JPS6057896A - Sound preventor for water discharge port of water wheel or the like - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a soundproofing device for a water outlet of a water turbine, etc., which prevents infrasound generated from the water outlet of a dam or weir having an underdrain from being radiated into the atmosphere. Regarding.

In general, it is well known that so-called infrasound, which has a low frequency and cannot be heard, is generated from the water outlets of hydroelectric power plants, etc., and has a negative impact on the living environment. The generation of this infrasound has rarely been a problem when hydroelectric power plants are built deep in the mountains and private homes are far away, as in the past.

However, recently, power plants, etc. are being built next to private houses, or private houses are often coming close to power stations, and as a result, the generation of infrasound has become a problem. This is often the case.

To explain the water discharge route of a conventional general power plant with reference to Fig. 181, the water discharged from the water turbine 1 is G...
4rEverything is led to the plummeted water discharge channel 5, which has a straight ridge-shaped cross section with its top open.

In the figure, 6 indicates the position of the water surface, and GL indicates the position of the ground surface.

In the water discharge route as described above, ultra-low frequency pulsations generated due to various causes propagate through the water of the suction pipe 2 from the outlet of the water turbine 1, reach the water discharge opening 3a, and are 5
a, that is, the part that first comes into contact with the air, the water surface 6
It is converted into vibrations in the air above and radiated into the air as infrasound. The infrasound that was emitted into the atmosphere was propagating through the atmosphere, affecting nearby houses.

In view of the above points, an object of the present invention is to transmit infrasound generated from the water outlet of a water turbine to the water outlet. It is characterized by forming a cavity consisting of an air layer surrounded by water, waterway side walls, building walls, and coverings.

Hereinafter, the implementation of the present invention will be explained with reference to FIGS. 2 to 7 of the drawings.

FIGS. 2(A) and CB) show a first practical example of the present invention with a building wall 4 and a cover 8a having a predetermined height and length.
A muffling chamber 9 consisting of an air layer 7& is formed, and a tail pipe 10 is further formed.
The upper part of the part corresponding to is also covered by a cover 8b formed lower than the cover 8a so as to form an air layer 7b,
A conduit 10 is formed by the water surface 6, the waterway side wall 5a, and the cover 8b. In the figure, 8C indicates an end wall of the silencing chamber 9.

According to this embodiment, pulsations generated due to various causes associated with the operation of the water turbine reach the opening 3a of the water outlet 3 from the water turbine outlet through the suction pipe 2, and from the opening to the upper part of the water outlet 3. At the first point in contact with the air, it is converted into vibrations of the air above the water surface 6, and is radiated into the air as infrasound.

However, above the water surface 6 of the water outlet opening 3a, a silencing chamber 9, which is an air layer 7a, is formed. It gradually attenuates due to the reflection and interference of the tail pipe 10.
is radiated into the atmosphere through the This sound radiated into the atmosphere contains almost no infrasound. Therefore, infrasound propagating to private houses around the power plant will be significantly reduced.

FIGS. 3(A) and 3(B) are a longitudinal cross-sectional view and a cross-sectional view showing a second embodiment of the present invention. In this actual flifll, a U-shaped spillway 5 is laid on the outside of the building wall 4 where the water turbine 1 is installed, and is connected to the building wall 4 around the water outlet opening 3a so that the upper surface of the spillway 5 is and Utsusemi layer 7 & and 7 on both sides
Covers 8a and 8d are provided so that 8 is formed, and a silencing chamber 9 is formed by these air layers 7a+7(+), and an air layer 7b is also formed above the portion corresponding to the tail pipe 10. A cover B and a lower cover 8b are provided, and a pipe is formed by the cover 8b, the water surface 6-, and the waterway side wall 5a.

In this embodiment, in particular, the building wall 4 and the vertical wall portion 8c of the cover 6a in the silencing chamber 9 are provided with insertion portions 21 that protrude toward the internal silencing chamber 9, further enhancing the silencing effect. In order to promote
is lined.

According to this embodiment, pulsations generated due to various causes associated with the operation of the water turbine are first converted into vibrations of the air above the water surface at the water outlet, and are radiated into the air as infrasound.
After the infrasound passes through the building wall 4, it is gradually attenuated in a silencing chamber 9 formed continuously above and to the side of the waterway 5 due to reflection and interference effects.

