JP2979144B1 - Pipe channel air elimination device - Google Patents

Abstract

An object of the present invention is to efficiently remove air entrained from an inflow water tank, to reduce the size of the ventilation device, and to achieve an integral structure with the inflow water tank. SOLUTION: An air collecting tank 12 whose upper part is open and connected to a main pipe 13 of a pipe waterway, an inflow water tank 10, and an air collecting tank 12 are provided.
And a connection pipe 11 for connecting The air collecting tank 12 and the connecting pipe 11 have a diameter of 1.9 to 2.1 times the diameter of the main pipe 13, and the distance from the connection between the inflow water tank 10 and the connecting pipe 11 to the downstream wall of the air collecting tank 12 is The diameter of the main pipe 13 is four times or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for removing air mixed in or carried into a pipe waterway such as agricultural water, water supply and sewerage, and industrial water.

[0002]

2. Description of the Related Art In a pipeline, if a large amount of air is trapped or entrained in a pipeline, it not only obstructs the flow but also causes surging and an air hammer, which may adversely affect a water transmission and distribution facility. There is. In general, in pipeline systems having free water surfaces such as intake facilities, stand-type diversion works, and adjustment facilities, air is entrained by falling water veins,
A ventilator for removing air is provided in order to form bubbles and mix in the pipe channel.

According to the land improvement project plan design standard / design “pipeline” standard / technical book (1998) (hereinafter referred to as design standard) supervised by the Ministry of Agriculture, Forestry and Fisheries Structural Improvement Bureau, the water flows into the pipeline from a water distribution tank or stand. Downstream of the inlet,
Since local pressure drop is likely to occur due to aeration and contraction of the flow, it is necessary to provide a device for removing air, and a vent is generally used.

FIG. 3 shows an example of the installation of the ventilation holes described in the design standards. Bubbles are generated by flowing water into the inflow water tank 30. A vent hole 32 is provided in the middle of a pipe D having a diameter D in order to remove air mixed in and carried into the flow from the inflow water tank 30. According to the design standard, the diameter of the vent hole 32 is usually in the range of 50 to 200 mm in diameter, and the discharge water depth h of the contraction part is usually obtained as h = 0.61H. The connection part between the inflow water tank 30 and the pipe waterway 31 is determined. From vent 3
It is stated that the distance L to 2 needs to be separated by 7 to 10D.

[0005] According to the design standard, the ventilation stand is also required to have a large capacity of intake / exhaust capacity in order to have a function of alleviating the water hammer pressure. It is said that there are many. For the ventilation stand, use a T-shaped pipe with the same diameter as the pipeline, a "straight vent type stand" using centrifugal reinforced concrete or the like for the riser, or a reinforced concrete with an internal size equal to or greater than the water cross section of the pipeline It is said that there is a "box vent type stand" equipped with a box stand.

[0006]

In the vent apparatus shown in FIG. 3, the diameter of the pipe channel 31 is D = 100 mm, and the diameter of the pipe channel 31 is from the connecting portion between the inflow water tank 30 and the pipe channel 31 (the pipe channel inlet) to the vent hole 32. The experiment was conducted using an apparatus in which the distance L of L was 900 mm (9D). As a result, the aerated water flowing in from the mouth portion of the pipe channel 31 is contracted, and a space 33 is formed at the mouth of the channel channel. A part of the air mixed in the flow in the inflow water tank 30 was sometimes mixed downstream of the vent hole 32. In addition, the flow in the pipe channel 31 fluctuates and is in a pulsating state, and water may be ejected from the vent hole 32.

As an application device of the ventilation stand, as shown in FIG. 4, the diameter of the ventilation stand 42 connected to the inflow water tank 40 and the connection pipe 41 is made larger than the diameter of the pipe water passage 43 to increase the area in contact with the atmosphere. Thus, a prototype of an improved ventilation stand that made it easier for air mixed in the flow to float was manufactured. The diameter of the pipe channel 43 is D = 100 mm, and the inflow water tank 40
L = 800 mm (8D), the distance from the connection portion between the pipe and the connecting pipe 41 to the downstream wall of the ventilation stand 42,
Of the same diameter as the inflow water tank 40 with a diameter of 300 mm (3
D). As a result, although the contraction generated near the connection between the inflow water tank 40 and the connection pipe 41 is smaller in size than in the case of the vent hole device, part of the air mixed in the flow passes through the ventilation stand 42. Therefore, it was found that they could be mixed further downstream.

[0008] As described above, in the conventional ventilation device, air may be further mixed downstream from the ventilation device. In addition, if a vent is used, the vent must be 7
When the ventilation stand is used and the ventilation stand is used, there is a problem that there is a distance of about 8D from the pipe channel mouth to the downstream wall of the ventilation stand, and the ventilation device becomes large. The present invention has been made in view of such problems of the related art, and efficiently eliminates air entrained from the inflow water tank, and sets the installation position of the ventilation device as close as possible to the water tank, thereby improving the ventilation device. It is an object of the present invention to provide an air elimination device that can be made compact, integrated with an inflow water tank, and can reduce costs by shortening the construction period.

