US2188315A - Condensing steam locomotive - Google Patents

Description

Jan. 30, 1940. c. A. SCHELLENS ET AL 2,188,315

CONDENSING STEAM LOCOMOTIVE 1956 4 Sheets-Sheet 1 Filed Feb 15 Jan. 30, 1940. c. A, SCHELLENS ET AL 2,183,315

CONDENSING STEAM LOCOMOTIVE Filed Feb. 15, 1936 4 Sheets-Sheet 2 i a 1 r 44 E I r 72 Jan. 30, 1940- c. A. SCHELLENS ET AL 2,138,315

CONDENSING STEAM LOCOMOTIVE Filed Feb. 15, 1936 4 Sheets-Sheet 3 50 /44 I7? 0611 i ars.

r a. W Hy. 7 L 1% 1940- c. A. SCHELLENS ET AL 2,188,315

CONDENSING STEAM LOCOMOTIVE Filed Feb. 15, 1956 4 Sheets-Sheet 4 Jnveniows. Claw-1 A M d L- M iii) Patented Jan. 30, 1940 UNITED STATES CONDENSIN G STEAM LOCOMOTIVE Christopher A. Schellens, Marblehead, Mass., and Eugene L. Schellens, Ridgewood, N. J., assignors to -8 Engineering Company, Englewood, N. J a corporation of Delaware Application February 15, 1936, Serial No. 64,076

17 Claims.

This invention relates primarily to steam locomotives and particularly to electrically propelled steam locomotives wherein the electric generator that supplies the current for the wheel motors is driven by a steam turbine.

For efficient operation of such a locomotive it is highly desirable to utilize the expansive force of the steam as completely as is practicable and hence it is desirable to expand the steam in the turbine to a pressure that is below atmospheric pressure and hence to utilize a condenser for the turbine exhaust steam, the condenser preferably operating at a constant high vacuum regardless of the load on the turbine, so that the efliciency be high at all loads.

It is also desirable to condense the exhaust steam, apart from reasons of efliciency, for the purpose of conserving the supply of water from which the steam is made, so that the locomotive can make a long run without the necessity for replenishing the water supply. Locomotives are operated in regions where the water is scarce. Locomotives are also operated in regions where the water supply while plentiful is bad for boiler use by reason of containing large quantities of scale forming material. Such water deposits scale on the surfaces subjected to high temperature water and steam and requires frequent removal with consequent loss of service of the locomotive.

The application of a condenser to a locomotive presents problems peculiar to the locomotive. Height and width are limited to vertical and transverse dimensions that cannot be exceeded. The longitudinal dimension is also restricted although not perhaps to such a great degree as the other dimensions.

The condenser, furthermore, should be of the air cooled type since condensing water, due to the large amount required, cannot well be carried by the locomotive. An air cooled condenser, especial- 1y when adapted for condensing the steam required for large power outputs, as for instance, 1800 wheel horse-power, requires a large amount of cooling air and a large extent of heat dissipating surface. A suitable and economical disposition of the heat dissipating surfaces and the passage of large amounts of air thereover within the very restricted dimensions available on the locomotive without interference with or restriction of other essential parts of the locomotive, and while providing for the ready accessibility of all essential parts of the locomotive, and for the comfort of the locomotive operatives, and for good track visibility by the locomotive driver, by mechanism not harmfully affected by vibration and speed changes, has been a problem solved by the present invention.

Hence an object of the present invention is the provision of a locomotive having a steam-oplarge capacities is one wherein the steam to be condensed passes through generally parallel tubes disposed in approximately cylindrical configuration and communicating at their ends with headers and with air moving means which forces air in opposite directions through the ends of the cylinder transversely of the tubes. Such a construction constitutes a further object of the invention.

Another object of the invention is the provision of a condenser constructed as above described wherein air moving means, as draft fans, are disposed within both open ends of the tube cylinder and operate to discharge heated air outwardly of the cylinder in opposite directions.

A further object of the invention is a construction wherein both draft fans are secured to the same vertical driving shaft, the shaft being suspended from its upper end and the lower end being provided with means to maintain it against radial displacement.

Another object of the invention is the provision of a plurality of similar condensing units as above described wherein the draft fans of all units are driven from a common cross shaft that has means therein between the units and also preferably between the units and the driving means for the cross shaft, such means being of the nature of universal joints and axially displace-able shaft sections, for the purpose of permitting relative expansional movement between the condenser units without interfering with the reliable operation of the respective fans of the units.