In this practical example, the insertion part 21 is provided protrudingly at a position corresponding to the entrance of the silencing chamber 9 as described above, so that the air layer above the water rM6 in the discharge channel 5 and the air in the silencing chamber 9 are The layers are partially partitioned through the insertion portion 21, so that the reflection and interference of sound within the sound deadening chamber 9 is promoted, and furthermore, the sound absorbing material 22 is placed inside the sound deadening chamber 9. Coupled with the fact that it is taut, the sound deadening effect within the house 9 is further promoted.

Therefore, the ultra-low solid wave sound E-1- emitted from the water outlet
FIGS. 4A and 4B are a vertical cross-sectional view and a cross-sectional view showing a third embodiment of the present invention. In this embodiment, in particular, directly above the water outlet opening 3a, a part of the cover 8a which covers the upper part of the water surface 6 of the water discharge channel 5 with the entire air layer interposed therein is provided with a part of the cover 8a arranged at a constant interval above the water surface 6. It is characterized in that a resonance chamber 24 is formed which has an opening 26 at the bottom and has a predetermined length in a direction perpendicular to the opening, and on the downstream side of the resonance chamber 24, a first
Similar to the embodiment, a conduit 10 is formed which includes a water surface 6, a waterway side wall 5a, and a cover 8b.

According to this example, the pulsations that occur due to various causes during the operation of the water turbine are converted into vibrations on the water surface directly above the water outlet after exiting the water outlet opening 6a, resulting in infrasound waves. However, since a resonance chamber 24 is formed just above the water surface of the water outlet opening 3a, the infrasound emitted during the sudden air is emitted from the resonance chamber 24. Entrance 23 of chamber 24
The infrasound enters into the resonance chamber 24, resonates within the resonance chamber of a predetermined length that has a certain relationship with the wavelength of the infrasound, and the amplified sound energy attempts to enter the opening 26. The infrasound acts to cancel each other out, and is attenuated, and is then radiated into the atmosphere through the tail pipe 10.

Therefore, the sound radiated into the atmosphere contains almost no infrasound.

FIGS. 5A and 5B are a longitudinal cross-sectional view and a cross-sectional view showing a fourth embodiment of the present invention. In this actual gun example, the resonance chamber 24 in the third actual example is installed in the horizontal direction. That is, a resonance chamber 24 having an opening 23 in the cover directly above the water outlet opening 3a and having a predetermined length in the horizontal direction is an extension 8b' of the cover 8b forming the earthen wall of the pipe 10.
is formed along its top.

According to this actual example, similar to the third actual example, pulsations generated due to various causes during operation of the water turbine cause water discharge opening 6
The infrasound that is converted into vibrations in the air on the water surface directly above a and radiated into the air enters the resonance chamber 240 through the entrance 23, hits the end wall 8c and returns, causing resonance. The amplified sound energy acts to cancel the sound entering through the opening 23 and is attenuated,
It is radiated into the atmosphere through the tail tube 10. Therefore, the sound radiated into the atmosphere contains almost no infrasound.

In addition, since this resonance chamber 24 is formed parallel to the cover 8b of the tail g10, the structure can be formed lower and more compact than that of the third example, and the manufacturing process is also comparable. It is easy to understand.

FIGS. 6(A) and 6(B) are a longitudinal cross-sectional view and a cross-sectional view showing a fifth practical example of the present invention. In the first to fourth embodiments, the cavity formed above the water surface of the water outlet communicates with the air layer 7b of the pipe 10, whereas in the sister example, the cavity formed above the water surface of the water outlet communicates with the air layer 7b of the pipe 10. The tip of the end wall 8c, which forms part of the cover and faces the building wall 4, is extended until it is submerged in water, and a closed cavity 25 is formed inside.

Therefore, according to this real-life example, the pulsation caused by various causes is caused by the water discharge opening! The vibration of the sudden air on the water surface in contact with the building wall 4 of the a% is converted into vibration and is radiated as infrasound. The infrasound that travels downstream on the water surface 6 from the area near the water surface 6 and returns after being reflected by the end wall 8C acts to cancel out the newly emitted infrasound as described above, resulting in so-called reaction. Since it becomes a resonance state and is reduced, and is further sound-insulated by the walls of the sealed cavity 25, infrasound propagating into the atmosphere is reduced.

