Method of refurbishing an energy conversion facility and refurbished energy conversion facility

Abstract

A method of refurbishing a facility for converting hydraulic energy into electrical energy including the following steps: providing a first cover plate, a second cover plate, a first opening located at an inner head cover, a second opening located at a hub, a third opening located at a runner; connecting the first cover plate to the inner head cover; connecting the second cover plate to the hub, wherein the first cover plate and the second cover plate surround an axis, and a part of an outer surface of the inner head cover, a part of an outer surface of the hub, an inner surface of the first cover plate, and an inner surface of the second cover plate are confining an annular shaped space.

Claims

1. A method of refurbishing a facility for converting hydraulic energy into electrical energy, the method comprising the steps of: providing: a first cover plate, which includes an inner surface; a second cover plate, which includes an inner surface; a first opening located at an inner head cover, which includes an outer surface; a second opening located at a hub, which includes an outer surface; a third opening located at a runner; connecting the first cover plate to the inner head cover; connecting the second cover plate to the hub, the first cover plate and the second cover plate surrounding an axis, wherein a part of the outer surface of the inner head cover, a part of the outer surface of the hub, the inner surface of the first cover plate, and the inner surface of the second cover plate confine an annular shaped space in order to allow a gas to flow from inside the inner head cover and through the first opening, the annular shaped space, and the second opening and to be discharged through the third opening into a water passage during operation of a refurbished said facility, wherein the refurbished facility includes: the water passage; a turbine including the runner of an axial flow type, the runner being located within the water passage, being moveable around the axis, belonging to a rotatable part of the turbine, and including the hub and a plurality of blades connected to the hub; a drive shaft connected to the runner; and the inner head cover, which is located adjacent to the hub, surrounds the drive shaft, and belongs to a non-rotatable part of the turbine.

2. The method according to claim 1, wherein the hub includes a bottom, the third opening being located at the bottom of the hub.

3. The method according to claim 1, wherein the hub includes a side, the third opening being located at the side of the hub between the plurality of blades.

4. The method according to claim 1, wherein the method further includes the step of providing a gas passage and an inlet aperture, the gas passage being within one of the plurality of blades, wherein the third opening is located at the blade including the gas passage, wherein the gas passage extends between the inlet aperture and the third opening in order to allow the gas discharging through the third opening into the water passage to flow through the gas passage by passing the inlet aperture.

5. The method according to claim 4, wherein the third opening is located at a trailing edge of at least one of the plurality of blades.

6. The method according to claim 4, wherein the third opening is located at a periphery of at least one of the plurality of blades.

7. The method according to claim 4, wherein the third opening is located at a suction side of at least one of the plurality of blades.

8. The method according to claim 1, wherein the method further includes the step of providing a separated gas flow passage located within the hub.

9. The method according to claim 8, wherein the separated gas flow passage extends between the second opening and the third opening in order to allow the gas discharging through the third opening into the water passage to flow through the separated gas flow passage.

10. The method according to claim 8, wherein the method further includes the step of providing a gas passage and an inlet aperture, the gas passage being within one of the plurality of blades, wherein the third opening is located at the blade including the gas passage, wherein the gas passage extends between the inlet aperture and the third opening in order to allow the gas discharging through the third opening into the water passage to flow through the gas passage by passing the inlet aperture, wherein the separated gas flow passage extends between the second opening and the inlet aperture in order to allow the gas discharging through the third opening into the water passage to flow through the separated gas flow passage.

