US1358469A - Marine propulsion - Google Patents

Description

H. F. SCHMIDT.

MARINE PROPULSION.

APPLICATION FILED JUNE 30. 1915.

1 58,469. Patented Nov. 9, 1920.

2 SHEETSSHEET l.

HIS ATTORNEY IN FACT H. F. S CHMIDT. MARINE PROPULSION.

APPLICATION FILED JUNE 30, 1915.

0 R m 2. O A 9 T F 1T N in N i W m I w N N M W 2 n T .w T a A 5 H un ts) STATES PATENT orrlcs.

E. SGlEIl/ZIDT, OF PITTKSBURGH, PENNSYLVhNIA ASSIGNOR TOEJVESTINGHGUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

MARINE PROPULSION.

Specification of Letters Patent.

Patented Nov. 9, 1920.

. ition relntcs in general to power d elopin apparatus and in particular to nized turbine apparatus, which is well adapted for use in marine propulsion.

in object of the invention is to produce s highly eiiicient merino turbine apparatus which operat at low or cruising speeds with high e (money and is more eilicient, while operstlng under such conditions, than nuiriuc turbines now in use or known to me.

A further object is to produce an organized turbine uipurotus for marine propulsion, which comprises separate cooperating turbine sections. which is more eiiicient under varying conditions of load and speed than other turbine apparatus known to me and is so arranged that substantially full s-specd may be developed, although one or more of the turbine sections oi the organized 12 ppurutus, is incapacitated.

in marine propulsion, and particularly in the propulsion of vc. ls having twin or quuoruple screws or propellers, it is desirable to transmit an equal amount of power to each screw. In the quadruple screw vessels it is also desirable to transmit approximut ly equal power to such pair of scufews. that is" the power transmitted to the inboard .-:crcw;=' must be substantially equal to the power tran mitted to the. outboard screws, though this is less important when the vessel is being propelled at low or cruising speeds.

it has been tound in practice that it desirable to employ speed reducingmechanisms between the propelling turbine oppsrotus and the screws and that the most istoctory results are obtained by employing spced reducing gcurings es the speed reducingmechanisms. ltihos also been found that in vessels of large power it is desirable to employ two or more pinions in each gearing and to employ driving or propelling apparatus so arranged that each pinion re- 1 es power from :1 separate power developection of the apparatus. This is in cause it desirable to reduce the amount of power transmitted through each, pinion us much as possible. It is also (lGSll'tl'llQ to transmit an equal amount of powe' to each pinion while the propelling apparatus is developing full power in order to reduce the amount or power transmitted by such pinion to a minimum. In apparatus fulfilling these conditions, it is desirable to increase the speed ofeach turbine. section as much as possible for the purpose of reducing the weight of the propelling apparatus. The permissible blade speed in o turbine however limits the diameter of the turbine section and this in turn limits the area through the last row of low pressure'bla-des and consequently the amount of steam which can be completely expanded through the turbine section. develop a large amount of power and to reduce the weight of the apparatus as much as possible, itbecomes necessary to employ two or more low pressure turbine sections operating in parallel on the motive fluid discharged from a high pressure turbine section.

Experience has demonstrated that in turbines operating under widely varying loads it is desirable to employ ahigh pressure turbine element, of the partial or yariablc admission type in connection with a low pressure element of the full peripheral odmission type. The full peripheral admission type of turbine is more effective while operating at relatively low, or it may be said, practical speeds, than any other type of turbine now in commercial use. The efficiency of such turbines is, however, impaired if the motive fluid, hereinafter termed steam, delivered to them is throttled for the purpose of reducing the amount of power developed. On the other hand, the partial or variable admission type of turbine, while less eflicient at practical speeds than the full peripheral admission type operating under full load conditions, is capable oimsirr training its etliciency under widely varying conditions of load, since the steam delivered to it isnot throttled but is varied in amount by being delivered through a greater or less number of nozzles. It is therefore evident that a, combination ofthese two types of turbines, in which the partial or variable type of turbine is employed as the high pres sure section while a full peripheral admis sion type of turbine is employed as the low In order therefore to economically iii) pressure section, results in an organized turbine apparatus which is highly efiicient under widely varying loads. It is well known that in such a turbine apparatus in which the initial or high pressure section is a single multiple velocity drop impulse stage, it is desirable to abstract, in the impulse stage, one-fourth of thetotal energy of the steam which is rendered available by expanding the steam from initial to condenser pressure. By employing apparatus in which this is accomplished, three fourths of the available energy of the steam must therefore be abstracted by the low pressure section or sections of the turbine apparatus.

