between the pipes, 12 and 37, may be seen from the section shown in Figure 3, in which the wall,

3:), is also shown and parts of the pipes, 36 and 37. In addition in the section in Figure 2, the wall, 35, is shown which encloses the dome, 1, and the sand-boxes, 34, as well as the regulator, 3.

In the devices described above regulation is effected entirely by hand. With this arrangement, assuming a suitable design of the cams, by adjustment of the one hand lever,

14, the power of the engine can be regulated and also the proportion of steam from the two boilers necessary to the production of 1 the desired power.

Various results may be obtained by using appropriate shapes for cams 15 and 16, and by adjusting'them angularly with respect to each other on the shaft 13. This angular adj ustment is made possible by mounting the cams on the shaft independently of each other, normally holding them in position, for

example, by the arrangement shown in Fig.

16, which is known in the art. Referring to Fig. 16, the cam 15 is mounted on shaft 13 in such a manner as to be rotatable, but is normally held against rotation by being pressed between a disk 76, which is fixed to the shaft 13, and nut 77 and lock-nut 78. In this arrangement it is evident that any desired angular position may be given to cam 15 by loosening the nuts.

In Figure 5, a form of development of the profiles of the two cams, 15 and 16, is shown by way of example. On rotation of the shaft, 13, as the two curves rising from the point, a, are coincident, the two regulators, 2 and 3, are opened at the same rate. This action continues until the point, 5, is reached, when both regulators are open to the greatest possible extent and so remain as the reguator shaft rotates through a further angle, corresponding to the part, b to 0. Further rotation of the regulator shaft, in consequence of the gradual fall of the curve of the lowpressure cam from 0, results in a gradual closing of the low-pressure regulator,.2, while the high-pressure regulator still remains fully so open. At (1, the low-pressure regulator is completely closed as at this point the swell of the cam, 15, has decreased to zero, but the highpressure regulator, 3, still remains fully open. Further rotation of the shaft in the same direction will then gradually close. the highpressure regulator until at the point, 6, it is likewise fully closed.

The cam profiles shown in Figure 5 are given only by way of example. By using other profiles or by adjusting the cams in relation to one another on their shaft, any desired conditions of distribution can be secured. For example during thestarting period which corresponds to the part, a to b, in Figure 5, instead of taking the same quantity of steam from the two boilers, as shown, different -quantities might be taken. An example of cams for this latter type of operation is shown in Fig. 6.

The starting period extending from a to b. The low-pressure regulator at first, due to the more quickly rising profile of the cam, 15, is opened more than is the high-pressure regulator by the cam, 16. The low-pressure regulator is fully open at the point, f, corresponding to a half-opening of the highpressure regulator. From 6 to e the curves of Figure 6 correspond to the region, I) to e, in Figure 5. Other profiles than those shown in Figures 5 and 6 can be provided as required.

Figures 7 and 9 show embodiments of the inventive idea, in which regulation .of the power and of the distribution of steam from the two boilers can be efiected by hand, the

distribution of steam being in addition automatic.

In the arrangement shown in Figure 7, the low-pressure regulator in-the dome, 1, is indicated diagrammatically by the auxiliary valve, 6, only, while the high-pressure regulator is similarly indicated by the auxiliary valve, 10. The regulatorshaft, 13, as before, can be rotated by the hand lever, 14, in the locomotive cab. The cams which operate the auxiliary valves, 6 and/or 10, and thereby the regulators, 2 and/or 3, in this arrangement are mounted on a sleeve, 38, which is splined to the regulator shaft, 13, so as to be displaceable thereon in a longitudinal direction. The configuration of the cams, 15 and 16, of which, as before, the former actuates the low-pressure valve, 2, and the latter the high-pressure valve, 3, differs from those already described above since the cams in the present case take the form of cam sleeves.- The cam, 15, like the cam, 16, extends longitudinally for a certain distance along the sleeve, 38, its swell over the whole of this distance increasing gradually from one end to the other. The cam, 15, for example, which lies at that end of the sleeve remote from the hand lever has'its greatest swell at the end nearer the hand lever. On the other hand, at each point of its length, a rise and a fall of the cam profile occurs in the circumferential direction of the sleeve. Successive sections of the cams, 15 and 16, transverse to the longitudinal axis of the sleeve would present a number of similar cam profiles in which the swells on one side are greater than on the opposite side. A cross-section on an enlarged scale, taken through the sleeve at the point of greatest swell of the cam, 16, on the line, 8-8, of Figure 7 is shown in Figure 8.

