JP2005023630A - Structure of suction water tank - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure of a miniaturized suction water tank unnecessary for maintenance for removing deposit without providing a grit chamber. <P>SOLUTION: The structure of the suction water tank 4 storing influent from an influent passage 2 therein and, at the same time, installing a pump 3 pumping and draining the influent to be stored therein is so constituted that an inclined guide surface 4a guiding solid foreign matter mixed with the influent is formed along an opening section 3a of the pump 3 at an angle θ of inclination larger than a sliding angle of the solid foreign matter toward the bottom site of the suction water tank 4 on which the opening section 3a of the pump 3 is faced. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a structure of a suction water tank in which inflow water from an inflow water channel is stored and a pump for pumping and discharging the stored inflow water is installed.
[0002]
[Prior art]
Conventionally, if a swirling flow or vortex is generated on the free water surface of the suction tank, cavitation, vibration, etc. will occur and drainage becomes impossible. When the connection gradient of the bottom surface of the suction water tank is defined and becomes a gradient larger than a predetermined gradient, the distance from the inclined portion to the opening of the pump is sufficiently secured.
[0003]
[Non-Patent Document 1]
Supervised by the Ministry of Land, Infrastructure, Transport and Tourism Policy Planning and Construction Planning Section “Technical Standards for Pumping and Drainage Pumps (Draft)”, edited and published by the Association of River Pump Facilities Association, February 2001, P249
[0004]
[Problems to be solved by the invention]
However, according to the conventional technique as described in Non-Patent Document 1 described above, solid foreign matters such as gravel and sand mixed in the water flowing into the suction water tank at a slow flow rate reach the vicinity of the opening of the pump. It was deposited on the bottom away from the opening of the pump without being carried, and maintenance work was required to periodically remove foreign substances such as sand accumulated from the suction water tank. In order to reduce such maintenance work, it is necessary to provide a sand basin and a screen for removing foreign substances in the front stage of the suction water tank, which has the disadvantage of increasing the size of the facility.
[0005]
In view of the above-mentioned conventional drawbacks, the present invention is to provide a small suction water tank structure that does not require maintenance for removing sediment without providing a sand basin.
[0006]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the first characteristic configuration of the structure of the suction water tank according to the present invention is that, as described in claim 1 of the column of the claims, inflow water from the inflow water channel is stored, A structure of a suction water tank in which a pump for pumping and discharging stored inflow water is installed, and the slant guides solid foreign substances mixed in the inflow water toward the bottom part of the suction water tank facing the opening of the pump The guide surface is formed.
[0007]
That is, solid foreign substances such as gravel and sand that flow into the suction water tank together with the inflow water are guided toward the bottom part of the suction water tank where the opening of the pump faces by the inclined guide surface. Since it will be drained and will not accumulate in the suction water tank, it will not be necessary to provide a sand basin or the like that will lead to an increase in the size of the equipment or to maintain frequent removal of foreign matter.
[0008]
As described in claim 2 of the same column, the second characteristic configuration is that, in addition to the first characteristic configuration described above, the inclined guide surface is provided in a stagnation portion of the suction water tank.
[0009]
Foreign matter mixed into the inflowing water is likely to be deposited particularly on the stagnation portion having a very low flow velocity, and providing the inclined guide surface on the stagnation portion is effective in reducing the accumulation of the foreign matter.
[0010]
In the third characteristic configuration, as described in claim 3 of the same column, in addition to the first or second characteristic configuration described above, the inclined guide surface is formed along the opening of the pump. It is in.
[0011]
The suction pipe, which is the pump opening, is usually composed of a cylindrical body that expands forward, but if the inclined guide surface is configured along the shape of such a cylindrical state, along the inclined guide surface Since the guided foreign matter is sucked with a uniform suction force, there is an advantage that fluctuations in pump load and uneven distribution of foreign matter can be eliminated.