For mechanical reasons, it is not practical to provide reduction gearing with more than two pinions. In the propulsion of vessels'of large power it therefore is de sirable to transmit power to eachpropeller shaft or screw through a reduction gearing having twopinions, each pinion receiving power from a separate turbine section. In quadruple screw ships each pair of screws, including one inboard and one outboard screw, must be driven by an independent turbine apparatus. Since, as above pointed out, it is desirable to employ a turbine apparatus having more than one low pressure section, and since it is desirable that each pinion should receive power from a separate turbine section, it becomes apparent that where four pinions are employed, at least twoof them must be driven by low pressure turbine seztions. Since it is desirable to utilize one-fourth of the available energy of the steam in the hi h pressure turbinesection, the remaining threefourths of the available energymust be abstractedin the low pressure sections. In order to develop an equal amount of power in each low pressure section and in order that the power developed by each low pressure section shall be approximately equal to that developed by the high pressure section, it becomes apparent that ideal condi tions are fulfilled by employing three low pressure sections, each of which is capable of expanding one-third of the total amount of steam delivered to'the organized apparatus through a rangeof three-fourths of the heatdrop. YVith such an arrangement, each low pressure section develops onefourth the total power of the organized ap paratus and is capable of being operated independently of the'other sections. In addition to the above noted advantages obtained by such an arrangement of turbine sections whi'le 'the organized apparatus is developing full'power, one or moreof the low pressure sections may be cut out for the purpose of reducing the amount of power developed without materially affectinqthe efficiency of the operating sections. When one or more of the low pressure sections are out out, the pressure maintained at the inlet of the operating low pressure secvtions is increased for a given steam flow.

words, variations in the amount of steam O delivered from the high pressure .section. It is, therefore, apparent that an organized apparatus embodying the features above described will operate with high efliciency under widely varying load and speed conditions. A further advantage of such apparatus is that any two of the turbine sections are capable of driving the vessel at approximately full speed when the other sections are incapacitated. This is of particular importance in naval vessels since in an emergency speed is of paramount importance. In order that any two of the sections may develop full power, it is necessary for each section to be connected to a condenser. Change over valves or valves in the exhaust line are bulky, heavy, difficult to operate and difficut to maintain steam tight. It is, therefore, desirable to produce a turbine in which each low pressure section is permanently connected to a condenser, so that each low pressure section will be capable of expanding steam from initial to condenser pressure during emergencies without the necessity of employing change over valves. The principal object of my invention has been to produce a turbine or organized turbine apparatus embodying all the features and the advantages above enumerated and outlined.

The foregoing objects and others, which will be made apparent throughout the further description of the invention, are attained by means of apparatus embodying the features herein described and illustrated.

In the drawings accompanying and forming a part hereof, Figure 1 is a diagrammatic plan view of power developing apparatus embodying my invention.

Fig. 2 is a'more or'less diagrammatic side elevation of a low pressure turbine section which forms a detail of my invention.

rig. 3 is a developed section along the section 4 and three low pressuresections 5, 6, and 7, which are adapted to operate in parallel on the motive fluid discharged from the high pressure section and which in eiiect form a multiple flow low pressure section for the high pressure section .4. In addition to this means are provided such that the fluid exhausted from the high pressure section may be delivered to less than the total number of low pressure sections. so that one or more of' the low ya'essure sections may be rendered inoperative, under certain load and speed conditions.

