US1141473A - Steam-turbine. - Google Patents

Description

J. F. METTEN.

STEAM TURBINE.

APPLlCATlON FILED LY 6.1912.

Patented June 1, 1915.

mvemon ATTORNEYS {WEED snares PA @FFICE.

JOHN F. METTEN, F PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO THE WM. CHAMP 8t SONS SHIP -& ENGINE BUILDING COMPANY, A CORPORATION OF PENNSYLVANIA.

STEAM-TURBINE.

Application filed July 6, 19122.

To all whom it may concern:

Be it known that I, Join: lvflnrrnn, a. citizen of the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements in Steam-Turbines, of which the following is a full, clear, and exact specification.

This invention relates to improvements in blading for steam turbines, and has particular reference to means for preventin r eddying which results when the stream 0 elastic propelling fluid strikes corners and recesses in the passages, as turbines are ordinarily constructed.

In turbines as ordinarily constructed, the apparent axial clearance between the stationary and the moving blades is less than the actual distance traveled by the steam from the exit of one blade passage to the entrance of the succeeding one. The width of the space through which the steam actually travels is thus considerably wider be tween the blades than the length of travel between the blades, which causes the stream to spread to some extent and thereby cause eddying where the extreme portions of the stream strike against the flat sides of'the shrouding, both on the moving and the fixed blades, and also on the projections or blade- .carrying shoulders of the elements, as turbines are ordinarily constructed.

Accordin to this invention, eddying be tween the b ades is obviated by angling the shoulders of the blading grooves both on the rotor and stator on the entrance side, and also making the shronding on the blades angled on the same side. The flaring of the shrouding on the entrance side also has the efl'ect of giving its periphery a sharp edge,

which largely reduces leakage past the blade tips; the tendency being to deflect the spreadin edges of the stream toward the center 0 the passage and thereby-tend to keep practicallythe entire stream centered through 1 the passage, without wasted; eddy expansion or leakage.

In the accompanying drawings, Figure 1 represents in longitudinal section, a portion of a turbineembodying the invention; and Fig. 2 represents a section through adjoining stationary and fixed blades taken on the line 2, 2 of Fig. 1.

1 represents a peripheral section of a rotor or wheel having peripheral slots 2 in whi ,1;

Specification of Letters Patent.

Serial No. 707,978.

moving blades 8 will be fastened, the blades being separated by calking strips 4 and rigidly fastened in any approved manner, 5 being the base of the blade fitting into the slot 2 and undercut as at 6 so that the blade will rest firmly ,on the peripheral shoulder 7 of the rotor 1. The peripheral'shoulders 7 on the rotor are beveled on the'entrance side as at 8, the blade 3 being corres ondingly cut so as to fit firmly on the beve ed face 8, as shown in Fig. 1.

9 represents the stator having slots 10 in which the bases 11 of stationary blades 12 are fastened in a similar manner.

13 represents peripheral shoulders similar to 7 and 14 inclines similar to 8, suitable fastening and spacing means being provided for the blades 12, as will be well understood.

16 represent shroud rings for the stationary blades 12, the same being fastened thereto as by heads 17 and being provided with outwardly inclined surfaces 18 on the enter ingside, forming sharp edges 19 below th bases of the moving blades 12.

20 represents a shroud ring for the moving blades 3 havin the inwardly inclined entering surface 21 ormin a. sharp edge 22 on the entering side, whic as will be seen from Fig. 1, will be outside of the base of the adjacent fixed blade 12.

Patented June 1, 1915.

wardly by the surface 18 and the edges 19,

the result being that eddies will be prevented and thesteam directed toward the center of the "passage and the main body of theflow. In like manner, the inclines 18 at the bases of the moving blades 3'and the inclines 21,.with edges 22,0f the shroud ring at. tips of the moving blades, will direct the steam at the edges of flow toward the center of the passage and the main body of flow.

While it would be within the scope of this narily necessary since the steam, in leavin the bases and tips. of the blades-will cover most of the clearance space before it begins to eddy and at which points are placed the inclined shoulders and shroud rings for the purpose of preventing such eddies. In Fig. '2, the line A represents the axial clearance between the stationary and moving blades, but the line B represents the general path of the steam, it being seen, however, that the spaces transversely of the line B into which the steam can eddy considerably exceed the travel of the steam in passingfrom one set of blades to the next in an ordinary turbine not provided with the beveled shoulders and shroud rings coiiperating as herein described.

Nhile the invention has been described for steam turbines, itis applicable to other forms of expansion fluid turbines without substantial modification, and various changes in the details of construction herein shown may also be made without departure from the invention.

Having thus described my invention, I declare that what I claim as new and desire to secure by Letters Patent is:

1. A shroudring for connecting the moving blades of turbine having its entering side coned outwardly with a sharp edge at the points of greatest diameter at the blade tips to dircctthe fluid flow inwardly.

2. In a turbine, the combination with a turbine element having a circumferential beveled shoulder, and projecting blades supported by said shoulder, of a shroud ring carried by said blades, said shroud ring having an oppositely beveled surface qoiiperating with said beveled surface to concentrate the flow.

3. In a turbine, the combination with a stationary element having an internally projecting beveled shoulder, and internally projecting blades supported by said shoulder, of a movable element separated from said stationary element toform a fluid passage and having a circumferential beveled shoulder axially displaced from the shoulder of said stationary element, said beveled portions being inclined in the direction of flow toward the middle of said fluid passage, of moving blades supported by the shoulder of said moving element, the entrance portions' of said blades overlying said beveled portions.

4'. In a turbine, the combination with 11.

stationary element having inwardly projecting blades, of a shroud ring carried thereby having one side beveled from the blade tips inwardly, and a movable element having outwardly projecting blades axially displaced from said stationary blades, and a shroud ring carried by said moving blades having its side corresponding to the beveled side of said stationary ring beveled outwardly.

5. The combination with stationary blades having a shroud ring beveled outwardly from the entering sides of the blades, of oppositely projecting axially displaced movable blades having a shroud ring beveled oppositely to the bevel of said stationary ring from the entering sides ofsaid movable blades.

6. In a turbine comprising a moving blade carrying element constituting a steam passage, means carried by the blades and by the blade support for rendering said passage of larger area at the entering than at the leaving edges of said blades.

7 In a turbine comprising a moving blade carrying element constituting a steam passage, means between the blades in part at the base and in part at the ends of said blades for rendering said passage of larger area at the entering than at the leaving edges of said blades.

8. In a turbine comprising movable and stationary elements each carrying blades, a.

steam passage formed between two successive blades of each element having inwardly beveled deflecting surfaces at its ends on the fluid entering blade edges, the leaving side being narrower as compared with the entering side.

9. In a turbine, a blade supporting element having a. circumferential beveled shoulder for contracting the steam passage between the blades at the blade base, and a, shroud ring connecting the ends of a plurality of blades having a beveled surface for contracting the steam passage at its opp0 site endbetween the blades.

In testimony whereof I aflix my signature, in presence of two witnesses. I

JOHN METTEN.

Witnesses:

Isaac Anson, ROLAND L. How.

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