US3107084A

US3107084A - Elastic fluid turbine apparatus

Info

Publication number: US3107084A
Application number: US247788A
Authority: US
Inventors: Sr Joseph D Conrad; Robert L Reynolds
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1962-12-12
Filing date: 1962-12-12
Publication date: 1963-10-15
Anticipated expiration: 1980-10-15

Description

0 L 1963 J. D. CONRAD, sR., El'AL I 3, 07,

ELASTIC FLUID TURBINE APPARATUS Filed Dec. 12, 1962 {Sheets-Sheet 1 INVENTORS JOSEP H 0.00HRAD SF ROBERT LJREYNOLDS 1963 J. D. CONRAD, sR.. E'IAL 3,107,084

ELASTIC FLUID TURBINE APPARATUS Filed Dec. 12, 1962 2 Shee ts-Sheet 2 v m 09m m9 m INVENTORS JOSEPH. D. CONRAD,SR. ROBERT L. REYNOLDS 91 Mm m a 3 no.

m mm mm mm. Em) mm m k s I I 2 S g 8 X. ///f N\ i 3,107,984 ELASTIC FLUID TURBENE APPARATUS Joseph D. Conrad, Sta, Springfield, and Robert L.

Reynolds, fidley Park, Pa, assignors to Westinghouse Electric Corporation, Pittsburgh, Pa, a corporation of Pennsylvania Filed Dec. 12, 1962, Ser. No. 247,788 14 (Zl'aims. (Qt. 253-67) This application is a continuation-in-part of our copending application Serial No. 785,861, filed January 9, 1959, now abandoned.

This invention relates to fluid actuated turbines, more particularly to elastic fluid actuated turbines having a plurality of progressively movable fluid admission valves for regulating the fluid flow rate thereto, as required for varying load conditions, and has for an object to provide improved and thermally more etficient apparatus of this type.

Axial flow steam turbines of the double-flow type; for example, opposed flow, comprise two turbine sections within which is disposed a rotor structure having at least two annular rows of blades, one row in each section. Motive steam is usually directed through one row of blades in one direction and through the other row of blades in the opposite direction, but at substantially the same rate of flow, thereby balancing the axial thrusts imposed by the motive steam on the rotor.

In partial admission turbines, steam is admitted to the turbine through one or more arcuate nozzle chambers with increasing load, as required. During such partial admission operation, severe bending forces are imposed upon the rotor at the blade rows by the localized forces of the steam. Hence, if the blade and labyrinth seals are not provided with sufficiently wide radial clearances, the bending forces on the rotor may deflect the rotor sufficiently to cause serious rubbing which may severely damage or even destroy the turbine. However, such wide clearances are not desirable, since they reduce the thermal efficiency of the turbine.

Accordingly, it is a further object of the invention to provide an improved turbine of the above type in which the forces imposed on the rotor structure during partial admission operation are substantially balanced, so that blade and labyrinth seals with much smaller radial clearances may be provided with the same degree of safety.

Although the forces imposed on the rotor structure during partial admission operation may be balanced by directing steam concomitantly to a pair of diametrically opposed nozzle chambers in the same annular row of nozzle chambers, such an arrangement would undesirably subject the rotor blades to two shocks per revolution as they sweep past the discontinuous arcuate streams of steam from the active nozzle blade groups.

In view of the above, it is a further object of the invention to provide an arrangement for maintaining a substantial balance of the forces on the rotor, while subjecting the rotor blades to only one shock per revolution during all phases of partial admission.

In accordance with the invention, a double-flow turbine comprising a pair of turbine sections is provided with a pair of annular rows of arcuate nozzle chambers for admitting steam to their associated turbine sections. The nozzle chambers in each row are preferably equal in number, for example, four, and are provided by annular nozzle box structure.

A plurality of fluid admission valves, progressively movable in opening and closing directions, are provided for initiating and regulating the fluid flow to the arcuate nozzle chambers, as required, to provide variable power.

In the first embodiment shown, the valves are arranged in such a manner that each valve controls the total flow to two diametrically opposed nozzle chambers, one

-jh-lfih i Patented Get. 15, 1963 of the nozzle chambers being in one row and the other being in the other row.

In the second embodiment, the valves are arranged in jointly operable pairs, with one of a pair controlling flow to one nozzle chamber in one row and the other of said pair controlling flow to a diametrically opposed nozzle chamber in the other row.

Hence, a single valve in the first embodiment is equivalent in function to a pair of valves in the second embodiment, and such valve or pair of valves may be broadly termed a valve means.

The valve means are arranged to operate in a prescribed sequence, wherein the motive fluid is progressively admitted to adjacent nozzle chambers in both rows with increase in power requirements. Accordingly, during operation with partial admission, as successive adjacent nozzle chambers are rendered active, the two arcs of admission are maintained in diametrically opposed relation and merely increased in magnitude. Hence, as the rotor blades sweep past the active adjacent nozzle chambers, they are subjected to only one motive fluid shock per revolution.

