US2294983A - Steam turbine apparatus - Google Patents

Description

Sept. 8, 1942. R. HERTL 2,294,983

STEAM TURBINE APPARATUS Filed April 29, 194i ATTORNEY -v 30 F7619; 3 ROBERT I RTL Patented Sept. 8, 1942 STEAM TURBINE APPARATUS Robert Hertl, Lansdowne, Pa., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application April 29, 1941, Serial No. 390,863

4 Claims.

My invention relates to an elastic-fluid turbine wherein the rotor and the cylirl'der define chambers separated by blading and it has for an object to provide apparatus of this character in which the equilibrium passage or conduit connecting the chambers includes a passage formed in a nozzle vane or block so that the length of the turbine may be shortened and its critical speed raised.

With a large steam turbine of the high-pressure and high-temperature type having a full peripheral impulse stage, the dummy may be locat-ed so close to the impulse Wheel that there is little, if any, space left for an equilibrium space or passage. To answer this need, in accordance with the present invention, the nozzle block or a nozzle vane, or a partition wall or rib, is formed to provide a portion of the equilibrium passage, it being remembered, of course, that an equilibrium pipe or passage is necessary to avoid excessive end thrust and consequent thrust bearing trouble or failure. If, with a full peripheral admission turbine, conventional practice is followed, it becomes necessary to lengthen the turbine sufficiently so that the dummy is spaced from the impulse wheel adequately to accommodate the equilibrium pipe or passage; however, increasing the length of the turbine lowers the critical speed, involves increased expense and waste of space, and, because of critical speed requirements, may make the design of a large turbine prohibitive.

A further object of the invention is to provide an impulse stage having a single row of movin blades with an equilibrium passage, or conduit for connecting together the spaces at the inlet and outlet sides of the blades and wherein one or more nozzle vanes of the stage accommodate portion or portions of the equilibrium passage.

These and other objects are effected by my invention as will be apparent from the followin description and claims taken in accordance with the accompanying drawing, forming a part of this application, in which:

Fig. 1 is a fragmentary, longitudinal, sectional view of a portion of a turbin showing the improved equilibrium passage applied thereto;

Figs. 2 and 3 are enlarged detail sectional views, and are taken along the lines II-II and III-III of Figs. 1 and 2, respectively;

Figs. 4, 5, 6 and '7 are detail sectional views showing a modified form in which a vane itself has a portion of the equilibrium passage;

Fig. 8 is a detail sectional view showing a order to accommodate a portion of the equilibrium passage; and

Fig. 9 is a detail sectional View of a Rateau stage having an equilibrium passage connecting the spaces at opposite sides of the Wheel, the passage having portions thereof formed in nozzle vanes.

Referring now to the drawing more in detail, in Fig. 1 there is shown a turbine rotor l0 and a cylinder H defining chambers l2 and i3 separated by the blading l4 supplied with steam at suitable velocity by means of nozzle passages 15 defined by nozzle vanes I'6 carried by the nozzle block l1.

As shown in Fig. 1, the chamber 12 is arranged between the rotor impulse portion I ia carrying the moving blades of the blading l4 and the dummy [8. In order that the dummy may be subjected to the same pressure as that existing in the chamber 13 at the discharge side of the blading 14, it is necessary to provide one or more equilibrium pipes or passages, one being shown.

Because of the relatively close spacing of the special nozzle vane having greater axial length in dummy l8 and the impulse stage in Fig. 1, the nozzle block has a radially-extending passage 20 aligned with radial passages 22 formed in the block H. The cylinder has a passage 23 formed therein, one end of the passage 23 communicating with space I3 and the other end communicating with the outer radial opening or passage 22. Thus, there is provided, an equilibrium passage having a portion thereof extending radially of and incorporated in the nozzle block.

As shown in Figs. 1 and 2, the nozzle block portion 29 of the equilibrium passage is provided by a pipe section 2| arranged ahead of the inlet edge 25 of one of the nozzle vanes.