11. A refurbished facility for converting hydraulic energy into electrical energy, the refurbished facility comprising: a facility that is configured for being refurbished by way of a methodso as to result in the refurbished facilitythat includes the steps of: providing: a first cover plate, which includes an inner surface; a second cover plate, which includes an inner surface; a first opening located at an inner head cover, which includes an outer surface; a second opening located at a hub, which includes an outer surface; a third opening located at a runner; connecting the first cover plate to the inner head cover; connecting the second cover plate to the hub, the first cover plate and the second cover plate surrounding an axis, wherein a part of the outer surface of the inner head cover, a part of the outer surface of the hub, the inner surface of the first cover plate, and the inner surface of the second cover plate confine an annular shaped space in order to allow a gas to flow from inside the inner head cover and through the first opening, the annular shaped space, and the second opening and to be discharged through the third opening into a water passage during operation of the refurbished facility, wherein the refurbished facility includes: the water passage; a turbine including the runner of an axial flow type, the runner being located within the water passage, being moveable around the axis, belonging to a rotatable part of the turbine, and including the hub and a plurality of blades connected to the hub; a drive shaft connected to the runner; and the inner head cover, which is located adjacent to the hub, surrounds the drive shaft, and belongs to a non-rotatable part of the turbine.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:

(2) FIG. 1 is a facility for converting hydraulic energy into electrical energy;

(3) FIG. 2 is an axial flow turbine before refurbishment;

(4) FIG. 3 is an axial flow turbine after refurbishment according to a first embodiment of the invention;

(5) FIG. 4 is a gas flow path in the refurbished turbine according to FIG. 3;

(6) FIG. 5 is an axial flow turbine after refurbishment according to a second embodiment of the invention;

(7) FIG. 6 is an axial flow turbine after refurbishment according to a third embodiment of the invention;

(8) FIG. 7 is an axial flow turbine after refurbishment according to another embodiment of the invention;

(9) FIG. 8 is an axial flow turbine after refurbishment according to another embodiment of the invention;

(10) FIG. 9 is an axial flow turbine after refurbishment according to another embodiment of the invention; and

(11) FIG. 10 is an axial flow turbine after refurbishment according to another embodiment of the invention.

(12) Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate embodiments of the invention, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.

DETAILED DESCRIPTION OF THE INVENTION

(13) FIG. 1 displays a facility for converting hydraulic energy into electrical energy in a very schematic way. The facility includes an upper and a lower reservoir of water, a turbine and a generator connected to the turbine. Of course, the reservoirs can be part of a body of flowing water such as a river. In this case the river upstream of the turbine is the upper reservoir and the river downstream of the turbine is the lower reservoir. The turbine includes a runner of the axial flow type moveable around an axis. Water flowing from the upper reservoir to the lower reservoir passes the turbine and causes the runner to rotate around its axis and the connected generator to generate electricity. The facility includes a water passage, and the water flows through the water passage, and the runner is located within the water passage.

(14) FIG. 2 displays a part of a turbine with a runner of the axial flow type before refurbishment. The runner includes a hub, which is designated by 1, and several blades connected to the hub 1. In FIG. 2 only one of the blades is shown and is designated by 2. In the case of a so-called propeller type turbine the blades are fixedly connected to the hub. In the case of a so-called Kaplan type turbine, the blades are pivot-mounted to the hub. The runner is connected to a drive shaft, which is designated by 4. The turbine includes an inner head cover which is located adjacent to the hub 1 and surrounds the drive shaft 4. The inner head cover is designated by 3.

(15) Hub 1, blades 2, and drive shaft 4 belong to the rotatable part of the axial flow turbine, whereas the inner head cover 3 belongs to the non-rotatable part of the axial flow turbine.

(16) The axial flow type runner shown in FIG. 2 is a propeller type runner, and the blades 2 are fixedly connected to the hub 1. Other axial flow type runners (Kaplan type runners) have blades 2, which are pivot-mounted to the hub 1. In this case the hub 1 is bulkier than a comparable propeller type hub 1 since it has to contain a way for pivoting the blades 2. Usually, the remaining inner space of a hub 1 of a Kaplan type runner is filled with oil or water.

(17) FIG. 3 displays the part of a turbine shown in FIG. 2 after refurbishment according to a first embodiment of the present invention. The refurbished turbine includes a first cover plate, which is designated by 5 and which is connected to the inner head cover 3, and a second cover plate, which is designated by 6 and which is connected to the hub 1. Both cover plates 5 and 6 are surrounding the axis of rotation of the runner, but for the sake of convenience FIG. 3 shows only the right part of the cover plates 5 and 6 respectively. Cover plates 5 and 6 meet at a seal, which is designated by 7. Since the first cover plate 5 is a non-rotatable part of the turbine and cover plate 6 is a rotatable part of the turbine, the seal 7 is a so-called rotatable seal.

