JP2001172949A - Energy dissipating and sound absorbing device for force of current - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an energy dissipating and sound absorbing device for the force of a current capable of accomplishing energy dissipation with variations in slow speed and obtaining the effect of sound absorption as required. SOLUTION: An assembled channel 112 of a plurality of small channels 117 having a cross sectional area smaller than that of a channel 111 is provided to the channel 111 required for energy dissipation, and as the high water level, required energy dissipation can be obtained by combining the size of roughness coefficient of the channel 117, total cross sectional area of the assembled channel 112, channel extension and other conditions and, at the same time, the occurrence of sound or vibration caused by a turbulent flow with the sudden energy dissipation can be reduced to the minimum by making flowing water in the assembled channel 112 run off into a fluid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a demagnetization muffling device for a flow to reduce the flow and to reduce noise and vibration caused by the flow.

[0002]

2. Description of the Related Art In order to reduce the flow force in a pipeline flow, a valve structure type is selected. this is,
This is a method in which a restricting mechanism is arranged in a flow path to generate a head loss, and there are valve bodies having various structures in which various measures are taken to prevent cavitation of the valve body due to deenergization. However, those having any valve structure are very expensive. Moreover, although the purpose of energy reduction can be achieved, noise and vibration accompanying the energy reduction are large. Nevertheless, no effective drastic measures have been taken to prevent the generation of noise and vibration, and the sound source is only covered to cover the generated sound source.

[0003] On the other hand, when the power is reduced in the inclined water flow or the falling water flow of the open channel, it is referred to as a power reducer.
There is a method in which resistors having various shapes are provided in a flow path and a water stream is caused to collide. This is to reduce the flow force by the disturbance caused by the collision of the water flow, and the purpose of the reduction is achieved, but a mechanism that is an effective countermeasure against turbulence noise and vibration is also incorporated. Not. In other words, there is no change in sound insulation to the extent that the same equipment as described above is provided.

[0004] As described above, the conventional deenergizing means and method creates a turbulent state with a sudden change in the speed of the water flow, so that it is difficult to take effective measures to reduce noise and vibration. is there.

[0005]

SUMMARY OF THE INVENTION The present invention has been made on the basis of the above-mentioned circumstances, and its object is to change the conventional idea of energy dissipation due to a turbulent state accompanied by a sudden speed change, and to provide a gradual change. It is an object of the present invention to provide a power flow demagnetization muffler capable of achieving a noise reduction effect while achieving power reduction with speed fluctuation.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a flow path requiring a deenergization of a collecting flow path composed of a plurality of narrow flow paths having a cross-sectional area smaller than the cross-sectional area of the flow path. It is installed in a channel to make it full, and the required energy is obtained by a combination of the roughness coefficient of the narrow channel, the total sectional area of the collecting channel, the length of the channel, and other conditions. By taking out the powder into the fluid, a measure is taken to minimize the generation of noise and vibration due to the turbulent flow caused by the sudden deenergization by gradually reducing the generation.

In the present invention, the water flow is divided into a large number of narrow channels having a large roughness coefficient, and the friction loss head and the inflow / outflow loss head of the narrow channel are obtained, thereby achieving the energy reduction. This deenergization realizes a gentle speed fluctuation (deceleration) of the water flow. In addition, the generation of compression waves, that is, turbulence that causes noise and vibration is suppressed by reducing (lowering) the inflow velocity into the still water region.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As is apparent, the device of the present invention is intended to reduce the flow force, and at the same time, to reduce the noise and vibration accompanying the power reduction as much as possible. belongs to. For this purpose, a predetermined flow path is assumed, and a collective flow path including a plurality of narrow flow paths is provided in the predetermined flow path. The narrow channel has a cross-sectional area smaller than the cross-sectional area of the original channel, and is referred to as an aggregate channel since the narrow channel takes a form of being aggregated.

By passing water through a plurality of narrow channels and channels having a large roughness coefficient, the resistance of flowing water can be increased and the flow velocity can be gradually reduced. The extension of the collecting channel to obtain the required energy reduction, the cross-sectional area of the narrow channel, the number of the narrow channels, etc. are determined by theoretical calculation based on the roughness coefficient. Confirm it experimentally and calculate the final numerical value.

