GB691144A - Inlet control device for radial flow turbine wheels - Google Patents

Abstract

691,144. Turbines; centrifugal blowers. BœCHI, A. Feb. 6, 1951 [Feb. 16, 1950], No. 2941/51. Classes 110(i) and 110(iii) [Also in Group XXVII] The supply of working fluid to a radial flow turbine is controlled by two guide devices at least one of which is slidable in the direction of the turbine axis and which comprises a set of guide vanes movable, at least partially, into or out of the motive fluid ahead of the turbine. In the arrangement shown, Fig. 1, the control comprises an outer set of guide vanes 5 which are fixed to the casing 2 and an inner set of vanes 6 which are attached to an axially' slidable sleeve 4. The sleeve 4 is actuated by movements of a piston 16 through a link 20, crank 11 and cam 14. The movements of the piston 16 may be controlled by the pressure in the cylinder 17 which may be the pressure in the discharge of the blower 23 driven by the turbine 1, the pressure in the working fluid supply chest 25 or in a stage of the turbine. The vanes 6 may be formed as straight wall-surfaces forming a wedge-shaped cross-section with the thicker portion on the inlet side. The turbine shown has two supply ducts 30, 31, Fig. 5, and these ducts are maintained separate up to the stationary guide blades by means of partitions 34, 35. If desired there may be more movable guide vanes 6a than fixed guide vanes 5. Each outlet end of a guide vane 5 fits upon the entrance end of each second guide vane 6a so as to ensure continuous guiding of the gas stream. In the arrangement shown, the vanes 6a which do not abut against the exit edge of a guide vane 5 may project into the intermediate space between the vanes 5. The vanes 6a are thin and of the same thickness throughout. A modification, in which the turbine has four supply ducts and the axially slidable sleeve 4 is operated by a spring-loaded lever so that the movable guide vanes are either in the gas stream or completely withdrawn from it, is described. In this modification the vanes 5 do not abut against the edges of vanes 6 but project into the intermediate spaces between them. In a further modification, the slidable sleeve 4 is operated by hand. In this arrangement, alternate vanes 6 are made radially shorter and the vanes 5 are arranged to abut against the shorter vanes. In another modification, both sets of guide vanes are arranged to be axially slidable. These sets of guide vanes may be operated by independent levers or may be attached to a single lever so that when one set of guide vanes is withdrawn from the gas stream, the other set may be inserted in it. In this arrangement the two sets of guide vanes may be interdigitated. Means for guiding the vanes and preventing leakage of the motive fluid are described. Arrangements in which the slidable sleeve 4 is operated by a speed governor driven by the turbine and, when the turbine forms part of an exhaust gas turbine driven supercharger for an internal combustion engine, by the governor of the internal combustion engine are also described.