(18) In the arrangement shown in FIG. 3, a part of the outer surface of the head cover 3, a part of the outer surface of the hub 1, the inner surface of the first cover plate 5, and the inner surface of the second cover plate 6 are confining an annular shaped space, which is located outside of the original turbine and within the original water passage.

(19) The refurbished turbine includes a first opening located at the inner head cover 3 leading from the inside of the inner head cover 3 to the annular shaped space. The first opening is designated by 8. The refurbished turbine can include more than one first opening 8. The refurbished turbine includes a second opening located at the hub 3 leading from the annular shaped space into the inside of the hub 3. The second opening is designated by 9. The second opening 9 is located near the top of the hub 1. The refurbished turbine can include more than one second opening 9. The refurbished turbine includes a third opening, which is located at the runner and is designated by 10. The third opening can be located at various parts of the runner. In any case the third opening 10 is configured to allow gas flowing from inside of the runner into the water passage surrounding the runner. In the embodiment according to FIG. 3 the third opening 10 is located at the bottom of the hub. The third opening 10 could be located at any suited part of the hub, e.g., in the region between the blades 2. The refurbished turbine can include more than one third opening 10.

(20) The arrangement according to FIG. 3 enables the refurbished turbine to discharge gas into the water passage. FIG. 4 shows the flow path of the discharged gas whereas the flow path is indicated by the arrows. The gas enters the first opening 8 from inside the inner head cover 3. Through the first opening 8 it enters the annular shaped space and flows towards the second opening 9 through which it enters the hub 1. Then it passes the hub 1 and is discharged into the water passage via the third opening 10. The rotatable seal 7 mitigates water infiltration from the surrounding water passage.

(21) It is clear that the gas has to be delivered to the inside of the inner head cover 3 before it can flow in the described manner. How this is achieved strongly depends on the detailed structure of the existing facility. In most cases the gas can be delivered into the inner head cover 3 by providing additional pipes and by using existing compartments inside the facility. The gas can be delivered using a compressor or just by the influence of atmospheric pressure.

(22) FIG. 5 displays a refurbished turbine according to another embodiment of the present invention. The third opening 10 is located according to this embodiment at the trailing edge of at least one of the blades 2. The gas is flowing to the third opening 10 through a gas passage inside the corresponding blade 2, which is designated by 13. The gas enters from inside the hub 1 into the gas passage 13 by passing an inlet aperture, which is designated by 11. Alternatively, the third opening 10 can be located at the radial periphery of the blade 2. Discharging gas at this position can mitigate cavitation and vibration.

(23) FIG. 6 displays a refurbished turbine according to another embodiment of the present invention. In addition to the embodiment according to FIG. 5 the embodiment according to FIG. 6 includes a boundary plate, which is designated by 12 and is located within the hub 1. The boundary plate 12 separates the gas flow passage within the hub 1 from the remaining space inside the hub 1. This can be useful in case the original hub 1 was filled with oil or water. In the refurbished hub the remaining space inside the hub 1 can again be filled with oil or water and the gas flow through the separated passage is not hindered by the oil or water. Alternatively, the separated gas flow passage inside the hub can be located completely in the hub shell. In this case the complete inside of the refurbished hub can again be filled with oil or water. The later alternative embodiment is especially useful for Kaplan type runners because the space inside the hub is very limited. Another alternative way to separate the gas flow passage within the hub can be achieved using one or more pipes within the hub connecting a second opening 9 with a corresponding third opening 10 or with a corresponding air inlet aperture 11. Note that a separated gas flow passage inside the hub can also be applied in case that the third opening is located at the bottom of the hub 1.

(24) FIG. 7 displays a refurbished turbine according to another embodiment of the present invention. The difference to FIG. 3 is that the third opening 10 is not located at the bottom of the hub 1 but located at the side of the hub 1 between the blades 2.

