Inlet casing for steam turbine
AssigneeAsea Brown Boveri AG
InventorRomuald Puzyrewski
Life of this patent
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Abstract
In a single-flow steam turbine, the inlet casing is designed to comprise two intertwined spiral casings (1, 2). These spirals have concentrically arranged annular openings (1',2') which face the inlet to the blading and extend over 360.degree. of the circumference. The spirals can be shut off and/or throttled, allowing infinitely variable partial admission to the reaction admission (sic) (13, 14, 15). The spirals (2) dimensioned for the smaller flow and their annular opening (2') is arranged on the rotor side in the radial direction. The first row of blading supplied from the annular openings (1', 2') is an after the (sic) action control wheel (13). The radially inner boundary wall of the spiral dimensioned for the small flow is arranged in the plane of the balance piston.
Claims4
Inlet casing for a single-flow, axial-flow high-pressure steam turbine having a balance piston, the flow to the first stage of which is from two mutually separated concentric annular openings, each annular opening being connected to its own inflow line, the inflow lines being two concentrically arranged spiral casings which can be shut off or throttled separately and are provided on the outlet side with annular openings extending over 360.degree., the spiral cross-section of both spirals furthermore being designed to produce an angular momentum over the entire circumference, such that the working medium flowing out of the annular openings has, irrespective of the load under which the machine is operated, a tangential component which is of the order of the peripheral velocity of the first-stage blade sector supplied with the working medium and finally the cross-sections of the spiral casings being dimensioned for different mass flow and the concentric annular openings having correspondingly different heights with an annular opening of one of the spiral casings being dimensioned for a smaller flow than the other of the spiral casings, characterized in that
- the annular opening of the spiral casing which is dimensioned for the smaller flow is radially arranged to be closer to the rotor than the other spiral casing,
- a first row of blading downstream from the annular openings is a row of rotor blades with a small degree of reaction,
- and a radially inner boundary wall of the spiral dimensioned for the small flow is arranged at least partially in the plane of the balance piston and is provided on its outside with a labyrinth-like shaft seal.
Dependencies are inferred from the claim text.