US1155516A

US1155516A - Marine turbine.

Info

Publication number: US1155516A
Application number: US78946313A
Authority: US
Inventors: Henry F Schmidt
Original assignee: Westinghouse Machine Co
Current assignee: Westinghouse Machine Co
Priority date: 1913-09-12
Filing date: 1913-09-12
Publication date: 1915-10-05
Anticipated expiration: 1932-10-05

Description

Patented Oct. 5, 1915.

2 SHEETS-SHEET I.

v \N w\ mm INVENTOR.

WITNESS IS ATTORNEY IN'FACT H. F. SCHMIDT.

MARINE TURBINE.

APPLICATION men szPTqz. 191a. 1.,155,516.-

Patented Oct. 5, 1915.-

2 SHEETS+SH EET 2 llllll II J2 1 i INVENTOR.

'H/ ATTORNEY IN FAC I .ir sate a name.

HENRY F. SCHMIDT, OF PITTSBURGH. PENNSYLVANIA, ASSIG-NOR TO THE WESTING- HOUSE MACHINE COMPANY, A CORPORATION OF PENNSYLVANIA.

MARINE TURBINE.

Specification of Letters Patent.

Patented Oct. 5, 1915.

To all whom it may concern:

Be it known that I, HENRY F. SCHMIDT, a citizen of the United States, and a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have made a new and useful Invention in Marine Turbines, of which the following is a specification.

This invention relates to turbines and has for an object to produce a turbine, or combination of turbines, which is well adapted to be employed .in marine propulsion.

,A further object is to produce a highly eflicient marine turbine which operates at low or cruising speeds with high, and better economy than other turbines known to me. v

A further object is to produce a marine turbine. or organized turbine apparatus, which is lighter, in proportion to its capacity, and occupies less space than other turbines known to me.

A further object is to produce an organized apparatus for marine propulsion comprising separate cofiperating turbines, so constructed and arranged that substantially full speed may be developed even though one of the turbines, included in the organized apparatus, is incapacitated.

These and other objects I attain by means of a turbine, or organized turbine apparatus, embodying the features herein described and illustrated in the drawings accompanying and forming a part of this application.

In the drawings, Figure 1 is a diagrammatic sectional view of a turbine embodying any invention and shown in connection with aconventional plan view of a. reduction or transmission gearing, which may be employed between the turbine and the apparatus to be driven thereby. Fig. 2 is a sectional View along the line 22 of Fig. 1

and illustrates an arrangement of nozzles,

which may be employed in one of the turbines, or turbine stages, forming a part of my invention. Fig. 3 is, a diagrammatic sectional View of a turbine, or organized turbine apparatus, which forms an embodiment of my invention.

Referring to the drawings, and particularly to Fig, l, the apparatus illustrated, 'as an embodiment of my invention, may be termed a triple flow turbine, since the motive fluid after having traversed a working stage or a portion of the working passage of the turbine, is divided into three streams and 1s caused to pass through a divided flow low pressure section including three sepabeing discharged from the initial stage, is

divided into three streams and is delivered to three reaction sections, two of which are shown as comprising a separate turbine, or turbine section. It will be apparent that the'motive fluid may be partially expanded, a greater or less amount, in the initial stage and that additional sets of eXpansion nozzles and additional rows of blades may be employed inthe initial stage. It will also be apparentthat my invention contemplates a turbine in which the low pressure sections are impulse instead of reaction sections, or a turbine in which any combinations of the different types of turbine sections may be employed.

As illustrated in Fig. 1, the turbine, or organized turbine or turbine element apparatus. consists of a turbine 10, comprising a. rotor i. and its in'closing casing 5, and a turbine or turbine element 10, comprising a rotor G and its inclosing casing/T. hile the turbine 10" is, in eflect, a low pressure turbine, the turbine 10 cannot be accurately termed a high pressure turbine, although high pressure motive fluid is delivered to it, and a portion of the fluid is then after having been partially expanded, delivered to the turbine 10 during the development of full power by the organized turbine apparatus. The turbine 10 is equipped with a low pressure section which is operative during the entire operation of the organized turbine. and while the turbine 10 is operating alone as a cruising turbine. sure section of the turbine 10 is adapted to expand motive fluid to exhaust or condenser pressure, it is not of suflicient size to pass all of the motive fluid delivered to the. initial stage of the turbine when the organized apparatus is running at full speed or is de veloping full power. The motive fluid is therefore divided, prior to being delivered \Vhile the low pres to the low pressure section of the turbine 10, and a portion of the motive fluid is delivered to the turbine 10.

Throug ut the further description of my invention have considered the embodiment of it as consisting of three turbine elements operating as an organized apparatus, but it will be clearly with the nomenclature of the turbine art, that the embodiment of the invention illus trated would more accurately be described as a single turbine divided into ,two sections and provided with a reversing stage,since neither of the turbine elements 10 nor 10 is in reality a completeturbine capable of efficiently developing full power without the cooperation of the other.

The turbine 10, as illustrated, is provided with an inlet port 11, which communicates with a source of high pressure motive fluid and is adapted to deliver 'motive fluid to one or more expansion nozzles 12. The nozzles 12 may be, and preferably are adapted to partially expand the motive fluid passing through them and to deliver it to impulse blades 13, mounted on a wheel 14 forming a part of the rotor 4. Two rows of blades 13 wheel, but it will are shown mounted on the be understood that the energy, rendered available by the expansion of the motive fluid, may be abstracted by any desired number of rows of blades. In the turbine illustrated the nozzles 12 and blades 13 constitute, what may be termed, a variable or partial admission, initial or primary section of the turbine and the motive fluid delivered 7 from this section then passes through the =lc pressure section or sections of the turis illustrated the low pressure sections are equipped with reaction blades and are capableof expanding the fluid down to exhaust or condenser pressure. It will, of course, be understood that if desired, one or more impulse stages may be employed and that the low pressure section may be materially modified without departing from the i l invention.