(25) FIG. 8 displays a refurbished turbine according to another embodiment of the present invention. The displayed embodiment includes two third openings 10, which are located at the suction side of a blade 2.

(26) FIG. 9 displays a refurbished turbine according to another embodiment of the present invention. The displayed embodiment includes a third opening 10, which is located at the periphery of a blade 2 near the leading edge of the blade 2. The opening is located at the suction side of the blade 2.

(27) FIG. 10 displays a refurbished turbine according to another embodiment of the present invention. The displayed embodiment includes a third opening 10, which is located at the periphery of a blade 2 near the trailing edge of the blade 2. The opening is located at the suction side of the blade 2.

(28) Alternatively, the third opening 10 in the embodiments according to FIGS. 9 and 10 could be located directly at the tip of the blade 2. In this case the discharged gas would enter the water passage in the space between the blade and the boundary of the water passage.

(29) The somewhat edged shape of the first and second cover plate 5 and 6 shown in the FIGS. 3 to 10 is just for the sake of simplicity. Of course, the contours especially at the outside of the cover plates 5 and 6 can be shaped smoother so that the adjacent water flow is not or just minimally disturbed. Also, the radial width of the annular space can be much smaller as shown in the FIGS. 3 to 10.

(30) The method of refurbishing a facility for converting hydraulic energy into electrical energy according to the present invention includes at least the following steps: Providing a first cover plate 5, Providing a second cover plate 6, Providing a first opening 8 located at the inner head cover 3, Providing a second opening 9 located at the hub 1, Providing a third opening 10 located at the runner, Connecting the first cover plate 5 to the inner head cover 3, Connecting the second cover plate 6 to the hub 1,
whereas the first cover plate 5 and the second cover plate 6 are surrounding the axis of rotation of the runner, and a part of the outer surface of the head cover 3, a part of the outer surface of the hub 1, the inner surface of the first cover plate 5, and the inner surface of the second cover plate 6 are confining an annular shaped space in order to allow gas to flow from inside the inner head cover 3 through the first opening 8, the annular shaped space, and the second opening 9 and to be discharged through the third opening 10 into the water passage of the facility during operation of the refurbished facility.

(31) The cover plates 5 and 6 can be connected to the mentioned parts by welding or bolting. The cover plates 5 and 6 can be formed as an integral part. In this case the runner or the runner blades must be dismounted during refurbishment. The cover plates 5 and 6 can alternatively consist of several segments which can be connected by welding or bolting. Depending on the runner geometry the second cover plate 6 may include recess clearances for the runner blades. In the case of a Kaplan type runner the recess clearances must allow pivoting of the blades.

(32) For the embodiments according to FIGS. 5, 8-10, the method of refurbishing includes the following additional steps: Providing a gas passage 13 within a blade 2, Providing an inlet aperture 11,
whereas the third opening 10 is located at the trailing edge or the radial periphery of the blade 2 (or other locations of the blade 2 mentioned before) including the gas passage 13, and the gas passage 13 extends between the inlet aperture 11 and the third opening 10 in order to allow the gas discharging through the third opening 10 into the water passage to flow through the gas passage 13 by passing the inlet aperture 11.

(33) The gas flow passage 13 can be machined into an existing blade 2 by machining a shallow groove in the blade 2 and providing an overlying cover plate (compare FIG. 10 in U.S. Pat. No. 4,924,842). The cover plate can by welded or bolted to the existing blade 2.

(34) For the embodiments mentioned in connection with FIG. 6, the method of refurbishing includes the following additional steps: Providing a separated gas flow passage located within the hub 1, whereas the separated gas flow passage extends between the second opening 9 and the third opening 10 or the inlet aperture 11 in order to allow the gas discharging through the third opening 10 into the water passage to flow through the separated gas flow passage.

LIST OF REFERENCE SIGNS

(35) 1 Hub 2 Blade 3 Inner head cover 4 Shaft 5 First cover plate 6 Second cover plate 7 Seal 8 First opening 9 Second opening 10 Third opening 11 Inlet aperture 12 Boundary plate 13 Passage

(36) While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.