The rotor element of the high pressure section at and the rotor element of the low pressure section 5 are shown operatively connected to a driven shalt, such for example, as a propeller shaft 8, by means of a transmission gearing 9, which is of a well known type and will hereinafter he more fully described.

The rotor elements oi the low pressure sections 6 and-7' are shown operatively con nected to a second driven shaft. as for example, propeller shatlt 10. through the agency of a transmission gearing 11, which is similar in construrtion to the gearing As illustrated. a condenser 12 is arranged to receive the fluid exhausted om the low pressure sections 5 and and a separate condenser 13, of half the capacity or the condenser l2, arranged to receive the fluid or;- hausted from the low pressure se-r Zen 7.

As shown, the high pressure section 4-. is provided with an ahead power developing element let and an astern power developing element 15, both of whi h are located in the same casing, but are separated one from the other by means of a diaphragm or partitioa l6, whiz h divides the interior oi the easing into ahead and astern compartments.

The power developing element 14 is illustratcd as a single impulse including expansion nozzles 1?, adapted to receive the high pressure motive fluid delivered to the inlet port 18 ot the ahead compartment and adapted. to expand the motive fluid a determined amount and to deliver it to the moving blades 19, which are diagrammatically illustrat. l as mounted. on a single blade can lug wheel. The ahead compartment is preferably provided with a plurality of nozzles 17, as shown in Fig. 3, which are controlled in groups or singly by means of valves 17, and the impulse stage, of which these nozzles form a part, is preferably a multiple velocity drop stage. It will, however, be understood that the high pressure section may include two or more impulse stages, such as described, or that it may consist or one or more stages of some other type of turbine element, so long as the stages are of the partial or variable admission type. By the term partial or variable admission type I mean that type of turbine in which the motive fluid may be delivered to a portion only oi the first row of moving blades,

as distinguished from the full peripheral the ahead turbine element and receives n motive nuid from an inlet port whicn communicates with a plurality o'l delivery nozzles 23, adapted to deliver the n'iotiwv fluid to blades 24 mounted upon the blade carrying wheel. This turbine element is preferably of the impulse type. The motive fluid exhausted from the blades 24 is delivered through an exhaust port 25 to a receiver or header 26 which, as will. hereinafter be described, is arranged to deliver motive fluid to astern power developing elements included in each of the low pressure sections 5, 6 and 7.

lhe low pressure sections may be of similar construction and consequently I will describe the principal details of construction of the section 7, a. transverse section of which is diagrammatically illustrated in Fig. l. The casing 27 of this turbine section is provided with an inlet port 28, which re ceives motive fluid from the header 21, and it is also provided at the other end with an inlet portion 29, which receives motive fluid from the header The casing, however',.

is provided with a single exhaust port adapted to communicate with the condenser 13, it being understood that the exhaust ports of both of the sections and 6 communicate with the condenser 12. The ahead power developing element of the low pres sure section is adapted to receive the partially expanded motive fluid delivered from the element 1d and to expand the fluid to exhaust or condenser pressure. It is illus trated as of the full peripheral admission type, in which a single row of moving blades is employed in each stage. By the term stage I mean a working section oi a turbine in which the motive fluid is expanded and all of the velocity or kinetic energy resulting from the expansion is abstraited. Each stage of the low pressure sections includes but one row of moving blades whether the section is of the reaction type or some other type not embodying the re action principles. The ahead element, as illustrated, consists of alternate rows of moving and stationary blades through which the motive fluid successively passes and from which it is finally discharged through the exhaust into the condenser. The moving blades are shown mounted 'on a drum 31, which forms a part of the rotorelenient and which is provided with counterbalancing drum 3-2 for counterbalancing'the endwise thrust occasioned by the motive fluid traversing the element. The reversing turbine element forming a part of the low pressure section 7, and consequently of each of the sections 5 and 6, includes a single blade carrying wheel 33, on which two rows of impulse blades 34: are mounted. It also includes one or more expansion nozzles for delivering fluid to the blades 34 and a row of directing vanes 35 located between the two rows of blades 34 for the purpose of directing the fluid, discharged from one row, into the next row of blades. The fluid discharged from the final row of blades 34 is delivered to the exhaust port 36, which as has been described, communicates with the condenser.