However, the specific valve arrangement is not critical and may be varied in any desired manner to permit fluid at substantially equal flow rate to be concomitantly delivered to two diametrically opposed nozzle charnbers, as described above. Accordingly, during partial operation, the two forces imposed on the rotor by the diametrically opposed streams of fluids are of equal magnitude and diametrically opposed. These forces each have a component parallel to the axis of the rotor structure and a component normal to the axis of the rotor structure and exerted in a direction tangential to the rotor structure. Since the two axial components (also known as axial thrust) are equal and opposite to each other, in the case of an opposed flow turbine, the axial thrusts on the rotor are balanced or cancelled. Also, since the two tangential components are equal and opposite to each other, their net efiect in a direction normal to the rotor axis is balanced, so that they exert no deflecting force or force normal to the rotor axis tending to bend or bow the rotor, although they are effective to produce moments about the rotor axis for driving the rotor. Although couples about axes normal to the axis of the rotor formed by the above forces are not balanced, due to the spacing between the above-mentioned forces, these couples are of low magnitude and are effectively resisted by the bearings, which may be conventionally disposed at opposite ends of, and support, the rotor structure.

The foregoing and other objects are efiected by the invention as will be apparent from the following description and claims taken in connection with the accompanying drawings, forming a part of this application, in which:

FIGURE 1 is a longitudinal schematic view of a double-flow turbine of the opposed flow type incorporating the invention, the upper portion thereof being shown in longitudinal section to show internal structure;

FIG. 2 is a transverse sectional view taken on line HII of FIG. 1;

FIG. 3 is a transverse sectional view taken on line HIHI of FIG. 1 and looking in the same direction as FIG. 2;

FIG. 4 is a diagramamtic view showing the steam admission valve structure and the associated connections to the nozzle chambers;

FIG. 5 is a longitudinal view of another form of double-flow turbine of the opposed flow type, employed with the invention, the upper portion thereof being shown in longitudinal section taken along line V-V in FIG. 6, to show internal structure;

FIG. 6 is a transverse sectional view taken on line VI-VI of FIG.

FIG. 7 is a diagrammatic view, similar to FIG. 4, but showing another form of steam admission valve structure and associated connections to the nozzle chambers; and

FIG. 8 is a sectional view showing a portion of the structure in FIG. 5 on a larger scale.

Referring to the drawings in detail, FIGS. 1 to 4, inclusive, show a first embodiment of the invention. In FIG. 1 there is shown an axial flow steam turbine of the opposed double-flow type having a-ri-ght-hand section 10 and a left-hand section 11 disposed in coaxial alignment with each other and having steam admission valve mechanism 12 for regulating steam flow thereto in a manner subsequently to be described in detail. The right-hand steam turbine section ll has an outer tubular casing 13 within which is provided a rotor portion 14, rotatably supported in any suitable manner (not shown). The rotor portion 14 is or" the multi-stage type having a pair of rows of impulse blades 16 and a plurality of rows of reaction blades 17 having suitable radial clearance with the casing 13 and cooperating with rows of suitable stationary blades 18 and '19, respectively, as well known in the art. The first row of impulse blades :16 is disposed down-stream of and in cooperative association with an annular row of nozzle blades 26. The nozzle blades 20 are disposed in communication with an annular nozzle box structure 22 which, as illustrated, may be formed in the casing 13 and connected to the steam valve mechanism 12 by a plurality of (for example, four)

steam inlet conduits

23, 24, 25 and 26, as best shown in FIG. 3. The steam conduits are angularly spaced from each other about ninety degrees, and the nozzle box structure 22 is provided with a plurality of radial walls or partitions 27 dividing the same into an annular group of four (preferably, though not essentially, equal) circumferentially disposed

arcuate nozzle chambers

28, 29, 30 and 31, each of which is fed by its associated

steam inlet conduit

23, 24, 25 and 26, respectively.

The left-hand turbine section 11 is provided with a rotor portion 33 rotatably supported within an outer casing 34 and having cooperating rows of rotating and stationary blades of the impulse and reaction types disposed in a manner similar to the right-hand section 10. The first impulse blade row is also disposed downstream of and in cooperative association with an annular row of nozzle blades 35 which, in turn, are disposed in communication with an annular nozzle box structure 36 carried by the casing 34 and directing steam flow in a direction opposite to nozzle box 22. As best shown in FIG. 2, the annular nozzle box structure is divided into an annular group of four

arcuate nozzle chambers

37, 38, 39 and 40 by radial partitions or walls .41.

nozzle chambers

37, 38, 3'9 and 40 is disposed in communication with its associated

steam inlet conduit

42, 43, 44 and 45 which are, in turn, connected to the steam admission valve mechanism 12.

