| 摘要 |
1,271,822. Gas turbines; axial-flow compressors and pumps. SULZER BROS Ltd. July 24, 1969 [July 26, 1968], No. 37290/69. Headings F1C, FIG and F1T. In a turbine, compressor or like machine having angularly adjustable stator blades 5, each blade is journalled in a respective housing 4 secured to the outer side of the machine casing 1 so that the bearing surfaces are remote from the working fluid-flowing through the machine. Each housing 4 has spaced tubular walls 9, 20 defining cooling air chambers 14, 15 surrounding plastics dry running bearings 10, 11 in which the blade journal 8 is mounted. The chambers 15 of circumferentially adjacent housings 4 are inter-connected by resilient bellows 16 so that cooling air supplied through two diametrically opposite pipes 19 can flow to all the chambers 15. The cooling air from the latter passes through ports 18 into the chambers 14, each of which contains a U-shaped sheet metal baffle 36 to direct the air along the walls of the chamber. The neck 6 of each blade has cooling fins 23 around which is tightly fitted a sleeve 30. Each of the fins 23 has a segment 35 milled away, the milled regions alternating from fin to fin by 180 degrees so that the cooling air leaving region 46 at the open lower end of chamber 14 follows a tortuous path in flowing over the fins 23 before exhausting through holes 39 in sleeve 30 and ducts (not shown), into the working fluid. Sleeve 30 is a loose fit within a plate 22 and is urged by spring 31 against a recess 32 in a ring 33. Plate 22 is clamped in position by housing 4, the latter being secured to casing 1 by screws passing through flange 21. A thrust bearing comprising a collar 24, two discs 25 and a retaining ring 26 is provided at the top of each journal 8, leakage past the ring 26 being prevented by an O-ring seal 55. A collar 27 carries the blade adjusting lever 28. The journal 8 is formed from a material having good dry running properties and is shrunk or force fitted over the blade stem 7. In a modification, Fig. 5 (not shown), the journal 8 is cast with the blade, the aero-foil portion 5 being of heatresistant steel and the journal 8 of dry running material. The junction between the two materials is in the region of the fins 23. In this modification additional cooling of bearing 10 is effected by diverting some air from region 46 to a chamber (44) in journal 8 in the region of bearing 10, the air exhausting to atmosphere through bores (47), 40 in the journal. |
