US2985427A

US2985427A - Adjustable blading for fluid flow machines

Info

Publication number: US2985427A
Application number: US548992A
Authority: US
Inventors: Houghton Warren William
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1955-11-25
Filing date: 1955-11-25
Publication date: 1961-05-23
Anticipated expiration: 1978-05-23

Description

y 1961 w. w. HOUGHTON 2,985,427

ADJUSTABLE BLADING FOR FLUID FLOW MACHINES Filed NOV. 25, 1955 INVENTOR.

BY @04 l United States Warren William l lougli toli; Manchester, Mass., assignor to Genera] Electric Company, a corporation of New York '3 Filed Nov. 25, 1955, "set. No. 548392 scams. c1. 2ss-ss machine is desired which will operate over a large range of operating refinement; it is highly nes'ifame that the effective flowiarea of thenozzle diaphragm in the case of a turbine, or difluser assembly in the case of a compressor, ,be adjustable in order "to minimize losses. conventional manner for providing the desired adjustable effective flow area feature has been to provide a nozzle ring or diffuser assembly in which the nozzle or difiuser vanes are pivotally mounted for rotation through a limited arc to vary continuously the effective area between them. In a design of this type it is important that the pivot point for each blade be located near the center of the blade so that the aerodynamic torque exerted on each blade by the fluid flowing across its surface to minimize the force required to control the assembly. However, when a blade is thus centrally pivoted without further provision, it is subject to the criticism that as it is rotated, the clearance between the edge of the vane and the adjacent rotor of the machine varies considerably. From an aerodynamic standpoint, both in compressor and turbine design, it is important that this clearance be kept as small as possible at all times. Accordingly, it is an object of the present invention to provide an adjustable blade which provides a reduced variation in clearance between an edge of the blade and an adjacent rotor.

It is another object of the invention to provide an improved adjustable blade assembly in which the individual blades are pivoted centrally to minimize aerodynamic torque thereon with means to maintain a small and constant clearance between an edge of the blade and an adacent rotor.

Briefly, these and other objects of the invention are accomplished by providing means to change the radial position of the axis of rotation of an adjustable blade with respect to an adjacent rotor as the blade is rotated.

The invention will be better understood from the following description taken in connection with the accompanying drawing in which:

Fig. l is an elevation view showing an adjustable blade apparatus constructed in accordance with the invention;

Fig. 2 is an enlarged partial sectional view taken along the lines 2--2 of Fig. 1;

Fig. 3 is a partial elevation view of part of the structure shown in Fig. 1 showing the apparatus showing the blades in the closed position;

Fig. 4 is an enlarged sectional view taken along the lines 44 of Fig. 3;

Fig. 5 is an enlarged partial elevation view of the apparatus that is shown in Fig. 1 from the reverse side; and

Fig. 6 is a partial elevation view of the apparatus shown in Fig. 3 also from the reverse side.

i Referring'to Fig. 1, a radial flow type of rotor is indicated generallyfatltl. Mounted adjacent the rotor is 'a plurality of 'circuinferentially and uniformly spaced vanes 11. Each of the vanes is provided with 'a- Control shanm of circular seetion which is mounted for reta- "tion within an eccentric bearing 13. The bearing 13 is called eccentric" in that it isgcylindrical in cross sec tion and the shaft 12 is journalledeccentrically therein; Each eccentric bearing 13 is in tuin journalled in an opening 14 in a bearing support member 14 forrotation therebetweenl Fastened to the end of each control shaft 12 to control the rotation threof is a clevis member 15 which engages a pin 19 on a positioning ring 18. Clevis member 15 and pin 19 comprise linkage means fordrivingly connecting positioning ring 18 with shaft 12 and vane 11 for rotation thereof. In order to rotate the eccentric bearing 13 within the support 14, a pinion 17 is fastened to the'sha'ft which meshes with teeth on theperiphery of the positioning ring 18.- The pin and 'clevis'can best be seen in Figs. 5 and 6. The pin'and clevis arrangement 'th'en operates to rotate the control shaft 12 within the eccentric bearing 13 whereas the'ring and pinion arrangement operates to "rotate the eccentric bearing within its opening '14 in the bearing support 14 upon rotation of the positioning ring 18. By proper sizing of the eccentric bearing 13 and the parts in the ring and pinion arrangementand also'the clevis and pin arrangement described above, a resulting arrangement can be. obtained in'whi'ch the position or the vanes 11 is adjusted by rotating the positioning ring 18 to vary the flow area therebetween, but in varying from the closed position as indicated by Figs. 3, 4, and 6 to the maximum area position as shown in Figs. 1, 2, and 5, the clearance between the periphery 26 of the rotor '10 and the adjacent edge 27 of the blades 11 is maintained at a constant or nearly constant magnitude.

