US2186952A

US2186952A - Elastic fluid turbine

Info

Publication number: US2186952A
Application number: US214909A
Authority: US
Inventors: David J Bloomberg
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1938-06-21
Filing date: 1938-06-21
Publication date: 1940-01-16
Anticipated expiration: 1957-01-16

Description

Jan.l6, 1940. D. J. BLOOMBERG 2,136,952

I ELASTIC FLUID TURBINE Filed June 21, 1938 Flgl. 10 21 Fig. 3.

" ii/Illa I Inventor:

David \J. Bloomberg, b ax/M91- His At'torne g.

Patented Jan. 16, 1940 UNITED STATES PATENT OFFICE General Electric Company,

New York a corporation of Application June 21, 1938, Serial No. 214,909 a 3Claims.

The present invention relates to elastic fluid turbines in which elastic fluid discharged from the bucket wheel of a higher stage is conducted to the diaphragm of a lower stage considerably spaced from the bucket wheel of the higher stage.

=Axial spacing of turbine stages is necessary, for instance, in cases in which the first stage includes a large diameter Curtis type bucket wheel from which the fluid is to be conducted to a second stage small diameter diaphragm. It has been found that considerable energy loss of the elastic fluid takes place on its path between axially considerably spaced stages, particularly when the higher stage is operated with partial admission,

1 that is, when the elastic fluid is supplied only along a comparatively small arc of the higher stage.

The object of my invention is to provide an improved construction and arrangement of elastic 2o fluid turbines whereby the aforementioned drawback is overcome. This is accomplished in accordance with my invention by the provision of an elastic fluid guiding and directing device intermediate axially spaced stages of a turbine.

For a consideration of what I believe to be novel and my invention attention is directed to the following description and the claims appended thereto in connection with the accompanying drawing.

In the drawing Fig. 1 illustrates a sectional view of an elastic fluid turbine embodying my invention; Fig. 2 shows a section along lines 2-2 of Fig. 1; and Fig. 3 shows a modification of my invention.

The arrangement of Figs. 1 and 2 comprises a turbine casing III with inlet conduits ll connected to a chest 12. The chest has a plurality of partitions l3 dividing it into several, in the present instance 6 sections. A rotor is disposed within the casing and includes a shaft il, a first stage large diameter bucket wheel l5 and a second stage small diameter bucket wheel 16 secured to the shaft ll. Elastic fluid is conducted from the chest l2 to the nozzle forming buckets of the first stage wheel l5 by means of a first stage diaphragm or nozzle plate l'l suitably secured to and supported on the casing l0. Elastic fluid discharged from the nozzles of the first stage bucket wheel I5 is conducted to the second stage bucket wheel It by means of a second stage nozzle diaphragm l8 provided ahead of the second stage bucket wheel I6 with regard to the direction of flow of fluid.- The nozzle diaphragm l8 has an outer ring l9 secured to the casing III to support 5| the diaphragm I8.

The arrangement so far described is typical of elastic fluid turbines with partial admission of elastic fluid to the first stage bucket wheel. During starting, elastic fluid is supplied through one of the inlet conduits II to a section of the first 5 stage diaphragm l1, whence this fluid is directed to a section of the first stage bucket wheel l5 adjacent the aforementioned section of the first stage diaphragm ll. Thereafter valve means, not shown, provided in the other conduits II are 10 successively opened, thus increasing the arc of admission of elastic fluid to the first stage. With all inlet valves in opening position fluid is supplied to the first stage over an angle of about and fluid is discharged from the first stage wheel 15 i5 over a similar angle of about 120. In order to reduce energy loss in the space between the wheel l5 and the second stage diaphragm i8, due to whirling and rotation of the fluid in said space, I provide means for properly directing and guid- 50 mg the fluid on its path from the first stage to the second stage. In a preferred embodiment this meansacts at the same time to eflfect distribution of the elastic fluid in the second stage andthereby increases the efiiciency of the latter. a The guiding and directing device comprises a plurality of vanes 20 intermediate the first and the second stage. These vanes in the present instance are secured to a curved plate or ring segment 2| which in turn is fastened to the outer ring IQ of the diaphragm l8 by means of a plurality of screws 22. The vanes are arranged along an arc having a center coinciding with the center of the shaft. The length of the arc is about 120, that is, equal to the total are of ada mission. The vanes have outer, straight or plane portions 23 which are inclined about 45 from the corresponding direction through the center of the shaft. With the exception of the two vanes shown on the right-hand side of Fig. 2 w the vanes have curved portions 24, the curved portions of the vanes shown on the left-hand side being longer than the length of the curved portions shown on the right-hand side of Fig. 2 in order to eiiect substantially uniform distribution 45 of the elastic fluid discharged from the first stage among the sections of the second stage. The direction of flow o'f fluid is indicated by arrows in the drawing. During operation, fluid discharged irom the first stage wheel I5 is directed a axially and radially inward by the vanes 20 to-. wards the nozzles of the diaphragm Ill. The vanes.20 also reduce rotation in the space between the first and the second stages.

