JPS62131978A - Once-through water turbine - Google Patents

Abstract

PURPOSE:To prevent the leakage of flowing water from both sides of a guide vane and improve efficiency at the time of low load operation by providing circular collars on both sides of said guide vane of a once-through water turbine. CONSTITUTION:Circular collars 4, 4 having the maximum diameter in a degree of not coming into contact with a runner 6 centering around a guide vane shaft 5, are provided in an integrated form with the both sides of the guide vane 3. These circular collars 4, 4 are fitted into circular grooves which are provided on the inner wall face of a casing 2 and on a partition board 8 respectively. And, packing 13 for sealing is provided between the outer periphery of the circular collar 4 and the inner peripheral surface of the circular groove.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to once-through water turbines, and more particularly to a device for optimizing guide vane side seals.

[Background of the invention]

In a once-through water turbine, as shown in FIG. 1, the flow rate and direction of water flowing from a suction pipe 1 is adjusted by a guide vane 3 installed inside a casing 2, and reaches a runner 6. In this case, the guide vane A gap (seal gap) of about 0.1 mm exists on both sides of the casing 2 and the partition plate 8. It has been confirmed through experiments that the leaking water from this seal gap disturbs the flow from the guide vane 3 to the runner 6, and significantly reduces the efficiency especially during light load operation. In particular, as shown in FIG. 3, water leaking from the guide vane/head side surface α affects the flow β leading to the runner 6 when the guide vane is open, significantly reducing the partial side efficiency. Therefore, eliminating water leakage from this seal gap is an essential element for improving efficiency during light load operation.

As described in Japanese Utility Model Application Publication No. 59-116580 and shown in FIGS. 4 and 5, packing grooves 11 are provided near the outer periphery of both side surfaces of the guide vane 3, and an elastic body or
The basic idea is to embed the bearing material to prevent water leakage from the seal gap.Furthermore, as shown in Figure M6 and Figure 7, a pressure introduction hole 12 is provided in the aforementioned packing groove 11, and the seal is installed in the packing groove 11. The sealed seal material 10 is placed on the guide base/
30 surface and the water pressure introduced into the pressure introduction hole 12
A method is disclosed in which the sealing effect is enhanced by pressing the seal against the inner wall surface of the casing 2 and the partition plate 8 shown in the figure.

However, with the conventional structure in which sealing material is attached to both sides of the guide vane, a complicated backing groove must be machined on the side of the guide vane 3 along the guide vane profile, resulting in high costs and difficult assembly and adjustment. However, there are drawbacks such as the risk of the packing 13 being worn and falling off.

[Purpose of the invention]

An object of the present invention is to provide a once-through water turbine that prevents leakage from both side surfaces of a guide vane and ensures safety when the guide vane slides.

[Summary of the invention]

The present invention provides the guide vane side surface of a once-through water turbine with a circular brim having a maximum diameter that does not touch the casing inner wall surface 2 centered on the guide vane axis 5 and the protruding portion 8A of the partition plate 8, or the runner 6, Correspondingly, grooves are provided in the inner wall surface of the casing 2 and the partition plate 8 to fit with the circular collar 4, and by fitting the circular collar 4, there is a gap between the side surface of the guide vane 3 and the inner wall of the casing. Try to eliminate the gap.

[Embodiments of the invention]

An embodiment of the present invention will be described with reference to FIGS. 1 to 3.

In the guide vane 3 installed correspondingly upstream of the runner to control the flow rate and flow direction, a flow path from the inner wall surface of the casing 2 centered on the guide vane shaft 5 and the suction pipe l is partitioned on its side surface. Projection part 8 on partition plate 8
The guide vane 3 is installed so that it has a single circular brim 4 with a maximum diameter that does not come into contact with people or the runner 6, and also covers the guide vane head 3A, which has a large effect on reducing efficiency. Consider. The water flow surface of the circular collar 4 is made to be on the same plane as the inner wall of the casing 2 and the water flow surface of the partition plate. Correspondingly, fitting recesses of the same type are provided on the inner wall surface of the casing 2 and the partition plate 8, and the circular collar 4 is mounted inside this recess. Further, a backing 12 is attached to the circumference of the circular collar 4. Since this circular collar 4 slides together with the guide vane 3 inside the fitting recess, the seal gap on the side surface of the guide vane is ,not exist.

According to this embodiment, leakage of water from the side surface of the guide vane can be completely prevented within the range where the side surface of the guide vane intersects with the circular boxwood.

Compared to the conventional guide vane seal device, this implementation series has the following advantages:
We solved the problem of wear resistance by enclosing the bearing 9 in the fitting groove in the circular flange 4 that is integrated with the side surface of the guide vane, ensuring good lubricity at all times. By completely eliminating the seal gap between the side surface 3, the casing member 2, and the partition plate 8 within the circumference of the disc collar, a water leakage prevention effect greater than that of the prior art can be obtained. In particular, as shown in Fig. 3, when the guide vane 3 is in the open state, the leakage water α from the three sides near the guide vane head is significantly affected by the flow β from the guide vane head to the runner. However, in the present invention, by completely covering the guide vane head 3A with the circular brim 4, it is possible to completely prevent water leakage from the side surface of the guide vane head.

〔Effect of the invention〕

According to the present invention, the guide vane side gap can be almost eliminated, so efficiency during snack driving can be improved.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a longitudinal cross-sectional view of a once-through water turbine according to an embodiment of the present invention, Fig. 2 is a view taken from the I[-I[ arrow in Fig. 1, and Fig. 3 is a conventional Vertical sectional view with the upper part of the casing of a once-through turbine removed, No. 4
6 are longitudinal sectional views of a conventional guide vane, and FIGS. 5 and 7 are plan views of a conventional guide vane. 1... Suction pipe, 2... Casing, 3... Guide vane, 4°... Circular collar, 5... Guide vane shaft,
6...Runner, 2-7...Runner shaft, 8...Partition plate.

Claims (1)

[Claims] 1. In a once-through water turbine with a guide vane installed upstream of the runner to control the flow rate and flow direction, the runner and A once-through water turbine characterized in that a collar having a maximum circumference that does not contact is integrated, and corresponding fitting recesses are provided in the inner wall surface of the casing and the partition plate.