Improvements in or relating to pump, compressor, turbine or the like assemblies

摘要

956,732. Centrifugal pumps; turbine casings. DE LAVAL STEAM TURBINE CO. April 17, 1962 [Aug. 11, 1961], No. 14920/62. Headings F1C and F1T. An assembly comprises a series of axially stacked sections constituting the stages of a pump, compressor, turbine or the like and a number of flat double-ended tie bars which extend parallel to the longitudinal axis of the assembly with their flat faces substantially tangential to an arc about the axis, the heads of the tie bars, being engaged respectively behind oppositely facing faces of the respective first and last section of the series for maintaining the assembled sections in axially-compressed stacked relationship. An outer casing 4, Fig. 1, of a pump 2 contains an inner assembly which comprises nested concentric sections 14 positioned between end sections 16, 18, and diffusers 22 bolted to the sections. The sections 14, 16, 18 are clamped together by flat oblong steel tie bars 24 provided with heads 26 having shoulders 28. As shown in Fig. 2 the shoulders 28 abut the face 32 of a flange 29 on the end section 18 and a face 321 of a flange on the end section 16. The flanges are provided with channels 30, 301 which are wider than the tie bars 24. The length L 1 of the tie bars 24 is made less than the distance L 2 between the faces 32, 321, so that the tie bars have to be thermally expanded, by heating to 300‹F. or more, by an amount E before fitting. Thus, on contraction, the tie bars are put in tension and thereby hold the sections 14, 16, 18 -together. The length L 1 is determined by the clamping force required taking account of the length L c , which is the length to which the sections 14, 16, 18 are compressed by the differential pressure between the inlet 6 and the outlet 8 of the pump.