US1223914A - Radial steam-turbine. - Google Patents

Description

0. A. W|BERG- RADIAL STEAM TURBINE.

APPLICATION FILED JAN. 15. 19H.

1,223,914 Patented Apr. 24, 1917.

" 2 SHEETS--SHEET l.

Fig. l. "1' Tn l? m2 WM h if l m e a a' 22? la' ifid b :f 9 a? a7' g A. WIBERG. RADIAL STEAM TURBINE. APPLICATION FILED IAN. I5, ISI?.

Puentcd Apr 24, HN?.

l' I f changes as correspond to the workin OSCAR ANTON WIBERG, 0F FINSPONG, SWEDEN.

RADIAL STEAM-TURBINE.

Specification of Letters Patent. Patented Apr, 241; 191K,

Application led January 15, 1917. Serial No. 142,525.

To all whom t may concern:

Be it known that I, OSCAR ANTON WI- BERG, a subject of the King of Sweden, residing at Finspong, Sweden, have invented certain new and useful Improvements in Radial Steam-Turbines, of which the following is a specification.

The present invention relates to radial flow elastic fluid turbines and specifically to that type having a system of blades through which they motive fluid flows radially outward, and a second system of blades surrounding the first through which the motive fluid flows axially, the former system being composed of blade carrying members that rotate in opposite directions, and the latter system of stationary fluid directing means and blades coperating therewith, which blades also rotate in opposite directions with those of the radial flow system. In such turbines the stationary blades or fluid directing devices for the axial flow portion have been rigidly and directly attached to the casing or to separate rings or supports rigidly secured to the casing.

This rigid arrangement of the stationary blades is open to certain objections; viz., that it requires initially an. accurate centering of the rotor and casing with respect to each other which cannot be maintained during the repeated changes of temperature due to .wide variations in.` load and to such and non-working periods of the turbine. wing to the difficulty of maintaining the accurate centering of the coperating parts under the conditions specified, it has been found necessary' to provide relatively large clearances, especially in a radial direction between the relatively rotating parts of the axial flow system as, for example, between the' outer ends of the rotating blades and the-adjacent part of the turbine casing.

In this connection it should be borne in mind that the outer casing is relatively cold as itl delivers the exhaust directly into the condenser, and henceunder normal conditions has a substantially constant temperature. The rotors receive high pressure high temperature fluid at their center and d1scharge it outwardly, and hence there is a gradual fall in temperature from the inside out. Since the* load on a turbine varies widely at times it follows that the temperatures in different parts thereof vary with said changes and the more abrmupt these changes are the more danger there is of distortion, accompanied by rubbing of the parts or enlargement of the clearances, or both, in different parts of the turbine.

The object of the present invention is to overcome the objections above noted, and to provide a supporting arrangement for the stationary fluid directing means which is unaected, in so far as changes in clearances are concerned, by variations in temperature of the motive fluid whereby the initial clearances ma be reduced and the leakage of motive fluid and consequent loss of power on the one hand, and frictional engagement or rubbing of the parts on the other, avoided.

In carrying out my invention the stationary fluid directing means or blades instead of being rigidly attached to the turbine casing, as before, are attached to a ring or member which is supported by the turbine casing in such manner that it and the casing may freely expand and contract without the movements of one causing'any displacement or distortion of the other. In other words, the support for the fluid directing means will change its diameter to the same, or substantially thev same, degree as the rotor, and in substantially the sameperiod of time, with the result of maintaining the blade clearances substantially constant in amount at all times. p

The means employed to support the member or ring from the turbine casing can be made in a variety of ways, the essential feature being to allow the member to have certain amount of movement perpendicular to the turbine axis, but restrainl it against lateral movement. In other Words, expansions and contractions in all radial directions should be uniform and unrestrained so that the ring will maintain its central position at vall times.

