US1405091A - Steam turbine - Google Patents

Description

K. BAUMANN.

STEAM TURBINE. APPLICATION FILED MAY 4, 1918. 1,405,091 Patented Jan. 31, 1922.

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1,405,091, Patented Jan. 31, 1922.

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K BAUMANN. STEAM TURBINE.

APPLICATION FILED MAY 4, 1918.

1,405,091 Patented Jan. 31, 1922.

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STEAM TURBINE. APPLICATION FILED MAY 4. 1918.

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STEAM TURBINE.

APPLICATION FILED MAY 4, 1918.

Patented Jan. 31, 1922, E 6gHEETS-SH EET 6.

u a N a a a N W a a 1 a g a}. 2 a l 2 3g if d E. a ll a x a nun? 2 INVENTOR UNITE- STATES p F CE" KARL BAUMANN, or umvrsron, ENGLAND, ASSIGNOR TO THE BRITIsH-wEs'rInG-, HOUSE ELECTRIC AND MANUFACTURING COMPANY LIMITED, .1; COMFANY or GREAT BRITAIN.

STEAM TURBINE.

To call whom it may concern:

Be it known that I, KARL BAUMANN, a citizen of the Confederation of Switzerland,

and a resident of Urmston, in the county ofthe axial flow type.

' One of the limitin factors which deterb mines the output of steam turbines of a given speed and efiiciency IS the maximum per- .missible length of the moving blades in the low pressure stages. In order that the length of the low pressure blades may be kept within permissible limits, the low pressure portion of a turbine is sometimes constructed as a multiple stage, one portion of the steam only acting in parallel in each section of the multiple stage, and flowing through adjacent sections thereof in opposite directions.

It has also been proposed to construct turbines in which the steam flowing in substantially the same direction throughout a low pressure part of the turbine is segregated into annular portions, which are expanded at the same or different rates and pass from a plurality of rows of moving blades to the exhaust. Y

According'to the present invention a portion only of the steam leaving an intermediatestage flows through a segmental part of the next succeeding row or rows of station ary guide blades and co-operating moving blades and thence to the exhaust and another portion thereof flows through over or around the remaining segmental part of said next succeeding row or rows of blading, little or none of its energy being transformed or abstracted therein and then flows in substantially the same axial direction through a further rowor rows of stationary guide blades and (to-operating moving blades and thence to the exhaust. 7

Steam turbines in accordance with the invention maybe constructed in a varietyof ways, some of which are illustrated by way of example in the accompanying drawings in which Fig. 1 is a. central, longitudinal section of a steam turbine constructed in accordance with the present invention, and Fig. 2 is a cross-section taken on the line II-II of Fig.

1. Fig. 3 is a central, longitudinal section Specificationof Letters Patent. Patented an. 31, 1922. Application'filed May 4, 1918. Serial No. 232,571. i

and Fig. 4 a half section on the lin'e IV-IV ofF 1g. .3 showing awmodified construction. F 1g. '5 1s a new similar to Fig. 3,'and Fig. 6

a half section on theline VI'VI of Fig.1 5 if showing a modification of the construction shown in Figs. 3v and .4. Fig. 7 is a view sim1lar to Fig. 3 and Fig. 8 a half section on the l1neX-X of Fig. 7 illustrating another modification Fig. 9 is a central, longitudinal section and Fig. 10 a half sectional view on the line XIIXII of Fig. 9, showing a low pressure turbine constructed in accordance with the invention. v

- Referringnow to Figs. 1 and 2, the turbine cylinder is indicated at .13 and .the shaft at 14, the turbine here illustrated being of the' impulse type the steam is admitted to a nozzle box 15 and thence through a pluralityof rows of stationary nozzles 16, 16, 16 etc. and moving blades 17, 17*,17", et,c-., respectively co-operating therewith, eachrow "of stationary blades and co-operating mov-- ing' blades comprising a stage. Stationary guide blades 18 are provided in the fixed 7 diaphragm 19 extending over asegmental portion only'of a row of moving blades 20, the upper portion of the segmental diaphragm 19 being constructed, as shown,-.to