In the turbine shown, the motive fluid delivered from the blades 13 is received by an annular chamber .15, which communicates with the inlet end of the low pressure section and also with a passage 16, which extends around a section 17 of thelow pressure section and communicates with an annular chamber 18, formed within the casing 5.

The section 17 may for convenience of description and also'tor the purpose of conforming to accepted nomenclature, be termed the intermediate section of the turbine 10, and this section, under certain conditions 0 operation, is by-passed by motive fluid passing through the lay-pass passage 16. The fluid is delivered by the passage 16 to the chamber 18 and from the chamber 18 to the first row of stationary apparent, to those acquainted bine sections, such as blades of the working 7 section located immediately adiacent to the intermediate section 17, which, for the reasons above assigned, may betel-med the low pressure section 19 of the turbine 10. This section 19 is a full peripheral admission sec-. 'tion and communlcates with the exhaust passages formed within the casing 5 and through them with the exhaust port and the condenser, which is notshown. Communication betwen the chamber 15 and the bypass 16 is controlled by means of a Valve21 which, in the drawings, is shown as being capable of manual control, since it is provided with an operating hand wheel 22. The casing 5 of the turbine 10 also incloses a reversing stage or turbine which, as illustrated, consists of a series of expansion noz zles 23 and cooperating impulse blades 24. The blades 24 are shown mounted on a wheel 25, which forms a part of the rotor 4. The nozzles 23 communicate with a port 26, which is formed in the casing and is adapted to communicate with a source of high pressure fluid supply through pipe 27. It will, of course, be understood that two or more stages may be employed in the reversing turbine'and that this turbine may be of any desired type or' combination of different types; for example, it may be a combination of the impulse and reaction types of turthe turbine 10 just described. As illustrated, the motive fluid, discharged from the last row of blades 24, enters the exhaust passages formed within the casing 5 and is discharged into the condenser.

In the drawings I have diagrammatically shown means for hermetically separating the ahead turbine 10 from the reversing turbine, which consists of an ordinary labyrinth packing or fluid seal. This packing is formed by means of alternatelyv arranged and interleaving rotating and stationary annular ridges which are respectively mounted 5 and is located between the rotor wheels 14 and 25. The drum 27 may be so proportioned that it maybe employed in counterbalancing the end thrust imparted to the rotor by the fluid traversing the low pressure sections of the turbine 10 The turbine 10*, in effect, supplements the low pressure section 19 of the turbine 10. It receives motive fluid from the chamber. 15 which is delivered through piping 31 to inlet ports provided within the casing 7. Communication between 'the chamber a I the turbine 10 is controlled by means of u f valve 32. which, as shown, is located in piping 31 and is preferably adapted to 1 a manually controlled.

' As illustrated, the turbine 10 is a strai double flow turbine, that is to. say, mo

fluid delivered to it is divided into two suhit stantially equal streams and passes through two bilateral symmetrical working passages toward both ends of the turbine. The turbine 10 is provided with two reaction sections 33 and 33,'which are located atopposite ends of the casing 7 and through which motive fluid is adapted to pass in opposite axial directions toward exhaust-passages 34, located in each end of the casing 7 I however do not desire to limit the invention to the use of reaction turbine elements in the sections 33 and 33 of the turbine 10, since turbine sections of any desired type may be substituted for these sections. The turbine is also shown as provided with a' single row of impulse blades 35, which are mounted on a wheel 36, forming apart of the rotor 6 and located midway between the sections 33 and 33% These blades 35, together with oppositely disposed

nozzles

37 and 37" (diagrammatically shown in Fig. 1), comprise 'what may be termed the primary stage of the turbine lo but which is adapted to operate as a part of the low pressure section of the turbine 10, when the turbines l0 and 10 are, 006 eratin or functionin as an 7 t:

organized apparatus or single turbine formed in two sections. The nozzle or series of nozzles 37 are located on one side of the wheel 36, and deliver motive fluid to the reaction section 33 of the turbine, after having partially expanded the fluid and .dis-

charged it intothe blades 35. On the other hand, the nozzle or series of nozzles 37 are located on the opposite sides of the wheel 36, and after partially expanding the motive fluid, deliver it to the blades 35in such a way that it is delivered to the blades'of the section 33, after it has passed through the blades 35 w In the drawings diagrammatic means are shown for dividing the motive fluid, delivered from the chamber 15 of the turbine 10,

'the

nozzles

37 and 37 of the turbine 10 but it will be apparent, to those skilled in the art, that various means may be employed for accon'iplishing both the division of the fluid into two streams and the delivery of the separate streams to the separate sections of the turbine, and that each of the nozzles or separate groups of nozzles 37 and37 may be separately controlled by means of valves or other devices ordinarily employed to obtain what is termed, nozzle control. It will also be understood that the

nozzles

37 and 37 have equal areas and are identical in design so that the pressure drop through them is substantially equal. It will be understood, however, that the existing space, around portions of the wheel 36, which communicates with the space on both sides of the wheel will operate as an equalizing passage should there be any tendency to create differences of pressure on opposite sides of delivering it to half traverses the section 33'.

the Wheel due to slight variations in the

nozzles

37 and 37. It will also be understood that the velocity energy of the motive fluid, rendered available by its partial expansion in passing through the nozzles, may be fractionally abstracted and that two or more rows of impulse blades may be employed in stead of the single row shown.

