JP2006316487A - Entrained-air control system for headrace - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an entrained-air control system for a headrace which can effectively control air entrained into flowing water without requiring the upsizing of existing equipment or requiring large-scale equipment. <P>SOLUTION: In a combined structure wherein a vertical shaft 2 for injecting taken-in water by using a fall is connected to the headrace 1, a barrier 5 is provided in the upper section of the head race positioned on the side of the downstream of a section to which the vertical shaft 2 is connected; an exhaust pipe 6 is connected to the upper part of the headrace 1 which is positioned between the vertical shaft 2 and the barrier 5; and a protrusion 7 which is protruded into the head race is formed in the lower section of the headrace 1 which is positioned directly below and near the vertical shaft 2. An energy dissipating mechanism for reducing the depth of the penetration of water to be injected can also be provided in the vertical shaft 2. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a mixed air control apparatus provided in a merge structure that injects and merges water taken into a pressure conduit such as a hydroelectric power plant.

  In hydropower plants, there are facilities (dam waterway type power plants, etc.) that take mountain streams for effective use of water collection areas and inject and merge the collected water into pressure conduits. is there.

  For example, in the facilities shown in FIG. 3 and FIG. 4, the pressure conduit 1 is constituted by a main water channel 1a and a branch water channel 1b that injects and joins water taken by bypassing the main water channel 1a. The collected water to be injected and merged is injected with a drop through a resister 2 connected to the water channel 1b.

  In such a confluence structure, when water 3 that has fallen freely from the inlet 2a of the resisting 2 has entered the surface of the water, a large amount of air 4 flows into the water channel as shown in FIG. There is concern about inconveniences such as mixing in running water, air pockets formed in the water channel by this mixed air, leading to head loss, generating a dangerous air hammer action, and reducing the efficiency of the water turbine. ing.

  In addition, when the stream intake water is merged into the pressure conduit 1, it is also required by laws and regulations that there is no risk of significant damage to the waterway and water turbine due to air entrainment (“Technology related to power generation hydropower equipment”). “Ministerial Ordinance for Establishing Standards”, Article 29-4 (b)).

  Therefore, when using such a confluence structure, it is necessary to limit the amount of water intake in the mountain stream in order to prevent the above phenomenon, so that effective water use cannot be achieved, and the amount of power consumption is increased. There is concern about the inconvenience that cannot be handled.

  As measures against this, as shown in the following non-patent literature, (a) a method of removing bubbles by free floating, (b) a method of removing air under the action of water pressure, (c) water and air together It is also effective to adopt a method that prevents the camera from falling.

Here, the removal method by free levitation of the bubbles in (a) is a method of removing the bubbles that are entrained with the free-falling water veins and enter the water by free levitation, taking the cross-sectional area of the resist The method of removing air under the action of water pressure in (b) is a method in which a bubble removal chamber having a larger channel cross section is provided, the flow rate of the mixed flow of water and air is lowered, the bubbles are lifted and exhausted from the exhaust pipe. (C) The method of preventing the water and air from falling together is to keep the flow in the resister always in a full-pipe state so that air bubbles are not mixed by free fall or This is a method in which air is allowed to fall freely in a vacuum and air is prevented from being mixed.
Shinichi Chiaki, “Hydraulic power generation exercise”, 7th edition, Gakushinsha Co., Ltd., February 10, 1988, p265-271

  However, in the measure (a) described above, since the rising speed of the bubble varies depending on the mixing rate of the bubble, it is necessary to increase the cross-sectional area of the resist in order to remove the bubble, and the measure (b) In this case, since it is necessary to provide a bubble removal chamber having a large cross section of the water channel, the equipment becomes large, and there is a disadvantage that it is also affected by fluctuations in the free-falling water vein. Furthermore, in the measure (c), it is necessary to fill the inside of the reaction chamber with water or to make it in a vacuum state, so that the facility becomes large and there is an inconvenience that it is not possible to cope with an inexpensive facility.

The present invention has been made in view of the circumstances as described above, and it is not necessary to enlarge existing facilities, and to effectively control air mixed in running water without requiring large facilities. The main problem is to provide a mixed-air control device in a water conduit that can be used.