In the accompanying drawings, Figure l is a longitudinal quarter section of a turbine illustrating one form of the invention; Fig. 2 is a sectional view of a portion of the same on a larger scale; Fig. 3 is a crosssection of a modified form of the invention; Fig. 4 is an axial section of a further modiication wherein an expansion ring is employed, and Fig. 5 is an axial sectional view of a further modification.

a designates the turbine casingand b and 0 two shafts rotating in' opposite directions andv carrying the turbine disks d and e respectively, said casing being divided in an axial plane as is usual in such machines. On the outer sides of the disks are concentric packing rings d and e extending between which are similar rings (Z2 and e2 carried by flat plates mounted in the turbine casing. The purpose of this arrangement is to provide a means. for balancing the end thrust on the disks, said packing rings serving to reduce the leakage. Motive fluid is admitted to the rotor lthrough'chests a from which it flows -through suitable passages a2 in the chests and a3 in the disks to the inner` blades of the radial flow system. Mounted on the disks are axially extending blades f and g arranged in concentric rows and forming the radial flow portion or system of the turbine. The disks are also provided with radially extending blades la, and i which form a part of the axial flow portion or system of the turbine. Cooperating with the blades 71, and z' are stationary fluid directing devices lc and Z of any suitable design which are mounted on an annular member or ring m;

The inner ends of the directing'blades are secured in any suitable manner 'to rings Z and 7c that closely surround these portions of the rotors carrying the radial flow blade system and serve to prevent leakage of motive fluid at this point. The ring m is substantially V-shaped in cross section and has two outwardly curved surfaces m and 'mfg which direct the motive fluid from the radial flow system into the stationary blades of the axial flow system. The purpose of the curved surfaces is to avoid shocks and eddies in the motive fluid and to gradually 2 this is attained by the following means:

Projecting inside the turbine casing is a ring, flange, or rib r which is suitably faced off on opposite sides and is supported from the casing by the studs or projections p. The purpose of using these projections as distinguished from a complete annulus is two-fold, it permits of an equalization of the pressures of the motive fluid exhausting on opposite sides and also permits of access to the securing means. The periphery of the central part of the ring is provided with a groove, the side walls of which engage the faced portion or surfaces of the ring r and are free to slide radially thereon under temperature changes. Either as an additional support, or as a sole support, as requirements dictate, are radial pins n of which a plu-I rality are provided. There should be at least three of these pins and spaced equidistant. They serve to center the ring and also to guide it when moved in response to temperature changes. The pins may be xed either in the blade carrying ring m or in the stationary part or parts r as desired, or they may be loosely arranged in both and provided with cross pins o to allow of only a certain limited longitudinal displacement. It is obvious that the pins fn. may be replaced by radial guiding devices of any other form, for instance, dove-tail shaped projections protruding from one part and engaging correspondingly shaped projections extending from the other part. These pins also serve as a means to prevent the ring from turning due to .the action of the motive fluid flowing through-the guiding or directing blades. 'Owing to the fact that the flow of motive fluid is equally divided left and right the axial anced.

It is unnecessary for the guiding devices themselves to extend radially, as it is only essential thatthey guide the blade ring in a direction perpendicular to` the shaft axis. For instance, the arrangement shown in Fig. 3 may be employed wherein m represents the deflecting and blade carrying ring as before and s bars or links of suitable width having enlarged ends which are seated in sockets in the ring and in the turbine casing or connected parts respectively. By arranging the bars or links as shown the-ring m can freely expand and contract, but is always held in a central position with respect to the rotor axis. Y

In Fig. l is shown a modification wherein an expansion ring t is provided which`is, or may be, slightly conical in shape. Its ends are enlarged to form circular anchoring devices which are seated on the one hand in a socket formed in a suitable part of the ring m, and on the other hand in a socket in a ring t that is located in the turbine casing and secured by a calking strip t2. If

ythrust on the ring is baldesired, the ring may be slotted as at t3.

' surfaces on the two rotors.

mascia the ring 7' which is supported by projections p from the turbine casing. The bridges should be relatively thin and long in the direction of the axis of the turbine so as to give the desired elasticity.

