JP2017133873A - Flow rate data creation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flow rate data creation method with which it is possible to collect flow rate data from many places at low cost and create a flow rate map in order to investigate unidentified water at many places of a sewer pipeline facility.SOLUTION: Provided is a method for creating flow rate data at a plurality of places A(1) to A(N) in order to investigate unidentified water at the plurality of places A(1) to A(N) (for example, 100 places) of a sewer pipeline facility, said method being designed to obtain flow rate data at the plurality of places A(1) to A(N) by using measured data transiently measured by a flowmeter 1 or a velocity meter at each of the plurality of places A(1) to A(N), Manning's formula, and water level data continuously measured by a water level gauge 2 installed at each of the plurality of places A(1) to A(N).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for creating flow rate data at a plurality of locations in order to investigate unknown water at a plurality of locations in a sewer pipe facility.

  There is an unknown water problem as an important issue in the maintenance of sewage pipeline facilities. Unknown water means the difference between the amount of sewage flowing into the sewage treatment plant and the amount of water supply (water supply). Unknown water is mainly composed of rainwater intrusion water that flows in rainy weather, and always intrusion water into which groundwater, irrigation water, seawater, etc. flow. In general, the sewerage usage fee is calculated from the water supply usage fee, but if there is a lot of unknown water, not only will the processing costs exceed the plan, but there will be contamination of public water areas due to overloading of the treatment plant, Unknown water has become a very serious problem in terms of sewage maintenance and management, such as hollowing around the pipeline, sinking the road, and shortening the life of the pipeline facility itself. In recent years, with the spread of sewerage, the business has changed from construction center to stock management (life management and risk management) of pipeline facilities, but there are situations where the corresponding technology has not caught up. In particular, the optimization of screening (face-to-face survey) technology, which is equivalent to the health examination of pipeline facilities, is recognized as important because it plays an important role in the promotion of the entire business. For example, the following (1) conventional general method, (2) simultaneous multi-point flow rate survey (3) backward flow instantaneous flow rate distribution survey, (4) epidemiological method using existing data, (5 ) Method by temperature distribution survey, (6) Method by electrical conductivity distribution survey] have been announced.

  As a conventional general method of (1), there is a method of quantifying unknown water for a relatively long period of time by installing about five flow meters at an appropriate scale that is not a wide area. This is quantified from the differential flow rate during rainy weather inflowing in rainy weather, and the constant flow rate that is correlated with the midnight minimum flow rate that is expected to have the least sewage effect and the groundwater level, irrigation channel level, tide level, etc. Although it is a method, only minimal research has been conducted in terms of cost effectiveness. The simultaneous multi-point flow rate survey of (2) is a method of quantifying the distribution of unknown water by temporarily installing approximately 20 to 100 flow meters of the type that can be temporarily set up in a short time. The method for quantifying unknown water was the same as in the previous section, and the cost was significantly reduced, but the cost was not reduced to the level required for screening. The backward flow type instantaneous flow rate distribution survey in (3) is a survey for the purpose of quantifying constantly intruded water out of unknown water. This is a method that mainly measures the instantaneous flow rate flowing into the manhole at midnight, and quantifies it while going back from the downstream to the upstream. . The epidemiological method using the existing data in (4) is a simple survey method for the inundation area in rainy weather. This is to investigate the distribution of rainwater intrusion at the AMeDAS mesh scale using the treatment plant inflow sewage amount and AMeDAS data for 3 years. An error may occur if there are many places such as a flood or manhole pump that are full. The method of temperature distribution survey in (5) is a method of investigating the unknown water distribution from the temperature difference during rainy days and daytime and nighttime using the temperature difference between sewage, rainwater and groundwater, but the temperature difference is clear. In some cases, an error may occur. The method based on the electrical conductivity distribution survey in (6) is a method of investigating the unknown water distribution from the electrical conductivity difference during rainy days or daytime and nighttime using the electrical conductivity difference between sewage, rainwater and groundwater. However, in the case where the difference in electrical conductivity is not clear, an error may occur.

  However, the above-described techniques (1) to (3) are limited to measurement at several tens of places at most because of cost problems, and a flow rate map that covers many places has not been created. In addition, for the techniques (4) to (6), a wide area map having a flow rate accuracy has not been created.

  The present invention has been made in view of the above problems, and in order to investigate unknown water at a large number of locations in a sewage pipeline facility, it is possible to collect a continuous flow rate data at a large number of locations at low cost and create a flow rate map. It is to provide a flow rate data creation method.