  In order to achieve the above object, a mixed air control apparatus in a water conduit according to the present invention is an apparatus provided in a junction structure to which a resist for injecting water taken into the water conduit with a drop is connected. A barrier is provided on at least the upper part of the water conduit located downstream from the site where the resist is connected, and an exhaust pipe is connected to the upper part of the conduit that is located between the resist and the barrier, Furthermore, a projecting portion that projects into the water conduit is provided at a lower portion of the water conduit that is located directly under or near the counterweight (Claim 1).

  Therefore, when the water taken in falls through the counter and penetrates into the surface of the water, a large amount of air is mixed into the running water. This mixed air is guided upward by the protrusion provided at the lower part of the water conduit. Therefore, the bubbles are guided to the upper part of the water conduit and removed from the exhaust pipe provided in front of the barrier above the water conduit.

  Further, in order to achieve the above-mentioned problem, the mixed air control device in the water conduit is a device provided in a confluence structure to which a resist for injecting water taken into the water conduit with a drop is connected, You may make it provide the depressing mechanism which makes the penetration depth of the inject | poured water small to the said resist (Claim 2).

  Accordingly, the momentum of the injected water is attenuated by the reduction mechanism, so that the momentum of the water penetrating the water surface is reduced, and the amount of air mixed into the water is reduced or reduced by reducing the penetration depth of the water vein. It becomes possible to do.

  More specifically, the depressing mechanism is configured by providing a plurality of projecting bodies that protrude into the resist and receive the water veins by shifting the upper and lower sides of the resist (Claim 3), and the falling water veins are the projecting bodies. It is also possible to reduce the penetration depth by reducing the penetration speed by causing them to collide one after another. Further, the de-energizing mechanism is configured by providing a partition wall for vertically partitioning the inside of the resisting wall, and providing a through hole in this partition wall (Claim 4), and depressurizing by causing the falling water vein to collide with the partition wall. Then, the penetration speed may be reduced by flowing down through the through hole to reduce the penetration depth.

  Further, the de-energizing mechanism is constituted by a float that floats on the water surface within the resist (Claim 5), the falling water vein collides with the float to de-energize, and the speed of water penetrating the water surface is reduced to reduce the penetration depth. However, the depressurization mechanism is provided with a means for spirally flowing water taken up on the inner wall of the resisting wall (Claim 6), and the water vein is reduced by flowing spirally. The penetration depth of the water surface may be reduced.

  As described above, according to the first aspect of the present invention, a barrier is provided on the upper portion of the water conduit downstream from the resist connected to the conduit, and at the upper portion of the conduit between the resist and the barrier. Since an exhaust pipe is connected, and a projecting part that projects into the water channel is provided at the lower part of the water channel that is located directly under or near the resistance, even if air enters the running water due to the penetration of the water vein Because the mixed air can be led to the upper part of the water conduit by the protrusion and exhausted from the exhaust pipe, it is not necessary to enlarge the existing equipment, and it is possible to remove the mixed air without requiring large equipment. It can be effectively removed.

  Further, according to the inventions according to claims 2 to 6, since the force of the injected water is attenuated by providing a depressing mechanism to the resist connected to the water conduit, the penetration depth of the water vein is reduced. It is not necessary to increase the size of existing equipment, and it is possible to eliminate or reduce the amount of mixed air without requiring a large-scale equipment.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS The best embodiment of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, a merging structure for injecting and merging mountain stream intake water from a ridge 2 erected in a pressure conduit 1 is shown.
In this example, the merging structure has a barrier 5 that prevents bubbles floating on the upper part of the water conduit 1 located downstream from the site where the resisting channel 2 of the pressure water conduit 1 is connected. An exhaust pipe 6 for exhausting the air accumulated on the upstream side of the barrier 5 is connected to the upper part of the water conduit 1 located between the barrier 5 and the resister 2. Moreover, the protrusion part 7 which protrudes in a water channel is provided in the lower part of the water channel located in the direct vicinity or in the vicinity of it, and the direction of the flowing water in the water channel 1 is made to face upwards by this projection part 7. Yes.