In the condenser of the present invention the condenser tubes depend from an upper steam header, which header is connected to the exhaust steam part of the turbine casing. In order to allow for free expansion of the condenser tubes it is an object of the present invention to support the weight of the condenser, at least mainly, by the steam header. The header, in turn, is supported by the turbine, the header resting at one end on the turbine casing and at the other end on a supporting beam over which it is freely movable for the purpose of allowing longitudinal expansion and contraction of the header. With this arrangement the condenser tubes are not under harmful strain. Preferably the bottom or condensate header is supported on springs or ill) equivalent resilient supporting means which, however, are" not intended normally to assume more than about half the weight of the condenser unit. Provision is made, however, for supporting the entire weight of the condenser unit by the springs for the purpose of enabling the steam header to be detached from the turbine casing when desired. Such construction constitutes a further object of the invention.

A yet further object of the invention is the provision of a locomotive having a frame or deck provided with an opening conformed to the configuration of the condensate header of the con denser and in which said header is located and by which lateral shifting of the header is prevented and free egress of the heated air from the condenser is permitted.

Another object of the invention is the provision of a locomotive having a condenser so arranged that the cooling air is discharged, at least in part, below the deck of the locomotive and be tween it and the road bed and in a location where the flow of the heated air stream is not impeded by a locomotive truck.

A further object of the invention is the provision of a condenser of the type above described wherein certain of the condenser tubes, as the innermost circular row of tubes, is connected to the condenser air pump and through which air present in the exhaust steam and liberated from the condensate is extracted, such tub-es also serving to condense any uncondensed steam that may pass into said tubes with the air.

Since the flow of cooling air required to be passed through the condenser is approximately proportional to the steam consumption of the turbine for any power output of the latter, it is an object of the present invention to drive the air circulating fans of the condenser at speeds approximately proportional to the power demand on the turbine.

It is a further object of the invention to drive the condenser draft fan by an exhaust steam turbine operated by the exhaust steam from the main turbine and located in and supported by the exhaust steam duct connecting the main turbine with the condenser.

Since the power developed in the exhaust turbine is dependent partly upon the condensation of steam or pressure in the condenser, and hence is dependent upon the rate of operation. of the draft fan which it drives, there may be conditions, such as those set up momentarily by change of load on the main turbine, wherein the power required to move sufiicient cooling air for condensation of the steam is less than the power put into the fan by the exhaust turbine and hence the condenser pressure, or vacuum, will tend to change undesirably. Hence it is an object of the present invention to supplement the driving of the fans by additional power means, as an electric motor, preferably one having substantially constant power characteristics irrespective of the speed thereof so as, in combination with the exhaust turbine, always to supply a reasonably sufficient excess of power for driving the condenser draft fans to maintain a constant condition. of vacuum in the condenser and stable operation at such constant vacuum and at any power output of the main turbine, at least up to the maximum intended output thereof.

Preferably the supplemental fan driving motor is a series motor energized from a constant voltage source and thereby operating at constant power output, or energized by the main turbine generator and in such instance receiving power in proportion to the generator output. Such arrangements constitute further objects of the invention.

The locomotive of the present invention includes a boiler receiving heat from burning fuel supplied with combustion air by a turbine driven draft fan, the turbine of which receives steam at pressures approximately proportional to the load on the main turbine. For stable operation of the locomotive at any output thereof up to its intended maximum output both the power supplied to the boiler draft fan and to the condenser draft fans should be at least equal to the power required to move the amount of air required for combustion and condensing. Hence the provision of means for supplying said fans with power responsive to the load on the main turbine and additional power sufiicient to satisfy the above requirements is a further object of the present invention.

A yet further object of the invention is generally to improve the construction and operation of steam power generating and condensing systerns and apparatus.

Fig. 1 is a plan view of a portion of a locomotive with the roof and certain of the frame members removed to expose the apparatus of the present invention.

Fig. 2 is a side elevation of Fig. l, certain parts being shown in longitudinal section.

Fig. 3 is a side elevation partly in section of a condenser unit embodying the present invention.

Fig. 4 is a sectional detail illustrating resilient Fig.7 is a sectional detail of the exhaust steam turbine and supplemental motor drive for the condenser draft fans.

Fig. 8 is a sectional detail of a regulating valve for the boiler draft turbine.

