| 摘要 |
635,270. Centrifugal pumps and compressors; elastic-fluid turbines. SOC. RATEAU. Jan. 3, 1947, Nos. 303 and 304. Convention dates, Jan. 4, 1946 and Nov. 18, 1946. [Classes 110(i) and 110 (iii)] In a centrifugal pump or compressor at least a part of the boundary layers having a reduced velocity is removed through passages provided on the diffuser walls, the passages being without any direct return connection with the diffuser. The boundary layer is withdrawn from the diffuser d through annular slots 1, 2, Fig. 5, into chambers h, i, and is either rejected to atmosphere or conducted by way of pipes 12, 13 and an annular chamber 15 to an annular nozzle 16 at the inlet. Directing vanes 17 may be provided. In a modification having a double-sided impeller (Fig. 6, not shown) the re-entry takes place at a point intermediate between inlet and outlet. In constructions in which the diffuser is bladed, Fig. 3, the boundary layer may be withdrawn through slots 11, 2<1> into hollow diffuser blades k<2> which communicate by way of bores s<1> with collecting chambers. Fig. 7 shows a construction in which the returned fluid gives up some of its energy to turbine blades 22 carried by the impeller 11. The turbine blades may be carried by a separate wheel keyed to an extension of the impeller shaft. By the use of an auxiliary compressor 23, Fig. 8, the withdrawn fluid may be returned to the delivery pipe d<1>. The auxiliary compressor may be driven by an auxiliary motor, which may be of a variable speed type, or else by means connected to the control mechanism of the main compressor so as to ensure that its speed bears a pre determined relation to that of the main compressor. Removed boundary layer fluid may be used for feeding fluid-tight shaft packings and for lubrication of bearings. In a gas turbine plant, Fig. 9, air withdrawn from the compressor 11 is fed through pipes 26 to cool the turbine rotor 28. The bearings, shaft and blades of the turbine may be similarly cooled. |