In Fig. 3, there is shown in detail how the component elements of the nozzle block structure are connected together, the inner and outer ends .of the vanes 16 being connected to inner and outer portions of the nozzle block I! in any sui able manner and the pipe 2| having its ends fitting closely portions of the block I! provided with the al'gned passages 22 and preferably being welded, as shown at 26, to the edge of the adjacent outer and inner members of the nozzle block to prevent leakage.

In Figs. 4 to 7, inclusive, there are shown nozzle block structures having vanes l6 defining nozzle passages 15 and wherein one of the vanes is modified so as to incorporate the radial passage portion 20 of the equilibrium passage.

In Figs. 4 and 5, the passage 20 is defined by a pipe Zia incorporated within the structure of the vane, the ends of the pipe preferably extending through inner and outer portions of the nozzle block and providing the passage portion 20.

In Figs. 6 and '7, the passage 28 is defined by an opening extending longitudinally of the vane, the ends of the passage aligning with radial openings 22 formed in the nozzle block structure II. The welds 28 provide for sealing of the joint between adjacent ends of the passages and I5.

In Fig. 8, there is shown a further form of the invention representing a combination of the features of Figs. 4 and 6. In this view, one of the vanes lfia has substantially greater axial length than the other vanes, the relatively greater axial length making it possible to provide a passage a which is of curved and elongated section.

In Fig. 9, there is shown a form of the present invention particularly suitable for a single row impulse or Rateau turbine stage. This type of stage incorporates alternately arranged nozzle vane structures or diaphragms 29 and turbine dis-cs or wheels 39, each diaphragm 29 preceding a Wheel 30 having nozzle vanes 3| providing nozzle passages for supplying steam at suitable velocity to the blades or buckets 32 carried by the succeeding disc or wheel 3%. In this view, there is shown one of the discs or wheels 30 with diaphragms-preceding and succeeding the latter. As there may be a difference in pressure between the steam inlet and outlet sides of the blades or buckets 32, it is desirable to provide an equilibrium passage to assure of the maintenance of identical pressures atv opposite sides of the Wheel or disc. Accordingly, the diaphragms at either side of the wheel or disc 38 have radial passages 22a formed therein and aligned and operatively continuous with the radial passages 201) formed in the vanes 3!. The outer ends of the passages 22a are connected by an axially-extending passage 23a having portions thereof formed in the diaphragms and in the cylinder structure I la.

The expression nozzle vane structure, as used herein embraces the nozzle block and the vanes collectively; and, when it is stated that such structure has a passage formed therein, this covers either formation of the passage in a vane or in a separate pipe or structure.

While the invention has been shown in several forms, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modifications without departing from the spirit thereof, and it desired, therefore, that only such limitations shall be placed thereupon as are specifically set forth in appended claims.

What I claim is:

1. In a turbine, a cylinder and a rotor providing chambers therebetween, blading separating the chambers, nozzle vane structures cooperating with the blading, and means including a passage formed in a nozzle vane structure to provide an equilibrium passage connecting the chambers.

2. In a turbine, a cylinder and a rotor providing chambers therebetween, blading separating the chambers, a nozzle block including nozzle vanes defining nozzle passages for supplying elastic fluid to the blading, and means including a passage formed in the nozzle block to provide an equilibrium passage connecting the chambers.

3. In a turbine, a cylinder and a rotor providing chambers therebetween, blading separating the chambers, a nozzle block attached to the cylinder and including vanes defining nozzle passages for supplying elastic-fluid to the blading, and means including communicating passages formed in the structures of the cylinder and of the nozzle block and extending axially of the structure of the cylinder and radially of the structure nozzle block to provide an equilibrium passage connecting the chambers.

4. In a turbine, a cylinder and a rotor providing chambers therebetween; an impulse stage including stationary and moving blades carried by the cylinder and by the rotor, respectively, and a nozzle block provided with nozzle passages for supplying elastic fluid to the blades; a dummy construction cooperating with the rotor and with the cylinder and providing for the imposition of steam thrust on the rotor; one of said chambers being arranged between the dummy construction and said stage at the elasticefiuid inlet side of the latter and theother chamber being arranged at

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