US1430398A - Blading for turbines - Google Patents

Description

C. A. PARSONS, A. Q. CARNEGIE, M. BONE, AND S. S. COOK.

BLADING run T URBINES. APPLICATION FILED JULY 7.1919.

1,430,398, Patented Sept. 26, 1922.

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.APPLI'CATION FILED JULYJ, I919.

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P IE1 CHARLES ALGERNON PARSONS, ALFRED QUINTIN CARNEGIE, AND MATTHEW BONE,

OF NEWCASTLEUPOl\T-TYNE, AND STANLEY SMITH COOK, 0F WALLSEND-UPON- TYNE, ENGLAND; SAID CARNEGIE, SAID BONE, AND SAID COOK ASSIGNORS TO SAID PAR-SONS.

BL-ADING ron Term nus.-

Application filed July 7, 1919. Serial No. 309,207.

To all whom it may concern:

Be it known that we, CHARLES ALoERNoN PARSONS, K. C. 13., ALFRED QUINTIN CAR- NEGIE, and MATTHEW Bonn, all subjects of the King of Great Britain and Ireland, and all residing at I'Ieaton Works, Newcastleupon-Tyne, in the county of Northumberland, England, and STANLEY SMrrH Coon, a subject of the King of Great Britain and Ireland, and residing at Turbinia Works, IVallsend upon Tyne, in the county of Northumberland, England, have invented certain new and useful Improvements in Bladings for Turbines, of which the following is a specification.

The present invention relates to the manufacture of turbine blading.

In blading systems in which the portion of the blade contained within the circumferential groove in which the blading is secured is of the same section as the part which projects, the blades may be formed by cutting off lengths from a bar rolled to the requlsite section, suitably formed packing pieces being interposed with the blades in the circumferential groove.

The present invention relates to a method in which the blades are formed integral with a base different in section from that of the blade, this base being in some cases extended to constitute the neighbouring packing piece, and in some cases so formed as to space the blades the required distance apart and in cor rect position.

In such a construction the cutting 016 01? the blades from a rolled or drawn bar is not employed. The formation of the blade and its base by milling or other machining operations is both laborious and expensive.

It is the principal object of the present invention to provide a turbine blade having an integral base such that it may be produced economically by the applicationof methods which occupy less time and are generally more expeditious than those at present employed.

IVith this general object in view, the invention consists in anextruded turbine blade having a base integral therewith and more specifically includes various features of construction herein described in connection with the drawing and more particularly pointed out in the claims.

In producing turbine blades according to the invention, the blade proper may be extruded from a small billet through a die havmg an aperture in which the base or a 'base blank is formed integral with the blade.

Preferably, the extrusion of the blade and the formation of an integral base or base blank is accomplished in the same operation by means of a quick acting press or drop hammer.

In the accompanying drawing, which ill-us trates suitable apparatus for producing turbine blades in accordance with the invention: 1

Figure 1 shows a sectional elevation of the die with the billet of metal placed therein. I

Figure 2 is a plan of the die.

Figures 3 and 4: are sectional elevations of the die showing the blade after formation but before removal from the die.

Figure 5 is a view of the convex face of the blade with its base integral therewith. b Figure. 6 is a plan View of the blade and ase.

Figure 7 is a longitudinal sectional view of the article. I a I In the apparatus here shown as an example, a die 1, preferably divided into two or more portions, is placed within a suitable supportQ so as'to register with one or more keys An aperture 4 in the die is of'a cross-section either the same as that of the base of the blade or such' that the base can be readily machined from the mass of metal shaped in it. At the bottom of the aperture 4 an orifice 5 is cut, this orifice being ofthe,

shape ofthe blade proper. The mouth of the aperture 4: is preferably tapered, as indicated, in order'to facilitate introduction of the billet of metal 6 which has the same general crosssection as that of the aperture I but is somewhat smaller.

While, however, we have shown the aperture 4 as parallel-sided over the greater part of its length, we do not confine the construction of the die to this form as in some cases it may be found advantageous to form the aperture with converging sides along the whole of its length. In cross-section also the aperture may be of any form found most suitable for the particular shape of base of the blade desired.