In Fig. 2 I have illustrated the means employed for connecting each of the sections 5 and 6 to the receiver or header 21 and the means employed for connecting each of the sections5, 6 and 7 to the receiver or header 26. As illustrated, the header 21 passes below the low pressure sections and a separate riser 37 extends upwardly from it to the inlet port of each of the sections 5 and 6. This riser is provided with a valve 38 which, as shown, is adapted to be manually controlled for the purpose of placing its corresponding turbine section in communication with the exhaust port 20 of the ahead turbine element of the high pressure section 4:. The construction employed for connecting the section 7 to the header 21 is'substantially simi lar to that described except no valve is located in the riser which communicates with the inlet port of this section. A valve 39 is, however, provided in the header itself and as illustrated is located between the sec tions 6 and 7. With this arrangement, motive fluid exhausted from the ahead turbine element of section 4 may be delivered to any one or to all of the ahead turbine elements of the low pressure sections 5, 6 and 7.

The inlet port 29 of each of the sections 5,

6 and '7 communicates with the'receiver or header 26 through a separate riser d1. Each elements of the sections 5, 6 and 7.

The gearings 9 and 11 are employed for the purpose of driving the driven shafts at a speed less than that of the turbine shafts.

Each reduction gearing consists of a gear, directly connected topth driven shaft, and two pinion s, each of whichisflcomiected to the shaft of one of the turbine elements.

Both these pinions mesh with the gear. and

they each may be of the same diameter if the turbine sections to which they are directly connected are adapted to run at the same speeds. if, p to operate at a higher speed than anothenthe pinion which is'connected to the high speed section will be of smaller diameter than that connected to the section of lower speed.

As illustrated, the reduction gearing'filr is so arranged that the'pro 'ieller shaft 8 may be driven jointly by the high pressure section 4t and by the low pressure section 5, or it may be driven independently by either of these sections. The reduction gearing 11 is so arranged that the propeller shaft 10 may be driven jointly by both of the sections 6 and 7, or separately by either of them;

While the organized turbine apparatus is operating under full power, motive fluid discharged from the high pressure section 4: is deliveredto all of the low pressure sections 5, 6 and 7. Consequently all of the sections operate as power developing elements and deliver power to the two propeller shafts 8 and 10. The low pressure sections are preferably, though not necessarily, so designed that they operate at the same speed and de velop the same power when operating under the same pressure conditions. When it is desired to reduce the speed of the vessel to cruising speed and consequently to reduce the power developed by the organized apparatus, the valves 38 supplying fluid to the low pressure sections 5 and 6 are closed. Under such conditions the motive fluid discharged from the high pressure section i is delivered only to the low pressure section 7. Under such conditions power is delivered to each propeller shaft by one pinion only and the sections 5 and 6 run idle, being driven by the gearings 9 and 11 respectively. It will of course be understood that these sections may be connected to the gearings by means of disconectible clutches or couplings so that they may be disconnected while not delivering power.

If desired, the section 7 may be designed for diiferent speed conditions from those obtaining in the sections 5 and 6. With the type of apparatus illustrated this may be accomplished by providing a greater num' ber of stages in the section 7 than is provided in either the sections 5 or 6, so that the velocity ratio is higher in this section than the others. VTith such an arrangement. the section 7 will operate most efficiently while running at lowor cruising speed, and the operating sections t and 7 will develop high economy while driving the vessel at cruising speeds. i

i wever, one section is designed.