[0009]

In the apparatus in which the ventilation stand is improved as shown in FIG. 4, there is air that passes through the ventilation stand and enters downstream. Then, the entrained air elimination device shown in FIG. 5 was prototyped. In this entrained air elimination device, an air accumulation tank 52 for accumulating and eliminating air is installed, and the diameter of a connecting pipe 51 connecting the inflow water tank 50 and the air accumulation tank 52 is twice as large as the diameter of the pipe channel 53. The purpose is to reduce the flow velocity and increase the levitation speed of the air.
The diameter of the pipe channel 53 is D = 100 mm, the diameter of the connecting pipe is 2D (200 mm), and the distance L from the connection between the inflow water tank 50 and the connecting pipe 51 to the downstream wall of the air collecting tank 52 is L = 8.
The diameter of the open portion of the air collecting tank 52 was set to 300 mm (3D), which is the same as that of the inflow water tank 50.

As a result, almost all of the entrained air entrained in the flow in the inflow water tank 50 is taken up by the air accumulation tank 52.
In this case, no air gap was generated due to the contraction. However, the inflow water tank 50 and the connecting pipe 51
There was a distance of about 8D from the connection portion to the downstream wall of the air accumulation tank, which was unsatisfactory in terms of making the ventilation device compact.

Next, as shown in FIG. 6, the diameter of the connecting pipe 61 connecting the inflow water tank 60 and the air collecting tank 62 is determined by the pipe waterway 6.
A prototype of the entrained air elimination device 1.5 times as large as the main tube of No. 3 was manufactured. The diameter of the pipe channel 63 is D = 100 mm, and the connecting pipe 6
1 has a diameter of 1.5D (150 mm), the distance L from the connection between the inflow water tank 60 and the connection pipe 61 to the downstream wall of the air accumulation tank 62 is L = 500 mm (5D), and the open part of the air accumulation tank 62 has an inflow. The diameter was 200 mm (2D), the same as the water tank 60.

As a result, although no void is generated due to the contraction, if the water depth in the inflow water tank 60 is shallow, the air accumulation tank 62
In some cases, some of the air that was not removed in the above was mixed into the pipe channel 63 further downstream. Thus, the connection pipe 61
Of the inflow water tank 60 even if the diameter of the
A distance of about L = 5D is required from the connection portion between the connection pipe 61 and the downstream wall of the air accumulation tank 62.

[0013] The present invention has been completed on the basis of the above-described experiments, and is an apparatus for removing air entrained from an inflow water tank into a pipe waterway. An air collecting tank having an open top connected to the pipe, and a connecting pipe connecting the inflow water tank and the air collecting tank are provided, and the air collecting tank and the connecting pipe have a diameter of 1.9 to 2.1 times the main pipe. And the distance from the connection between the inflow water tank and the connection pipe to the downstream wall of the air accumulation tank is at least four times the diameter of the main pipe. The air collecting tank and the connecting pipe can be manufactured by processing a ready-made T-shaped pipe.

According to the present invention, the diameter of the connecting pipe connecting the inflow water tank and the air collecting tank is made about twice as large as that of the main pipe, the flow velocity is reduced, the air is easily floated, and the air is mixed into the flow. Air can be removed efficiently. At the same time, by making the diameter of the opening of the air collecting tank and the diameter of the connecting pipe the same, and making it shorter than before, the inflow water tank, connecting pipe, and the air collecting tank are integrated using a ready-made T-tube, and the structure is simplified. Can be achieved.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view showing an example of an entrained air removing device for a pipe waterway according to the present invention. Inflow water tank 1
0 and the air accumulation tank 12 are connected by a connection pipe 11.
Assuming that the diameter of the pipe channel 13 is D, the air accumulation tank 12 and the connecting pipe 11 have the same diameter 2D. The diameter 2D of the air accumulation tank 12 and the connecting pipe 11 depends only on the diameter D of the pipe channel 13 and does not depend on the diameter of the inflow water tank 10. When the flow enters the inflow water tank 10, air bubbles are generated. However, the air entrained and entrained flow has a connecting pipe 11 having a diameter twice as large as that of the pipe channel 13.
The flow velocity in the inside becomes slow, and the entrained air becomes easy to float. The air thus floated is removed by the air collecting tank 12, and a flow containing no air flows into the pipe channel 13 connected to the air collecting tank.

