GB815032A - Improvements in or relating to multi-stage axial-flow turbines and compressors - Google Patents

Abstract

815,032. Turbines; axial-flow compressors. MASCHINENFABRIK AUGSBURG-NURNBERG A.G. March 27, 1957 [March 27, 1956], No. 10052/57. Classes 110 (1) and 110 (3). In an axial flow turbine or compressor comprising an undivided guide vane supporting ring associated with each rotor blade stage, each of the rings engages radial guide means in at least two intersecting planes through the turbine axis and is connected to an axially adjoining ring through interposed guide vane means and at least one of the rings is fixed against axial movement. The multi-stage axial flow turbine, Fig. 1, comprises four stages of rotor blades 2, 2<SP>1</SP>, 2<SP>11</SP>, 2<SP>111</SP>, with which are associated four stages of guide vanes 3, 31, 3<SP>11</SP> 3<SP>111</SP>, held respectively by annular one-piece supporting rings 4, 4<SP>1</SP>, 4<SP>11</SP>, 4<SP>111</SP> surrounding the rotor blades. The supporting rings axe connected together by the guide blade roots which are provided with radial collars 5, 6, Fig. 3, engaging peripheral slots 4a, 4<SP>1</SP>a in the rings. Clearances a allow for differential expansion. The inlet guide vanes 3 form a closed ring 3a which is guided during expansion on three guide pins 7 which pass through a supporting ring 4 and are secured in extensions 8 of rigid axial guide rails 9. The ring 3a is thereby fixed against axial movement. The supporting rings are each provided with three slideways 10 which engage three guide rails 9. Two of these guide rails lie in the horizontal plane through the axis of the rotor and the third in the vertical plane through the same axis. The rails may however be arranged in planes through the axis at 120 degrees to one another. The rails are secured by angle pieces 11, 12 to robust annular supports 13, 14 mounted on a rigid frame. Locating pins 11a secure the rails in the angle pieces 11 and guide keys 12a fixed to the rails engage slots in the pieces 12. An insulated housing 17 subdivided into four segments, as well as inlet and outlet housings 18, 19 are also secured to the supports 13, 14. The space 20 may be filled with a stagnant or cooling gas. The rails 9 and supports 13, 14 may also be provided with cooling passages. The blades may be held in position by a clamp, Fig. 4a (not shown), attached to the supporting rings or by a steel band, Fig. 4b (not shown), which encircles the blade roots. The ends of the steel band may be joined together by means which allow of expansion, e.g. springs. An arrangement in which the walls and edges of the supporting rings and rotor blades are inclined to the axis is also described. In this arrangement the stator is located against axial movement at one end of the turbine and the rotor at the other end. This allows the clearances between the rotor blade tips and the adjacent supporting rings to increase on cooling of the turbine. The invention may be applied to axial flow compressors.