It will be apparent that the economy of the apparatus as a whole is improved by employing a small condenser tor the section 7 rather than connecting it to 'a large condenser which is designed to serve all of the sections. This is oi particular importance in naval installations, since the full power turbine sections are operative only while the vessel is driven at full speed. By providing separate auxiliaries for each oi" the condensers one complete condensing" set may be shut down except when theturbine apparatus is developing full power. One of the principal advantages gained by employing apparatus embodying my inve tion is therefore the betterment of the economy at cruising speeds. if it is des rable to run the inoperative sections idle, a high vacuum may be maintained in the idle sections by operating the air pump of the idle condenser or by providing other means for maintaining a vacuum in these sections.

Under full power conditions the steam exhausted from the high pressure section is delivered to the condensers through a plurality of paths and consequently the amount of steam delivered will determine the pressure drop through the initial section. The apparatus may be so designed that when motive fluid is shut off from the sections 5 and 6, the absolute pressure in the receiver 2i will be increased about three or tour times over what it would be if these sections were receiving fluid, or over the pressure whr'h would exist at the inlet to the full peripheral admission section of an ordinary single flow turbine capable of developing the same amount of power as the turbine apparatus illustrated when operating under the same conditions. It will also be apparent that the successive closing of the nozzles 17, of the high pressure section, will accomplish in a measure the same results accomplished by closing the valves 38 supplying the sections 5 and 6, and that the economy of the organized apparatus is improved at all powers between that developed with these valves wide open and with them closed. Then the valves 38 supplying sections 5 and 6 are closed the expansion range of the impulse portion of the organized apparatus or of the section 4 is reduced, and the expansion ratio of the low pressure section 7 is increased, thus increasing the efficiency of the turbine under low power conditions. This result is of course less marked when but one of the valves 38 is closed but even so, the efficiency of the apparatus operating under such conditions would be higher than that attainable by a single turbine capable of replacing the organized apparatus illustrated. This is because the speed of rotation of th turbine is reduced and consequently the available energy which can be eflicientlv abstracted by the initial stage is materially do creased and hence in order to obtainthe maximum efliciency for the initial stage it is necessary to reduce the amount of available energy delivered to it. This isaccomplished by maintaining the initial pressure at the inlet constant and increasing the pressure at the discharge from the initial stage.

It the section 7 is designed for low speed conditions, as above sugaiasted. the economy of the apparatus will be substantially the same at cruising speeds as it is when the organized apparatus is developing full power and running at full speed.

Another advantage of my invention is that the apparatus embodying it is materially lighter than ordinary turbine apparatus capable of developing the samepower under the same operating conditions. This results from the fact that a number of working passages are provided through which the motive fluid passes to the condenser, and consequently each turbine section may be materially reduced in diameter below that of a single flow turbine of the same power and of the same fluid area through the last few rows of low pressure blades. In fact, the diameters of the low pressure sections illustrated need only be about 57% of the diameter of asingle flow turbine of equivalent capacity. In addition to this, the blades ofthe low pressure sections are approximately but 57% of the length of the blades of a single flow turbine of equal power and blade area. The reduction in diameter of these low pressure sections has the additional advantage of reducing the amount of distortion and also the efi'ect of any distortion which may occur in either the rotating or stationary parts of the sec tion. As a result the sections may operate with closer clearances than are ordinarily possible, and the leakage of motive fluid through the clearance spaces will therefore be reduced.

Another advantage of apparatus embodying my invention is that the initial section 4, which receives high pressure motive fluid. and is consequently subjected to relatively high temperatures, is isolated from the low pressure sections or from the portions of the organized apparatus in which distortion is not only obje tionable, but is liable to wreck the apparatus. The section 4:, as illus trated, is of the impulse type. consequently relatively large clearances may be maintained and distortion or either the casing or the rotor element of this section will there-,

fore not be as objectionable or as liable to cause trouble as it would be if it occurred in any one of the low pressure sections.