Movement due to the cam, 15, is again transmitted to the auxiliary valve, 6, by a forked lever, 17, which is mounted on the spindle, 20, and by way of the lever, 17, link, 21, and lever, 22, rocks the spindle, 23,'and thereby lifts or raises the auxiliary valve, 6,

by means of the lever, 24. In a similar manner movement due to the cam, 16, is transmitted to the spindle, 31, by way of the forked lever, 26, on the spindle, 20, lever, 26", link, 29, and lever, 30, the auxiliary valve, 10, being finally operated by way of the lever, 32 on the spindle, 31.

For automatic operation, the end, 39, of

a piston rod, 40, co-operating with a piston, 41, movable in the cylinder, 42, engages in any desired manner with the end of the sleeve, 38, remote from the hand lever. For example, the end, 39, of the piston rod may be formed as a fork provided with pins slidable in a groove in the sleeve,38. In addition, in the cylinder, 42, a. spring, 43, is arranged in the space between the plston and the cylinder cover, while steam can be admitted through the pipe, 44, to the opposite side of pressure the piston this steam in the case described being conveniently taken directly from the low-pressure boiler or from a pipe connected thereto.

The arrangement described with reference to Figure 7 can in the first place be operated by the hand lever, 14; for example, the rollers of the forked levers, 17 and 26, when starting, can be positioned on the cylindrical part of the sleeve, 38, at about the middle of the length of each cam, 15 and 16. On rotating the regulator shaft, 13, by means of the hand lever, 14, the two regulators will open a certain amountldepending on the shape of the cams at this pointand as a consequence corresponding quantities of steam will be taken from the boilers. If during working, too high a pressure occurs in one of the boilers, for example in the low-pressure boiler where it is particularly undesirable, the automatic adjustment of the distribution of steam from the two boilers comes into action. The rising pressure of the low-pressure boiler causes brought about, the opening of the auxiliary valve, 6, and thereby also of the main valve of the low-pressure regulator, 2, is increased while the opening of the auxiliary valve, 10, and thereby the opening of the corresponding main valve of the high-pressure regulator, 3, is decreased. The supply of steam from the low-pressure boiler is therefore increased while that from the high-pressure .boiler is decreased. 3

The mechanism serving for the displacement of the sleeve can be modified as desired. For example, the piston, 41, instead of being subject to the action of steam of one pressure only, may be operated by the difference in etween the highand low-pressure steam.

In Figure 9 an arrangement of this kind is shown in which high-pressure steam acts on the one side of a difl'erential piston, 45 and low-pressure steam on the other side. Alteration in the ratio of the-two pressures will then automatically vary the distribution of steam from the two boilers by adj ustment of their regulators.

For example, if the pressure in the high pressure boi er rises'too far, the sleeve, 38, in contradistinction to the case above described in which too great a pressure occurred in the low-pressure boiler, is displaced in the opposite direction and thereby more steam is taken from the high-pressure boiler and less from the low-pressure boiler.

Another form of apparatus for automatically adjusting the distribution of the total steam from the two generators in conjunction h a andperated arrangement for regulating the power of the machine and the distribution of the steam is diagrammatically shown in Figures 10 and 11.

The regulating shaft, 13, rotatable by the hand lever, 14. carries the two cams, 15 and 16, lying one behind the other in the drawing. By rollers, 18 and 19, and levers 46 and 47, which are pivot-ed respectively at 48 and 49, movement due to the cams is transmitted to the auxiliary valves, 6 and 10, respectively through appropriate connections. The mechanism between the lever, 46, and the auxiliary valve, 0, of the low-pressure regulator comprises a rod, 51, guided at 50, to the end of which a link, 52, is pivoted, this link by way of a second link, 53, being connected with a rod, 55, guided at 54, to the other end of which rod is pivoted the lever, 57, rotatable about the fulcrum, 56, and serving to move the auxiliary valve, 6. The mechanism operating the auxiliary valve, 10, similarly comprises arod, 59, guided at 58, and connected at one end with the lever, 47, and at the other end with the link, 60, which in turn by means of a second link, 61, is connected with a rod, 63, guided at 62, to the end of which is pivoted the lever, 65, rotatable about the point, 64, and serving to operate the auxiliary valve, 10.