The rotor portions 14- and 33, as illustrated, are integrally interconnected by a preferably short shaft portion 46 extending through the casings to form a unitary rotor and are jointly rotatable in the same direction,.for example, as indicated by the arrows R. However, if desired, they may be separately formed and joined to each other in any desirable manner (not shown) and suitable laby rinth seals 47 may be provided between the rotors and the casings to leakage of steam to atmosphere.

The steam valve'mechanism 12 is of the progressively or sequentially operated type, and, as illustrated in FIG.

4, may be provided with a steam chest 50' which is connected to a suitable steam source (not shown) by a supply conduit 51. Within the chest 50 there is provided a plurality of

valve members

52, 53, 54 and carried by 'a horizontal actuator bar 56 which is vertically movable to any position within its range of travel by a pair of Each of the rods 57 slidably received in the steam chest and connected to a suitable servo-motor (not shown). -As illustrated, the

valves

52, 53, 54 and 55 are provided with stems of increasing length loosely received in the actuator bar 56, so that as the actuator bar is moved in upward direction, valve member 52 will be lifted and open first, and as the bar 56 is moved fiurther upwardly, valves 53, '54 and 55 will open in succession. With this arrangement, the steam flow rate to the turbine sections 10 and 11 may be jointly regulated, as desired, to maintain any desired load.

As illustrated schematically in FIG. 4, the

steam conduits

42 and 23 are connected to each other downstream of the valve housing 49 by a main conduit 60, so that when valve member 52 is opened, steam from main conduit 61} will flow in parallel paths through

conduits

42 and 23 to nozzle chamber 37 in the left-hand section and nozzle chamber 28 in the right-hand section, respectively. It will be noted that nozzle chamber 37 is diametrically opposed to nozzle chamber 23 with respect to the rotational axis of the rotor structure.

It will be further noted that the remaining nozzle chambers and conduits are connected in a similar manner;

specifically,

steam inlet conduits

43 and 24 are connected to each other downstream of the valve member 53 by a main conduit 61, so that, when valve member 53 is opened, steam is jointly, and at substantially the same rate, t ed to nozzle chamber 38 in the left hand section and diametrically opposed chamber 29 in the right-hand section. In the same manner,'stea-

m inlets

44 and 25 are connected to each other downstream of the valve members 54 by a main conduit 62, while

steam inlets

45 and 26 are connected to each other downstream of valve member 55 by a main conduit 63.

During operation at relatively light load, the valve actuator bar 56 is moved upwardly sufficiently to open valve member 52, thereby permitting steam to flow to

nozzle chambers

37 and 28 at a substantially equal rate, as mentioned above. During such partial admission,

steam will flow from the nozzle chamber 28 through the turbine section 10 to the right, motivating and imposing a [force on the rotor portion 14 to the right and downwardly, while steam flow through the nozzle chamber 37 will flow through the turbine section '11 to the left, motivating and imposing a force to the left and upwardly upon the rotor 33. Each of these forces has a component parallel to the rotor axis, termed axial thrust, and a component normal to the rotor axis and exerted tangentially to the rotor, termed tangential force. As well understood in the art, the tangential forces form a couple that is elfective to drive the rotor. Since the amount of steam fed to the two sections is approximately equal, the axial thrusts imposed thereby upon the rotor are of equal magnitude and in opposite directions, so that the net resulting axial thrust is zero. In addition thereto, the tangential force on the right-hand turbine section 10, which is one of the principal factors tending to deflect the rotor 14 in one direction normal to the rotor axis, is opposed to the tangential force on the left-hand turbine section 11 tend ing to laterally deflect the rotor 33 in the opposite direction normal to the rotor axis. Therefore, the principal bending force, that is, the net force tending to move the rotor normal to its axis is zero. 7

Since the two rotor blade rows are axially spaced.

from each other, the two tangential forces do form a secondary couple effective about an axis normal to the axis of the rotor tending to'defiect or how the rotor. Although this couple is not balanced, it is inherently of small magnitude and may be further minimized by mini mizing the length of the connecting shaft portion 46. Also, since the axial thrusts are eliective at diametrically opposite portions of the two blade rows, they too form a secondary couple effective about an axis normal to the 7' axis of the rotor tending to how the rotor. This'couple is also inherentiy of small magnitude and may be further minimized by reducing the diameter of the blade rows. These secondary couples are resisted in the usual manner by the bearing supports for the rotor structure (not shown). However, the principal bending forces imposed upon the rotor are substantially balanced. Accordingly, during partial admission operation, lateral bending of the rotor structure (14, 33 and 45) is minimized, so that the rotor is maintained in the generally straight position.