Another feature of my invention is that the losses known as rotation losses are imterially reduced.- It is well known hat rotation losses, in a turbine, vary directly as the cube of the revolutions per minute of the rotor, and asthe fifth power of the diameter ol the rotor; hence a reduction by one-hal1 of the diameter of the rotor and the doubling of the revolutions per minute, for the 'developingreduced power and of operating at reduced speed materially less than the losses occasioned in. ordinary marine turbines. Inall marine turbines known to. me the elements termed cruising elements, are run idle whilethe. turbine is developing full power and operating at maximum speeds and consequently the rotation losses occasioned are. high. It is well lrnown that the friction and windage losses occasionedrby rotating a turbine element in an atmosphere of steam is directly proportional to the cube of the revolutions-per second and is also directly proportional to the density of the steam surrounding the element; consequently, one of the principal objections to marine turbines employing cruising stages, which are run idleat high speeds, is thatthe windage and frict-ionjof the blades result in temperature rises which, may and in fact often do result in trouble by causing either the rotor 01' the stator element oi the cruising section to distort. In a turbine embodying my invention, the low pressure elements revolve idly in steam at condenser pressure and only when the speed is reduced. For example, the sections 5 and 6 will revolve idly when the speed of the organized apparatus is reduced to about three-fourths full speed, the heattageous conditions will therefore be about 42% of the heating encountered in turbines employing separate cruising elements revolving idly at full speed.

Another advantage of my invention is that substantially full speed may be developed by'employing any two of the low pressure sections for driving the vessel either ahead or astern. This is accomplished ,highpressure steam to each riser 37, and in the case of the reversing sections 1 provide a separate high pressure inlet 4.5 for supplying high pressure steam to the nozzles of each section.

With such an arrangement any one of the low pressure sections may operate under high pressure steam, While the others are relng encountered under the most disadvanceiving low pressure steam from the initial section.

iinother advantage of the invention is that the temperaturerise resulting from. the idle running of the reversing elements while the ahead elements are developing power is materially reducedby'employing the i111- pulse elements for reversing. With such an arrangement full power may be developed while the apparatus is reversing, but the number of rows of blades employed in each reversing-section for developin full power is so, small that the tempera-i'zure'rise is insignificant andwill not have a (lQlZIlHlL effect on the operation, of any one oi? the turbine sections.

It will, of course, be understood that the arrangement or the low pressure elements with relation to the gearings 9 and 11 may be varied, that under some conditions the gearings may be omitted and each turbine section directly connected to the driven shaft and that under some conditions each turbine section may be operatively connected to electric transmission apparatus such as issometimes employed for marine propulsion.

In accordance with the patent statutes, l have illustrated and described what I now consider the preferred embodiment of my invention, but I desire it to be understood that various changes, substitutions, modifications, additions and omissions may be made in the apparatus illustrated without departing from the spirit and scope of the invention as set forth by the appended claims,

That I claim is:

1. In combination with a plurality of propelling agents, an organized turbine apparatus for driving said agents, comprising a separate high pressure turbine, a plurality of low pressure turbines operating in parallel onfluid discharged from, the high pres-- sure turbine, and means whereby at least one of said low presssure turbines may be rendered inoperative without rendering any of said propelling agent inoperative.

2. In combination with a plurality of pro pelling agents, an organized turbine apparatus for driving said agents, comprising a separate high pressure turbine, a plurality of low pressure turbines. operating in parallel on fluid discharged from the high pressure turbine, means whereby at least one of said low pressure turbines may be rendered inoperative without rendering any of said propelling agents inoperative, and at least two condensers for receiving fluid from the low pressure turbines, each of said coudensers serving less than the entire number of low pressure turbines.

In combination with a plurality of propelling agents. an organized turbine apparatus for driving said agents, compris ing a separate high pressure turbine, a plurality of low pressure turbines operating in parallel on fluid discharged from the high pressure turbine, means whereby at least one of said low pressure turbines may be rendered inoperative without rendering any 01'? said propelling agents inoperative, and

two condensers recei 'rinp; fluid from the low pressure turbines, each serving less than the entire number and one having twice the capa city of the other.

l. in combination with a plurality of propelling agents, an organized turbine apparatus for driving said agents, comprising a separate high pressure section and a plurality of separate low pressure sections operating in parallel on fluid discharged from the high pressure sections, gearing "for transmitting power from said organised apparatus to said agents so arranged that one or more of said low pressure sections may be rendered inoi ierative without rendering any of said agents inoperative and means for rendering at least one of said low pressure sections inoperative.