  In order to achieve the above object, the flow rate data creation method of the present invention is a method for creating flow rate data at a plurality of locations in order to investigate unknown water at a plurality of locations in a sewage pipeline facility, Use measurement data temporarily measured by flowmeters or velocimeters at each location, Manning's formula, and water level data continuously measured by water level meters installed at each of the plurality of locations. To obtain flow rate data at the plurality of locations (claim 1). Moreover, in this invention, the flow-rate data creation method of Claim 1 which uses a surface velocity type flow meter as said flow meter is provided (Claim 2). According to the present invention, there is provided a flow rate data creation method according to claim 1, wherein a flume type flow meter is used as the flow meter (claim 3).

In continuously investigating the flow rate at a plurality of locations (for example, several 10 to several hundred locations) of a sewer pipe facility in order to investigate unknown water, Manning's average flow rate formula V _m = (1 / n) ・ R ^2/3・ I ^1/2
[Note that the flow rate Q = AV _m , A: fluid product, V _m : average flow velocity, n: roughness coefficient, R: depth of diameter (A / P), I: gradient, P: Junbe (flow crosses) Length that touches the wall))
The step of obtaining the average flow velocity V _m in a transient manner, the step of continuously measuring the water level at each of the plurality of locations using a water level meter (for example, a water level sensor with a data logger), and the average obtained A step of obtaining continuous data of the flow rate Q based on the flow velocity V _m and the obtained water level h. Therefore, in the present invention, only a low-priced water level meter (for example, a water level sensor with a data logger) is installed and installed at each of a plurality of locations. On the other hand, an expensive surface speed type flow meter or a flume type flow meter is not fixedly installed. By obtaining the average flow velocity V _m at that location by rotating them around, it becomes unnecessary to use a plurality of expensive surface velocity flow meters, for example, to obtain the average flow velocity V _m at each of the locations ( A portable type, for example, a single surface velocity type flow meter is used so that the average flow velocity can be obtained by one-time measurement at each location) and a coefficient required for obtaining the flow rate Q (for example, flow product) A, diameter depth R) is a function of the water level obtained by a water level meter (for example, a water level sensor with a data logger), and the flow rate at multiple locations in the sewer line facility using these and one-time measured average flow velocity values. There is an effect that all Q can be obtained. As a result, in the present invention, continuous flow rate data at a plurality of locations (for example, several tens to several hundreds) of the sewage pipeline facility can be created at low cost.

It is a figure for demonstrating the flow volume data creation method which concerns on this invention, and has expanded and illustrated one part.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited thereby. In FIG. 1, the flow rate data creation method according to this embodiment is configured so that the plurality of locations A (1 ) To A (N), which is a method of creating flow rate data, and the measurement data temporarily measured by the flow meter 1 or the velocimeter at each of the plurality of locations A (1) to A (N) By using Manning's average flow rate formula and the water level data continuously measured by the water level gauge 2 installed at each of the plurality of locations A (1) to A (N), the plurality of locations A (1). Continuous flow rate data at ~ A (N) is obtained.

The water level gauge 2 is installed and installed at all the plurality of locations A (1) to A (N). Moreover, in this embodiment, a water level sensor with a very inexpensive data logger (for example, with a recorder and an accumulator) is used as the water level meter 2. On the other hand, in this embodiment, as the flow meter 1, an ultrasonic surface velocity type flow meter (for example, manufactured by our company or mainstream) frequently used in the flow measurement of sewers is used. This surface velocity type flow meter calculates the flow rate from the average flow velocity measured by the Doppler velocimeter and the cross-sectional area of the flowing water obtained from the water level measurement, but is expensive (about 2 to 2.4 million yen), In this way, the average flow velocity V _m is measured. Similarly, an expensive flume type flow meter may be used as the flow meter 1. Measurement data can also be obtained with an anemometer. In the present invention, instead of using a plurality of expensive surface velocity type flow meters 1 to install (fixed installation) at a plurality of locations and calculating the flow rate, one surface velocity type flow meter 1 is not fixed installation but one unit. The surface velocity type flow meter 1 is carried around, for example, so as to be measured temporarily (for example, only once). And the water level sensor 2 is installed and installed at each location A (1) -A (N) at the same time when the surface speed flow meter 1 is carried around to each location A (1) -A (N). .

  The water level sensor 2 can be temporarily installed by a dedicated mount in a short time. That is, in the case of a small-diameter dedicated mount, a spring fixing type is used, and the water level sensor 2 is fixed by the fixing bracket using the spring function of the mount itself. In the case of a medium-diameter dedicated mount, a turnbuckle fixed type is used. In addition, a sensor fixed type (insertion type) can also be used. This is because the water level sensor 2 is attached to the support bracket in a state where the tip of the water level sensor 2 faces the unknown water flow (the tip is directed upstream of the flow). And is fitted in the bracket. The support metal fitting and the metal fitting are fixed to the mount in advance. Further, a type of mounting a water level sensor 2 fitted with a water passage hole on the mount surface and buffering high flow dynamic pressure with this cover can be used. In this way, the water level sensor 2 can be temporarily installed in a short time, and measures are taken to cope with adhesion / deposition of filth and the like in unknown water and further to cope with unknown high water flow velocity.