Should a larger load be assumed by the turbine, the actuator bar 56 is moved further upwardly, thereby further opening valve member 52, but in addition thereto opening valve member 53, so that steam is now jointly irected to nozzle chamber 38 in the left-hand turbine section and diametrically opposed nozzle chamber 29 in the right-hand turbine section. Hence, during operation at such increased load, the flow of steam into the righthand turbine section is effected through

adjacent nozzle chambers

28 and 29, and the single arc of admission is increased. In a similm manner, steam flow through

adjacent nozzles

37 and 38 in the left-hand turbine section turbine section provides an increased and continuous arc of admission. During such operation, the tangential and axial components r rce are balanced in a manner similar to that mentioned above in conjunction with operation of the unit with

only nozzle chambers

23 and 37 activated.

As load demand further increases, the actuator bar 56 is moved further upwardly, opening valve 54 and jointly admitting steam to nozzle chamber 31) in the right-hand section and nozzle chamber 39 in the left-hand section, thereby further increasing the arc of admission.

Finally, at full load operation with the bar 56 in its uppermost position, the valve 55 is opened, permitting steam to flow jointly to the remaining nozzle chamber 31 in the right-hand section and nozzle chamber 41' in the left-hand section. During this phase of operation, the steam flow to both turbine sections is continuous. Here again, the axial and tangential components of force are balanced in the preceding manner. However, the above forces are effective on the entire periphery of the rotor due to peripherally continuous steam admission and have no unbalanced secondary couples.

Considering the right-hand turbine section it during partial admission operation with valve member 52 open, so that nozzle chamber 28 is active, as the rotor blades 16 sweep past the active nozzle chamber, they are subjected to a shock fiorce by the kinetic energy of the howing steam. Accordingly, with every revolution of the rotor, the rotor blades are subject to this shock force. However, during operation at increased load, wherein valve 53 is also open, the arc of admission is increased, and, since the active chambers 28 and 2 are consecutive, the rotary blades are still subjected to only one shock per revolution. In a similar manner, as valve members 54 and then 55 are opened, the steam admission are is further increased, so that the rotor blades still incur only one shock per revolution. Finally, at full operation, the rotary blades are subjected to a continuous and steady force, so that the shock force is eliminated. With this arrangement, the rotor blade stresses are minimized, thereby insuring longer and more trouble-free life.

The left-hand turbine section 11 is also susceptible to the same blade shock analysis.

FIGS. 5 to 7, inclusive, show another embodiment of the invention. In FIGS. 5 and 6 there is shown an axial flow, partial admission steam turbine 65 of the opposed double-flow type comprising a right-hand turbine section 6'5 and a left-hand turbine section 63 disposed in coaxial alignment with each other and having steam admission valve mechanisms 6? and 7% (see FIG. 7) for regulating steam flow thereto.

In this arrangement, the two turbine sections 66 and 68 are enclosed in unitary outer and

inner casing structures

74 and 75, respectively, within which a rotor 75 is supported adjacent its ends by a pair of suitable bearings 77 for rotation, as indicated by the arrow T. The right 6 and left-hand turbine sections 66 and 68 are divided by a suitable annular partition 78 extending radially inwardly from the inner casing 75 to the rotor 76.

The left-hand turbine section 68 includes a pair of rows of impulse blades 79 and a plurality of rows of reaction blades 8% carried by the rotor 7 6 and cooperating with rows of suitable

stationary blades

81 and 82, respectively. The first row of impulse blades 79 is disposed in cooperative association with an annular row of nozzle blades 83, and the nozzle blades 83 are disposed in communication with an annular nozzle box structure 84 which, as illustrated, may be disposed within the inner casing 75 and comprises an annular array of nozzle boxes jointly providing an annular group of (for example, four) arcuate nozzle chambers L1, L2, L3 and L4, in generally the same manner as described in connection with the first embodiment.

In this arrangement, steam is initially directed through the impulse blades 7i in rightward direction and then reversed and directed by suitable passages to the react-ion lades fill in leftward direction. After expansion in the reaction blades, the steam is exhausted from the turbine section 68 through a suitable exhaust conduit 94.

The right-hand turbine section 66 is a mirror image of the left-hand section 68 and is provided with rows of rotating blades or" the impulse and reaction types, cooperating with rows of stationary blades disposed in a manner similar to the left-hand turbine section 68. The first impulse blade row is also disposed downstream of and in cooperative association with an annular row of nozzle blades as, which, in turn, is disposed in communication with an annular nozzle box structure 97 (similar to nozzle box structure 34) disposed in the inner casing structure 75 and directing steam how in a direction opposite to the nozzle box structure 84. As shown in FIG. 7, wherein the nozzle box structures are viewed as in PEG. 6, the nozzle box structure 97 provides four arouate nozzle chambers R1, R2, R3 and R4.