Both the turbines 10 and 10 are shown directly connected to a separate pinion shaft of a reduction gearing 38, which may be employed in driving any apparatus to be driven, such, for example, as the propeller shaft of a vessel. The reduction gearing illustrated is provided with a gear 39, mounted on a shaft 41, and two

pinions

42 and 42*, both of which mesh with th: gear 39, but are located on diametrically opposite sides of it. The pinion 42 is mounted on a shaft 43 which is directly connected to the turbine 10 by means of a flexible coupling 44 or, if desired, a clutch mechanism capable of being disengaged. The pinion 42 is mounted on a shaft 43 which is directly connected to the turbine 10 by means of a flexible coupling 44?, or a clutch mechanism capable of being disengaged. The

pinions

42 and 42* shown, are of the same size and consequently the turbines 10 and 10 illustrated are so constructed that they operate at the same speeds while operating as component parts of an organized apparatus or as separate sections of a single turbine. While it is preferable to operate the two turbines at the same speed, it will be apparent that the two turbines may operate at different speeds.

While the two turbines are operating as an organized apparatus, motive fluid is de livered through port 11 to the nozzles 12 of and deliver it to After traversing the blades 13.

expand the motive fluid blades 13.

approximately one-third of the motive fluid is delivered through the bv-Dass 16 to the low pressure section 19 of the turbine 10. while the remaining two-thirds is delivered through the piping 31 to the nozzles 37 and 37' of the turbine 10*. These nozzles. as has been described, partially expand the fluid traversing them and deliver it to a row of impulse blades 35 in such a way that approximately one-half of the motive fluid. received from the turbine 10, traverses the section 33 of the turbine 10. while the other With such an arrangement three separate working passages are provided through which the motive fluid passesto the condenser, and consequently each of the turbines may be inaterially reduced in diameter below that o a single flow turbine of the same power anof the same area through the last few rows; of low pressure blades. In fact, the diameters of the separate turbines, forming com 10, the

I have referred; and in addition to this,

and consequently at reduced power,

ponent parts of the illustrated embodiment of my invention, need only be 57% of the diameter of the single flow turbine to which the blades of the triple flow stage are approximately but 57% of the length of the blades of a single flow turbine of equal power and blade area. Such blades are about 5.3 times as rigid as the blades required in the sin gle flow turbine.

\Vhile the reduction in the diameter of the Y two turbines 10 and 10 increases the leakage of fluid through the clearance space be tween the ends of the turbine blades and the casings, this slight loss is more than offset by the fact that there is but one counterbalancing piston or dummy and that the diameter of this dummy is but 57% of the diameter of the counterbalancing piston, which would be employed in the single flow turbine of the same power; the loss is further offset by the fact that the blade and dummy clearances may safely be much the single flow turbine be smaller than in cause of the smaller diameters of the rotors and the shorter blades employed. The ac tual difference in the total leakage of fluid through the clearance spaces of the turbine is almost negligible and the small loss in efficiency resulting from the small difference, which may exist, is more mechanical efficiency of the apparatus.

Itis well known that rotation losses in a turbine v'ary directly as the cube of the revolutions per minute of the rotor and as the fifth power of the diameter of the rotor; hence a reduction by one-half of the diameter of the rotor and a doubling of the revolutions per minute of the rotor (giving the same blade speed in each case) results in reducing the rotation losses to 25% of the rotation losses in a single flow turbine of the same power.

The principal advantage gained by employing apparatus embodying my invention is, however, the betterment of the economy at cruising speeds and also the great reductionin the weight of the turbine.

While the turbine is running at low speeld, t 1e valves 21 and 32 are closed; this shuts oil the supply of 'motive fluid to the turbine 10 and therefore all of the fluid delivered to the nozzles 12 of the turbine 10 must pass through the intermediate and low pressure sections of that turbine. Inasmuch as the motive fluid has but one path to tho condenser and that path is approximately but one-third of the area available while the turbine 10 is receiving fluid from the turbine absolute fluid pressure at the inlet end of the" intermediate section or in the chamber 15 will be three times as would be if the valve 32 were open, ones it would be in a single fiow turbine developing of the impulse portion than offset by the ratus with higlrQas it the same power under the same conditions. The turbine 10 may be-so designed that the closing of both of the valves 21 and 32 will increase the absolute pressure in the chamber 15 to about 5 or 6 times what it would be with the valves open, or what the pressure would be in a single flow turbine of equal power operating under similar conditions. It will also be apparent, to those skilled in the art, that the successive closing off of nozzles of both the