enclose the upper portion of the'row of 'm-oving blades 20. In this way a'segmental' portion only of the steam'leaving the preceding row of moving blades 17 passes through the row of moving blades 20 and enters the ex- 'haust fully expanded, From the radial edges 21 of the upper portion 19 of the diaphragm which encloses the upper portion of the moving blades 20 a division wall or diaphragm 22- extends within the exhaust casing 23downwards, as shown, to the exhaust outlet of the turbine 24. The diaphragm 22 is moving blades 17 which passes through the stationary blades 18 and moving blades QO to the exhaust outlet 24, extending to and-being merged into the exhaust casing 'at its sides as shown. A diaphragm 25 containing a ring of stationary guideblades 26 is secured in the cylinder and a final row of moving blades 27 co-operating therewith Iris mounted on a wheel on the shaft 14. Space is provided between the upper portion of the diaphragm 19. and the cylinder so'thatzthe portion of thesteam leaving .the row .of mov ing blades 17 which does not pass through the segmental set of guide blades 18 can flow freely over or round said upper enclosing portion of the diaphragm 19 and pass through the final ring of guide blades 26 and the final row of moving blades 27 fully expanded to the exhaust opening 2 1. The steam on its way to the ring of stationary blades 26 will be partially guided by the upper surface of the diaphragm 22.

Preferably, though not necessarily, the exhaust casing enclosed below the diaphragm 22 and the rear portion of the exhaust casing which receives the steam from the final row of moving blades 27 are provided with internal guide walls such as 28, 29, 30 of the kind described either in the specification of patent application, Serial No. 123,697 filed the 4th October, 1916, or of patent appli- 'cation, Serial No. 187,963 filed the 24th August 1917.

If desired a suitable curved gulde or guides may be provided for that portion of only exists.

the steam leaving the moving blades 17 which does not pass through the stationary blades 18 so that this portion of steam will be separated from the steam which flows through said blades 18 and will be deflected so as to pass over that part of the diaphragm which encloses the upper section of the moving blades 20.

In order that windage and other losses of that port-ion of the row of moving blades 20 through which no steam passes may be reduced as far as possible, the upper portion of the diaphragm 19 enclosing the moving blades 20 is placed in communication with the exhaust of the turbine through the passage 32 so that thatportion of the row of moving blades 20 which is running idle will rotate in a region in which exhaust pressure In the case of a reaction turbine the inner circumference of the diaphragm 19 is preferably furnished with dummy strips or the like 31 so as to provide a packing and prevent the escape of steam from the stationary blades 18 into the interior of the upper portion of the diaphragm 19.

From the foregoing it will be observed that in a turbine constructed in accordance with this invention the steam leaving an intermediate stage passes through a plurality of rows of moving blades to one or more of which there is partial admission only of the steam, and to the final row of which there is either total or partial admission.

In the construction shown in Figs. 3 and 4: the upper portion of the row of moving blades 20 is not enclosed by the diaphragm 19 and that segmental portion of the steam leaving the moving blades 17 which does not pass through the guide blades 18 will pass freely over the extremities of the moving blades 20 as well as through them to the ring of stationary guide blades 26. In this form of the invention the diaphragm 19 which contains the segmental set of stationary blades 18 for that portion of the steam leaving the moving blades 17 which passes through the moving blades 20 and thence direct to the exhaust extends over the whole circumference of the disc containing the moving blades 20. Suitable packings indicated at 31 are preferably provided between the diaphragm 19 and the disc of the blade wheel 20 and between the exhaust side of said disc and the upper circumferential edge of the internal guiding diaphragm 22, which forms a flange opposite the upper part of said disc, so that an effective seal is formed against leakage of steam between the intermediate stage of the turbine and the exhaust. For the same reason the clearances between the radial edges 21 and the moving blades 20 and between the edge formed by the diaphragm 19 and the moving blades 20 should be as fine as possible, suitable packings being preferably provided to ensure this.

The turbine shown in igs. 5 and 6 is similar to that illustrated in Figs. 3 and 4 except that there is no provision made for the steam leaving the upper portion of the mov ing blades 17 to pass above or round the extremities of the moving blades 20 on its way to the final ring of 1 stationary, blades 26. With this construction all the steam leaving the moving blades 17 which does not pass through the segmental set of stationary blades 18 passes through the upper portion of the row of moving blades 20. As in the constructions described above, leakage of steam from the intermediate stage 17 of the turbine to the exhaust is substantially prevented by dummy strips or suitable packing 31 between the inner circumference of the diaphragm 19 and of the internal guiding diaphragm 22 respectively and the disc of the blade wheel 20. v

In the modification illustrated in Figs. 7 and 8 part of the steam leaving the upper segmental portion of the moving blades 17 flows through a segmental portion of a row of moving blades 20 on its way to the exhaust, the remaining part of said steam flowing through the stationary blades 26 and moving blades 27 and thence to the exhaust. The construction illustrated will be clear from a comparison of these figures with 12 Figs. 1 and 2 without further detailed description, the parts 19 and 22 being substantially duplicates of the corresponding parts 19 and 22.