Thus, an improved adjustable vane assembly is provided in which the flow area between the vanes is variable, the minimum of aerodynamic torque exerted thereon and at the same time maintaining a desired clearance between the vanes and an adjacent rotor.

While a particular embodiment of the invention ha been illustrated and described, it will be obvious to those skilled in the art that various changes and modifications may be made without departing from the invention and it is intended to cover in the appended claims all such changes and modifications that come within the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In a fluid flow machine the combination of a plurality of vanes circumferentially and equally spaced about a fluid flow rotor, each of said vanes being mounted for rotation about its own axis of rotation control means interconnecting said vanes to provide simultaneous rotation of each about its axis of rotation; and rotatable bearing cumferentially spaced about an axis of rotation of said rotor, a plurality of vanes, a plurality of shafts each aflixed to one of said vanes and eccentrically journalled in one of said bearing members, a clevis member aflixed to each said shaft, a positioning ring circumferentially drivingly engaging said bearing members, and a pin drive cumferentially to said positioning ring,usuch.that.rotation of said positioning ring produces rotation of said vanes and said bearing members to adjust the positions of said shafts. and said .vanes in a predetermined synchronized relationship such .that? an edge of each of said vanes describes an arcuate' circular. path, concentriclwith said axislof rotationoffsaid rotor. ,j .l 3. In a fluid flow'machine including a rotor rotatable about a fixed axis,.the combination of a plurality .of vanes circumferentially spaced about said rotor, support means, a plurality of bearing means each rotatably supporting one of said vanes, each of said bearing means mounted in said sup-port means for rotation about an axis ofiset from the axis of rotation of said one of said vanes supported therein, and control means drivingly connected with each of said'bearing means and each of said vanes for simultaneous rotation thereof in a predetermined synchronized relationship such that a leading edge of each of said vanes describes a circularpath concentric with said fixed axis.

4. In a fluid flow machine having a rotor, the combination of a plurality of vanes circumferentially spaced aboutan axis of rotation of said rotor, a plurality of shafts each connected to one of said vanes for rotation thereof, support means, a plurality of bearing means each rotatably supporting one of said shafts and a corresponding one of said vanes connected thereto, each of said said axes of rotation thereof about said eccntric'axe'sin .a predetermined synchronized .relationship, .whereby. an

edge of each of said vanes describes an arcuate circular path concentric with said axis of rotation of said rotor.

5. In a fluid flow machine including a rotor rotatable about a fixed axis, the combination of a plurality of vanes circumferentially spaced" about'said rotor, each said vane having, a. leadingedge radially spaced. a predetermined distance from'said fixedaxis, support means, a plurality of bearing means'each rotatably supporting one of said vanes, each of said bearing means mounted in [said support means for rotation aboutan axis offset from the-axis of rotation of said one of said vanes supported therein, a plurality of linkage means each drivingly connected with one of said vanes, and rotatable'positioning means drivingly connected with each .of said linkage means and each of said bearing means for simultaneous rotation of each of said vanes and each of said bearing means, to rotate said axis of rotation of each' of said vanes about said axis of rotation of eachof said bearing'means inia predetermined synchronized relationship such'that' the lead ing edge of each of said vanes remainsradially spaced from said .fixed axis substantially said: predetermined distance.

bearing means mounted in s'aidsupport 'means for rota- I tion about an eccentric axis offset from the axis of rotation of the corresponding one'of said-shafts and a corresponding one of said vanes supported therein, and control means drivingly connected with said shafts: and said bearing means to rotate each of said vanes and to rotate References Cited in the file of this patent UNITED STATES PATENTS