In this embodiment, the steam flow to each of the nozzle chambers is individually controlled. Accordingly, as diagrammatically shown in FIG. 7, the steam admission valve mechanism 6-9 is provided with a steam chest 163 connected to a suitable steam source (not shown) by dual conduit structure 109. Within the steam chest 1% there are provided for valves U1, U2, U3 and U4, operated in a sequential manner, as required for varying load conditions, by a suitable servo-mechanism 115.

Similarly, the steam admission valve mechanism 7%? is provided with a steam chest ll?) connected to the same steam source by dual conduit structure 119. Within the steam chest 11% four valves 31, B2, B3 and B4 are provided, which valves are also operated in a sequential manner by a servo-mechanism 123.

The valves U3, U2, U3 and U4 are connected to respective upper nozzle chambers R1, R2, L3 and L4 by conduits 11b2, 133, 9'2 and ?3, respectively. Hence, these valves individually control flow of steam to the upper nozzle chambers in both turbine sections 68 and 66 'The valves B1, B2, B3 and B4 are connected to respective bottom nozzle chambers L1, L2, R3 and R4 by conduits )8, 91, 164 and 195, respectively. Hence, these valves individually control flow of steam to the lower nozzle chambers in both

turbine sections

63 and 66.

The two servo-mechanisms and 123 may be connected in parallel to a suitable load sensing or control device (not shown) by a fluid pressure conduit 125 and arranged in a manner to be operated jointly by a variable control pressure to maintain any desired load. More sp cifically, the servo-

mechanisms

115 and 123 are arranged to jointly and at the same rate initially open both valves U1 and B1 for light load then both valves U2 and B2 for greater load, subsequently both valves U3 and B3 for still greater load, and finally both valves U4 and B4 for full load.

Hence, it will now be seen that each pair of jointly operable valves U1 and B1, U2 and 32, U3 and B3, and U4 and B4 are equivalent in function to the individually

operable valves

52, 53, 54 and 55 of the first embodiment. In View of the above, the termvalve means may be employed to include the individually operable valves of the first embodiment and the pairs of jointly operable valves of the second embodiment.

Hence, during light load conditions, steam is jointly admitted in two opposed streams to nozzle chamber L1 in the left turbine section 63 and to diametrically opposed nozzle chamber R1 in the right turbine section 66. As explained in connection with the first embodiment, since the tangential components of force of the steam imposed on the rotor 76 by the two streams of steam are opposed to each other and are of equal magnitude, their effects tending to deflect or how the rotor normal to its rotational axis are imposed against each other and therefore canceled, even though they form moments which assist each other in rotating the rotor. At the same time, the axial components of force are opposed to each other and are of equal magnitude, so that the net axial thrust on the rotor is zero. Also, the secondary couples formed by the axial and tangential components of force due to their spacing are resisted in the usual manner by the bearings 77 and their supports.

As larger load conditions are assumed by the turbine 65, additional steam is jointly admitted in two opposed streams to diametrically opposed nozzle chambers L2 and R2, thereby still maintaining the above mentioned balance of tangential and axial forces. Also, since the adjacent nozzle chambers L1 and L2. are activated and the adjacent nozzle chambers R1 and R2 are activated, the rotor blades are still subjected to only one shock pe revolution.

The remaining portion of operation, at still greater and full load conditions, is substantially similar to the above and need not be further explained.

It will now be seen that the invention provides a steam turbine of the double-flow type Which may be operated at varying partial load values to full load value without the imposition of excessive deflecting forces on the rotor structure or net axial thrust thereon; 7

It will further be seen that the invention provides a turbine of the above type in which the rotor blades in each section are subjected to only one steam admission shock per revolution during all phases of partial admission.

Although, in the examples, the nozzle box structure is shown as having four nozzle chambers of equal arcuate span in each turbine section, the nozzle box structure may be arranged to provide more or fewer chambers, and an even or odd number of chambers may be employed, if desired. However, for optimum operation, the arcuate span of diametrically opposed chambers that are jointly activated should be equal so that, Whenever one nozzle chamber is activated, the force produced by steam fioW therethrough is equal in magnitude to the force produced by steam flow through the activated chamber diametrically opposed therefrom and in the other row.

Also, although in the second embodiment the steam admission valve mechanisms 69 and 7d are arranged to control admission of steam to the upper and lower nozzle chambers, respectively, they may, for facility of manufacture and piping connections, be arranged to control the left-hand and right-hand nozzle chambers. This may be readily understood by rotating F G. 7 ninety degrees counterclockwise and considering the upper and lower nozzle chambers as left-hand and right-hand nozzle chambers. 7

While the invention is shown in several forms, it will be obvious to those skilled in the art that it is not so fications without departing from the spirit thereof.