5. [in organized turbine apparatus comrn'isinp,- a plurality of low pressure sections adapted to operate in parallel on motive fluid delivered from a high pressure section, a high pressure section. isolated from the low pressure sections and having" a separate rotor and a separate casing, and two condensers for receiving the motive fluid delivered from low pressure sections, each condenser serving less than the entire number of the low pressure sections and one being of half the capacity of the other.

6. An organized powerdeveloping apparatus comprising a high pressure section, three separate low pressure sections adapted to operate in parallelon the motive fluid discharged from the high pressure section, each section having a separate casing and separate rotor element, and a separate condenser serving at least one of said sections.

7. An organized power developing apparatus comprising a high pressure section, a plurality of low pressure Sections operating in parallel on fluid delivered from the high pressure section, and two condensers receiving fluid deliveredtrcna the low pres-- sure sections, each condenser serving. less than the entire number of low pressure sections and one being; of materially greater capacity than the other.

8. An organized power developing apparatus comprising a high pressure section, a plurality of low pressure sections operatin parallel on fluid delivered from the high pressure section. at least one of the low pressure sections being solated from the high pressure section by being provided with a separate casino; and separate rotor element, and two condensers receiving the fluid exhausted from the low pressure se tions, each condenser serving less than the total number ot'high pressure elements, and one being of substantially twice the capacity of the other.

9. An organized power developing apparatus, comprising a high pressure section of the partial or variable admissiontype, having a separate rotor and stator, a plu rality or low pressure sections adapted to operate in parallel on fluic discharged from the high pressure section, each having independent rotor and stator elements,and capable of developing substantially the same amount of power as the high pressure section while operating on fluid discharged therefrom, and two reduction gearings be tween which said turbine sections are so distributed that substantially the same amount of power is delivered to both gearings when the apparatus is developing full power and when it is developing less than full power.

10. An organized power developing apparatus, comprising a high pressure section,

having a separate rotor and stator, three low pressure sections, adapted to operate in parallel on fluid discharged from the high pressure section, each having inde iendent rotor and stator elements and each capable of developing substantially the same amount of power as the high pressure sections, while operating on fluid discharged therefrom, two driven shafts, two reduction gearings operatively connected to said shafts, and so connected to the separate turbine sections that both of said shafts receive substantially the same power while the organized apparatus is developing full power and both receive approximately the same power while the organized apparatus is developing half power.

11. An organized power developing;- apparatus comi irisinn ahigh pressure section, and three low pressure sections adapted to operate in parallel on the fluid r antzed from the high pressure section and each havinp' independent rotor and stator elements, a driven shaft, a reduction gearing operatively connected to the driven shaft, and having: two drivinr; pinions, one being; operatively connected to the high pressure section and one to one of the low pressure sections, a second driven shaft, a second reduction rearing operatively connected thereto and having; two driving pinions, each operatively connected to a separate low pressure turbine section. and means for rendering one low pres'mre section connected to each nearing inoperative.

12. An organized power developingapparatus comprising a high pressure element, and three independent low pressure elements adapted to operate in parallel on fluid discharged from the high pressure; element, said high pressure element compris ng a partial or variable admission ahead section, and a partial or variable admission reversing high pressure element, comprising an ahead 7 section, including-a single multiple velocity drop impulse stage, and a reversing section comprising a single multiple velocity drop impulse stage,three low pressure turbine ele ments adapted to operate inv parallel on the fluid discharged from the high pressure element, each low pressure element comprising a full peripheral admissionfal iead section, and a reversing section comprising a single multiple velocity drop impulse stage, means for placing the ahead section or each of the low pressure elements in communication with the exhaust 01" the ahead section of the highpressure element, and means for plao ing the reversing section of each low pressure element in communication with the exhaust of the reversing section of the high pressure element. 7

