US2272831A - Turbine blade - Google Patents

Description

Feb. 10, 1942.

J. F. CHALUPA TURBINE BLADE Filed Sept. 8, 1939 INVENTOR -/O5PH FT CHALUPA.

Q4 V 7 M ATTdRNEY Patented Feb. 16, 1942 TURBINE BLADE Joseph F. Chalupa, Norwood, Pa., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application September 8, 1939, Serial No. 293,869

4 Claims.

This invention relates to turbine blading, more particularly to blading of the impulse or Curtis type and has for an object the provision of a plurality of such blades formed integral with a single root structure.

Another object of the invention is the provision of a turbine blade unit having a single root and a plurality of pairs of circumferentially-spaced blades integral therewith.

A further object of the invention is the provision of a turbine blade unit having a single root, a plurality of pairs of axially-spaced blades integral therewith.

Yet another object of the invention is the provision of a turbine blade unit having a plurality of blades grouped together both axially and circumferentially and. integral with a common root.

A further object of the invention is the provision of a turbine blade unit including a plurality of axially and circumferentially-spaced blades integral with a root which is bifurcated to provide branches extending axially beneath the blades.

These and other objects are effected by my invention as will be apparent from the following description and claims taken in connection 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 turbine embodying the invention;

Fig. 2 is a sectional View taken along the line IIII of Fig. 1, looking in the direction of the arrows;

Fig. 3 is a sectional view taken along the line III-'-III of Fig. 1, looking in the direction of the arrows; and,

Fig. 4 is a sectional view showing a modification of the root structure of Fig. 2.

Referring now to the drawing, there are shown a turbine rotor l and a stator H, the latter being provided with a passage l2 for flow of motive fluid to the nozzles it. These nozzles are comprised by a nozzle group bolted, or otherwise secured, to the stator ll. As shown, there are two rows of moving blades l4 and an intervening row of stationary reversing blades l5, each pair of moving blades it having a common root portion l6 mounted in a slot H in the rotor lil.

Preferably, each turbine blade unit i8 is comprised by a group of four moving blades l4 arranged as two circumferentially-aligned pairs, the blades of each pair being axially-aligned with the blades of the other pair. The four blades are formed integral with a common root I6 and, in

the embodiment shown in Fig. 2, the root portion is bifurcated to provide two branches [9.

Each branch l9 has its front and. rear walls serrated by alternating projections 2| and recesses 22 adapted to interengage, respectively, with the corresponding recesses 23 and projections 24 formed on the front and rear walls of the rotor grooves l1. Preferably, each root branch I9 is radially aligned with an axially aligned pair of blades M.

The outer ends of the blades M are provided with any desired type of shroud, such as shown at 26, and held in place by suitable means, such as deposits of weld material 21.

In Fig. 4 there is shown a modification of the previously described structure wherein the root Ilia has a single interlocking portion Illa provided with serrated front and rear walls formed by the projections Zla and recesses 22a adapted to cooperate with the recesses 23a and projections 24a, respectively, of the front and rear Walls of the rotor slot Ila.

As a result of having axially-aligned pairs of blades in the first and second moving rows formed integral with a common root, high resistances to axial and tangential loadings are obtained. Furthermore, this construction provides for ease in manufacture, not only of the blade units themselves, but also of the slots I! in the rotor disk receiving the root portions I9. Obviously, with this arrangement, a single slot may be machined axially of the rotor disk in one operation to provide for blades of the two rows.

While I have shown only two pairs of axiallyaligned blades in each blade unit, it is contemplated that a greater number of such pairs may be used when desirable.

While I have shown my invention 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 I desire, therefore, that only such limitations shall be placed thereupon as are specifically set forth in th appended claims.

What I claim is:

1. A turbine blade unit comprising a side-entry root, and a plurality of pairs of axially-spaced blades integral with the root, said pairs of blades being circumferentially spaced and aligned.

2. A turbine blade unit comprising a bifurcated root, the branches thereof extending axially, and a plurality of blades radially-aligned with each branch of the bifurcated root and integral therewith.

3. A turbine blade unit comprising a bifurcated side-entry root, the branches of said. bifurcated root extending axially and having serrated front and back faces adapted to engage and fit rotor-blade-slot serrated faces, and. a plurality of pairs of circumferentially-spaced blades integral with the bifurcated root and radially aligned with the branches thereof.

4. An impulse turbine moving-blade unit comprising a pair of successive moving-row groups of blades and a root integral therewith, said groups of blades including axially-aligned pairs and the root being bifurcated with the branches thereof extending axially and aligned radially with respect to the axially-aligned pairs of blades.

JOSEPH F. CHALUPA.

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