| 摘要 |
<p>869,576. Axial-flow compressors. ROLLSROYCE Ltd. April 14, 1959 [May 15, 1958], No. 15642/58. Class 110 (1). A compressor adapted to form part of a gas turbine engine comprises a band encircling the compressor casing and means for giving the band at least a radial component of movement so as to move it between, and retain it in, a closed position in which the band covers and seals air bleed apertures in the casing and an open position in which it uncovers the apertures so as to allow a bleed of air out of the compressor. A circumferential row of holes 18 is provided in the casing of the high-pressure compressor of a gas turbine engine of the by-pass type, the holes being situated between the stator blades 16 of an intermediate stage. The bleeding of air from the intermediate stage into the by-pass passage 17 of the engine is controlled by a valve in the form of a two-part band 19, 20. The lower end of each band part 19 or 20 is pivotally connected to an arm 27 which is pivoted about a point 28, thermal expansion of the compressor casing being accommodated by a spring 28a connected between each arm 27 and an abutment 29. The adjacent ends of the band 19, 20 may instead be connected by, say, a coil spring. The band valve 19, 20 is of steel with a lining 26 of a sealing material woven from asbestos and steel. In the closed position, the band valve 19, 20 is tensioned into sealing contact with circumferential flanges 21, 22 by means of toggle links 31 ... 33 connected to the free ends of the parts 19 and 20 and operated by an hydraulic cylinder 40. Opening movement of the band valve 19, 20 is limited by a circumferential abutment 23 supported through a corrugated web 25 by a bracket 24. The band bleed valve may be applied to the single compressor of a simple gas turbine engine.</p> |