[0012]
In the fourth feature configuration, as described in claim 4 of the same column, in addition to any of the first to third feature configurations described above, the inclined guide surface has an inclination angle greater than an angle of repose of the solid foreign matter. It is in the point formed by.
[0013]
By constructing the inclined guide surface to an inclination angle equal to or greater than the repose angle of the foreign object serving as the guided object, the foreign object can be reliably guided to the bottom portion of the suction water tank where the pump opening faces without being deposited on the inclined guide surface. it can. For example, when the foreign substance is sand, the inclination angle may be set to 30 degrees or more larger than the repose angle of sand.
[0014]
In the fifth feature configuration, in addition to any of the first to fourth feature configurations described above, the inclined guide surface sucks the foreign matter from the opening of the pump. It is to guide to the possible area.
[0015]
Although the foreign material is guided toward the bottom surface portion of the suction water tank where the pump opening faces by the inclined guide surface, the above-described configuration ensures that the foreign material guided to the bottom surface portion does not accumulate on the spot. It will be sucked into the pump.
[0016]
In the sixth feature configuration, as described in claim 6 of the same column, in addition to the fifth feature configuration described above, the region that can be sucked from the opening of the pump is a predetermined variable having the diameter of the opening as a variable. It is determined by the function of
[0017]
In order to specifically set the area that can be sucked from the opening of the pump, it is determined by a predetermined function using the diameter of the opening of the pump as a variable, so that it is possible to perform construction without variation.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the structure of the suction water tank according to the present invention will be described below. As shown in FIG. 1, a pumping / draining treatment facility 1 installed at a pumping / draining pump station is connected to a suction water tank 4 for storing water and an upper part of the suction water tank 4, and the inflow water falls into the suction water tank 4. And a pump 3 for pumping and draining the inflow water from the inflow water channel 2 to the downstream drainage channel.
[0019]
The suction water tank 4 is provided with a pressure detection type water level sensor (not shown), and when the stored sewage water level reaches a predetermined discharge water level (HWL), the pump 3 interlocked with the water level sensor is provided. By operating, the sewage is sucked from the opening 3a which is the suction port of the pump 3, and the sewage is transferred from the discharge port 3b toward the subsequent drainage channel until reaching a predetermined standby level (LWL).
[0020]
The opening 3a of the pump 3 is a vertical axis submersible pump arranged in a posture facing the bottom surface of the suction water tank 4, and not only dirty water but also dirty water by a rotary blade (not shown) connected to the shaft core of the motor. It is configured to be capable of sucking and transferring the small-diameter solid foreign matters mixed therein, and guides the solid foreign matters 5 such as sand and pebbles mixed in the inflowing water to the suction water tank 4 toward the bottom portion facing the opening 3a. The inclined guide surface 4a is formed by placing mortar or concrete, so that the solid foreign matter 5 mixed in the sewage flowing down from the inflow water channel 2 is dropped and conveyed along the inclined guide surface 4a and is opened together with the sewage. It is configured to be sucked and transferred from the portion 3a.
[0021]
The inclined guide surface 4a is provided in all or a partial area of the stagnation portion of the suction water tank 4 where the suction action to the solid foreign matter by the pump 3 does not reach, and thereby the range in which the solid foreign matter reaches the suction action by the pump 3 By being guided to the (suctionable area), a large amount of solid foreign matter accumulates on the bottom of the suction water tank 4 and the occurrence of a situation where maintenance for removing the foreign matter is required can be avoided.
[0022]
The region that can be sucked from the opening 3a of the pump 3 is determined by a predetermined function having the diameter D of the opening 3a as a variable. Specifically, the lower edge of the inclined guide surface 4a when the opening 3a is installed at a distance of 1D from the bottom surface of the suction water tank 4 is set to be 1D from the axis of the pump 3, The guide surface 4a is formed at an inclination angle that is equal to or greater than the repose angle of the solid foreign matter that flows in. For example, when the inflowing solid foreign matter is mainly sand, the inclination is 30 degrees or more, which is an inclination larger than the repose angle of sand in the direction away from the axis of the pump 3 from the lower edge of the inclined guide surface 4a. It is set to incline at an angle θ.