The links, 52 and 53, or 60 and 61, form two 95 toggle systems designed to vary the opening of the auxiliary valves, 6 and 10, in opposite directions. The arrangement indicated by the numerals, 40 to 43, serves in response to alterations in the pressure of the low-pressure steam entering through the pipe, 44, to effect such adjustment by the following mechanism The piston rod, 40, is extended and preferably guided at several points, for example at 66, 67 and 68. Beyond the aide, 68, the piston rod is pivotally connected at the point 69, with one end of a rod, 71, the other end of which is connected to the point of attachment, 70, of the two links, 60 and 61. Be- 110 tween the guides, 66 and 67, the iston rod,

40, is provided with a lug, 72 igure'11) having a pivotal point of attachment, 73,

from which a connecting link, 74, leads to the point of attachment, 75, of the two links, 52

and 53. As shown in Figure 11, the rod, 74,

the connecting point, 75, and all the rods, 51

to 55, lie on'pne side of the plane containing the pistoIrrod, 40, which in the drawing lies in the plane of the paper.

On a movement of the piston, 41, occurring due to an increase of pressure in the low-pressure boiler, against the action of the spring,

43, as will be seen in Figure 10, a displacement of the two points, 75 and 7 0, occurs in 125 the direction shown by the arrows. As a consequence the two-ad acent ends of the rods,

51 and 55, associated with the auxiliar valve,

6, approach one another, while on the contrary, the lunar ends oi the rods, 59 and. 63, 1

associated with the auxiliary valve, 19, increase their distance apart. The auxiliary valve, 6, and the regulator, 2, therefore, are opened more Widely, while simultaneously the auxiliary valve, 10, and regulator, 3, are moved toward the closed position. On adecrease of pressure in the low-pressure boiler, the reverse action takes place, that 15, the opening of the low-pressure regulator, 2, is reduced and simultaneously the opening of the highpressure regulator, 3, increased.

The apparatus referred to above-controls in diflerent ways the general working of the steam-generating plant but in specialcases, and under certain conditions of working, it is desirable, especially in the case of a locomotive having a two-pressure steam generator, to provide a supplementary device for controlling the above described apparatus and this result is attained by the present 1nvention.

For the purpose of explanation reference is made to Figure 12 of the accompanying drawings, in which the generation of steam, D is plotted in relation to the coal consumption, R, per unit grate area in the two steam generators of a two-pressure steam-generating plant for a locomotive in which the high-pressure steam generator takes the form of a firebox.

The curve, a, shows the total generation of steam in the two generators in relation to the coal consumption per. unit grate area and shows in particular the manner in which the quantity of steam generated increases with increasing coal consumption. Curve, 6, shows similarly how the quantity of steam generated in the high-pressure steam genera to icreases with increasingconsumption of coal. From this diagram it is clear that the ratio of the steam production in the highpressure fire-box boiler to the total steam production is the greater, the smaller the coal consumption per unit grate area. At low powers or when the engine is stopped or running light, the high-pressure boiler generates approximately 100 per cent of the total steam produced in the two boilers; at higher powers, however, the relation between steam generation in the highand low-pressure, boilers respectively alters so that for a certain coal consumption per unit grate area, 50 per cent of the total steam is generated in the high-pressure and 50 per cent in the lowpressure boiler. I

Supposing, for example, that the locomotiv'c isstationary for a considerable period, steam will continue to be generated in the high-pressure boiler. since heat is still radiated from the furnace but in the low-pressure boiler, the steam production will be either zero or negligible. The pressure in the highpressure boiler will therefore rise, with a probability of the safety-valve blowing off. It is desirable, therefore, when the locomotive is stopped, to have a pressure in the highpressure boiler suchthat the point at which the safety valve blows off is not reached.

The invention provides a simple means for effecting such a lowering of the pressure by alteration of the distribution of the steam taken from the two boilers so that before stopping the locomotive, more steam is taken from the high-pressure boiler than is being generated therein.

Such an alteration of the distribution of the steam from the two boilers, in the sense that the ratio of the steam generated in the boiler to the total steam delivered to the engine is greater than this boilers share of the total steam production, may also be advantageously applied for example to the starting and acceleration of the locomotive and can likewise be effected by the present invention.

