US1756958A

US1756958A - Elastic-fluid turbine

Info

Publication number: US1756958A
Application number: US310123A
Authority: US
Inventors: Henry F Schmidt
Original assignee: Westinghouse Electric and Manufacturing Co
Current assignee: CBS Corp
Priority date: 1928-10-03
Filing date: 1928-10-03
Publication date: 1930-05-06
Anticipated expiration: 1947-05-06

Description

May 6, 1930. H. F. SCHMIDT 1,756,958

ELASTIC FLUID TURBINE Original Filed March 2, 1920 9. J Q a 71 v s h.

WITNESS INVEN'ILOR v 6. Henry F-schmldt I I BY ATTORNE Y Patented May 6, 1930 UNITED STATES PATENT OFFICE HENRY F. SCHMIDT, OF LANSDOWNE, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC 8: MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

ELASTIG-FLUID TURBINE Continuation of application Serial No. 362,773, filed March 2, 1920. This application filed October-3,

1928. Serial This application is a continuation of no application for packing No. 362,773, filed March 2, 1920. 4

My invention relates to an elastic fluid turbine, and it has for its object to provide a construction and an arrangement of the parts of the turbine to facilitate the centering or positioning of the rotor in the casing or stator.

More specifically it is an object of my invention to provide a construction of packing, for r the gland and the dummy, or either, and its arrangement in the turbine, whereby theradial packing clearancesmay be increased by axial movement of the rotor. I

The usual form of packing employed hitherto comprises a plurality of overlapping flanges mounted on the stator and rotor in such a manner that the tip of a'flange on the stator projects into the groove formed between two flanges onthe rotor, the flanges and groovesbeing of such depth thatthe radial clearance between the tip'of the flange and the bottom of a groove is but a few hundredths of an inch.

The permissible end or radial clearance of the blading of the turbine is considerably greater than that permissible I between the packing elements, and heretofore when it was desired to center the rotor with respect to the blade clearance between the tips thereof and the casing or stator, it was necessary to first remove the rings containing the packing flanges carried by the stator, so as to permit of greater radial movement of the rotor with respect to the stator than would be permitted were the packing flanges in place.

The rotor is centered with respectto the stator by first moving it laterally or radially until the blade tips on the rotor engage the shell of the stator. The position of the rotor is noted and the rotor is then moved horizontally in the opposite radial direction until the tips of the rotor blades on the opposite side of the rotor engage the stator shell. The total movement of the rotor from one extreme position to the other is then measured and the rotor is moved horizontally to a position midway between the extreme limitsof movement in the horizontal plane. The rotor is next moved vertically downward until the. blade tips of the rotor engage the bottom of the stator shell. Phe extreme lower position is noted after which the rotor is raised vertically until the blade tips of the rotor engage the upper stator shell. The rotor is finally moved to a position midway between the extreme limits of vertical moveing rings carrying the flanges, and therebygreatly reduce the time and expense usually involved in centering the rotor with respect to the stator. I I

Other objects will hereinafter appear throughout the further description of the apparatus embodying my, invention and illustrated in the accompanying drawing wherein Fig. 1 is a vertical section of .a portion of the upper half of a steam turbine having packing arranged in accordance with my invention.

Fig. 2 is a vertical section on enlarged scale of a detailof the packing.

I Referring to the drawing, the packing is shown applied to the dummiesand gland of asteam turbine of the combined impulse and full peripheral admission reaction type. As shown, the turbine includes a casing or stator 3, provided with a stationary blade ring 4 upon which the stationary reaction blades 5 of the turbine are mounted, and with a second blade ring 31 carrying impulse blades 32. The rotor 6 carries the moving reaction blades 7 and moving impulse blades 33.

The rotor is supported at each end in concentric relation with the blade rings 4 and 31 by means of suitable adjustable bearings 8 (only one of which is shown) which receive and support the shaft of the rotor. I The bearing 8 is adapted for universal radial adjustment within a pedestal 10 and is retained in adjusted position by means of the usual liners 11, four of which may be provided to hold the bearing in the desired position.