By means of the arrangement above described I am able to definitely and exactly center the blade carrying ring m relative to the rotating parts, and said ring will always remain in its central and proper position regardless of the expansions and contractions of the turbine casing. lt is thus possible to reduce to a small value the radial clearances, especially those between the outerl ends of the blades l1. and 'L' and the ring m, and also those between the rings at the inner ends of the guide blades and the coperating The clearances referred to are indicated at u and a in Fig. 4.

I have illustrated a certain construction or arrangement of parts herein whereby the motive fluid exhausting from the radial flow system is caused to decrease its residual velocity before entering the blades of the axial flow system. This is not claimed herein as it forms the subject matter of my applicaiin Serial No. 142,526, filed January 24,

lln accordance with the provisions of the patent statutes, l have described the principle of operation of my invention, together with the apparatus which l now consider to represent the best embodiment thereof; but l desire to have it understood that the apparatus shown is only illustrative, and that the invention can be carried out by other means.

What l claim as new and desire to secure I by Letters Patent of the United States, is

l. An elastic fluid turbine comprising a radial flow blade system, an axial flow blade system, stationary directing means which receive the fluid exhausting from the first system and deliver it to the axial flow system, and an inclosing casing` in combination with means for supporting the stationary directing means from said casing which permit the casing and means to expand and contract independently.

2. An elastic fluid turbine comprising a radial flow blade system, an axial flow blade system, stationary directing means which receive the fluid exhausting from the first system and deliver it to the axial flow system,

and an inclosing casing, in combination with means supported by the casing and attached to said stationary fluid directing means which permit the casing and directing means to'expand and contract independently and revent relative axial movement of the casingand said directing means. v

3. `An elastic fluid turbine comprising a radial flow blade system, an axial flow blade system, stationary directing means which rechanging the central position of said memy ber.

4. An elastic fluidy turbine comprising a radial flow blade system, an axial flow blade system, stationary directing means which receive the fluid exhausting from the first system and deliver it to the axial flow system, and an inclosing casing, in combination with an ann lar member which carries rows of fluid dlrecting means on opposite sides and has a deflector between, and means which are attached to the member and also to the casing which permit one of said parts to expand and contract independently of the other.

5. An elastic fluid turbine comprising a radial flow blade system, an axial flow blade system, stationary directing means which receive' the fluid exhausting from the first system and deliver it to the axial flow system, and an inclosing casing, in combination with a ring to which the directing means are rigidly attached, means for supporting the ring from the casing which permits the ring and casing to expand and contract independently, and means for holding the ring concentric with the turbine axis when said expansions and contractions take place.

6. An elastic fluid turbine comprising a radial flow blade system, an axial flow blade system, stationary directing means which receive the fluid exhausting from the first system and deliver it to the axial flow system, and an inclosing casing, in combination with a ring to which the fluid directing means are rigidly attached in sets, rings which unite the inner ends of said sets and occupy positions in close proximity to the rotors of said systems, and means for supporting the directing means from the casing which permits them to freely expand and contract independently but prevents relative axial movement. 1

7. An elastic Huid turbine comprising a radial flow blade system, an axial flow blade system, stationary directing means which receive the fluid exhausting from the first system and deliver it to the axial How system, and an inclosing casing, in combination with a ring to which the fluid directing means are rigidly attached, a support for the ring which is carried bythe casing, and guiding means between the support and ring which permit one to slide on the other, and means to center the ring with respect to the blade system. l

8. An elastic fiuid turbine comprising a loo radial flow blade system, an axial flow blade the projecting means and the ring to center 13 system, stationary directing means which rethe latter.

ceive the Huid exhausting from the first sys- In testimony whereof I afiix my signature tem and dleliver it to the axialbflow system, in presence of two Witnesses.

and an inc osing casing, in com ination with a ring to which the fluid directing means OSCAR ANTON WIBERG' are rigidly attached, means projecting in- Witnesses:

Wardly from the casing to form a support GUSTAF JANssoN, for the ring, and means that pass through FRITZ E. HALLIN.

Images