Fi 9 is a diagrammatic view of the apparatus illustrating especially the circuit connections between the generators and the motors.

The locomotive herein shown as forming a part of the present invention comprises a horizontal frame or deck !2 which supports the varione power elements of the locomotive and is in turn supported by trucks the forward one of which is shown at M. The trucks have electric driving motors It for the wheels thereof. The frame or deck 52 is preferably of a hollow box construction for strength and rigidity. The deck at an intermediate part thereof supports a main steam turbine l8 having, an exhaust casing 26. Said turbine preferably operates at constant speed regardless of the power output of the turbine and also is intended to operate at times when the locomotive is idle or when no wheel driving power is required. Saidturbine through the reduction gears of a gear casing 22 drives a main electric generator 24, the field windings of the main generator 24, control of the power supplied to the wheel motors being effected through regulation of the voltage of the field windings of the main generator by such means as'a variable resistor I! in the circuit between the field windings and the exciter 26. Pressure steam is supplied to the turbine through a pipe 21 from a boiler 28 located rearwardly of the turbine and generator. The turbine exhausts steam into a pair of similar condenser units 30, which are located forwardly of the turbine.

Each condenser unit 39, as shown most clearly in Figs. 2 and 3, comprises an upper steam header 32 and a lower condensate header 34. The top header is preferably rectangular in configuration and is formed by the top plate 36, the bottom plate 38, and the side plates 40, Fig. l. The top and bottom plates have registering circular air openings 42 therein and a circular plate 44 welded to the top and bottom plates 36 and 38 forms the wall of the opening. The ends of the header have outstanding attaching flanges 46 and 48 and are left open so that a series of said headers can be connected together, the steam to be condensed passing from one header into the next adjacent header. The open front end of the forward header is closed by a cover plate 50, Figs. 1 and 2. The rear end of the first header is closed by a cover plate 52 which is suitably apertured to register with the forward opening of an exhaust steam duct 54 to which duct the header is rigidly secured. The rear and bottom end of said duct is rigidly secured to and supported by the top of the exhaust steam casing 20 of the turbine.

The lower condensate header comprises circular top and bottom plates 56 and 58, respectively. Said plates are formed with aligned circular air openings 68 therein which are bounded by a circular wall 62 welded to the top and bottom plates. An outer circular wall 64 is welded to and bounds the outer circumference of said top and bottom plates.

A plurality of circular rows of condenser tubes 66 are extended between said headers and are connected at the top to the bottom plate 38 of the top header and at the bottom to the top plate 56 of the bottom header. Five concentric rows of tubes are herein shown. The tubes extend generally parallel with each other longitudinally of the cylinder which they form and are given a sinuous shape as illustrated on the left hand side of Fig. 3 for the purpose of permitting substantially free expansion and contraction of the tubes. Each tube is provided with heat dissipating or cooling fins 68 by which heat of the fluid within the tube is dissipated to the moving cooling air in contact with the fins. While the tubes are herein shown as being arranged in cylindrical formation they might be arranged in some other perimetrically closed configuration although at a sacrifice of space and thermal efliciency and at increased cost of manufacture.

Air is extracted from the condenser by being withdrawn from the bottom header through a portion of the condensing tubes. To this end the top header is provided with an air chamber that is separate from theexhaust steam space of the header by the provision of a circular partition wall 12 which is welded or otherwise secured in an air tight manner to the top and bottom header plates 36 and 38 and surrounds the open upper ends of the innermost row of condenser tubes.

The chambers 10 of the steam headers of the twocondenser units are connected together by a suitable connecting pipe 14, see Fig. l, and the air chamber of the rear condenser is connected by a pipe 16 with a condenser air pump 18, see Fig. 2, driven by an electric motor 80 which also drives the condensate pump 82.

The fluid flow in the steam headers and downwardly in the condenser tubes is adapted to be sufficiently rap-id to insure the flow of air with the steam and condensate into the condensate header from which. header the air is withdrawn upwardly through the innermost row of tubes. Uncondensed steam that may be in the bottom header passes upwardly with the air but is condensed within the innermost row of tubes and the condensate runs backwardly into the bottom header.

The bottom headers are connected through pipes 84 with a pipe 86 that conducts the condensate into the pump 82 from which the water is delivered into a hot well 88.

