GB1072483A - Improvements in or relating to turbines - Google Patents

Abstract

1,072,483. Steam turbines. ASSOCIATED ELECTRICAL INDUSTRIES Ltd. March 16, 1964 [March 28, 1963], No. 12365/63. Heading F1T. At least some of the interstage guide blades of a steam turbine have blade surfaces formed with slots which intercept erosive particles travelling along the blade surfaces. The erosive particles are passed to a region maintained at a lower pressure than that existing in the condenser. The invention is described with reference to an axially opposed double-flow steam turbine, Fig. I (not shown). As shown in Fig. 2, each blade 13 of a ring of hollow guide blades is mounted in and communicates with radially inner and outer manifolds 17 and 19 respectively. Either the concave blade surface 13A or the convex blade surface 13B or both, Fig. 4, are provided with slots 21 and/or 31 respectively, formed near the trailing edge 13T of the blade and extending inwardly from the radially outer end thereof for approximately half (or at least one third) the length of the blade. Steam passing through the slots entrains any water flowing along the slotted parts of the blade surface and this water passes through a drain hole 23 in the lowermost part of manifold 19 to a region maintained at a lower pressure than that existing in the condenser. In a modification, Fig. 5 (not shown), a hollow guide blade is provided with two radial rows of slots. The inner and outer manifolds and the interior of the blade are divided by a partition into two compartments, each of which communicates with one row of slots. The compartments are connected to two different points (one of which can be the condenser) for the disposal of collected water providing different degrees of suction appropriate to the respective positions of the rows of slots. In another modification, Figs. 6A, 6B (not shown), a ring shaped, external partition is fixed to the trailing edges of a ring of guide blades to divide the flow into two annular streams and internal partitioning means, similar to those used in the embodiment of Fig. 5, are utilized. The disposal points for the condensed water in this case are a feed water heater and a vacuum pump having its outlet connected to the condenser.