In reaction turbines, or turbines including a section of reaction blading, it is desirable that the .end clearance of the blading, that is, the space between the blade tips and the stator shell or rotor body, be as small as is practicable, and for this reason it is desirable that the rotor be accurately centered so that the clearance is uniform throughout the entire circumference of the blading. As practiced in the construction of large turbines, the permissible clearance is about one-eighth of an inch, while theclearance permissible between the flanges or the rings of the packing elements is but a .few hundredths of an inch. It is apparent that the radial movement of the :rotor provided 'withthe usual form of packing is thereforelimited by the radial clearance of the packing flanges and that in order to center the rotor, certain packing elements must first be removed.

It is theobject of this invention to provide the turbine with eflicient packing for the dummies .and the glands, that will permit of the centeringof the rotor with respect to the stator in the manner previously described, while the packing remains in the turbine casin g. The packing employed is shown applied to the dummies '12 and13 carried by the rotor and to the gland 14. Surrounding the dummiesis a stationary ring 15 provided with two separate packing rings 16 and 17 the former cooperating with a packing ring 18 mounted on the dummy 12 and the latter cooperating withthe packing ring 19 mounted on the periphery of thedummy 13. packing ring 2 0,forming a part of the gland packing, is shown mounted in the gland housing 21 of the casing 3 and cooperates with the packin' ring 22-mounted upon the shaft 9.

In Fig. 2 I show a longitudinal section illustrating on an enlarged scale, a fragment of the packingysnch as is used in the gland. The details of the packing elements used on the dummies are substantially the same as those employed in "the gland. Referring to Fig. 2, the packing comprises a ring or blade 22 carried by the rotor and provided with a series of annular, obliquely undercut grooves 23, separated by annular webs 24 which terminate in thin knife-edged wearing tips. A plurality of annularpacking flanges 25 are mounted in the packing ring in such man ner that a packing flange is-disposed opposite each groove The-exposed edge of each flange is cut away so asto leave a thin wearing tip 2.6 which extends into the groove 23 and slightly overlaps the web 24; The flanges '25 are made in segments placed end to end soas to form a continuous annular flange and the sleeve '20 may be made in halves adapted to separate on the horizontal plane so tliat the upper half may be removed The when the upper half of the stator casing is lifted.

When the packing elements are in their operative relation as indicated in Fig. 2, the

extreme edges of the flanges 26 just clear the inclined walls 27 of the grooves and form a seal preventing the escape of fluid past them. It will be observed that the direction of flow of fluid tending to pass through the gland will be reversed 1'11 each groove with the result that the gland is more effectually sealed than isthe'case where the walls of the grooves are normal to the axis of the rotor. The wearing tips 26 are reduced in thickness so that in'the event that they accidentally come in rubbing contact with the walls of the grooves they will bend or yield without causing serious injury to the gland elements.

When it-is desired to center the rotor with respect to the stator, the rotor is first moved longitudinally to the left until the flange tips 26 and the Webs 24 almost engage one another, as indicated by the position ot the tips shown in dotted lines at 28 in Fig. 2.

This movement causes sutflcient separation of l 1 dially in all directions to its extreme limits of radial movement without interfering with the packing elements. After the rotor has been centered in the mannerv previously dee scribed, it is moved longitudinally to'the right until the desired clearance is again obtained between the flange tips 26jand the in clined walls 27 of the grooves. There is alwayssutflcient longitudinalv clearance between tliemoving and stationary blading of the turbine to permit of sufiicient axial movenient to effect the desired longitudinal adjustment of the rotor with respect to the stator.

on the stationary and rotating parts, respectively, so that the relative movement'of the flange tips 26 from the full line position to the dotted line .positionat 28 takes place within the limited axial movement of the rotor. Referring specifically to the arrangementshown, the axial movement of the rotor changing the relative position ofthe flange tips 26 from full'line position to dotted line position at is indicated by the referencev character a. N ow the rings 20. and 22 must be positioned to. provide the minimum or working clearance with the rotor in a POST-1 tion in which there is an axial clearance between the left-hand side of the rotor blades and the right-hand side of the stationary The rings 20 and 22 are axially positioned lie blades, indicated at b in Fig. 1 (on a smaller scale than Fig. 2), so that sufficient movement of the rotor to the left may be permitted, in other words, the clearance I) must be equal to or greater than the distance a.