ses

37 and 37 will accomplish, in a measure, what is accomplished by closing the valve 32 and that the economy of the organized apparatus is improved at all powers between that developed with the valve 32 wide open and the power developed with the valve closed; in other words, the use of nozzle control in the turbine 10 produces substantially the same effect as the gradual closing of the valve 32 as the load decreases; but it eliminates theosses in economy which would result due to throttling of the fluid. Theresult gained by closing the valve 32 is that the expansion range of the turbine is re duced, and the expansion ratio of ther-eaction portion or low pressure sections is increased, thus increasing the efficiency of the turbine and insuring high'economy during cruising speeds, This result is, of course, more marked with both the valves 21 and 32 closed. It may be said that the turbine apparatus embodying my invention, ineffect, includes a specially designed cruising turbine which is capable of running at onethird speed and of developing one-thirtieth of the power of the organized turbine appahigh economy. The economy of this cruising turbine is substantially the same at cruising speeds as the economy 0 the entire or organized apparatus, while it is developing full power and running at full speed, because the reaction blades or separate stages of the turbine 10 are designed to meet conditionsof reduced speeds; that is, it has a large number of rows of blades or stages, while the turbine 10 has but a few rows of blades or stages since it, the turbine 10, operates only while the organized turbine apparatus is developing full power, at which time the blade speed is high, and

therefore only a few rows of blades'are required. It will be understood by those skilled in the art that the intermediate sec- 'tion 17 of the turbine 10 is diagrammatipared with the number of rows of blades or stages included in each separate low pressure section. By stage it mean a working section of a turbine in which the steam. or motive fluid is expanded or reduced in pres sure and approximately all ofthe velocity by ny invention over the weight of ordinary marme turbines operating under similar conditions and developing the same power,

because the smaller diameters of the rotor elements permit relatively high speeds and also because only a relatively smallportion of the total blading need be designed for low speed conditions. This reduction in weight is advantageous both in the operation of erecting the apparatus and in its use as the propelling apparatus of a vessel, since, in the first place, the parts of the small units can be easily and quickly handled, and in the second place, the reduction in weight reduces the fixed tonnage of the vessel and consequently renders it capable of carrying a greater tonnage of fuel or cargo than would be the case if it were equipped with 1 an ordinary marine turbine.

A further advantage is that the organized turbine apparatus embodying my invention occupies less space than ordinary turbines and there is noindependent cruising turbine or engine with theaccompanying gears. In addition to this, the steam piping is also materially simplified andthe turbine is Well adapted to be employed with a condenser which may be located beneath it.

Another principal advantage obtained by my invention is that either the turbine 10, the turbine or the reversing turbine may develop full power while operating independently. In case the turbine 10 is incapacitated, high pressure -motiv,e fluid is delivered to the turbine 10 and the by-pass valve 21 is,open, but the valve 32 is closed. This increases the pressure in the chamber to such an extent that practically the same wei ht of motive ,fiuid will pass through the'low pressure section of the turbine 10 as ordinarily passes through the sections 19, 33, and 33" while the valve 32 is open. If the turbine 10 is incapacitated, high pressure motive fluid may be admitted directly to the turbine lO and it, under such conditions, will develop full power with a small loss in efficiency. In Fig. 2 of the drawings I have shown a sectional View of the turbine 10 provided with

nozzles

45 and 45 for delivering high pressure motive fluid to the blades of theturbine. The casing 7 is provided with two ports 46 and 4.6, which are adapted to communicate with a source of high pressure fluid through pipes not shown and which communicate respectively with the nozzles and 45. It will be seen from the foregoing that practirally full speed can be maintained during high speeds.

emergencies with any two of the turbines out of commission. This is particularly advantageous in naval Vessels since a small loss in economy is of little importance during emergencies in which it is essential to obtain- In Fig. 3 of the drawings I have, diagrammatically illustrated a turbine or organized turbine apparatus embodying my invention,

which is well adapted to be employed as the driving agent of a ships propeller and which may be utilized in connection with a reduction gearing if desired. While the turbine illustrated in Fig. 3 embodies some of the featuresof the turbine illustrated in Fig. 1, it is well adapted to be employed as the propelling agent, for example, of a merchant vessel in which the difference between the two desirable speeds is not as great as -the difi'erence between cruising speed and full speed of a naval vessel.

The organized turbine apparatus as illus trated consists of two separate turbines or turbine elements 10 and 10 so arranged that the turbine 10 forms in effect a portion of the low pressure section of the turbine 10, while the two turbines are opcrating together, or, in other words, while the organized turbine apparatus ing full power.

The turbine 10", as illustrated, includes an initial stage of the impulse type, which consists'of expansion nozzles 48 and two rows of blades 49; The motive fluid, after having been partially expanded by the nozzles 48, is delivered to the blades 49 and then is discharged into an annular chamber or passage 51 which communicates with, what may be termed,- an intermediate section 52 of the turbine l0 or of the entire organized apparatus. This section, as conventionally illustrated, is of the reaction type and is arranged to deliver motive fluid, traversing it, to an annular chamber 53, which is formed Within the casing of the turbine 10 and which communicates with what may be termed one section 54 of the low pressure isdevelopstage of the organized turbine apparatus.

This section 54 is inclosed within the casing of the turbine 10 and is, in fact, the low pressure section of that turbine. It is con ventionally shown as of the reaction type and as discharging into an exhaust passage 55 formed in the casing and adapted to communicate with a condenser, whlch 1s not shown, but it may be of any suitable type.

The chamber 53 is provided with adelivery port 56 and the motive fluid delivered to it is divided into two streams, one of which passes through the section 54,]while its point, with reference to the casing, and is 4 divided so that it flows in opposite axial directions toward the ends of the casing in passing through the working passages of the turbine. As conventionally shown, the turbine is provided with two oppositely located sections 5,7 and 57 which are similar to each other and which are so constructed that the area through the last few rows of blades at the discharge end of each section is equal to the area through the last few rows of blades of the. section 54 of the turbine 10". However, the section 54 is preferablyprovided with a greater number of rows of blades than either of the

sections

57 and 57'. l Vith the arrangement described, twice as much motive fluid is de livered through the piping 56 as passes through the section 54 of the turbine 10 when the valve 58 in the piping is open.

