JPH0442529Y2 - - Google Patents

Description

[Detailed Description of the Invention] A. Field of Industrial Application The present invention relates to a so-called cross-flow water turbine in which water whose flow rate is regulated by guide vanes flows inside a runner so as to cross the runner.

B. Summary of the invention This invention makes the center of rotation of the guide vane eccentric from the center of the guide vane in a cross-flow water turbine, so that the runner side surface of the guide vane is aligned along the lower nozzle of the casing that supports the guide vane. By rotating the guide vane while keeping the gap with the lower nozzle constant without enlarging it, when the guide vane is throttled, the flow on the runner side of the guide vane changes from a contracted flow (squeezed and compressed flow) to an expanded flow ( This is intended to prevent cavitation and corrosion of guide vanes, runner blades, etc. due to cavitation.

C. Conventional technology The structure of a conventional cross-flow turbine is shown in Figures 5 to 7.
As shown in the figure. That is, 1 is the runner, 2
is the casing, 3 is the inlet pipe, 4 is the guide vane,
5 is a housing, 6 is a suction pipe, 7 is an air suction valve,
8 is an air valve cover. FIG. 6 shows the state when the guide vane 4 for flow rate adjustment is fully closed, and FIG. 7 shows the state when the guide vane 4 is fully open.

D. Problems to be solved by the invention In the conventional cross-flow water turbine, the support shaft of the guide vane 4 is located approximately at the center of the guide vane 4, so the guide vane 4 makes a turning movement about the support shaft. As a result, on the runner side surface of the guide vane 4, the water flow becomes a strong expanding flow in the range where the opening degree of the guide vane 4 is small, creating a cavity in this area and causing cavitation, which eats away at the guide vane 4, runner blade, etc. This has become a problem as it has caused problems such as deterioration of water turbine performance.
Further, there is a gap between the guide vane 4 and the side wall of the casing 2, and water leaks from this gap, which causes a problem of reduced efficiency.

The present invention was made in view of the current situation, and prevents cavitation by preventing the phenomenon of the flow changing from contraction to expansion even when the opening degree of the guide vane 4 is small, and also prevents cavitation between the guide vane 4 and the casing 2. It is an object of the present invention to provide a cross-flow water turbine which can also prevent water leakage from the gap between the water turbine and the side wall of the water turbine.

E Means for Solving the Problems In order to achieve the above object, the configuration of the present invention is to provide flanges on both end sides of the guide vanes to which the guide vanes are attached eccentrically, and to align the center of the flanges with the guide vanes. A rotatable support shaft is provided as the rotation axis of the vane and is concentric with the flange and supports the guide vane via the flange, while a recess into which the flange rotatably fits is provided on the casing side and the support shaft is It is characterized by forming a bearing part that supports the shaft.

F Effect With the above configuration, the runner-side surface of the guide vane rotates along the lower nozzle of the casing, thereby preventing a phenomenon in which the flow changes from contracting to expanding. Moreover, since the collar fits into the recess between the guide vane and the side wall of the casing, water leakage from between the guide vane and the side wall is also prevented.

G. Embodiment An embodiment of the present invention will be described below with reference to Fig. 1, which is a conceptual diagram of the mechanism with the guide vane open, Fig. 2, which is a conceptual diagram of the main part of the mechanism, and Fig. 2, which is a conceptual diagram of the mechanism with the guide vane closed. The explanation will be given based on FIG. 3, which is a diagram, and FIG. 4, which is a perspective view of a main part.

In FIGS. 1 to 4, components that are the same as those of the conventional system are denoted by the same reference numerals, redundant explanations thereof will be omitted, and explanations will be made using them as appropriate.

In Figures 1 to 4, 2a is the casing 2
The upper nozzle, 2b, is the lower nozzle of the casing 2. Moreover, 4a is a collar provided at both ends of the guide vane 4 to which the guide vane 4 is attached eccentrically. This collar 4a has a circular shape as shown in FIG. 4, and fits into a round hole 21 provided in the side wall 2c of the casing 2. Further, support shafts 4b are attached to both outer sides at the center position of the collar 4a, and the support shafts 4b fit into the bearing portion 22 and are rotatably attached to the bearing portion 22 together with the collar 4a and the guide vane 4. Supported.

In the figure, a indicates the height of the water passage on the casing side surface of the guide vane 4, and b indicates the water passage height on the runner side surface. In a general cross-flow turbine, b is selected to be 30 to 50% of (a+b), and the configuration is such that the guide vane 4 can be fully closed by turning the guide vane 4 (both ends of the guide vane 4 contact the casing 2 at the same time). ing. In the present invention, the center of rotation of the guide vane 4 is provided at a position e away from the center of the conventional guide vane 4 as shown in the figure, and the guide vane 4 is configured to move circumferentially around this center. . Therefore, b dimension is a
It is possible to select a value smaller than the dimensions, and in practice, it is possible to select b to be 10 to 20% of (a+b), thereby reducing the flow on the runner side surface of the guide vane 4, which is inefficient.

In addition, the flow on the runner side surface of the guide vane 4 is configured to be a contraction flow in the fully open state, and due to the circumferential movement of the guide vane 4, as it approaches the fully closed state, the guide vane becomes smaller than the conventional guide vane 4'. As shown by 4'', the tendency to become a contraction flow or an expansion flow can be alleviated depending on the relationship with the lower nozzle 2b (see FIG. 2).

Further, according to this structure, since the collar 4a is provided on the outer surface of the guide vane 4 and the collar 4a fits into the round hole portion 21, water does not leak from this portion, and water does not leak from this portion. The flow on the runner side surface of the guide vane 4 is not disturbed by water or objects protruding toward the water flow path, and efficiency can be greatly improved.

H. Effects of the invention As described above, according to the invention, the flow on the runner side surface of the guide vane can be reduced, improving efficiency, and the flow on the runner side surface of the guide vane can be expanded. This prevents cavitation, noise, and corrosion of guide vanes and runner blades, as well as performance deterioration due to this.It also prevents water leakage from between the guide vanes and the side walls of the casing, increasing efficiency. Effects such as significant improvement can be obtained.

[Brief explanation of the drawing]

Figures 1 to 4 show an embodiment of the present invention. Figure 1 is a conceptual diagram of the mechanism with the guide vane open, Figure 2 is a conceptual diagram of the main part of the mechanism, and Figure 3 is a conceptual diagram of the mechanism. A conceptual diagram of the mechanism when the guide vane is closed, Figure 4 is a perspective view of the main parts, Figure 5 is a partially cutaway perspective view of a conventional cross-flow water turbine, and Figure 6 is a diagram of the conventional guide vane. FIG. 7 is a conceptual diagram of the mechanism when the guide vane of the conventional example is fully open. Also, the symbols in the figure are 1: runner, 2: casing, 2b: lower nozzle, 2c: side wall, 4: guide vane, 4a: flange, 4b: support shaft, 21: round hole portion (recess), 22: is the bearing part.

Claims (1)

[Scope of utility model registration request] A collar is provided on both end sides of the guide vane to which the guide vane is eccentrically attached, and
A rotatable support shaft is provided that has the center of the flange as a rotational axis of the guide vane and is concentric with the flange and supports the guide vane via the flange, while the flange is rotatably fitted to the casing side. A cross-flow water turbine characterized in that a recess is provided to support the support shaft, and a bearing is formed to support the support shaft.