The condensers are adapted to be supported mainly by the top steam headers 32. As has been explained heretofore the rear end of the first steam header is rigidly secured to the exhaust steam duct 54 which in turn is supported I by the turbine casing 20. The forward end of the forward header is. provided with a supporting foot 90 which rests upon a cross beam 92, see Fig. 2, of the frame of the locomotive. Thus the rigidly connected headers are supported mainly by the cross beam 92 and the turbine casing 20. The foot 90 is free to move forwardly and rearwardly upon the beam 92 to allow for free contraction and expansion of the headers.

The lower headers 34 are located in circular openings 94 of the frame or deck I2 of the 10- comotive, which openings pass completely through the frame and are open to the space therebeneath. The circular bottom headers 34 are a sufficiently close fit in the circular openings 94 so that there can be no harmful lateral movement of the bottom headers in response to changes of longitudinal or transverse movement of the locomotive.

Resilient means, as coil springs 96, Figs. 2 and 4, are located under and have their upper ends bearing against the bottoms of the headers and their lower ends resting upon vertically adjustable supports 98 screwthreaded or otherwise secured to brackets I00 of the deck. The vertical adjustment of the supports is preferably such as to stress the springs sufiiciently to take approximately one-half the weight of the condensers, the remainder being taken by the turbine casing and the beam 92. By screwing the supports upwardly, however, the springs can be made to support the entire weight of the condensers and also to raise the condensers so that they can be readily separated from each other and from the turbine casing for purposes of removal or repair.

Cooling air is drawn through the cylinder formed by the condensing tubes of each condenser and is discharged outwardly in opposite directions through the end of the cylinder by upper and lower draft fans I02 and )4, respectively. The upper draft fan rotates within the circular air opening of the upper header while the lower draft fan rotates within the circular opening of the lower header. The fans are arranged to discharge the heated air from the interior of the tube cylinder respectively upwardly and downwardly and thereby to induce a radial flow of air from the outside of the condenser transversely through the tube .rows, and into the the fan shaft.

interior of the tube cylinder.

The air exhaust openings at the top and bottom of the condenser are maintained substantially free and unimpeded. It will be noted in Fig. ,2 that the forward truck M is set mainly forwardly of the bottom air opening of the forward condenser so thatthere is afree passage of .air downwardly and out of said condenser.

-'The'fans m2 and IE3 are mounted on a verticalshaft HIE andare fixed removably to flanges IOSJ-and I I9 respectively of said shaft. The shaft at its upperend passes into a :gear housing H2 ried, by a bearing support I24. Saidsupport has alower spherical face lift which rests upon a corresponding spherical face of the gear housing. The weight of'the fans and shaft is thus suspended from said bearing support. The hearing support is free to shift on its spherical seat on the housing and the radius of the spherical seat has its. center common with theapices of the bevel gearcones. Thus the fan shaft can tilt withoutcausing misalignment between the bevel gearsl I8 and 123, exceptthat under certainconditions the depth of engagement of the gear teeth may change, which is not harmful. This arrangement permits-a reasonable amount of mis- .alignment of the fan shaft and the .driving or cross shaft I it without harm.

The lower end of the fan shaft IE6 is supported by an anti-friction bearing I28 carried by a housing I30 which is held against radial displacement by tie or tension rods I32, the outer ends of which are fixed to the bottom header. Access to the interior of the header may be had by removingthe tie rods and withdrawing the lower fan from the shaft. The air thrust of the two fans is in opposite directions and is approximately counter-balanced so that the gear housing I l2 has mainly to support only the weight of the fan unit.

The cross shafts H6 for the two fan units are connected together for conjoint rotation by a connecting cross shaft 534 through universal and slip joints I35 which permit annular displacement and changes in position of the fan units by-reason of expansion and contraction of "the condensers Without harmful effect.

The transverse width of the condenser unit is substantially less than the width of the deck I2 and hence alleys I138 are provided on both sides of the condensers by whichaccess may be had to the forward compartment I lii adapted to contain auxiliary apparatus. Good vision of the road bed may also be had through said alleys from the rear of the condensers by locomotive operatives sta- 'tioned in the turbine compartment.