  Here, the projecting portion 7 may be a block-like projecting body attached to the lower portion of the water conduit, or may be integrally formed by raising the lower portion of the water conduit. Furthermore, the protrusion part 7 provided in the lower part of a water conduit may be one, or plural. In this example, the protrusions 7 are provided at two locations immediately below the stand-off 2 of the water conduit 1 and in the vicinity of the downstream side thereof.

  In such a configuration, when the water 3 that has fallen freely through the resister 2 enters the surface of the water, a large amount of air is mixed into the flowing water. It is led to the upper part of the water conduit 1 along with running water whose flow has been changed upward by the projecting portion 7 provided at the bottom of the water, and is accumulated on the upstream side of the barrier 5 and exhausted from the exhaust pipe 6 connected to the upstream side of the barrier 5 Will be.

  Therefore, it is not necessary to increase the cross-sectional area of the resist 2 in order to remove bubbles, and it is not necessary to provide a bubble removal chamber having a larger cross section of the conduit, so there is no need to increase the size of the equipment. Is assumed to be mixed in the running water, so there is no inconvenience caused by fluctuations in the free-falling water veins. Furthermore, according to the above-described configuration, it is possible to cope with measures in the water conduit, so that it is possible to cope with an inexpensive facility without requiring a large facility.

  The above configuration is a configuration in which mixed air is effectively removed by measures in the water conduit 1, but it may be dealt with by improving the structure in the resister 2. That is, a mechanism that prevents the water taken from the upper part from falling freely and does not directly penetrate the water surface, in other words, a depressurizing mechanism that reduces the penetration depth of the water may be provided.

  FIG. 2 shows an example of the configuration of such a depressing mechanism. The depressing mechanism shown in FIG. 2 (a) has a plurality of projecting bodies 8 that receive water veins on the inner wall of the resist 2 on the upper and lower sides of the resist 2. A plurality (two in this configuration example) are provided by being shifted. That is, by providing a plurality of projecting bodies 8 that project substantially vertically from the inner wall so as to reduce the cross section of the passage 2 in the vertical direction, and projecting bodies that are adjacent in the vertical direction are alternately projected into the interior. The passage portions constricted by the respective protrusions 8 are not overlapped when projected in the axial direction of the counterweight 2. The uppermost protrusion is formed at a position where the water 3 flowing down from the inlet of the resist 2 collides directly.

  Therefore, the water 3 taken in from the upper part of the stand 2 collides with the uppermost projecting body 8, and then falls downward through a portion whose passage section is narrowed by the projecting body 8, and again. It collides with the lower projecting body 8 and flows down to the water surface through a portion where the cross section of the passage is narrowed by the projecting body 8. For this reason, it becomes possible to slow down the speed of the water vein which penetrates into the water surface by the protrusion 8, thereby making it possible to reduce the penetration depth of the water vein and to reduce the air 4 mixed in the running water. .

  The de-energizing mechanism shown in FIG. 2 (b) is configured by providing a partition wall 9 that partitions the interior of the stand up and down and providing a through hole 9 a in the partition wall 9. The through-hole 9a is formed at a position where the water 3 flowing down from the inlet of the stand 2 does not enter directly. In this example, the partition wall 9 having the through-hole 9a formed at the center is provided with the stand-up 2 It is configured by fixing in the middle.

  Therefore, the water 3 taken in from the upper part of the stand 2 collides with the partition wall 9, then flows down through the central through hole 9a, and flows down to the water surface. For this reason, it becomes possible to slow down the speed of the water vein penetrating into the water surface by the partition wall 9, thereby making it possible to reduce the depth of penetration of the water vein and to reduce the air 4 mixed in the running water. .

  The de-energizing mechanism shown in FIG. 2 (c) is constituted by a float 10 that floats on the water surface in the stance. That is, a spherical float 10 having a diameter smaller than the inner wall of the resist 2 is floated on the water surface in the resist, and water flowing down from above is applied to the float 10.