[0023]
As shown in FIG. 2, the inclined guide surface 4 a is formed along the opening 3 a of the pump 3, that is, the lower edge of the inclined guide surface 4 a has a shape along the opening 3 a of the pump 3. Thus, it is preferably formed around the entire periphery of the opening 3a. However, the present invention is not limited to this. If it is formed at least at a part of the periphery of the opening 3a, it is solid within that range. The accumulation of foreign matter can be prevented.
[0024]
Hereinafter, another embodiment will be described. When the inflow water channel 2 is connected to the suction water tank 4 and a plurality of pumps 3 are installed, as shown in FIG. 3, the inclination angle θ between the pumps 3 faces the opening 3 a of each pump 3. However, as shown in FIG. 4, at least the opening 3 a of the pump 3 is formed from the bottom surface of the suction water tank 4. The lower edge of the inclined guide surface 4a when installed at a distance of 1D is set so that the lower edge of the inclined guide surface 4a is a distance of 1D from the axial center of the pump 3, and the three walls except for the wall connected to the inflow water channel 2 A predetermined effect can be obtained if the inclined guide surface 4a is formed so as to be inclined at an inclination angle θ.
[0025]
In the above-described embodiment, the inflow water channel 2 is connected to a portion having a step from the bottom surface of the suction water tank 4, and the inflow water from the inflow water channel 2 falls and flows into the tank. Thus, the structure which is comprised by the inclined bottom face continuously connected from the bottom part of the inflow water channel 2 to the bottom face of the suction water tank 4 may be sufficient. In this case, what is necessary is just to comprise so that an inclination bottom face may act as the inclination guide surface 4a.
[0026]
In the above-described embodiment, the configuration in which the inclined guide surface 4a is configured so that the lower edge portion of the inclined guide surface 4a is formed in a circular shape with the entire circumference or a part along the circular opening 3a of the pump 3 has been described. However, the lower edge portion of the inclined guide surface 4a is not limited to a shape similar to the shape of the opening 3a, and may be formed so as to substantially follow the shape of the opening 3a. And can be appropriately constructed.
[0027]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a small suction water tank structure that does not require maintenance for removing sediment without providing a sand basin.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of a pumping and draining treatment facility according to the present invention. FIG. 2 is a schematic plan view of a pumping and draining treatment facility according to the present invention. FIG. 4 is a schematic plan view of a pumping and draining treatment facility showing another embodiment. FIG. 5 is a schematic sectional view of a pumping and draining treatment facility showing another embodiment.
1: Pumping and drainage treatment equipment 2: Inflow water channel 3: Pump 3a: Opening (suction port)
3b: Discharge port 3b
4: Suction water tank 4a: Inclined guide surface D: Diameter of opening θ: Inclination angle

Claims (6)

Inflow water from the inflow water channel is stored, and the structure of the suction water tank in which a pump for pumping and discharging the stored inflow water is installed,
The structure of the suction water tank in which the inclination guide surface which guides the solid foreign material mixed in inflow water is formed toward the bottom face part of the said suction water tank which the opening part of the said pump faces. The suction water tank structure according to claim 1, wherein the inclined guide surface is provided in a stagnation portion of the suction water tank. The suction water tank structure according to claim 1, wherein the inclined guide surface is formed along an opening of the pump. The structure of the suction water tank according to any one of claims 1 to 3, wherein the inclined guide surface is formed at an inclination angle greater than an angle of repose of the solid foreign matter. The structure of the suction water tank according to any one of claims 1 to 4, wherein the inclined guide surface guides the foreign matter to an area that can be sucked from an opening of the pump. The suction water tank structure according to claim 5, wherein an area that can be sucked from the opening of the pump is determined by a predetermined function having a diameter of the opening as a variable.

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