The draft fans for the condensers are driven by an exhaust steam turbine having a turbine wheel Hi2, see Figs; 2 and 7, located inthe exhaust steam duct 5t and receiving the exhaust steam of the main turbine through nozzles M l from the exhaust steam casing 26 of the turbine. The turbine wheel shaft H6 is journalled in a gear'casing Iii? suitably supported from the duct -54 as by a bracket I513. The turbine shaft I has a gear l5? fixed thereto which drives an intermediate gear I54 journalled in the gear houspecialiy Fig. 1.

ing, ;-said'.intermediate gear driving an endgear I56 which also is journalled insaidcasingn The shaft I58 of said end gear has'a universal and slip connection I60 with a cross shaft l62which extends to the cross shaft N6 of the first :draft fan and is connected theretoby means of a second universal joint and slip coupling I64, see es- Thus the auxiliary or exhaust steam turbine drives both draft fans, the speed of theturbine andfans being approximately .proportional to the amount of-exhaust steam :discharged from'the'main turbine.

Since the exhaust steam turbine is driven by the exhaust steam from the main turbine, and hence thepower available'is dependent'not only; upon the amount of steam passed through.--the main turbine but also upon the condenser vacuum which, .in turn, is dependent upon the amount of power supplied'to and the1speed of the condenser d'raft fans driven by the exhaust turbine, a condition may result wherein the power output of the exhaust turbine to the draft fans at the required vacuum does not equal -or-exceed the required power throughout the range of condenser vacuum and throughout the range :of

power outputof the-main turbine upto its-maxi-mum output. The poorer vacuum resulting might occasion a diminution of power and consequently speed of the saidfanturbine. turn would result in a further diminution of vacuum and so forth and stability might 'be reached only at a much reduced :vacuum. That is to say, suppose the vacuum dropped for-any reason as a sudden increase in load. The exhaust turbine power would "then beless what it would be at the increased load and the normal highvacuum. .Hence the cooling air would be insuflicient and the vacuum either would surge about some meanvalue or stableoperation would be regainedonly at some lower -,vacu-.-.

um, resulting either in runsteady. operation or loss of efliciency. I

In order to insure a power input into=the condenser draft fans always definitely equal toand preferably-above the power required to circulate through the condenser sufiicient air for condensing all the steam therein, to maintain a constant high vacuum and stable operation thereat for any load up to the .maximumputput-rating of the main turbine, additional orstabilizingpower is supplied to the condenserzdraftifans. Bythis means the operation of the system is made stable at all loads .at or about at a single desired vacuum.

Said stabilizing or supplemental power is provided by-an electriomotor 168 which iszsuitably supported on the bracket 1-50 and has a driving 'connectionwith'the intermediate gear I54. Thus the motor and the auxiliary turbine I42 conjointly operate to supplypower to-the condenser.

draft fans. Themotor I68 preferably isrof the type having a substantially constant :power characteristic,irrespective of speedsuch, for instance, as a direct current series motor. Said motor can be energized from .a constant :potential source as from the exciter generator through conductors I69 and "hence operate at constant power although at a variable speed dependent 'uponthe speednfthe exhaustturbine. Furthermore, the electric driven motor may serve .for-v idling the fanswhen .there is no steam flowing to the condenserxto ensure the maintenance of a vacuum irrespective of the load .on the .,main turbine.

In addition to definitely supplying sufficient power to the condenser draft fans for moving the air for the condensation of the steam throughout the operating range of the main turbine, it is also important to supply draft air to the boiler for the combustion of the fuel and also to supply fuel at a rate corresponding to the power output of the main turbine throughout its operating range so that there will never be a deficiency of steam for operating the turbine at any demanded power output within its range.

The boiler 28 is or can be of the type disclosed in our copending application Serial No. 51,616, filed November 26, 1935. The rate of combustion of fuel in the boiler furnace is intended to be governed by regulation of the amount of air and fuel passed through the boiler furnace. The boiler draft fan I66 acts on the combustion gases of the boiler and hence the power input into the draft fan I66 must be such as to produce steam equal to and preferably somewhat above the requirements of the main turbine I8 throughout its operating range. The boiler draft fan I66 is operated by a steam turbine I14 receiving steam through a pipe I16 from an intermediate stage of the main turbine I8, the pressure of which steam varies with the amount of steam passing through the main turbine. The turbine I14 discharges its exhaust steam into the aforesaid condensers through pipe I11. With this arrangement the boiler draft fan I66 receives power generally varying in accordance with the power demand on the main turbine but at times ordinarily receiving insufficient power. To provide for a power input into the boiler draft fan more nearly 1 meeting the exact requirements of the power demand on the main turbine at all loads a regulating valve I18 having a spring loaded valve member I19, see Fig. 8, is interposed in said pipe I16. Said valve member I19 is operative in response to pressure in the pipe I16 in such manner as to move further in an opening direction with an increase of pressure whereby to increase the amount of steam supplied to the draft fan with increase of power demand upon the main turbine and thereby to keep the power closely in accordance with that required for any power demand on the main turbine within its range.