The flow path in which the collective flow path composed of the plurality of narrow flow paths is provided may be a pipe flow, or may be applied to an inclined water flow or a falling water flow of an open channel. In addition, since the flow end of the collecting channel is released into the water, the water flow flowing out of the narrow channel is diffused in the water without colliding with the water surface, so the turbulent flow due to deenergization is moderate and small. Stop at. Therefore, the magnitude of noise and vibration is extremely small.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail with reference to the illustrated embodiments. In the drawings, prior to the description of each embodiment, a conventional example having the same flow channel type as each embodiment is shown for comparison.

FIG. 1 is a schematic diagram showing a pipe waterway 11 and a sudden deenergization of the pipe waterway 11 by a deenergization valve 12 conventionally performed. The flow is very steep as seen in the attenuation section 13 of the attenuation curve shown by the two-dot chain line.

FIG. 2 shows an embodiment 1 in which the apparatus according to the present invention is implemented for a pipe channel 111.
In addition, a collecting channel 112, which is an aggregate of narrow channels 117, is installed, and a flow control valve 113 is interposed downstream to control the flow rate. In the first embodiment, the flow is
The part 2 is gently but sufficiently deenergized (dissipating part 114). Therefore, even the water control valve 113 does not suddenly lose its energy (the energy reducing section 115).

FIG. 3A shows a first embodiment of the apparatus according to the present invention.
FIG. 2 shows a cross-sectional view of the present invention, and relates to a structure of a collecting channel installed in a pipe channel. The narrow channel 11 is provided inside the pipe 116.
7 has a configuration in which a large number of small diameter pipes are inserted. FIG.
(B) shows a first modification of the first embodiment, in which the narrow flow path is constituted by a corrugated tube. The waveform shape indicates that the narrow channel 117 has a required roughness. By using a corrugated tube or the like having a large roughness coefficient as the narrow channel 117, it becomes possible to shorten the entire length of the narrow channel 117 or to set the diameter thereof large, so that a more economical collecting channel 112 can be obtained. it can.

FIG. 4 shows another modification 2 of the first embodiment of the apparatus according to the present invention, in which a pipe channel 111 is branched into a plurality of branch channels, and a collecting channel 112 is formed in each branch channel. It has an installed configuration. The number of branches and the ratio of branching to each branch canal depend on the fluctuation range of the flow rate. In the case of two-way branching, for example, the ratio is divided into 2/3 and 1/3, and in the case of three-way branching, for example, 3/6. , 2/6, 1/6, etc., the set flow rate is changed in each of the branch waterways, whereby the water stop valve 118 can be operated according to the flow rate to obtain the necessary deenergization.
3 to reduce the amount of energy reduction by the energy reduction (the energy reduction unit 115),
Generation of noise and vibration due to turbulence can be minimized.

In the modification shown in FIG. 4, reference numeral 119 denotes a valve for drainage. Each valve 119 is provided with the water shutoff valve 11.
8 is provided immediately after the downstream side, and exerts a facility maintenance function by backwashing the narrow channel 112.

FIG. 5 shows an open channel 21 having a predetermined cross-sectional area.
And a schematic diagram of energy dissipation by the energy dissipation device 23 with respect to the inclined water flow 22 therein. In the downstream part of the sloping water flow, the energy damper 23
Remarkable jumping water 24 is generated due to this, and as a result, noise and vibration are generated.

FIG. 6 shows a second embodiment in which the apparatus according to the present invention is implemented for an open channel.
The energy dissipation at the inclined portion 122 of FIG. In the second embodiment, the collecting channel 123, which is an aggregate of narrow channels, is installed in the inclined water flow portion to reduce the flow and minimize noise and vibration.

In the first embodiment relating to the pipe channel flow, the flow end naturally flows out into the water, but the second embodiment belonging to the open channel.
In the following examples, the flow end 124 is discharged into water. In the case of the second embodiment relating to the inclined water flow, the same deenergizing action as in the first embodiment can be obtained, and therefore, noise and vibration accompanying the deenergization can be minimized.

