GB1135767A - Improvements in or relating to steam turbines - Google Patents

Abstract

1,135,767. Steam turbines. ASSOCIATED ELECTRICAL INDUSTRIES Ltd. March 31, 1966 [April 2, 1965], No.14196/65. Heading F1T. The nozzle box 34, Fig. 2, of a steam turbine is located circumferentially within a cylindrical casing 5 by keys 121 engaging grooves 123, 125. Axial location is provided by keys 131 engaging grooves 133, 135, and inserted into place through a steam inlet duct 47. An inner wall 47B and a sleeve 93 are then inserted into the inlet duct 47 to engage packing 95, 97. The sleeve 93 prevents the keys 131 from coming out of place, but their free ends 131A may be fastened by bolts 137 to prevent chattering. The sleeve 93 is secured to the inner wall 47B near the inner end of the duct 47, while the inner wall 47B is clamped to the outer wall 47A of the duct near the outer end (not shown), relative thermal expansion being permitted by a sliding engagement with the packing 95, 97. Steam at a lower temperature than that admitted through passage 91 is introduced into the annular space 99 between the sleeve 93 and the outer wall 47A to cool the latter, and flows through holes 101 at about the mid-length of the sleeve into the annular space 103 between the sleeve and the inner wall 47B, and thence via an annular chamber 105 to a point of lower pressure. The cylindrical casing 5 is closed at one end by an end closure (9), Fig.l (not shown), inserted through the other end of the casing and bolted into place to provide a steam-tight seal at an annular seating (9A). The other end closure (7) is retained in place by a segmented ring (17), the parts of which fit within a circumferential groove (19) in the inner surface of the casing and are held against radially inward movement by a ring (21). A seal ring (23) is provided between the end closure (7) and the casing.