JPS58176404A - Drain removing device - Google Patents

Abstract

PURPOSE:To improve a drain removing effect, by mounting a lid such as a porous plate,a wire gauze and the like on a drain removing gutter defined in a web of a stationary blade of steam turbine and by properly selecting an opening amount of the lid. CONSTITUTION:A lid 5 constituted by a porous plate, a wire gauze or a slit plate for forming a fluid channel is mounted on a drain gutter 3 defined in the web of the stationary blade of a turbine 1. The gutter 3 communicates with a discharge outlet 4 and receives a low pressure of a condenser and the like. Moreover, a resistance imposed by a porous plate and the like during its passage is distributed in predetermined values by properly selecting an opening amount of the lid 5 relative to a radial direction. In this manner, since a low pressure of a condenser and the like affects upon an entire length of drain removing gutter 3,a drain removing effect can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drain removal device, and more particularly to an improvement in a drain discharge groove of a turbine stationary blade.

In turbomachinery that operates in humid steam, such as the low-pressure stage of a steam turbine, it is used to improve the efficiency of the blades and to prevent erosion of various parts within the turbine, especially the inlet edges of the blades.

It is important to effectively separate and discharge the generated condensate (moisture) from the working fluid. Droplet particles (drain) generated in the working fluid usually accumulate on the ventral surface of the turbine stator blade, form a thin liquid film on the ventral surface of the stator blade, and are dragged by the main steam flow and moved to the vicinity of the trailing edge of the blade. (.

Grooved stator vanes have traditionally been used to remove moisture by focusing on the above phenomenon. That is, the configuration is shown in FIGS. 1 and 2. The stator blade (1) is fixed to the stator blade ring (2) by welding or the like on the inner diameter side (blade root) and the outer diameter side (blade tip). Then, a groove (3) is provided on the ventral surface of the stationary blade (1), and the droplet mass accumulated there is removed from the blade surface using low pressure from a condenser etc. through an extraction port (4) provided at the blade tip. There is. At this time, the groove (3) is provided so as to be slightly inclined from the direction perpendicular to the mainstream, so that the shear component of the mainstream has a draining effect.

The stationary blade groove (3) is open to the main steam flow, and the low pressure introduced through the outlet (4) for this purpose is also opened to the groove (3).
) only acts near the wing tips. Therefore, the groove (3), which is long in the height direction of the stator blade, does not effectively remove the drain, and the liquid film accumulated in the groove (3) overflows from the groove (3) and scatters into the mainstream again. Sometimes.

The present invention solves the above-mentioned disadvantages in drain discharge in conventional turbine stator blades, and aims to improve the drain discharge ability of the drain outlet provided in the turbine stator blades. .

In order to achieve the above object, in the present invention, a drain discharge groove provided on the ventral surface of a turbine stator blade is provided with a groove cover such as a perforated plate or a wire mesh, and the opening ratio of the groove cover is appropriately determined in the longitudinal direction of the drain discharge groove. It is. With the above structure, a uniform suction force acts in the longitudinal direction of the drain groove, and a drain discharge force is generated over the entire length of the drain groove.

Embodiments of the present invention will be described with reference to the drawings.

In the first embodiment shown in FIG. 3, a turbine stationary blade (1)
A drain groove (3) provided on the ventral surface of the drain groove (3) is provided with a groove cover (5) made of a perforated plate, wire mesh, or slit plate to serve as a fluid passage. The groove (3) is, of course, connected to an outlet (4) as shown in FIG. 1, which is used to apply a low pressure such as a condenser. With this configuration, the low pressure of a condenser or the like introduced from the outlet can be utilized over the entire length of the drain outlet (3) by utilizing the suction resistance of the perforated plate or the like.

Furthermore, by appropriately determining the aperture ratio of the groove cover (5) corresponding to the radial direction, it becomes possible to distribute the passage resistance value of the perforated plate etc. to a required value corresponding to the radial position. As a result, the resistance value can be distributed in accordance with the pressure gradient at the radial position determined by the main flow, so that the stationary blade groove (3) can be utilized for drain removal over its entire length.

In the second embodiment shown in FIG. 4, the perforated plate (6) is arranged inwardly of the drain discharge groove (3) provided on the ventral surface of the turbine stationary blade so that the perforated plate (6) has a liquid pooling effect. (6) Shape one end to be inclined. By making the perforated plate into the shape described above, the suction resistance of the perforated plate is utilized, and the drain accumulates in the lower part of the perforated plate (6), and the drain discharge groove ( Since the low pressure of a condenser or the like introduced from the discharge port communicating with drain drain groove (3) acts over the entire length of the drain drain groove (3), the drain removal effect can be further improved.

[Brief explanation of the drawing]

Fig. 1 is a front view of a conventional turbine stator blade, Fig. 2 is a sectional view taken along the line ■-■ in Fig. 1, and Fig. 3 is a part of a turbine stator blade showing the first embodiment of the present invention. 4 is a partial sectional view of a turbine stator blade showing a second embodiment of the present invention. 1. Turbine stationary blade, 2. Stationary blade ring, 3. Drain discharge groove, 4. Discharge port, 5. Groove cover.

Claims (1)

[Claims] A drain removal device characterized in that a drain discharge groove provided on the ventral surface of a turbine stationary blade is provided with a groove cover having a fluid passage.