What is claimed is:

1. An axial flow elastic fluid turbine comprising casing structure,

a unitary rotor structure supported therein,

first and second annular rows of blades mounted on said rotor structure,

first and second annular rows of nozzle blades supported in said casing and associated with said first and second rows of rotor blades, respectively,

first and second annular nozzle box structures for delivering elastic fluid to said first and second rows of nozzle blades, respectively,

partition structure dividing each of said nozzle box structures into an equal plurality of arcuate nozzle chambers,

at least one of the nozzle chambers in said first nozzle box structure being diametrically opposed to one of the nozzle chambers in said second nozzle box structure,

means including a plurality of sequentially operated valve structures for admitting elastic fluid to said nozzle chambers, and

parallel connected conduit means connecting one of said valve structures to said one nozzle chamber in said first nozzle box structure and said diametrically opposed nozzle chamber in said second nozzle box structure. a

2. A double opposed axial flow elastic fluid turbine comprising tubular casing structure,

a unitary rotor structure supported therein,

first and second annular rows of blades mounted on said rotor structure,

first and second oppositely disposed annular nozzle box structures for delivering elastic fluid to said first and second rows of nozzle blades in opposite axial directions, respectively,

radial partition structure dividing each of said nozzle box structures into an equal plurality of circumferentially disposed arcuate nozzle chambers,

means including a pluralityrof sequentially operated valve structures for admitting elastic fluid to said nozzle chambers,

first parallel connected conduit means connecting one of said valve structures to a first nozzle chamber in said first nozzle box structure and a first nozzle chamber in said second nozzle box structure, said first nozzle chambers being diametrically opposed, and

second parallel connected conduit means connecting another of said valve structures to a second chamber in said first nozzle box structure and a second nozzle chamber in said second nozzle box structure, said second nozzle chambers being diametrically opposed.

3. An axial flow elastic fluid turbine comprising casing structure,

a unitary rotor structure supported therein,

first and second annular rows of blades mounted on said rotor structure,

first and second annular rows of nozzle blades sup ported in said casing and associated with said first and second rows of rotor blades, respectively,

partition structure dividing each of said nozzle box structures into an equal number of pairs of arcuate nozzle chambers,

j said pairs including firstrand second nozzle chambers in said first nozzle box structure and first and second nozzle chambers in said second nozzle box structure, a

e, 1 cause said second chambers being diametrically opposed, means including an even numbered plurality of valve structures for admitting elastic fluid to said nozzle chambers, and conduit means connecting each of said valve structures in parallel with said first nozzle chamber in said first nozzle box structure and said first nozzle chamber in said second nozzle box structure, said valves being operable in sequence to successively direct flow to consecutive nozzle chambers in said first and second nozzle box structures. 4. An axial flow elastic fluid turbine of the opposed flow type comprising tubular casing structure, a unitary rotor structure supported therein, first and second annular rows of blades mounted on said rotor structure, first and second annular rows of stationary nozzle blades associated With said first and second rows of rotor blades, respectively, means defining first and second annular groups of arcuate nozzle chambers communicating with said first and second nozzle blade rows, respectively, the number of said first nozzle chambers equalling the number of said second nozzle chambers, said number being an even number, means including an even numbered plurality of sequentially operated valve structures for admitting elastic fluid to said nozzle chambers, and parallel connected conduit means connecting said first and second nozzle chambers in diametrically opposed pairs to each of said valve structures, said first group of nozzle chambers directing elastic fluid through said first roWs of blades in one axial direction and said second group of nozzle chambers directing elastic fluid through said second rows of blades in the opposite axial direction. 5. An axial flow elastic fluid turbine of the opposed flow type comprising tubular casing structure, a unitary rotor structure supported therein, first wd second annular rows of blades mounted on said rotor structure, first and second annular rows of stationary nozzle blades associated with said first and second rows of rotor blades, respectively, means defining first and second annular axially spaced and oppositely disposed groups of arcuate nozzle chambers communicating with said first and second nozzle blade rows, respectively, the number of said first nozzle chambers equalling the number of said second nozzle chambers, means including a plurality of valve structures for admitting elastic fluid to said nozzle chambers, and parallel flow conduit means connecting said first and second nozzle chambers in diametrically opposed pairs to each of said valve structures, the arcuate span of said opposed pairs being substantially equal, said first group of nozzle chambers directing elastic fluid in one axial direction and said second group of nozzle chambers directing elastic fluid in the opposite axial direction, said valves being operable in sequence to successively direct flow to consecutive nozzle chambers in said first and second nozzle box structures. 6. An axial fiow elastic fluid turbine of the double opposed floW type comprising tubular casing structure, a unitary rotor structure comprising first and second rotors rotatably supported therein, means connecting said first and second rotors in tandem, first and second annular rows of blades mounted on said first and second rotors,

iii

first and second annular rows of stationary nozzle blades associated With said first and second rows of rotor blades, respectively,

means defining first and second axially spaced and opposed annular groups of arcuate nozzle chamber communicating with said first and second nozzle blade rows, respectively, the number of said first nozzle chambers equalling the number of said second nozzle chambers, means including a plurality of valve structures for admitting elastic fluid to said nozzle chambers, said valve structures being equal in number to the nozzle chambers in one of said groups,

parallel connected conduit means connecting the nozzle chambers in said first and second groups in diametrically opposed pairs to each of said valve structures,

said first group of nozzle chambers directing elastic fluid to said first rows of blades in one direction and said second group of nozzle chambers directing elastic fluid to said second rows of blades in the opposite direction, and

means for operating said valve structures in a prescribed sequence wherein adjacent nozzle chambers in each group are successively provided with motive fluid as said valve structures are successively opened.

