Patent GB-728815-A (GB)
Title: Improvements in or relating to adjustable blade arrangements for fluid machines
Inventor: BINNS PHILIP GORDON
IPC: F01D17/16
Filed: 1951-11-27
Abstract: 728,815. Axial flow and centrifugal compressors; turbines. ROLLS-ROYCE, Ltd. Feb. 24, 1953 [Nov. 27, 1951], No. 27845/51. Classes 110 (1) and 110 (3). In an axial flow or centrifugal compressor or turbine having an adjustable ring of stator blades which are coupled to move together by coupling means co-operating with one end of each blade which coupling means is actuated through two or more neighbouring blades by actuating means connected to the opposite ends of these blades, the actuating blades are interconnected at the end opposite the coupling means by a link connected by means of pivot pins to the ends of radius arms extending from the blades and the axes of the pivot pins are arranged to intersect at the point of intersection of the axes about which the blades are adjustable. By neighbouring is meant that the angle between the axes of adjustment of two torque transmitting blades is an acute angle. The inlet guide blades 10a, 10b, Fig. 1, of an axial flow compressor are coupled so to move together by radius arms 11 and a notched ring 12 carrying in the notches cylindrical barrels 13 with which the radius arms engage through pegs 14. The coupling means 11-14 is actuated by a hydraulic ram 15 connected by linkwork 28 35, 32 to the outer ends of two adjacent vanes, 10a, 10b. The axes of the pivot pins between the links 28, 35 and 35, 32 are arranged so that they intersect at the point of intersection of the axes 10d of adjustment of the vanes 10a, 10b. In the construction shown in Fig. 4, the actuating vanes 10a, 10b are provided with stub shafts 17 which are of large diameter as compared with the stub shafts of the remaining vanes. The stub shafts 17 are engaged in bearing bushes 19 mounted in an inner wall 16a of the compressor casing and are internally splined to engage the end 20a of a quill shaft 20. The other end of the shaft 20 engages a short hollow shaft'21 supported by ball bearings 22, 23 enclosed in a housing '24 mounted in the outer wall 16b. A bell crank lever 28 is engaged by splines 27 on one of the hollow shafts 21. The other hollow shaft 21 supports an arm 32.. One arm 28a of the bell crank is connected to the ram 15b of the actuating mechanism and the other arm is. connected through the link 35 with the arm 32. The lugs 29 and 33 are arranged at an angle to the centre lines of the arms 28b and 32 so that the axes 30a, 34a of the pivot pins intersect at the point of intersection of the pivotal axes 10d. of the vanes 10a, 10b. Preferably the included angle between the axis of the pivot pins is equal to the angle between the axes of an adjustment. of the blades and the angle between the axis of adjustment of one blade and the axis of the associated pivot pin is equal to the angle between the axis of adjustment of the other blade and the axis of its associated pivot pin. The radius arms may extend at right angles to their respective blade axes in which case the length ,of the link 35 must be greater by a predetermined amount than the spacing of the blades axes at the point of connection of the radius arms. Alternatively the link may be equal in length to the spacing of the blade axes, in which case when each radius arm lies in a plane through the axis of the ring of blades, the points of connection-of the radius arms, blade spindles and of the radius arms to the link lie at the corners of the base of a right rectangular pyramid of which the blades axes and the axes of the pivot pins form the inclined edges.