US1059618A - Means for securing blades in turbines. - Google Patents

Description

P. KNIGHT. v EEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE S.

V IIIIIIIIIIIIIIIII no. 222222 0. I 1 059 618 Patented Apr. 22, 1913.

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PERCY KNIGHT, 0F ANGLESEA, ENGLAND.

MEANS FOR SECURING BLADES IN TURBINES.

Specification of Letters Patent.

Application filed December 22, 1910.

Patented Apr. 22, 1913.

Serial No. 598,805.

To all whom, it may concern Be it known that I, PERoY KNIGHT, of 4.- iVesley Terrace, I-Iolyhead, Anglesea, England, Great Britain, engineer, have invented new and useful Improvements in Means for Securing Blades in Turbines; and I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawings, forming a part hereof.

This invention relates to improvements in the method of securing the blades in the rotor or casing of a turbine whereby a con- 'siderable economy in the fixing of the blades may be achieved and the blades be more effectually secured in the grooves, of the rotor or casing against any liability of their becoming displaced by reason of centrifugal action or expansion or creep due to variations of temperature.

With this end in view my invention consists in providing the roots of the blades with means adapted to be engaged by a memher located in the grooves in the rotor or stator casing in such a manner as to prevent them being accidentally displaced when once assembled in position.

In order that my said invention maybe readily understood and carried into practice by those skilled in the art to which it appertains I will now proceed to describe the same fully for which purpose reference is to be had to the accompanying drawings in which Figure l is a view of a blade under this invention. Fig. 2 is a view of a portion of a row of blades showing the position they occupy when first arranged in the groove of the rotor or stator casing and Fig. 3 is a similar view but showing the blades permanently secured in position. Fig. 4 illustrates a slightly modified form of my invention.

Accordin to this invention the blades a are made 0 continuous section such as from cold drawn or extruded bars as now gen- .erally adopted and are notched as at b on their edges 0 near the roots d of the blades. These notches are formed at such a distance from the lower extremity of the blade that they lie below the outer surface e of the rotor or stator casing when the blades are inserted in the grooves f. The blades a before being inserted in the grooves are assembled in sets, the notches b in the blade roots (1 of each set being engaged by an angle portion or flange 9 which may be termed the axial fiangeof a short curved section of angle bar it the other or radial flange of the bar lying against the edges of the blades below the notches. The axial width of the slots or grooves in the casing or rotor is just suificient to permit of the insertion of a section of the blades with its curved angle bar.

Before being inserted in the grooves f each section consisting of a series of blades a with their curved angle bar it and pitch or distance pieces disposed between the roots of the blades may all be brazed together at the roots so as to form an integral blade section but if required the set of blades in position on the angle bar may be inserted in the grooves the pitch pieces being afterward set between the blade roots. In each form whether brazed to the blades, or left free. the position of the angle bars h, when the blade roots bottom in the grooves, is such that a slight clearance z is left between the inner circumferential edges of the radial flanges and the bottom of the groove and the outermost edge of the groove is slightly above the corner of the curved angle bars. The metal of the casing or rotor at this edge is then Worked over on to the corner of the angle bars as shown at y Fig. 3 forcing the angle bar down in the groove and consequently also each of the blades. The angle portion 9 of the curved bars may be less than a right angle, and with respect to the body it, the notches may be formed to correspond and in this way any tendency of the blades to work out radially from the grooves, acts to open the angle bar thereby wedging the blades firmly against the opposite wall of the groove. If desired notches and retaining angle bar sections may be provided at both sides of the blades as for instance as shown in Fig. 4.

The retaining angle bars are made of suit able metal to provide against any possibility of their working loose in the grooves after being fixed therein owing to the expansion or contraction of the turbine parts when under steam. In the case of the shorter blades the usual shroud ring at the outer peripheries of the blades may be dispensed with by reason of the very efiicient attachment at the roots of the blades.

Such a system may be supplied to the fixbars and pitch pieces may be cut off as required from cold drawn or extruded bar sections the system lends itself to extreme economy in fixing while thesecurity of the fastening is absolutely reliable.

What I do claim as my invention and desire to receive by Letters Patent is 1. In a turbine, the combination with a grooved turbine member, and sections composed of assembled blades and blocks with a retaining member all brazed together to, form an assemblage, one wall of the groove of said turbine member being worked over in overlapping relation with the retaining member to anchor the assemblage to said turbine member.

2. In a turbine, the combination with a grooved turbine member, of a plurality of blades disposed in said groove and having downwardly directed notches in the sides thereof, and a retaining member anchored in said groove and having a downwardly projecting flange engaging said notches.

In a turbine, the combination with a grooved turbine member, of a plurality of blades disposed in said groove, and a member for retaining the blades in said groove, one Wall of said groove being worked over said retaining member in overlapping relation therewith for a continuous distance along the periphery of said turbine member to anchor said retaining member in said groove.

4. In a turbine, the combination with a turbine member provided with a groove having parallel side walls and a bottom Wall, blades and spacing blocks having parallel side portions engaging the bottom and one of the side walls of said groove and being free from engagement with the remaining side wall of the groove, said blocks and blades having notches on their free side por tions, and an angle strip provided with an angle portion engaging said notches and a body portion having fiat parallel walls engaging the free wall of said groove and the free sides of said block and blades, the

height of the body port-ion being less than the depth of the groove and said notches being located to maintain the bottom of said body free from the bottom of said groove and the top of said body below the outer face of said member, the margins of said turbine member being worked over the outer face of said strip, substantially as described.

5. In a turbine, the combination with a turbine member provided with a groove hav ing parallel side walls and a bot-tom wall, blades and spacing blocks having parallel side'portions engaging the bottom and one of the side walls of said groove and being free from engagement with the remaining side wall of said groove, said blocks and blades having notches on their free side portions, and an angle strip provided with an angle portion engaging the notches in said blades and blocks and having a body portion reduced in height with respect to the depth of said groove, the notches of said blades and grooves being located to maintain the bottom of said body portion free from the bottom of said groove, substantially as described.

6. In a turbine, the combination with a turbine member having av groove therein, blades and blocks disposed in said groove and having notches on one side thereof, and an anchoring strip having an angle portion engaging said notches and a body portion disposed between one wall of the groove and the blades and blocks, the lower extremity of the strip being free from engagement with the bottom of the groove and the upper extremity of the strip being below the face of the turbine member, said turbine member being worked over said strip to anchor. the same and said blades and blocks, substantially as described.

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

' PERCY KNIGHT. Witnesses:

G. B. STEPHENSON, J NO. H. I-IEBLETHWAIT Copies of this patent may be obtained for five cents each, by addressing the Ger'nmissi'oner of ratents, Washington. I). G.

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