The casing of the turbine 10, like that of the turbine 10, incloses a reversing turbine 59, which receives motive fluid through a port 61 formed in thecasing and which is separated from the initial stage of the tur bine-10 by means of a fluid seal 62, the cylinder of which may be employed as a counter-balancing piston in counterbalancing the end thrust imparted to the rotor of the turbine by the reaction stage.

\Vhile the organized turbine apparatus illustrated is developing full power, motive fluid is delivered through the nozzles 48 of the turbine 10, and the valve-58 is open so as to establish communicationbetween the chamber 53 and the inlet port of the turbine 10. Under such conditions, the motive fluid, after having been partially expandedin traversing nozzles 48, is delivered to the blades 49 where the available velocity energy is abstracted. The motive fluid, on leaving the blades 49, enters the intermediate section 52 in which it is fractionally expanded by the successive rows of reaction blades. It will be apparent that instead of employing straight reaction blades, the available energy may be abstracted from the motivefluid by impact and reaction in wh ich the motive fluid is fractionally expanded in both the rotary and the stationary blades, or that any other type of blading may be employed.

After the motive fluid has traversed the section 5'2 of the turbine, it is delivered to the chamb r 53 and is divided into two separate streams, one of which passes through the section 54, while the other of which is delivered to the turbine 10 and is again divided into two substantially equal streams which pass through the separate sections 57 and 57' of the turbine 10.

When it is desired to propel at low speeds a vessel, equipped with theturbines illus trated, the valve 58. is closed and consequently the range of expansion through the.

low-pressuresections of the turbine 10" is increased while the ressure dro throu h 'the nozzles 48 is diminished. This causes 'fluid is delivered directly to the inlet port of the turbine 10, through piping 60, the valve 58, of course, being closed. If the turbine 10 is incapacitated, the turbine 10 is caused to operate at full speed by increasing the amount of steam, delivered to it, over that normally delivered while it is operating in conjunction with the turbine, 10.

In both the illustrated embodiments of my invention a portion of the organized apparatus is revolving idly during operation at low speeds, at which time the heating effect, due. to the windage and friction of the blades, is so small that the temperature rise is of no consequence and will not cause distortion of the turbine cylinder and the consequent contact of the moving and stationary elements; whereas in all other marine turbine installations in which provision is v made for obtaining good economy at low cruising speed, the turbine elements employed during cruising or low power conditions are revolving idly during high speed or full power conditions. It is well known that the friction and windage loss occasioned by rotating a turbine element in an atmos phere of steam is directly proportional to the cube of the revolutions per minute and is alsodirectly proportional to the density ofthe steam surrounding the rotating element, consequently, since the low pressure element in my turbine is revolving idly in steam at condenser pressure and only when the speed is reduced, for example, to about three-fourths of full speed, the heating en countered under the most disadvantageous conditions will be but 42% of the heating encountered in turbines in which separate that this isolated section of the high pressure turbine may be single flow if desired, or in fact, it may itself be divided into three or more sections, some of which are locatedin separate casings.

While I have illustrated but two embodiments of my invention, I desire it to be understood that various changes, modifications, substitutions, omissions, and additions loimay be made in the apparatus illustrated without departing from the spirit and scope of my invention as set forth by the appended claims and that I do not limit my invention to marine installations, nor use in connection with reduction or transmission gear- Having thus described my invention, what I claim is:

l. A power generatingsystem comprising I a turbine having a high pressure turbine element, a divided low pressure turbine element communicating therewith, the separate sections of which are arranged to operat in parallel, one of the sections of-the divided low pressure turbine element being isolated by being located in a separate casing and being adapted to receive fluid from the high pressure element while the turbine is operating at full power and at high speed, '30 and means for shutting off the fluid to the isolated section when the turbine is operating at low speed and at reduced power.

2. A- turbine comprising an impulse stage and a full peripheral'admission low pressure 8 section, in combination with an,isolated low pressure section located in a separate casing and adapted to operatein; parallel with the motive fluid so received {to exhaust pressure,}. in combination with" a transmission gearing comprising a dr ven gear, a driving gear intermeshing with said driven gear and coupled to saidfirst mentioned turbine, and 5 a second driving gear intermesh-ing' with said gear and coupled to saidlow pressurev turbine.

4. In an apparatusof the character described, a turbine'inwhich motive fluid is, expanded from initial to exhaust pressure,-

, a second turbine havingoppositely; extend ing working passages, each adapted to expand motive fluid from an intermediate to exhaustpressure, and means for delivering motive fluid from an intermediate portion of the working passage of the first turbine.

to the inlet of the-second turbine.

5. In an apparatus of the character described, a turbine comprising a high presing motive fluid from an intermediate, point of the Working passage of the first to the inlet of the second turbine.

6. A turbine comprising a single flow high pressure stage and alow pressure turbine element divided into three separate sections,

two of sa-idsection's being inclosed within a separate casing.

7. A turbine comprising a single flow high pressure section and a low pressure working portion divided into three separate low pressure sections operating in parallel,

and each receiving motive fluid from said high pressure section, at least one of said low pressure sections being located in the same-casing with said high pressure section, and at least one of said low pressure sections being isolated by being located in a separate casing.

v 8. A turbine comprising a high pressure turbine element, a low pressure turbine element divided into three separate sections,-

two ofsaid sections being inclosed within a separate shell through which the motive fluid flowsin opposite directions, and means for controlling the delivery. of motivefluid to said shelL.

