TWO-LEVEL STAGE WITH DETACHABLE FORK BLADE Russian patent published in 2019 - IPC F01D9/04 

FIELD: machine building.

SUBSTANCE: invention relates to the field of power engineering and is intended to increase efficiency of double-level steps used as the penultimate stages in low-pressure cylinders (LPC) of condensation turbines. In the two-level stage for the low-pressure cylinder of the powerful condensing steam turbine, containing the diaphragm, the bottom level lower row nozzle assembly, nozzle apparatus of upper tier, partition of nozzle apparatus, working apparatus of lower tier, working device of upper tier, partition of working device, according to invention, working blades of two-level stage are made in form of permanent fork blades, and in diaphragm in front of steam inlet into nozzle grid profiles of upper tier two-tier stage distribution grid is located, formed by a system of annular conical contours with radial pitch l_i=(7°)⋅l₀/α, where l₀ – length of nozzle blades at inlet to nozzle profile grid, and angle α is angle of inclination of peripheral contour of nozzle assembly to longitudinal axis of step, and angles of inclination of tapered outlines to lengthwise axis of step β_i, which decrease from periphery to root by following law β_i=α-(7+i), where i is number of conic outline at its counting from peripheral contour of diaphragm.

EFFECT: technical result consists in improvement of efficiency and reliability of operation of double-stage LPC stages with sesquialteral exhausts.

1 cl, 2 dwg