It will be readily understood that the constructions illustrated either in Figs. 3 and 4 vor in Figs. 5 and 6 may also be modified in a similar way so that portions ofthe steam leaving the moving blades of an intermediate stage may be separately caused to pass 30 through three or more rows of moving blades or portions thereof on its way to the exhaust.

Figs. 9 and 10 show a construction which may be adopted for a low pressure turbine in which it is desired to utilize a large volume of steam such as that for instance coming from another turbine cylinder or engine. In this case the steam enters at the inlet 34 and portions thereof pass separately on their way to the exhaust through segmental portion only of two rows of moving blades and through the whole of a final row of moving blades. As the turbine shown in these figures is merely a constructional variation of the turbine shown in Figs. 1 and 2 and in Figs. 7 and 8, no detailed description of the same is deemed necessary. i

In my application, Ser. No. 414,301, filed Oct. 2, 1920, which is a division of this application, I have shown, described, and claimed a construction in which one of the segmental portions of elastic fluid undergoes expansion successively for cooperation with a plurality of rows of moving blades ar:

ranged in succession.

Although in the constructional forms of the invention described above and illustrated in the drawings, the steam leaving the intermediate stage is divided into two portions only, an upper and a lower portion, it is to be understood that the invention is not limited in this respect as it may be carried into effect in such a way that the steam leaving an intermediate stage is divided into a number of segmental portions greater than two and all such constructions are within the spirit and scope of the invention.

It is further to be understood that the invention is applicable either to turbines of the impulse or of the reaction type or to turbines comprising both impulse and reaction stages.

I claim a my invention:

1. In a steam turbine of the axial flow type, means for passing a portion only of the steam leaving an intermediate stage through a segmental part ofthe next succeeding row or rows of stationary guide blades and coop crating moving blades and thenceto the exhaust, and means for passing another portion of the steam around the remaining segmental part of said next succeeding row or rows of blading and through a further row or rows of stationary guide blades and cooperating moving blades and thence to the exhaust.

2. In a steam turbine of the axial flow type, means for directing all of the steam through intermediate stages, and directing a portion of the steam through a segmental part of the next succeeding row of blading and another portion of the steam through a segmental part of a further row of blading. 3. In a steam turbine of the axial flow type, a plurality of rows of blades, and a casing about a segmental portion of one of said rows of blades and adapted to deflect a portion of the steam around said row of blades and to a segmental portion of a suc: ceeding row of blades.

4. In a steam turbine of the axial flow type comprising a plurality of rows of moving and stationary blades, a curved diaphragm adapted to guide the steam. leaving a segmental portion only of an intermediate row of moving blades to the turbine exhaust and adapted to guide the steam leaving the remainder of that row of blades to a suc ceeding row of blades.

5. A steam turbine of the axialflow type comprising a plurality of rows of blades through which the steam is passed in the same axial direction, and means for admitting the steam to a segmental portion only of some of said rows of'blades and to the whole area of another of said rows of blades.

6. In a steam turbine ofthe axial flow type, means for absorbing energy from all of the steam in a series of intermediate stages, means for absorbing some of the remaining energy of a portion of the steam in a segmental part of a succeeding row of blades and means for absorbing some of the remaining energy of the rest of the steam in another succeeding row of blades.

7 In a steam turbine of the axial flow type, means for absorbing energy from all of the steam in a series of intermediate stages, means for absorbing some of the remaining energy of a portion of steam in a segmental portion of a succeeding row of blades, means for absorbing some of the remaining energy of another portion of the steam in a segmental portion of another succeeding. row of blades, and means for absorbing some of the remaining energy of the remaining portion of steam in a third succeeding row of blades. 7

8. A low-pressure section for an elastic fluid motor comprising a plurality of rows of moving blades and means for dividing the elastic fluid into a plurality of portions for partial peripheral admission to one of said rows of blades and for ,full peripheral admission to another row of blades.

In testimony whereof I have hereunto subscribed my name this twelfth day of March 1918.

KARL BAUMANN.

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