Figure 13 serves to explain the conditions under which such an alteration can be effected, the curves in this figure being based on the assumption that when starting and accelerating, more steam is taken from the lowpressure boiler than is being generated in it. All the curves in Figure 13 have as abscissa the distance travelled by the locomotive from one stopping place to another.

Curve, 0, shows the velocity of the locomotive, curve, 01, the cutoff, and curve, 6, the exhaust pressure. The exhaust pressure is higher when starting owing to the later cut- 0 but falls to a normal value to correspond with a normal cut-oil under average condition of working. Curve, f, shows the total steam taken from the boilers which for simplicity is assumed to be uniform for the whole period so that the curve, f, becomes a straight line parallel to the axis of abscisstc.

Curve, 9, shows the steam taken from the two boilers respectively, the ordinates, h, h and so forth lying above the curve, g, indicating the quantity of steam taken from the low-pressure boiler and the ordinates, 27, i and so forth lying below the curve, indicating the quantity of steam taken from the high-pressure boiler. It will be seen from the diagram that during the starting period, the amount of steam taken from the lowpressure boiler is greater than that taken roin the high-pressure boiler (ordinates, h, i). The proportion, however, alters as normal working is attained when in the example given more steam is taken from the highpressure boiler than from the low-pressure boiler, (ordinates 2', If), this distribution so affecting the pressure in the low-pressure. boiler shown in curve, is, that the latter falls during the starting period but gradually rises to the normal value, m, while the pressure in the high-pressure boiler shown in curve, 12, rises during the starting period to its normal value, 0. Before stopping the latter can, as above mentioned, be reduced to a lower value.

before a stopping an inoperatim position.

The invention contemplates the use of a paratus as above described for automatical y regulating the distribution of steam from the two steam generators but in special conditions' of working, (for example during startingor just before stop ing) in addition to. such normal ad ustin orces, additional which are either One form of the invention by way of example is shown in Figure 14, which coi're-- sponds to a part of Fig. '2'. In this figure, as before, the cam sleeve is indicated at 38, and the cam for the high-pressurc regulator at 15, while the piston rod, 40, of the piston, 41, is

displaceable as before in the cylinder, 42,.

against the spring, 43, under the action of the low-pressure steam entering at 44, so as thereby to move the cam sleeve and alter the dis-' tribution of the steam. l The novelty of this part of the invention lies in the fact that the spring, 43, butts against a plate, t, or the like which is moved by suitable means such as, for instance, a hand-wheel u. and serves to load the spring, 43, to a. greater or less degree. For example, the device, u, can be so adjusted that load is re moved from the spring, 43. In this case, the low-pressure steam acting on the piston, 41, will displace the latter to a greater extent so as to increase the quantity of steam taken from the low-pressure boiler. The adjustment of the spring by the driver, therefore, introduces an additional force, in this case negative which affects the automatic mechanism above described until, by re-setting the hand-wheel or the like, u, the spring,

the spring is decreased, the valve-operating mechanism acts automaticallyt'o increase the steam flow from the low-pressure boiler and thereby reduce its pressure. The load on the spring can be decreased, for example, just place where it can be reapplied to the same. extent.

A wholly automatic solution of the problem isshown byway of example in Figure 15. The regulating piston, 41, 'is of the differential type, low-pressure steam entering at 44' acting on its smaller area in a direction opposite to that in Figure 14. Due to this reversal of direction, the spring, 43, is arranged on the 0 posite side of the piston and the longitudinarprofiles of the cams, 15 and 16, are likewise turned end for end as indicatc-d. A pipe connected with the cylinder,

4&2, at 10, may be provided, if desired, leading 43 is again normally loaded. During the period when the load on for example to the exhaust ipe of the engine. As the exhaust pressure uring startin is higher than during normal working, see Figure '13) the pressure on the piston, 41, during this period is likewise higher than during normal working so that the cams, 15 and.16, are displaced longitudinally: in a direction such that more steam is ta on from the low-pressure boiler than is being generated therein. As a. consequence, the conditions mentioned above occur, namely, the pressure in the low-pressure boiler falls as in curve, k,'to a minimum, the amount of which is determined by the dimensions chosen, especially in respect of the regulatin piston. The length of time during which t is mini- -mum pressure is maintained depends on the steam pressure in the low-pressure boiler. In addition, if desired, avalve :v,.can be providedin the pi e, 10, which can be opened and closed by the driver.

