| 摘要 |
<p>1,274,680. Noise suppression means; gas turbine ducted fan engines. GENERAL ELECTRIC CO. Oct.30, 1969 [Nov. 8, 1968], No.53136/69. Headings F1G and F1J. The invention relates to a noise suppressor for fluid-flow apparatus which comprises a fluidflow passage with a sound source therein, the suppressor including a body of sound suppression material, there being means for positioning the body of material within the passage. The invention is described with reference to a gas turbine ducted fan engine, the fan casing 16 defining a fan duct 14. A series of arcuate panels 34 of sound absorbing material are supported by means of pairs of links 46 each pair being connected to an actuator 36 so that the panels may be disposed either in a projected position 30 in which the panels abut to form a ring of sound absorbing material within the fan duct 14, or a retracted position in which each panel is received within a recess 42 within the fan casing, the panels then forming a continuation of the inner surface 18 of the fan casing. The recesses 42 are lined with sound absorbing material which is operative when the panels are in the operative positions. In Fig. 3 the panels are in arcuate form being pivotally mounted at one end 56 to the fan casing and being movable by an actuator 36 acting through link 56 between the retracted position 28 and the operative position 30. Adjacent panels are pivotally interconnected at 62. In Fig. 4 (not shown), the panels are again of arcuate form, a gear pinion (56) being provided at one end, the pinions being engaged by a toothed ring (66) which is movable by an actuator 36 whereby the panels may be moved between their retracted and operative positions. In Fig. 5 (not shown), the panels are mounted on arcuate racks which are engaged by pinions (68), the pinions being rotatable by a ring gear (66) whereby the panels may be moved between their retracted positions within slots (40) and their projected positions.</p> |