Said combustion draft turbine also preferably drives a fuel oil pump I80 of the displacement type or other means for supplying the boiler with fuel, the pump drive being through gearing I82, I84 from the turbine shaft. Hence both air and fuel are inherently and automatically supplied to the boiler at a rate closely suiting the load 2 thereon.

An electric motor I86, preferably of the variable speed, constant power type such as a series motor, is coupled to the turbine shaft and is adapted to be connected to an auxiliary power source, as the storage batteries I81 of the locomotive, to rotate the draft fan and the fuel supply means when building up steam from a cold boiler or when the locomotive is idle. When the locomotive is in operation and the boiler draft 1 fan is being operated by its steam turbine, the

motor can be de-energized and can be rotated idly by the draft turbine.

We claim:

1. The combination of a steam turbine and a condenser for the exhaust steam thereof, said condenser comprising a steam header resting at one end upon said turbine and receiving steam therefrom, a support for the other end of said header, and condenser tubes and a condensate header depending from said steam header.

2. The combination of a turbine and a condenser therefor, said turbine having an exhaust steam casing, an exhaust steam duct communicating with and supported by said casing, said condenser having a steam header communicating with and supported rigidly by said duct, a support for the other end of said header and condenser tubes and a condensate header suspended from said steam header.

3. A locomotive comprising a locomotive deck, a turbine on said deck, and a condenser for the turbine, said condenser comprising an upper steam header bearing at one end upon and supported by said turbine, a support for the other end of said header, a condensate header and condenser tubes suspended from said steam header, said upper and condensate header having an opening therethrough forming with said tubes an air passage, said locomotive deck having an opening therethrough in which said condensate header is located, and means for discharging cooling air from said condenser through said condensate header and deck opening and through said upper header.

4. The combination of a condensing turbine and a high vacuum condenser therefor, said condenser having a draft fan which circulates cooling air over the condensing surfaces of the condenser, a duct conducting exhaust steam from said turbine into said condenser, an exhaust steam turbine in said duct operated by the exhaust steam therein at a speed dependent upon the amount of exhaust steam and the degree of vacuum in said condenser, means establishing a driving connection between said exhaust steam turbine and said draft fan, and supplemental driving means for said fan operating continuously with said exhaust steam turbine for continuously supplying additional power.

5. The combination of a turbine and a condenser, said condenser having a steam header, condenser tubes connected with said header, and a draft fan for circulating cooling air over the surfaces of said tubes, an exhaust steam duct supported by said turbine and communicating with and constituting a support for said header, an exhaust steam turbine in said duct operated by the exhaust steam therein, and means establishing a driving connection between said exhaust steam turbine and said draft fan.

6. A condenser comprising a steam header, an exhaust steam duct connected with said header at one end and constituting a support therefor, a support for the other end of said header, condenser tubes and a condensate header suspended from said steam header, a draft fan for circulating cooling air over the surfaces of said tubes, an exhaust steam turbine located in and supported by said duct and operated by the exhaust steam therein, and means establishing a driving connection between said turbine and draft fan.

7. The combination of a turbine, a condenser for the exhaust steam thereof, means for circulating a cooling fluid over the cooling surfaces of said condenser, driving means for said circulating means receiving power to supply cooling fluid in amount approximately proportional to the turbine output power, and additional power driving means for said circulating means operating to supply power continuously with said first driving means in amount sufficient to maintain an approximately constant vacuum in said condenser under all normal turbine operating conditions,

8. A power generating system including a turbine, a draft fan for supplying air which influences the turbine output, driving means therefor supplied with driving energy that varies with the turbine output, and supplemental constantpower driving means operative in conjunction with said first driving means for supplying said draft fan with additional driving power to maintain stable turbine operation at any output within its range.

9. The combination of a steam turbine, a condenser for the exhaust steam thereof, means for circulating a cooling fluid over the cooling surfaces of said condenser, driving means for said circulating means operated by the exhaust steam passing from said turbine to said condenser and responsive in speed to the amount of vacuum in said condenser, and supplemental driving means for said circulating means operating continuously in conjunction with said first driving means and supplying additional power that is independent of condenser vacuum for stabilizing the operation of the condenser at an approximately constant vacuum for any turbine output within its range.

