CS206589B1 - Regulation step,especially for extraction point of axial steam turbines - Google Patents

Description

(54) Control stage, in particular for the sampling points of axial steam turbines

The invention relates to a control stage, in particular for the sampling stations of axial steam turbines, which consists of a circular slide, axially flowing and provided with nozzle channels, a fixed ring of guide bodies and an impeller.

The control stages provided with round gate valves are essentially control stages with throttle control. In all known embodiments of the control stages of the above-mentioned kind, the dividing planes lie between the rotary ring slide and the fixed guide ring in a plane perpendicular to the axis, for example a book: Dejc, Trojanovskij Untersuchung und Berechnung axialer VEB Verlag Technik Berlin, 1973, p. 398. It is disadvantageous that as the throttle increases, i.e. the degree of opening is reduced, the throttling losses in the guide ring rim increase.

Therefore, there is a need to improve the efficiency of the control stages equipped with axially flowing circular gate valves.

The invention is based on the task that, even with a small degree of opening of the ring spool, an adequate flow velocity is created at the throttling points, preferably in the circumferential direction, and to be optimally applied to the next impeller.

This object is achieved by the control stage according to the invention, which is based on the fact that the opposing faces of the spigot webs, which are delimited by the side walls of the nozzle channels of the spigot and the fixed guide rim, are arranged in dividing planes which run centrally. symmetrically between a plane perpendicular to the axis of the ring spool and between the meridional planes up to those nozzle channel walls which lie on the pressure side.

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Suitably, the divider planes extend substantially perpendicular to those walls of the nozzle ducts which lie on the pressure side and to their outlet.

According to a further embodiment of the invention, it is suspended on flexurally elastic strips which are arranged in planes perpendicular to the dividing planes.

An essential advantage of providing the control stage according to the invention is, in particular, that in the case of a small degree of opening of the circular slide ae, the throttle losses in the guide ring rim are reduced and thus the efficiency of the control stage is improved.

The invention will now be described by way of example with reference to the drawing.

Giant. 1 shows an expanded portion of a portion of the control stage circuit.

Giant. 2 is an axonometric view of a cut-out of a circular slide and a ring of guide bodies which are pulled apart in the axial direction.

The control stage at the take-off point of the axial steam turbine (not shown) consists of a circular slide 1 as a control device, a stationary rim 2 of guide bodies and an impeller J. The opposing faces 2, 4 * of the webs 6, 6 'located between the nozzle channels 2. The circular slide 2 and the stationary guide body rim 2 are located in the separation planes 2, which extend between the plane 8 perpendicular to the axis and the meridional planes 6. The dividing planes 2 on the faces 4 'are guided in the stationary guide body rim 2 to the walls of the nozzle channels 5'. on the pressure side. It is advantageous to place the separation plane 2 close to the outlet of the wall lying on the pressure side and approximately perpendicular to this wall, so that at the throttling point on the nozzle channel 5, with a small cross-sectional opening, the throttled flow essentially has a circumferential direction. The size of the faces 4 of the webs 6 located on the circular slide 2 is chosen such that, in the closed state of the circular slide 2, the cross-sections of the nozzle ducts 5 * in the stationary ring 2 of the guide bodies are covered. The webs 6 are positioned in the circular slide 2 so that they project downstream; they engage the stationary rim of 2 guide bodies.

Circular valve 2 is hinged ^on its circumference at a plurality of flexurally elastic strip 10. which are situated in planes 22 »perpendicular or approximately perpendicular to the dividing planes of the two wide sides · strips 10 face the directions of movement of the slide ring 2, as indicated by arrow 12. The ends the belts 10 are clamped in bearings 22, 13 *; of these bearings, the bearing 13 is located on the annular slide 2 ^{and the} bearing 13 * on the arm 14 firmly connected to the stationary rim 2 of the guide bodies. The slider 2 receives its pivoting movement from a control drive (not shown).

Between the parallel annular faces 15, 15 of the circular slide 2 ^{and the} stationary guide ring 2, a clearance 16 is provided for the movement component of the circular slide 2 which is parallel to the axis.

Claims (3)

SUBJECT OF THE INVENTION Control stage, in particular for the sampling points of axial steam turbines, which consists of a circular slide, axially flowing and provided with nozzle ducts, a stationary shroud of guide bodies and an impeller, characterized in that the adjacent faces (4) , 4 ') of the legs (6, 6') of the circular slide (1), which are delimited by the side walls of the nozzle channels (5, 5 ') of the circular slide (1) and the stationary shroud (2) of the guide bodies. 7) which extend centrally symmetrically between a plane (8) perpendicular to the axis of the circular slide (1) and between the meridional planes (9) up to those walls of the nozzle channels (5 *) which lie on the pressure side. t 3 206589 Control stage according to Claim 1, characterized in that the separation planes (7) extend substantially perpendicular to those walls of the nozzle ducts (5 *) lying on the pressure side and to their outlet. Control stage according to Claim 1, characterized in that the annular slide (1) is suspended on bending-elastic bands (10) which are arranged in planes (11) perpendicular to the dividing planes (7).