A drop hammerram or similar tool 7 is arranged above the die so that in its descent it will press the billet or" metal 6 to the shape of the aperture l at the same time extruding part of the metal through the orifice 5 to form the blade 8 as indicated in Figures 3 and 4.

A slight clearance is of course necessary in practice between the tool 7 and the aperture 4, but this has been omitted in the drawings for the sake of clearness.

Suitable stops 9 are fitted on the support 2 or in any other appropriate position to arrest the motion of the drop hammer 7 when the required amount of metal has been extruded.

While we have *described a die in which pressure is applied opposite the extrusion orifice, we do not confine the invention to this construction.

It will be seen that the apparatus de scribed produces an extruded turbine blade having an integral base and which has the various characteristics more particularly pointed out in the claims.

The size of billet employed varies with the length of blade and size of base required; in any case, however, the billet is comparatively small and it is essential that the process be carried out quickly to avoid cooling the billet and extruded metal below the temperature at which it can be extruded. Therefore we prefer to employ a quick-acting press giving the necessary pressure but any other suitable means, such as a drop hammer 0r quick-acting hydraulic press may be used.

When employing a drop hammer the height of fall and weight of the hammer would be so regulated as to give the required pressure and velocity of extrusion.

e have found that in making blades according to this invention, in which a fine edge is required, it is advantageous to design the base portion so that its sides and particularly its corners do not coincide with the fine edges of the blade, to avoid excessive cooling of the metal in the neighbourhood of these edges by the chilling action of the die and to give such a distribution of the metal in the neighbourhood of the edges as will promote its equable fiow into the blade. l Ve find, however, that if the base is made substantially wider in every direction than the blade, and if the whole operation is carried out with sufiicient quickness, the metal of the billet remains sulficiently hot throughout to flow properly in all parts and permit of a fine edge being produced.

The billet is cooled by the die more rapidly on its outside than at its interior, so that the hotter interior is extruded to form the blade with its thin edge.

It has been found by experiment that there is a critical velocity of extrusion above which there is risk of seizure in the die.

form a bulb or bead or other suitable local thickening on the fine ec ge of the blade. We generally prefer to form this bulb or thickening on the convex side of the blade so that it may be easily removed by subsequent grinding, machining or drawing, but we may in some cases form it on the concave side of the blade, or it may take the form of a bulb projecting both on the concave and convex sides.

lit will be obvious that by replacing inthe above manner several milling or other operations hitherto necessary, and all of a comparatively lengthy nature, by one rapid operation, much time and labour are saved and expenditure thereby reduced.

A turbine blade in accordance with the present invention is of special utility inasmuch as, in contradistinction to previous blades integral with their bases, the graining of the metal is differentially disposed in blade and base so as to be especially adapted to withstand the working stresses to which these parts are respectively subjected.

The process disclosed herein has been made the subject matter of a divisional application filed December 7, 1921, Serial Number 520,623.

Having now described our invention, what we claim as new and desire to secure by Letters Patent is 1. An extruded turbine blade having a base integral therewith. i

2. An extruded turbine blade having an enlarged base integral therewith.

3. An extruded turbine blade having an: enlarged solid base integral therewith.

4-. An extruded turbine blade having integral therewith an enlarged base of'uniiform cross-section.

5 An extruded turbine blade having integral therewith a base projecting on all sides. from the blade.

6. An extruded turbine blade having a certain cross-sectional area and a base integral therewith of a greater cross-sectional area.

7. An extruded turbine blade having a u tegral therewith of a different cross-sectional outline entirely enclosingsaid firstrnentioned cross-sectional outline.

9. An extruded turbine blade having a 5 forged base integral therewith.

10. An extruded turbine blade having a die-forged base integral therewith.

11. A turbine element comprising a blade having a thin lateral edge and'an enlarged 10 base integral therewith, said blade being eX- truded and said base being forged.

12. A turbine element comprising a blade having a thin lateral edge and an enlarged base integral therewith, said blade being extruded and said base being forged and extending beyond the blade at all points including the thin edge portion.

In testimony whereof We have signed our names to this specification.

CHARLES ALGERNON masons. ALFRED enema CARNEGIE. MATTHEW near. STANLEY swan: c0011.

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