US1371327A - Turbine - Google Patents

Description

E. SCHNEIDER.

TURBINE.

APPLICATION FILED JULY 21,1920.

Patented Mar. 15, 1921.

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TURBINE.

APPLICATION FAILED JULY 21.1920.

Patented Mar. 15, 1921.

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UNITED STATES PATENT OFFICE.

EUG-NE SCHNEIDER, 0F PARIS, FRANCE, ASSIGNOR TO SCHNEIDER & CIE., 0F PARIS,

. FRANCE, A LIMITED J OINT-STOCK COMPANY 0F FRANCE.

TURBINE.

To @ZZ lw from t may concern Be it known that I, EUGNE SCHNEIDER, a citizen of the Republic of France, residing at Paris, France, have invented new and useful Improvements in Turbines, which invention is fully set forth in the following specication. i

Then the blades A of a. turbine wheel are not fixed individually to the turbine wheel C, but are merely held (as shown in Figs. I and 2 of the accompanying drawings) by their roots B of dovetail or other shape, in a groove of corresponding section formed all around the peripheryof the wheel C, it is i necessary to provide at a point C1 of said groove. for the engagement of the blades, a notch having a width equal to that of the roots of the blades. The blades B are inserted in succession through the said notch and the blades are pushed into the groove, the said roots being held as shown in Fig. 2 by the engagement of their' shoulders Z) under the ledges C1.

, By this means all the blades and their spacing piecescan be inserted except one of the latter which is generally made in two parts (Fig. 2) comprising namely a main velement D shaped like the root of a blade which is engaged in the groove through the notches C1 and which is then pushed so as to engagea part of the root under the ledges 01, and a locking piece E over which the upper partof thel root-shaped element D is turned down, so as 'to fill the gap left bt the notches.

The present invention has for its object to improve this fastening means, especially when monoblock blades are employed, that is to say, blades formed in one piece without separate spacing pieces in between the blades.

For this purpose a plurality o-f blades distributed partly on one side and partly on the other side of the axis of the entry notches C1 are shaped in such a manner that their roots bear against one another bym'eans of surfaces inclined relatively to the radii of the wheel. The filling blade then has a truncated root which is completed by the usual filling piece and locking piece which engage together as a whole into a space having a trapezoidal form in longitudinal section, the long base of the trapezoid being situated on the inside. In this manner the strains due to the action of centrifugal force Specification of Letters Patent.

VAplictaton led .Tuly 21, 1920. Serial No. 397,948.

upon the filling pieces, are taken not only by the said pieces but also by the two terminal blades against which they bear, and if dcsired, also bythe two blades that respectively follow and precede those first two blades, or any otherdesired greater number of similar blades. i

A practical constructional form of this invention is illustrated by way of example 1n the accompanying drawings.

Figure l is an axial section through the wheel between two ordinary blades;

Fig. 2 is a horizontal section of a developed section of the wheel.

Fig. 3 is a section on the line 3--3 of Fig. l. of a segment of a blade wheel comprising the special blades and the two fastening' pieces placed in position.

Fig. 4 is a section on the line i-i of Fig. 3.

Fig. 5 is a section on the line 5 5 of Fig. t. y

The blades A-B of the usual shape are placed in position by passing their roots through the entry notches C1 of the wheel C.

In the example shown, the four blades F-G, II-I, J-IQ L M are each formed with a peculiarly shaped root, and they are designed to withstand uniform strains due to the action o-f centrifugal force. For this purpose the roots G and M are made thinner at the base, so that the roots I and K will bear respectively with their complementary faces, z', c against the conical faces g and m of these roots.

On the other hand the lodgment for the filling pieces D and E has in longitudinal section the form of a. trapezoid having its long base situated on the inside. It is'toy be understood that the roots I and K have bearing surfaces l and ,701 formed with a corresponding inclination.

The filling piece D has a greater thickness at its base than at its top. Moreover it has two shoulders l adapted to engage under the root of the blade I in the gaps left free by the notch in the wheel.

The locking piece E is forcibly driven in between the part D and the bladeK.

After the locking piece E has been placed` in position, the top of the part D (indicated in dot and dash lines in Figs. 3 and 5) is turned over and burred down upon the locking piece E.

With this arrangement, the effects of cenand J-K which transmit a part of the strain to the adjacent blades F--G and L-M.

It will be perceived that notwithstanding the gaps in the ledges c1 of the groove of the wheel at the opening C1, the fastening parts D, E and a portion of the blades H-I, .I-K that do not bear against the ledges 01 j of the wheel, are stayed by the wedging ac tion of blades F-Gr and L-M inv such a manner that the strains will be distributed uniformly on the roots of the blades G, I, K, M.

It is an easy matter to arrange that a greater number of blades shall share in taking these strains by giving to their roots the special shape of the roots G and M.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is :Y

l. In a turbine, a wheel having a circumferential ledged groove provided with entry notches, a series of blades having shouldered roots at their inner ends to fit the the ledged groove successively introduced therein through the entry notches, the two terminal blades of the series having their roots spaced apart opposite the entry notches with the opposite faces of said roots inclined toward each other to form a lodg- Vment of trapezoidal section with its wider base on the inner side thereof, and comple# mentary filling and locking' pieces forced into the lodgment to press apart the roots of the terminal blades, eachterminal blade and the blade adjacent thereto having the mutual contacting faces of their roots in wedging engagement against outward displacement of the terminal blade so that the roots of the two terminal blades and of the blades adjacent thereto mutually opera-te to hold the filling and locking pieces against outward displacement through centrifugal force imparted by rotation of the wheel.

V2. In a turbine, a wheel having a circumferential ledged groove provided with entry notches, a series of blades having shouldered roots at their inner ends to fit the ledged groove successively introduced therein through the entry notches, the two -terminal blades of the series yhaving their roots spaced apart opposite the entry notches with the opposite faces of said roots inclined to-V -ward each other to form a lodgment of trifugal force imparted by rotation of the wheel..

3. In a turbine, a wheel having a circum- Y ferential ledged groove provided with entry notches, a series of blades having shouldered roots at their inner ends to fit the ledged groove successively introduced therein through the entry notches, the two terminal blades of the series having their roots spaced apart opposite the entry notches with the opposite faces of said roots inclined toward each other to `form a lodgment of trapezoidal section with its wider base onthe'inner side thereof, and comple'- mentary filling and locking pieces forced into the lodgment to press apart the roots of the terminal blades, vthe wedging action of the root-s of the terminal blades operating to hold the filling and locking pieces within the lodgment against outward displacement through centrifugal force imparted by rotation of the Wheel.

In testimony whereof 'I have signed this specification.

EUGENE Sonn-EIDER.

j Witnesses :V

ANDR Mosrroimn, CLEMENT S. EDWARDS.

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