The arrangement of Fig. 3 comprises a casing 2 Q v I 3. iliorminganinlctchestilwithanadmilion opening .21. A flrst stage including a diaphragm ornoaalebladeltandacurtistypebuoketwheel II and a second stage including a diaphragm I. g and a bucket wheel 8| are formed within the casing II. The second stage has a smaller diameter than theflrst stage and is axially considerably spaced from the latter. The elastic fluid directing device disposed between the two stages 10 comprises a plurality of straight or plane vanes 32 with outer edges fused to a ring, which latter is fastened by bolts It to an outer portion of the flrst stage diaphragm II. -An inclined ring segment II is welded to the blades 82 and to the 15 supporting ring or member 83 for properly directing the elastic fluid discharged from the first stage towards the inlet openings of the nossles oi the second stage diaphragm as indicated by arrows. so The elastic fluid guiding and directing device for conducting elastic fluid from a high stage bucket wheel to an axially spaced low stage diaphragm may be used advantageously in any arrangement in which elastic fluid is admitted to 26 the full are or a partial'arc of either stages and in which the diameter or one stage diflers substantially from that of the other stage.

Having described the method of operation of my invention. together with the apparatus which 30 I now consider to represent the best embodiment thereof, I desire to have it understood that the apparatus shown is only illustrative and that the invention may be carried out by other means.

whatlclaimasnewanddesiretosecureby 88 Letters Patent oi! the United States is:

1. An elastic fluid turbine comprising a flrst stage having a bucket wheel of large diameter and a second stage with a diaphragm of small diameter considerably axially spaced from said so bucket wheel, and a device comprising a plurality oispacedvanesarrangedonanarcwitheach vane having a straight portion inclined by about 45' towards the corresponding diameter oi the bucket wheel and some of the vanes having curved portions to direct elastic fluid discharged 5 from the bucket wheel and eflect distribution of the fluid among all sections of the diaphragm.

2. An elastic fluid turbine comprising a high pressure stage with a bucket wheel, partial admission means for conducting elastic fluid to an are 10 of the bucket wheel, a low pressure stage with a diaphragm for receiving elastic fluid discharged from the bucket wheel. the diaphragm being considerably axially spend from the bucket wheel and having a diameter substantially diflerent firom that of the bucket wheel, and a guiding and directing device interposed between the bucket wheel and the diaphragm and extending over an to the arc of admission to the bucket wheel m guiding elastic fluid from the bucket wheel exit arc to the diaphragm, saiddevice having a plurality of vanes with outer straight portions inclined by about 45' towards the bucket wheel diameters.

3. An elastic fluid turbine comprising a flrst stage having a bucket wheel, a second stage with a diaphragm considerably axially spaced from the bucket wheel and 01' adiameter substantially diii'erent from that of the'bucket wheel. and a device comprising a plurality of spaced vanes arranged on an arc with each'vane having a straight portion inclined by about 45' towards the corresponding diameter oi the bucket wheel and some of the vanes having curved portions to direct elastic fluid discharged from the bucket wheel and eilect distribution of the fluid among all sections of the diaphragm.

DAVID J. BLOOM. 40