9. A turbine comprising a single flow section and a double flow section, and means for deliveringmotive fluid to the double 'flow section from a point of intermediate pressure of the single flow section.

10. An apparatus of the character de; scribed comprising a turbine, a low pressure turbine communicating with an intermediate portion of the working passage of the first mentioned turbine, and means for bypassing'fluid around a section of'the Working passage of the first mentioned turbine, tothe low pressure turbine, contained within the same casing as the high pressure turune. g 1

11. An apparatus of the character described comprising a turbine, 'a'low pressure turbine communicating with the working passage of the first mentioned turbine at a. point of intermediate pressure, means for by-passing motive fluid around a 'r-' tion of the working passage of the 'i'st" 1 mentioned turbine, and means for controlling the' delivery of motive fluid through said by-pass to low pressure stage of the first mentioned turbine 12. An apparatus 'of. the character described comp-rising a turbine,. a low pressure turbine communicating With the Working passage of the first-mentioned turbine at a point of intermediate pressure, a bypass for by-passing motive fluid around a section of the working passage of the first a. valve for controlling mentioned turbine,

'fluid through the bythe delivery of motive pass and a -valve for controlling communicating with the high pressure stage and divided into separate divisions each adapted to operate in parallel, one of said divisions being designed for diilerent speed conditions from the other. i

14:. A turbine having a high pressure turbine element, a low pressure turbine element communicating therewith and comprising separately formed sections adapted to operate in parallel, one of said sections being constructed for dilie'i'ent speed and pressure conditions than the other, and means for shutting off communication between a section of the low pressure turbine element and the high pressure turbine element.

15. A turbine having a high pressure stage, a low pressure turbine element communicating therewith and comprising independently'formed separate sections adapted to operate in parallel, one of said sections being constructed to operate efiiciently at different speed and pressure conditions from the other, and means for shutting off communication between a, section of the low pressure turbine element and the high pressure stage.

" sa-id sections i I through the. by-pass.

16. Aturbine having a high pressure turb.ne element and a divided flow low pressure turbine element formed in separate sections adapted to operate in parallel, one of of the other and being constructed to operate with high efiiciency at ditlerent speed conditions from theother, a. by-pass communicating with the low pressure turbine element for by-passing fluid. around a section of the high pressure turbine element, and means for controlling the flow of fluid 17. A turbine having a high pressure portion and av low pressure portion through which motive fluidsuccessively flows, said pressure portion being formed in separate sections with each of said sections communicating with the high pressure portion and with one'of said sections independently formed and designed to give highest efficiency at different speed and pressure conditions-from the other, and means for shutting oft communication between said inde pendently formed section and the high pressure portion of the turbine.

I 18. A turbine comprising an initial stage,

being formed independently.

a divided flow low pressure section and a reversing section, said initial stage, one diand a common rotor, and the other division of the low pressure section having an independent casing and rotor.

19. A turbine comprising an initial section, a divided flow low pressure section, and a reversing section, said initial section, one division of said low pressure section, and said reversing section having a common r0 tor element, and a co-unterbalancing piston located between the initial section and the reversing section of the turbine.

20; An apparatus of the character de-- scribed comprising a turbine, a second turbine, means for delivering motive fluid from the first mentioned to the second turbine, a by-pass communicating with said means for b vpi ssing a section of the working passage of the first mentioned turbine, means for shutting ott comn'iunication between the turbines, means for closing the by-pass, and means for delivering high pressure motive fluid to the second turbine.

21.. An, apparatus of the character described, comprising a turbine, means'for bypassing fluid entering the inletoi the turbine around a section of the working passage thereof, a low pressure turbine, and means communicating with the first mentioned turbine, at a point ahead of the inlet to the bypass, for delivering niotiv'e fluid to the low pressure turbine.

22. A turbine comprising a high pressure stage, a full peripheral admission low pres sure section having a single row blades per stage, in combination with an iso lated low pressure section adapted to operate in parallel with the first mentioned low pressure section, and means for simultaneously delivering fluid discharged from said hi h )ressure sta e to both oi said low ares sure sections while the combined apparatus 13 developing full power.

scribed, comprising. a turbine having a divided flow low pressure section, one division of. which is located in a separate casin a I o gearing driven by the turbine and indepeiidentl vby the isolated portion of the low pressure section, and means for shutting off the motive fluid supply to the isolated por-- tion of the low pressure stage'wher. the turbine is operating at low speed.

I 1 20 24. An apparatus of the character de' 25. An apparatus of the character dc scribed, comprising a turbine having a d1- 'vided low pressure section, one division of nozzles, means for varying the number of nozzles eflective in delivering motive fluid to the blades or buckets of said sections, and a full peripheral admission low pressure section receiving motive fluid from the high pressure section, and in which a single row of moving blades is employed in each stage, incombination with a section isolated by being located in a separate casing from said high and low pressure sections, and means for simultaneously delivering motive fluid discharged from the high pressure section 'to the low pressure section and the isolated section While the combined apparatus is developing full power.

- 27. A power generating system comprising a variable or partial peripheral admission impulse high pressure section, two low pressure sections at times adapted to operate in parallel on the fluid exhausted from said high pressure section, at least one of said sections being isolated by being located in a separate casing from the high pressure section, and means, such as a valve, for cutting off the supply of motive fluid to the isolated section when the system is operating at re- .duced speed and is developing reduced power, and for delivering fluid from said high pressure section to said isolated section when the system is developing full power.