In such a configuration, even if the float 10 is not artificially fixed, the float 10 can be automatically placed directly under the water flow according to “Bernoulli's theorem”. 10 hits the water surface. For this reason, the speed of the water vein penetrating into the water surface can be slowed by the float 10, whereby the penetration depth of the water vein can be reduced, and the air 4 mixed in the running water can be reduced.

  The de-energizing mechanism shown in FIG. 2 (d) is configured by providing means for spirally flowing water taken up on the inner wall of the resist 2. Even if the means for flowing down the spiral is to provide a spiral guide on the inner wall of the stand 2 and guide the stream water intake to the spiral guide, the inlet of the stand 2 is provided. It may be provided so as to be substantially horizontal in the tangential direction of the ridge and to expel the stream water intake along the inner wall.

  Therefore, in such a configuration, the water 3 taken from the upper part of the resister 2 flows down spirally along the inner wall of the resister 2 and reaches the water surface, so that the water veins penetrating the water surface It becomes possible to reduce the speed, thereby making it possible to reduce the depth of penetration of the water vein, and to reduce the air 4 mixed into the running water.

  Note that the protrusion 8 shown in FIG. 2A and the partition wall 9 shown in FIG. 2B are fixed to the inner wall of the stand 2, even if the inflow amount of the mountain stream water intake varies. In order to cope with the accompanying fluctuations in the water surface, it may be moved up and down with the fluctuations in the water surface so that it is always positioned above the water surface. Moreover, you may make it use combining the measure in the water guide channel mentioned above, and the de-energizing mechanism provided in response.

FIG. 1 is a cross-sectional view illustrating a configuration example in which a structure in a water conduit of a merged structure in which a standing structure is provided in a pressure water conduit is improved. FIG. 2 is a view showing a de-energizing mechanism provided in the rectification of the merged structure in which the rectification is erected in the pressure conduit, and FIG. 2 (a) is provided with a protrusion on the inner wall of the rectification. 2B is a cross-sectional view showing a configuration example in which a partition wall is provided in the stand, and FIG. 2C is a cross-section showing a configuration example in which a float is suspended in the stand. Fig. 2 (d) is a cross-sectional view showing a configuration example in which intake water flows down spirally on the inner wall of the resist. FIG. 3 is a configuration diagram showing a configuration example in which a waterway that bypasses the main water channel is provided as an example of a merging structure provided in the pressure conduit, and FIG. 3 (b) is a cross-sectional view taken along line AA in FIG. 3 (a). FIG. 4 is a perspective view showing an example of a conventional configuration of the merge structure shown in FIG. FIG. 5 is a cross-sectional view showing an outline of a state in which water intake is injected into the resistance shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Water guide path 2 Resistance 5 Barrier 6 Exhaust pipe 7 Projection part 8 Projection body 9 Partition wall 9a Through-hole 10 Float

Claims (6)

A mixed air control device in a water channel provided in a confluence structure connected to a structure that injects water taken into the water channel with a head,
A barrier is provided on at least the upper part of the water conduit located downstream from the site where the resist is connected, and an exhaust pipe is connected to the upper part of the conduit that is located between the resist and the barrier; The mixed air control apparatus in a water conduit characterized by providing the protrusion part which protrudes in the said water conduit at the lower part of the said water conduit located in the direct vicinity or the vicinity of the said resist. A mixed air control device in a water channel provided in a confluence structure connected to a structure that injects water taken into the water channel with a head,
The mixed air control apparatus in a water conduit characterized by providing a depressing mechanism for reducing the penetration depth of water to be injected against the resist. 3. The mixed air control apparatus for a water conduit according to claim 2, wherein the depressurization mechanism is configured by providing a plurality of projecting bodies that project into the basin and receive the water veins by shifting up and down the basin. 3. The mixed air control apparatus for a water conduit according to claim 2, wherein the depressurization mechanism is configured by providing a partition wall for vertically partitioning the inside of the stand and by providing a through hole in the partition wall. The mixed air control apparatus for a water conduit according to claim 2, wherein the de-energizing mechanism is configured by a float that floats on a water surface in a basin. 3. The mixed air control apparatus in a water conduit according to claim 2, wherein the depressing mechanism is provided with means for spirally flowing water taken up on the inner wall of the standing wall.

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