FIGS. 7(A) and 7(11) are a vertical cross-sectional view and a cross-sectional view showing a sixth practical example of the present invention. This sister example is a modification of the fifth embodiment (FIG. 6), in which the wall of the culvert 26 in the spillway section is used as the earthen wall of the closed cavity 25, and the water surface 6, the side wall 5a of the spillway, and the building wall are 4 and the end wall 8C facing it form a closed cavity 25.

According to this embodiment, the emission of infrasound caused by the operation of the water turbine is reduced by creating an anti-resonance state in the same manner as in the case of i55, and furthermore, the emission of infrasound from the wall of the sealed cavity 25 is reduced. ~Out I
``F Ren'' 11th part of the cause (in addition to the supplement, the sealed cavity 25
Since a culvert is used to cover the area, construction costs can be reduced accordingly.

In addition, in each of the above-mentioned examples of assembly, each section of the silencing chamber, tail pipe, sealed cavity, etc. was formed in an inverted L-shape, but it may be rectangular, semicircular, or
It may be crescent-shaped, and the sealed cavity may be provided with an air bleed if necessary. Furthermore, the silencing effect can be promoted by appropriately partitioning the silencing chamber, the tail pipe, and the sealed cavity parallel to the flow direction. It is also possible to line the sound-absorbing material inside the sound-absorbing material to reduce medium and high frequency sounds.

Also, cavities (resonance chambers, sealed cavities, etc.) in each of the above actual reduction examples
The relationship between the dimensions of the infrasound and the frequency of infrasound can be expressed using a theoretical formula as follows.

In FIGS. 2 and 3, the effective length L including the corrected length of the silencing chamber cavity and the tail pipe is c L = -a-T(2n I) (11) where L: silencing chamber cavity. length and effective length of coccyx) (
m) f: Frequency of infrasound (Hz) t: Speed of sound of infrasound (m/s) n: Expressed as an integer.

In addition, in FIGS. 4 and 5, the effective length L including the length of the resonance chamber (that is, the side branch) and the correction length of the tail tube is L=±-' (2n-1) f Branch length and tail pipe length (effective length)
(m) f: Frequency of infrasound (Hz) C+ +Sound speed of infrasound (m/s) n: Expressed as an integer.

In Figures 6 and 7, the length L of the sealed body is L=±-'(
2n-1) L for f and \: Length of sealed cavity (m) f: Frequency of infrasound (Hz) C: Speed of sound of infrasound (m/s) n: Expressed as an integer.

As explained above, the present invention forms a sound-muffling cavity made of an air layer constituted by the water surface, the waterway side wall, the building wall, and the cover above the water surface at the waterway outlet. The pulsations that occur due to various causes associated with the operation of the water turbine are converted into infrasound and radiated from the part that first comes into contact with the air, that is, the water surface inside the above-mentioned sound-muffling cavity. It is attenuated by reflection and interference effects, and is then radiated into the atmosphere through the tail tube.

Therefore, the infrasound propagating to private houses around the power plant is greatly reduced, which is extremely effective in preventing pollution caused by infrasound.

[Brief explanation of the drawing]

FIG. 1 shows a water discharge channel of a general power plant, and FIGS. 2 to 7 show first to sixth embodiments of the soundproofing device for water turbine water discharge ports according to the present invention. (A) of each figure
is a vertical cross-sectional view, and (B) of each figure is a vertical cross-sectional view, and (B) of each figure is
-A sectional view. 1.-Waterwheel, toe waterway water discharge l114 series of pipes 5.--Discharge channel, 5a-Discharge channel side wall, 8a-8d-cover, ? - Silence chamber, 24 - Resonance chamber, 25 - Closed cavity bird 1 (A> Figure (8) Figure 6 (A) (β)

Claims (1)

[Scope of Claims] 1. A water wheel characterized by forming a cavity consisting of an air layer constituted by the water surface, the side wall of the waterway, the building wall, the cover, etc. above the water surface at the water outlet of the waterway. Soundproofing device for water outlets such as. A soundproofing device for a water outlet of a water turbine or the like as claimed in claim 1, wherein a cavity is formed by a soundproofing chamber provided with a soundproofing chamber. 8. Claim No. 8, wherein a cavity is formed by a resonance chamber having an opening at a height above the water surface directly above the waterway water outlet and having a predetermined length in the vertical or horizontal direction from the opening. A soundproofing device for a water outlet of a water turbine, etc., as described in item 1. 4. A soundproofing device for a water outlet such as a water turbine, in which a part of the cover "fc" and the end wall facing the building wall are constructed of a wall whose tip is submerged in water.