10. The combination of a main turbine, an air cooled high-vacuum condenser for the exhaust steam thereof, draft means for circulating cooling air over the cooling surfaces of said condenser, an exhaust steam turbine operated by and at a speed approximately proportional to the flow of exhaust steam from said turbine to said condenser for operating said draft means, and variable speed means operating in conjunction ,with said exhaust steam turbine for supplying said draft means with additional power that is independent of the amount of exhaust steam and is approximately constant at all operative speeds thereof.

11. The combination of a turbine, a condenser for condensing the exhaust steam of said turbine, draft means for moving cooling air over the cooling surfaces of said condenser, and dual power generating means supplying power concurrently to said draft means, one of said power generating means generating power that varies with the turbine output and the other power generating means generating a constant power, both power generating means in unison operating to drive said draft means at speeds to maintain a predetermined vacuum in said condenser at all turbine outputs within the turbine output range.

12. The combination of a turbine, a condenser for condensing the exhaust steam of saidturbine, draft means for moving cooling air over the cooling surfaces of said condenser, and dual variable speed power generating means supplying power concurrently to said draft means, one of said power generating means delivering variable power from the exhaust steam discharged from said turbine and said other power generating means delivering constant power in amount sufficient to stabilize the operation of the con.- denser at a predetermined vacuum for different turbine outputs. y

13. The combination of a steam turbine, a generator driven thereby, a condenser for the exhaust steam of said turbine, draft means for circulating a cooling fluid about the cooling surfaces of said condenser, a draft operating turbine operated by the exhaust steam of said main turbine at a speed responsive to the flow of exhaust steam, and means to stabilize the operation of said condenser at a predetermined vacuum for different turbine outputs comprising a constant power electric motor driving said draft means concurrently with said exhaust steam turbine.

14. The combination of a turbine, a boiler supplying steam to said turbine, a draft fan for supplying air to the boiler furnace, means for supplying fuel to said boiler furnace, and power means driving said draft fan and fuel supplying means, a power source for said power means variable with the variable output of said turbine, and meansautomatically responsive to the variable turbine output for modifying the driving power of said power means for driving said draft fan and fuel supplying means at different rates for different turbine loads, each rate being sufficient to generate the steam required for its associated load at rates proportional to the demands for power on said turbine.

15. The combination of a constant-speed steam turbine, a condenser for the exhaust steam from said turbine, driving means for circulating a cooling fluid through said condenser, and means for supplyingdriving power to said driving means in variable amounts dependent in part upon the amount of exhaust steam discharged from said turbine and sufficient to circulate sufficient cooling fluid under different normal conditions of turbine operation to maintain the same predetermined vacuum in said condenser, said means for supplying power to said driving means including means supplying a constant amount of power under different conditions of turbine operation and other means operating continuously therewith for supplying variable power dependent upon the exhaust steam output of said turbine and the degree of vacuum in said condenser.

16. The combination of a main turbine, a'condenser for the exhaust steam of said turbine, means for circulating cooling medium through said condenser, driving means for said circulating means including a variable power turbine operating on the exhaust steam of said main turbine at a speed and power output dependent upon the amount of' exhaust steam discharged from said main turbine, a constant voltage generator driven by said main turbine, and a variable speed constant power electric motor operated by said constant voltage generator and supplying a constant amount of variable speed pow-- er to said circulating means conjointly with said exhaust steam turbine to maintain the same constant condenser'vacuum for different power outputs of said turbine.

1'7. A power generatingsystem including a steam boiler, a steam turbine receiving driving steam therefrom, a fan for supplying draft air to said boiler, a displacement type fuel pump for supplying fuel to said boiler, steam operated driving means coupled in fixed driving relationship to said fan and said fuel pump, steam conducting means conducting steam from an intermediate stage of said turbine to said driving means, and a valve in said steam conducting means responsive to the intermediate stage steam pressure and operating'to open further in response to an increasing pressure in said stage, whereby both fuel and combustion air are supplied to said boiler automatically in the correct amounts for different rates of steam generation at a fixed boiler pressure in direct response to said rates.

CHRISTOPHER A. SCHELLENS. EUGENE L. SCHEILENS.

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