28. A power generating system compris ing a multiple velocity drop impulse turbine element, two or more independent low pressure turbine elements adapted to operate in parallel and to receive motive fluid from said impulse turbine element, at least one of said low pressure elements being isolated from the impulse turbine element by being located in a separate casing, and means for shutting off the supply of motive fluid to said isolated low pressure elements when the system is developing reduced power.

29. A marine turbine system consisting ofa high pressure turbine section and two low pressure sections designed to operate at the same terminal pressure, one of said low pressure sections being located in the casing with the high"pressurc section, the other low pressure section being in a separate casing and on a separate shaft, both low pressure sections being adapted to operate in parallel on the exhaust from the high pressure section when the system is developing full power.

30. A marine turbine system comprising a turbine element, having a high pressure section and a low pressure section located in the same casing, a second turbine element located in a separate casing adapted to operate in parallel with the low pressure section and to receive motive fluid from the high pressure section, a transmission gearing operatively connected to the shafts of both of said turbine elements and means for cutting off the supply of motive fluid to said second turbine element when the system is developing reduced power.

31. A marine turbine system comprising a turbine element having a high pressure section and a low pressure section located in the same casing and having a common rotor element, in combination with a second turbine element located in a separate casing, having a separate rotor element, and adapted to operate in parallel with the low pressure section and to receive motive fluid from the high pressure section of said first mentioned turbine element, a transmission gearing comprising a gear operatively connected to apparatus to be driven and two gears meshing therewith. each operatively connected to the rotor element of one of said turbine elements. and means for shutting off the supply of motive fluid to said second turbine element when the system is developing reduced power.

32. A marine turbine system. comprising a high pressure turbine element. a separate low pressure turbine element receiving motive fluid from said high pressure element and operating in parallel with a low pressure section thereof, a transmission gearing including two driving gears to each of which the rotor of one of said turbine elements is connected. means for shutting off the delivery of motive fluid from the high pressure turbine element to the low pressure element when the system is developin reduced power and means for delivering nigh pressure motive fluid to said element.

33. A marine turbine comprising a high pressure turbine element having a high pressure section and a low pressure section adapted to receive motive fluid from the high pressure section and located in the same casing as the high pressure section, a low pressure turbine element located in a separate casing and having fluid inlet nozzles for delivering motive fluid to the working elements thereof. and means for delivering motive fluid from the high pressure turbine element to the nozzles of the low pressure turbine element and to the low pressure section while the marine turbine is de veloping full power.

34. A marine turbine comprising a hi h pressure turbine element having a high peripheral admission low pressure pressure section and a low pressure section located in the same caslng and havinga common rotor element, a low pressure turbine element having a separate casing and parallel.

rotor element adapted to operate inwith said low pressure section but designed for different power and speed conditions from said low pressure section, and a transmission gearing having two driving gears, each operatively connected to the shaft of one of said turbine elements, and means for delivering motive fluid from the high pressure turbine element to the low pressure section and to the low pressure turbine element when the marine turbine is developing full power.

35. A marine turbine comprising a high pressure turbine element, having a high pressure section and a low pressure section adapted. to receive motive fluid from -the high pressure section, a low pressure turbine element having a separate rotor element and separate casing and adapted'to receive motive fluid from said high pressure section and to operate .in parallel with said low pressure section when the marine turbine is developing full power, a transmission gearing having a plurality of driving gears, one being operatively connected to the rotor of the low pressure section and one to the rotor of the low pressure turbine element.

36. A marine turbine comprising a high pressure turbine element having a high pressure section and a low pressure section adapted to operate in series, a low pressure turbine element designed for different power and speed conditions from said low pressure section and having a separate rotor and statorbut adapted to receive motive fluid from said high pressure section and to operate in parallel with said low pressure section when the marine turbine is developing full power, a transmission gearing including a plurality of driving gears, one being operatively connected to the rotor element of the low pressure section and one to the rotor element of the high pressure turbine element, and means for cutting off the supply of motive fluid. from the high pressure section to the low pressure turbine element when the marine turbine is operating at low speed, and for delivering high pressure motive'efiuid to the low pressure turbine element to operate it independently of the fhig h pressure turbine element.

37. A marine turbine comprising a high pressure turbine element, having a high pressure impulse section to which motive fluid is delivered through nozzles, two full sections at times adapted to operate in parallel on the fluid discharged from the high pressure section and at least one of which is isolated by being located in a se arate casing from the impulse section, a transmission gearing reduced power,

' pressure section,

having a separate driving gear operatively connected to the rotor element of each low pressure section means forshutting'oif the delivery of motive fluid to the isolated section when the marine and a reversing turbine 0p eratively connected to said transmission gearing.

38. A turbine comprising a variable or partial admission high? pressure section, a plurality of full peripheral admission low pressure sections a lapted to operate in par.- allel on the fluid discharged from the high isolated by being located in a separate casthe high pressure section and is designed for different speed conditions from the other, and means for shutting off the supply of motive fluid from the high pressure section to the isolated. section when the turbine is developing reduced-power.

39. A turbine comprising a variable or partial admission high pressure section, a plurality of full peripheral admission low pressure sections adapted to operate in parallel on the fluid discharged from the high pressure section, at least one of which is isolated by being located in a separate casing,-and means forshutting ofi the supply of motive fluid to said isolated section when said turbine is developing full power.