FIG. 2 is a view for explaining a method of manufacturing the air elimination apparatus of the present invention using a ready-made T-tube. As shown in the figure, an opening 21 for connecting a pipe waterway 22 having a diameter D is formed on the back of a ready-made T-tube 20 having a diameter 2D, and a lid 23 is provided on the bottom surface and a rising pipe 24 is connected. Since the elimination device can be manufactured, processing and installation are extremely simple as compared with the conventional air elimination device.

In FIG. 1, the diameter of the pipe channel 13 is D = 1.
An air exclusion device was manufactured in which the diameter of the opening of the air collecting tank 12 and the diameter of the connection pipe 11 was twice (200 mm) the diameter D of the pipe channel 13, and the experiment was performed by changing the length of the connection pipe 11. . As a result, the distance from the connection between the inflow water tank 10 and the connection pipe 11 to the downstream wall of the air accumulation tank 12 is L = 500 m.
When it is at least m (5D), almost all of the mixed air could be efficiently removed. If the distance from the connection between the inflow water tank 10 and the connection pipe 11 to the downstream wall of the air accumulation tank 12 is L = 400 mm (4D), the pipe waterway 1 is sometimes
In some cases, air bubble particles were mixed in No. 3, but this did not affect the flowing water in the pipe channel 13. L = 400mm
(4D) At the time above, the head height of the pipe channel 13 was stable, and no large fluctuation was found in the flow. Here, the diameter of the air collecting tank 12 and the connecting pipe 11 is
However, the diameter of the air accumulation tank 12 and the connecting pipe 11 does not need to be exactly 2D, and the same effect can be obtained if the diameter is in the range of 1.9D to 2.1D. Is obtained.

As described above, according to the entrained air removing device of the present invention, no air gap is generated in the flow due to the contraction, and almost all the mixed air can be efficiently removed in the air collecting tank 12. The distance L from the connection between the inflow water tank 10 and the connection pipe 11 to the downstream wall of the air accumulation tank 12 may be at least four times the main pipe diameter. Further, as described in FIG. 2, according to the present invention, since the opening of the air collecting tank and the diameter of the connecting pipe are the same, the air collecting tank and the connecting pipe are integrally formed using a ready-made T-shaped pipe. Can be manufactured. Further, since the air collecting tank is adjacent to the water diversion works, compact design and construction can be performed as an integral structure with the water diversion works.

[0019]

According to the present invention, in the pipe of the connecting pipe connecting the inflow water tank and the air collecting tank, the air bubbles mixed and entrained in the flow form a large air mass while floating on the top of the pipe. , It is possible to efficiently remove almost all the amount. From the point of view of device production, the air collecting tank can be installed adjacent to the inflow water tank, so that it is compact and can be designed and constructed as an integral structure with the water tank. Also,
Since the diameter of the air accumulation tank and the diameter of the connection pipe are the same, it is possible to manufacture an air elimination apparatus by processing a ready-made T-shaped pipe, and it is expected that the construction period will be shortened and the cost will be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of a device for removing air entrained in a pipe waterway according to the present invention.

FIG. 2 is a diagram illustrating a method of manufacturing an entrained air removing device using a ready-made T-tube.

FIG. 3 is a schematic view of a conventional entrained air elimination device using a vent.

FIG. 4 is a schematic view of a prototype device with an improved ventilation stand.

FIG. 5 is a schematic diagram of a prototype device of the entrained air removing device.

FIG. 6 is a schematic diagram of another prototype of the entrained air removing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Inflow water tank 11 ... Connection pipe 12 ... Air accumulation tank 13 ... Pipe waterway 20 ... Ready-made T-shaped pipe 21 ... Opening 22 ... Pipe waterway 23 ... Lid 24 ... Rise pipe 30 ... Inflow water tank 31 ... Pipe waterway 32 ... Vent hole 33 ... space ventilation 40 ... inflow water tank 41 ... connection pipe 42 ... ventilation stand 43 ... pipe waterway 50 ... inflow water tank 51 ... connection pipe 52 ... air accumulation tank 53 ... pipe waterway 60 ... inflow water tank 61 ... connection pipe 62 ... air accumulation tank 63 … Pipe canal

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) E03C 1/122 E03B 7/07

Claims (2)

(57) [Claims] 1. A pipe channel air elimination device for removing air mixed and entrained into a pipe channel from an inflow water tank having a free water surface, the air collecting tank having an open upper portion connected to a main pipe of the pipe channel. A connection pipe connecting the inflow water tank and the air accumulation tank, wherein the air accumulation tank and the connection pipe have a diameter of 1.9 to 2.1 times the main pipe, and The distance from the connection part with the said connection pipe to the downstream wall of the said air accumulation tank is 4 times or more of the diameter of the said main pipe, The air exclusion apparatus of the pipe channel characterized by the above-mentioned. 2. The air drainage device according to claim 1, wherein the air collecting tank and the connection pipe are manufactured by processing a ready-made T-shaped pipe.