The inclined surfaces or walls 27 are of sufficient inclination to increase the radial clearance between the flange tips 26 and the surfaces 27 to an amount, indicated by the reference character 0, which is greater than the radial blade or end clearance d.

I am aware that packing elements having inclined surfaces have been heretofore proposed, but I am not aware of any arrangement of such packing, or any other kind of packing, whereby suflicient radial clearance for centering the rotor may be obtained by axial movement. 7

It is obvious that the contours and shapes of the grooves and flanges of the packing may be varied through a wide range and that the modified packing will still fulfill in every respect the functions of the packing illustrated. The construction illustrated is but one of a number of simple forms of packing which may be devised to permit of adjustment of the radial clearance to suit the conditions and the invention is, therefore, not limited to the single specific construction illustrated in the drawings.

While the packing has been described as being applied to a rotor element and a stator element, it is obvious that the packing will be equally effective when used in turbines wherein the casing revolves in one direction and the rotor revolves in the opposite direction, or in any apparatus having two rotative elements wherein it is desired to pack the space between the relatively moving parts against the passage of fluid therethrough.

While I have shown my invention in but one form, 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 I desire, therefore, that only such limitations shall be placed there upon as are imposed by the prior art oras are specifically set forth in the appended claims.

What I claim is: v

1. In an elastic fluid turbine, the combination of a casing, an axially movable spindle within the casing and carrying radially-extending blades whose outer ends are disposed in close proximity to a part carried by said casing, cooperating packing elements carried by said casing and said spindle and, in one axial position of the rotor relative to the casing, providing normal radial packing clearances less than those between the outer ends of said blades and the adjacent part of the casing and in another axial position of the spindle providing a clearance greater than that between the outer ends of said blades and the adjacent part of said casing.

i 2. In an elastic fluid turbine, the combination of a casing, a rotor therein, interleaving rows of radial blades carried by the casing and the rotor and certain of said blades being disposed to provide radial clearances at the outer ends thereof with the rotor and the casing, respectively, cooperating packing elements carried by the casing and the rotor and normally providing radial clearances less than the blade clearances, said cooperating packing elements being 'so formed as to increase the radial clearances therebetween to anamount greater than the blade clearances upon axial movement of the rotor to an extent not more than the axial clearances between ing elements have radial clearances less than the radial clearances provided by said coop-; erating parts and, in another axial position within said limited axial movement, the packing elements have radial clearances greater than the radial clearances provided by said cooperating parts.

4. In an. elastic fluid turbine, the combination of a casing, a rotor therein capable of limited axial movement, cooperating blades carried by the casing and the rotor and having close end clearances with the adjacent parts, cooperating packing elements carried by the casing and the rotor, the packing elements carried by one member having thinedged portions extending radially toward the packing elements carried by the other member, said latter packing elements having frusto-conical surfaces cooperating with the thinedged portions, said frusto-conical surfaces being of such extent and inclination that, within the limited axial movement of the rotor, the packing elements of the rotor may move relative to the packing elements of the casing from a position in which the thinedged portions pack closely to the frustoconical surfaces with close normal working clearances to a position in which the radial clearances between the thin-edged portions and the frusto-conical surfaces are greater than said blade end clearances.

5. In a steam turbine, the combination of a casing, an axially movable spindle within the housing and carrying radially-extending blades whose outer ends are disposed in close proximity to a part carried by said casing, packing members carried by said spindle and having outer frusto-conical surfaces, radially-extending thin-edged packing members carried by said housing and cooperating With said frusto-conical surfaces, the inner edges of said last-mentioned packing members being intermediate the radial extent of said frusto-conical surfaces, and said frusto-conical surfaces being of sufficient radial extent I to provide, when the spindle is moved in clearance-lncreaslng dlrection, a clearance at least as great as thatbetween the ends of said blades and the casing.

In testimony whereof, I have hereunto sub scribed my name this 28th day of September,

HENRY F. SCHMIDT.