14. In a power developing apparatus, a plurality of low pressure turbine elements, each comprising an ahead section and a reversing section having separate inlets and a common exhaust, a high pressure element comprising an ahead section and a reversing section having separate inlet ports and separate exhaust ports, means for delivering fluid exhausted from the ahead section of the high pressure element to the ahead section of each low pressure element, means for delivering the fluid exhausted from the reversing section of the high pressure element to the re versing section of each low pressure element,

means for rendering at least one of said low pressure sections inoperative, and a plu rality of condensers serving the low pressure elements, each condenser serving less than the entire number of low pressure elements.

15. In an organized power developing apparatus, a high pressure element, three low pressure elements operating in parallel on the fluid delivered from the high pressure element, saidelements being so proportioned that each is capable of developing substane tially one-fourth the power developed by the organized apparatus, two double pinion reduction gearings operatively connected to the sections of the organized apparatus so that eachgearing is driven by two of said elements while the organized apparatus is developing full power, and means for cutting off communication between the high pres sure section and one low pressure section connected to each gearing when the apparatus is developing reduced power.

1 6. An organized turbine apparatus comprising a high pressure section, at least three low pressure sections operating in parallel on fluid discharged from the high pressure section and each having a separate rotor and a separate stator, a plurality of driven agents, reduction gearing between said sections and said driven agents,-said gearsbeing so arranged that at least one of said low pressure sections may be rendered inoperative without rendering any of said agents inoperative, and means for cutting off the supply of fluid delivered by the high pressure section from at least one of the low pressure sections.

17. An organized turbine apparatus comprising a high pressure section, three low pressure sections operating in parallel on fluid delivered from the high pressure sec tion, two driven agents, reduction gears between said turbine sections and said driven agents so distributed that two of said low pressure elements may be rendered inoperative without rendering either of said agents inoperative, and means for separately con trolling the delivery of fluid from the high pressure section to each low pressure section.

18. In combination with two driven agents, an organized turbine apparatus for driving said agents, comprising a separate high pressure section, and three separate low pressure sections operating in parallel on fluid discharged from the high pressure section, a high pressure reversing section operativelyconnected to the shaft of one ahead section, a low pressure reversing section operatively connected to the shaft of another of said ahead sections, reduction gears between the turbine sections and the driven agents so arranged that at least two of the low pressure sections may be rendered inoperative without rendering either driven agent inoperative, and means, for separately controlling. the delivery of fluid to said low pressure ahead sections and tosaid revers ing sections. V

19. In combination with two driven agents, an organized turbine apparatus comprising a high pressure ahead section, three low pressure ahead sections adapted to operate in parallel on fluid discharged from the high pressure section, a high pressure reversing section, three low pressure reversing sections adapted to operate on fluid discharged from the high pressure reversing section, means for separately controlling the delivery of fluid to each'section, and reduction gears between said sections and said agents so arranged that two low presoperative.

20. In combination 7 with two driven agents, an organized turbine apparatus comprising a high pressure section and three low pressure sections receiving fluid from the high pressure sectlons, reduction gears between said sections and said agents so ar-.

ranged that two of said's ections may be rendered inoperative Without rendering either of said agents inoperative, and means for separately controlling the delivering of fluid to each low pressure section.

21. In combination with a plurality of driven agents a plurality of turbine sections, a separate reduction gearing operatively connected to each agent, and transmitting power from a plurality of said sections, said gearings and said sections being so arranged that an equal distribution of power is attained among agents While all or half of said sections are developing power.

22. In combination with a plurality of driven agents, a compound turbine unit comprising a plurality of separate sections, a separate reduction gearing operatively coupled to each agent and operatively coupled to a plurality of said sections, and means for rendering certain of said sections inoperative and for maintaining an equal distribution of power among said agents.

In testimony whereof, I have hereunto subscribed my name this 28th day of J une,

HENRY F. SCHMIDT.

Witness E. W. McOALLIsTER.

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