The noise reduction silencer having the configuration of the second embodiment can also have the same functions as those shown in FIGS. 3 (a) and 3 (b). This is shown as an enlarged sectional view in FIG. In this figure, the elevation of the inlet of each of the narrow tubes constituting the narrow channel 125 is adjusted so as to correspond to the flow rate and the water depth, and the gap between the narrow tubes is closed or fixed without filling with a filler 126 such as concrete. Wall 1
At 27, the water level is raised. In addition, the narrow channel 125 is shown as what consists of a corrugated tube. FIG.
FIG. 7B is a cross-sectional view of FIG.

FIG. 8 shows the size of the water tank 34 together with the state of occurrence of the water surface fluctuation 33 in the falling water flow 32 flowing out of the flooded part which is a part of the water channel 31. This explains the principle of the generation of noise and vibration due to the compressional waves caused by the falling water flow 32, and also shows that a relatively large water tank capacity is required to suppress the water surface fluctuation 33 to an acceptable state.

FIG. 9 relates to a third embodiment according to the present invention, in which a falling water flow 132 flowing down from a flooded portion provided in a part of a water channel 131 is used as a pipeline flow to reduce the flow, thereby reducing noise and noise. This is an example of preventing occurrence of vibration and the like. The collecting flow channel 133 is installed almost vertically on the downstream side of the weir so that the falling water flow 132 passes through the collecting flow channel 133 which is an aggregate of narrow flow channels. The water tank 134 is used for the compression wave suppression effect of the configuration of the third embodiment.
Is significantly smaller than that of the conventional example. FIG. 9 schematically illustrates this. Therefore, the desired deenergizing action is obtained even for the falling water flow, and noise and vibration can be suppressed to a minimum.

FIG. 10 (a) shows a configuration obtained by adding a function similar to that shown in FIG. 3 or FIG. 7 in order to effectively reduce the flow which rises in response to the rise in the water level. The elevation of the inlet of the narrow tube constituting the narrow channel 135 is adjusted, the gap between the narrow tubes is closed or fixed without filling with a filler 136 such as concrete, and the water level is raised by the wall 137. Have been. Also in FIG.
5 is represented as a corrugated tube. FIG. 10B is a plan sectional view of FIG.

[0024]

The present invention is constructed and operates as described above. The present invention divides a water stream into a plurality of narrow channels having a large roughness coefficient, and a flow end of a collecting channel comprising a plurality of narrow channels. By draining the water into the water, the conventionally required damping structure valve and damper are not required, the effective damping is achieved by the collective flow path, and the noise and vibration are reduced by the disappearance of the sudden turbulence. Generation can be minimized. The effect of the present invention is the same not only for the pipe channel but also for the inclined water flow or the falling water flow of the open channel flow. It also has a remarkable effect.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a conventional deenergizing valve for a pipe waterway.

FIG. 2 is a schematic view of a first embodiment in which the water flow energy-absorbing silencer according to the present invention is applied to a pipe channel.

FIG. 3A is a cross-sectional view of the first embodiment. (B) A longitudinal sectional view showing a first modification of the first embodiment.

FIG. 4 is a schematic view of a second variation of the first embodiment.

FIG. 5 is a schematic diagram showing a conventional energy damper in an inclined water flow of an open channel.

FIG. 6 is a second embodiment in which the apparatus according to the present invention is applied to an open channel.
FIG.

FIG. 7A is a schematic diagram illustrating a variation of the second embodiment. (B) Transverse sectional view of the same.

FIG. 8 is a schematic diagram showing a conventional deenergization in a falling water flow.

FIG. 9 is a schematic view of a third embodiment in which the apparatus according to the present invention is applied to a falling water flow.

FIG. 10A is a schematic diagram illustrating a variation of the third embodiment. (B) Transverse sectional view of the same.

Claims (1)

[Claims] An apparatus for reducing flow force and reducing noise and vibration caused by the flow reduction, comprising a plurality of narrow flow paths having a cross-sectional area smaller than a cross-sectional area of a flow path. Install the path in the flow path that requires deceleration, set it to full flow, and reduce the required power by the combination of the roughness coefficient of the narrow flow path, the total cross-sectional area of the collecting flow path, the flow path extension and other conditions And the flow end of the collecting flow path is discharged into the fluid, whereby the generation of noise and vibration due to the turbulent flow accompanying the rapid deenergization is gradually reduced to minimize the flow. A power reduction silencer.