40. A turbine comprising a variable or artial admission high pressure section, a plurality of full peripheral admission low pressure sections adapted to operate in pau allel on the fluid discharged from the high pressure section, at least one of which is isolated bybeing located in a separate cas ing from the high pressure section and is designed for difierent speedconditions from the other, means of motive fluid from the high pressure section to the isolated section when the turbine is developing reduced power, and a transmission gearing having a separate driving gear operatively connected to the rotor element of the high pressure section and a separate driving gear operatively connected to the rotor element of the isolated section.

41. A turbine comprising a variable or partial admission high pressure section, a plurality of full peripheral admission low ing from turbine is developing- .pressure section, at least one of; which is for shutting oil the supply pressure sections adapted to operate in paiallel on the fluid discharged from the high at least one of which is isolated by being located in a separate casing. means for shutting off the supply of 'motive fiuid to said isolated section whensaid turbine is developing reduced power, and a transmission gearing having aseparate driv' ing gear operatively connected to the'rotor element of the isolated section.

49.. A turbine having a high pressure section and a plurality of low n-essure sections adapted to operate in parallel on the fluid discharged from the high pressure section, one of said sections being isolated by being located in a separate casing from the high pressure section and being designed for difpower, and a reversing section operatively ferent speed conditions from the other,

means for shutting off the supply of motive fluid from the high pressure sectionto the isolated section when the turbine is developing reduced power, and a transmission gearing having a driving gear operatively connected to the rotor of said high pressure section.

43. A turbine system comprising a high pressure turbine element having a variable or partial peripheral admission high pressure section, and a full peripheral admission low pressure section receiving motive fluid from the high pressure section and located in the same casing therewith, a low pressure turbine element adapted to operate in parallel with said low pressure section on motive fluid delivered from said high pressure section and having a partial peripheral admission initial section receiving motive fluid from said high pressure section, and a full peripheral admission section receiving mopressure turbine element adapted to operate in parallel with said low pressure section on motive fluid delivered from said high pressure section and having a partial peripheral admission initial section receiving motive fluid from said high pressure section, and a full peripheral admission section receiving motive fluid from said initial section, means for shutting off the supply of motive fluid from said high pressure section to said low pressure turbine element when the turbine system is developing reduced connected to said turbine system.

45. A turbine system comprising a high pressure turbine element having a variable or partial peripheral admission high pressure section, and a full peripheral admission low pressure section receiving motive fluid from the high pressure section and located in the same casing therewith, a low pressure turbine element adapted to operate in parallel with said low pressure section on motive fluid delivered from said high pressure .section and having apartial peripheral admission initial section receiving motive fluid I from said high pressure section, and a full eripheral admission section receiving m0- tive fluid from said initial section, means for shutting off the supply of motive fluid from said high pressure section to said low pressure turbine element when the turbine system is developing reduced power and means for delivering high pressure motive fluid to said low pressure turbine element.

I 46. A turbine system comprising a high pressure turbine element having a variable or partial peripheral admission high pressure section, a full peripheral admission in termediate section, and a full peripheral admission low pressure section, all operating in series and located in the same casing, a bypass around the'intermediate section, a low pressure turbine element located in a separate casing, adapted to operate in parallel with the low pressure section and designed for different speed conditions from the low pressure section, means for controlling the delivery of fluid through the by pass, and means for delivering motive fluid from the inlet end of the by-pass to said low pressure turbine element when the system is developing full power.

47. A turbine system comprising'a partial peripheral admission high pressure section, an intermediate pressure section, a fullperipheral admission low pressure section, all of said sections operating in series, a low pressure turbine element adapted to receive motive fluid from said high pressure section and to operate in parallel with said low pressure section, means for by-passing said intermediate pressure section, and means for delivering fluid to said low pressure turbine element when said system is developing full power.

48. A turbine system comprising a partial peripheral admission high pressure section, an intermediate pressure section, a full peripheralv admission low pressure section, all of said sections operating in series, a low pressure turbine element adapted to receive motive fluid from said high pressure section and to operate in parallel with said low pressure section, means for by-passing said intermediate pressure section, means for delivering fluid to said low pressure turbine element when said system is developing full power, and a transmission gearing between said system and the apparatus to be driven thereby having a driving gear operatively connected to the rotor of said high pressure section and a separate driving gear operatively connected to the rotor of said low pressure turbine element.

.49. A power developing system, comprising an initial section to which high pressure motive fluid isdelivered, a plurality of low pressure sections operating in parallel on the fluid discharged from said high pressure section, at least one of said low pressure sections being isolated by being located in a separate casing from the initial section, in a separate casing from the high pressure a power transmission shaft driven by the section, means for cutting off the supply of rotor element of the initial section, a sepafluid to the low pressure section when the rate power transmission shaft driven by the system is developing reduced power, and 5 rotor element of the isolated section, and separate power, transmission shafts opera- 20 means for cutting off the fluid supply to the tively connected to the rotor element of the isolated section when the transmission syshigh pressure section, and to the rotor eletem is developing reduced power. ment of the isolated section. v 50. A power developing system compris- In testimony whereof, I have hereunto 10 ing a high pressure section, two low pressure subscribed my name this 10th day of Sop-g5 sections operating in parallel on fluid distember, 1913. charged from the high pressure section, one HENRY F. SCHMIDT. of said low pressure. sections being designed Witnesses: p to operate efliciently at a different speed C. W. MGGHEE, 15 from the other and isolated by being located E. W. MoCALLrs'rnR.

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Washington, D. 0.