7. An axial flow elastic fluid turbine comprising casing structure,

a rotor supported therein,

first and second annular rows of blades mounted on said rotor;

first and second rows of nozzle blades supported in said casing and associated with said first and second rows of rotor blades, respectively,

first and second groups of arcuate nozzle chambers for delivering elastic fluid to said first and second rows of nozzle blades, respectively,

at least one of the nozzle chambers in said first group being diametrically opposed to one of the nozzle chambers in said second group, and

valve means for controlling flow of elastic fluid to said nozzle chambers,

said valve means being arranged in a manner to permit concomitant flow of elastic fluid at a substantially equal rate to said one nozzle chamber in said first chamber group and to said diametrically opposed nozzle chamber in said second chamber group.

8. A double opposed axial flow elastic fluid turbine comprising.

tubular casing structure,

a rotor supported therein and having a longitudinal axis,

first and second annular rows of blades mounted on said rotor,

first and second rows of stationary nozzle blades supported in said casing and associated with said first and second rows of rotor blades, respectively,

first and second groups of oppositely disposed arcuate nozzle chambers for delivering elastic fluid to said first and second rows of nozzle blades in opposite axial directions, respectively,

said first group of chambers including a first chamber and said second group of chambers including a second chamber,

said first and second chambers being of substantially equal arcuate extent and disposed diametrically opposite to each other with respect to said axis, and valve means for jointly and at a substantially equal rate controlling the rate 01 fluid flow to said first and second chambers.

9. A double opposed axial flow elastic fluid turbine comprising tubular casing structure,

a rotor supported therein,

first and second annular roWs of blades mounted on said rotor,

first and second rows of stationary nozzle blades sup- 1 l ported in said casing and associated with said first and second rows of rotor blades, respectively,

first and second oppositely disposed groups of arcuate nozzle chambers for delivering elastic fluid to said first and second rows of nozzle blades in opposite axial directions, respectively,

first valve means connected to and controlling admission of elastic fluid at the same rate to a first nozzle chamber in said first group and a first nozzle chamber in said second group,

said first nozzle chambers being diametrically opposed,

and second valve means connected to and controlling admission of elastic fluid at the same rate to a second chamber in said first group and a second nozzle chamber in said second group;

said second nozzle chambers being diametrically opposed.

10. An axial flow elastic fluid turbine comprising casing structure,

a rotor supported therein,

first and second annular rows of blades mounted on said rotor structure,

first and second rows or nozzle blades supported in said casing and associated with said first and second rows of rotor blades, respectively,

said first group including first and second nozzle chambers disposed adjacent to each other and said second group including first and second nozzle chambers disposed adjacent to each other, 7

said first chambers being diametrically opposed and said second chambers being diametrically opposed, and

first and second valve means for admitting elastic fluid to said first nozzle chambers and said second nozzle chambers, respectively,

said first and second valve means being operable in sequence to successively direct flow first to said first nozzle chambers and then to said second nozzle chambers.

11. An axial flow elastic fiuid turbine of the opposed flow type comprising tubular casing structure,

a rotor supported therein,

first and second annular rows of rotor blades mounted on said rotor structure,

first and second rows of stationary nozzle blades associated 'with said first and second rows of rotor blades, respectively,

means defining first and second annular groups of arcuate nozzle chambers communicating With said first and second nozzle blade rows, respectively,

the number of said first nozzle chambers equalling the number of said second nozzle chambers,

a plurality of sequentially operated valve means for controlling admission of elastic fluid to said nozzle chambers, and

said first and second groups of nozzle chambers being connected in diametrically opposed pairs to said valve means in such a manner that each of said valve means controls flow of fluid jointly to an associated pair of nozzle chambers,

said first group of nozzle chambers directing elastic fluid through said first row or" nozzle blades in one axial direction and said second group of nozzle chambers directing elastic fiuid through said second row of nozzle blades in the opposite axial direction.