It will be understood that utilizing the exhaust pressure is only an example of-a specific way 0 applying an additional force for actuating the valve mechanism and. that the same generic idea may be embodied. in various other ways.

The invention renders it possible to utilize the storage capacity of the one boiler at certain times and in this way to increase the eiiiciency of theinstallation.

What we claim is 1. In apparatus for the regulation of the working of steam-generating plants, especially in locomotives, comprising a plurality of generators producing steam at different pressures, a steam valve for each enerator, the valves of the several generators ing connected to a common automatic adjusting device, conduits between the common automatic adjusting device and a steam space of a generator, said device being adapted to re- .spond to alterations of pressure in said steam space, and a hand lever for the common manual adjustment of the several valves in addition to the automatic adjustin device.

'2. In apparatus for regulating t e working of steam-generating plants, especially in locomotives, comprising two. generators producing steam at different pressures, a regulator shaft, a throttle valve controlling the output from each generator, each throttle valve having connections to said regulator shaft. cams on the regulatorshaft ada ted to actuate said connections, and a ban lever at one end of the .regulator shaft for rotating it.

3. In apparatus as claimed in claim 2, a piston adapted to be actuated by variations of the pressure in the low-pressure steam generator. producing steam, connections between said piston-and the cams on the regulator shaft for controlling the hand-operated action of the cams.

4. In apparatus as claimed in claim 2, a

sleeve on the regulator shaft, said sleeve adapted to be displaced in a longitudinal direotion by a device actuated automatically by the variations in pressure of steam, the cams being mounted on said sleeve and having cross-sections varying alongthe length of the sleeve until they merge into the base circle, said cams adapted to alter the stroke of the valves both by rotation and also by longitudinal displacement of the sleeve.

5. In apparatus as claimed in claim 2, wherein the cams are adjustably mounted on the regulator shaft in relation to one another.

6. In apparatus as claimed in claim 2, a sleeve displaceable in a longitudinal direction on the regulator shaft, means responsive to variations in the steam pressure for displacing said sleeve longitudinally of said shaft, the cams being mounted on said sleeve and having. cross-sections varying along the length of the sleeve till they merge into the base circle, said cams being adapted on dis placing the sleeve longitudinally to increase the opening of'the high-pressure valve and at the same time to decrease the opening of the low-pressure valve and vice versa.

7. Apparatus for regulating the working of steam power plants especially in locomotives, comprisinga plurality of generators producing steam at difierent pressures, a separate regulator for each generator, connections for adjusting each re ulator, and a manually operated actuating evice common to all of said connections.

8-. Apparatus according to claim 7, in

which the operation of the manually operated actuating device regulates the total amount of steam taken from the generators as well as the proportion of steam taken from the individual generators. f

9. Apparatus according to claim 7 including, in addition to thev manually operated actuating device, an automatic device which regulates the proportion of steam supplied by the individual generators.

10. Ina power plant, a generator of high pressure steam, a generator of low pressure steam, an engine having a plurality of stages receiving steam from said generators, manually operable means for increasing and decreasing the fiow of steam from said generators to said stages, and means responsive to the pressure inone of said generators for varying the ratio between the rates of flow from said generators to said stages.

11. In a power plant, a generator of high pressure steam, a generator of low pressure steam, an engine having a plurality of stages receiving steam from said generators, manually operable means for simultaneously varying the flow of steam from said generators to said stages, and means independent of said manually operable means for varying the ratio of the flow of steam from said high pressure generator to the flow of steam from said low pressure generator.

12. In a control for a power plant having a generator of high pressure steam and a generator of low pressure steam, a manually rotatable shaft, a pair of cam members splined on saidshaft, each of said cam members being of varying cross-section between its ends, a pair of pivoted members engagin said cams and adapted to be actuated there y, a connection between one of said pivoted members and the throttle of the high pressure generator, and a connection between the other ivoted member and tlu throttle of. the ow pressure generator.

In testimony whereof we have hereunto set our hands.

OTTO H. HARTMANN. FRIEDRICH WEMPE.

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