12. An axial flow elastic fluid turbine of the double fio w type comprising tubular casing structure,

a rotor supported therein,

first and second annular rows of rotor blades mounted on said rotor,

12 first and second rows of stationary nozzle blades associated with said first and second rows of rotor blades, respectively, means defining first and second axially spaced groups of arcuate nozzle chambers communicating with said first and second nozzle blade rows, respectively, the number of said first nozzle chambers equalling the number of said second nozzle chambers, means including first and second pairs of valves for controlling admission of elastic fluid to said nozzle chambers, said first pair of valves being jointly operable and said second pair of valves being jointly operable, and means connecting one of said first and one of said second nozzle chambers in a diametrically opposed pair to said first pair of valves, and another of said first and another of said second nozzle chambers in a diametrically opposed pair to said second pair of valves, the arcuate span of each of said opposed pairs being substantially equal, said first group of nozzle chambers directing elastic fluid in one axial direction and said second group of nozzle chambers directing elastic fluid in the opposite axial direction, said pairs of valves being operable in sequence to successively direct flow first to said first pair of nozzle chambers and then to said second pair of nozzle chambers. 13. An axial flow elastic fluid turbine of the opposed flow type comprising tubular casing structure, a rotor supported therein, first and second annular rows of rotor blades mounted on said rotor, first and second arcuate rows of stationary nozzle blades associated with said first and second rows of rotor blades, respectively, means defining first and second axially spaced and oppositely disposed groups of arcuate nozzle chambers communicating with said first and second nozzle blade rows, respectively, the number of said first nozzle chambers equalling the number of said second nozzle chambers, means including first and second pairs of valves for controlling admission of elastic fluid to said nozzle chambers, said first pair of valves being jointly operable and said second pair of valves being jointly operable, and means connecting one of said first and one of said second nozzle chambers in a diametrically opposed pair to said first pair of valves, and another of said first and another of said second nozzle chambers in a diametrically opposed pair to said second pair of valves, said pairs of valves being operable in sequence to successively direct flow first to said first pair of nozzle chambers and then to said second pair of nozzle chambers. 14. An axial flow elastic fluid turbine of the double opposed flow type comprising tubular casing structure, a rotor rotatably supported therein, first and second annular rows of blades mounted on said rotor, first and second annular rows of stationary nozzle blades associated with said first and second rows of rotor blades, respectively, means defining first and second axially spaced and oppositely facing annular groups of arcuate nozzle chambers communicating with said first and second nozzle blade rows, respectively, the number or" said first nozzle chambers equalling the number of said second nozzle chambers, 7 said first group of nozzle chambers directing elastic fluid to said first row of blades in one direction and individual conduit means connecting the nozzle chamsaid second group of nozzle chambers directing elastic bers in said first and second groups in diametrically fluid to said second row of blades in the opposite opposed pairs to respective pairs of valves, and

direction, means for operating said pairs of valves in a prescribed means including a plurality of valves for controlling 5 sequence wherein adjacent nozzle chambers in each admission of elastic fiuid to said nozzle chambers, group are successively provided with motive fluid as said valves being arranged in a plurality of pairs of said pairs of valves are successively opened.

jointly operable valves equal in number to the nozzle chambers in one of said groups, No references cited.

Claims

1. AN AXIAL FLOW ELASTIC FLUID TURBINE COMPRISING CASING STRUCTURE, A UNITARY ROTOR STRUCTURE SUPPORTED THEREIN, FIRST AND SECOND ANNULAR ROWS OF BLADES MOUNTED ON SAID ROTOR STRUCTURE, FIRST AND SECOND ANNULAR ROWS OF NOZZLE BLADES SUPPROTED IN SAID CASING AND ASSOCIATED WITH SAID AND SECOND ROWS OF ROTOR BLADES, RESPECTIVELY, FIRST AND SECOND ANNULAR NOZZLE BOX STRUCTURES FOR DELIVERING ELASTIC FLUID TO SAID FIRST AND SECOND ROWS OF NOZZLE BLADES, RESPECTIVELY, PARTITION STRUCTURE DIVIDING EACH OF SAID NOZZLE BOX STRUCTURES INTO AN EQUAL PLURALTY OF ARCUATE NOZZLE CHAMBERS, AT LEAST ONE OF THE NOZZLE CHAMBERS IN SAID FIRST NOZZLE BOX STRUCTURE BEING DIAMETRICALLY OPPOSED TO ONE OF THE NOZZLE CHAMBERS IN SAID SECOND NOZZLE BOX STRUCTURE, MEANS INCLUDING A PLURALITY OF SEQUENTIALLY OPERATED VALVE STRUCTURES FOR ADMITTING ELASTIC FLUID TO SAID NOZZLE CHAMBERS, AND PARALLEL CONNECTED CONDUIT MEANS CONNECTING ONE OF SAID VALVE STRUCTURES TO SAID ONE NOZZLE CHAMBER IN SAID FIRST NOZZLE BOX STRUCTURE AND SAID DIAMETRICALLY OPPOSED NOZZLE CHAMBER IN SAID SECOND NOZZLE BOX STRUCTURE.