In the present invention, an absolute pressure detection type water level gauge (for example, a water level sensor with a data logger) 2 is temporarily installed at the water level detection positions at the plurality of locations A (1) to A (N), and the flow rate Q from the water level measurement value h. In this embodiment, the accuracy of measuring the water level (water pressure → water weight → water depth) cannot be maintained with only the absolute pressure (water pressure) P _1. One to several atmospheric pressure loggers (portions indicated by triangles in FIG. 1) L capable of measuring P ₂ are temporarily set near the water level detection, and the water level is calculated from the differential pressure (gauge pressure). In a certain area S _{1 to} S _n (in the area where the atmospheric pressure is considered to be almost the same everywhere), it is only necessary to provide the atmospheric pressure logger L at one place (for example, in area S ₁ , A (2)). Only the atmospheric pressure logger L may be provided). In FIG. 1, only the portions S ₁ and _Sn are shown enlarged.

The flow rate calculation is based on the Manning average flow velocity formula described above. However, the roughness coefficient n and the gradient I are actually measured values calculated from the water level and the average flow velocity at the water level meter installation locations A (1) to A (N), which are actually measured with a portable, for example, surface velocity type flow meter 1. Is used.
Manning formula V _m = (1 / n) ・ R ^2/3・ I ^1/2
[Flow rate Q = AV _m , A: flow product (m ² ), V _m : average flow velocity (m / sec), n: roughness coefficient, R: depth of depth (A / P), I: gradient , P: Junbe (length that the flow touches the transverse wall) (m)]
Since the diameter depth R in the Manning average flow velocity formula is calculated from the channel shape and water depth, (1 / n) × I ^1/2 can be calculated from the product A and the average flow velocity V _m .

Thus, in this embodiment, first, the transient data obtained by the surface velocity type flow meter 1 is used, and then the continuous water level data measured by the water level meter 2 for, for example, one month is used as the Manning formula. It is possible to obtain continuous flow rate data at the plurality of locations A (1) to A (N) simply by substituting for. That is, the measured value of the average flow velocity V _m (m / sec) measured by the surface velocity type flow meter 1 is, for example, 10 (m / sec). Since (I ^1/2 / n) = V _m / R ^2/3 (1), the measured value of 10 is substituted for V _m in equation (1),
(I ^1/2 ) ÷ n = 10 ÷ R ^2/3 (1) ′.

On the other hand, the measured value of the water level (water depth) h (m) measured by the water level sensor with data logger 2 is, for example, 0.5 (m). Moreover, the diameter depth R (= A / P) which is one of the coefficients in the Manning formula can be calculated from the channel shape and the water depth h (m). Here, a circular sewage pipe is taken as an example. That is, let the diameter (known value) of the sewage pipe line be r (m), and let θ be the circumferential angle corresponding to the wet side P.
The wet side P becomes P = π × r × (θ / 2π) = (r × θ) / 2 (2). The product A, which is one of the coefficients in Manning's formula, is A = (1/8) × r ² × (θ−sin θ) (3).
However, A = π × (r / 2) ² × (θ / 2π) − (1/2) × [2 × (r / 2) × sin (θ / 2) × (r / 2) × cos (θ / 2)]
= (1/8) * r < ² > * [[theta] -2sin ([theta] / 2) * cos ([theta] / 2)]
= (1/8) × r ² × [θ− (sin (θ) + sin (0)].
And
Substituting the equations (2) and (3) into R = A / P,
2R = (1/8) × r ² (θ−sin θ) / (r × θ) (4)
Also,
h = r / 2− (r / 2) cos (θ / 2)
Therefore, cos (θ / 2) = 1− (2 / r) × h.
Therefore, θ can be obtained from the water depth h (m) obtained from the water level sensor 2 and a known value (diameter r of the sewer pipe) obtained from the water channel shape. For example, h = 0.5 and r = 1. That is, the diameter depth R is calculated from the diameter r (m) (water channel shape) of the sewer pipe and the water level (water depth) h (m) measured by the water level sensor 2 from the equation (4).
Therefore, it is possible to calculate the value of the diameter depth R by substituting h = 0.5 and r = 1 into the equation (4), and substituting this diameter depth value into the equation (1) ′ (I ^1/2 ) ÷ n can be calculated and
Further, the measured value (= 10) of the average flow velocity V _m (m / sec) described above is multiplied by the product value shown in the equation (3), so that each of the plurality of locations A (1) to A (N) is multiplied. The flow rate Q can be measured.

In this embodiment, Manning's average flow velocity formula is used, the average flow velocity V _m temporarily measured by the surface velocity type flow meter 1, the value obtained from the channel shape and the water level h, and an inexpensive water level sensor. The continuous flow rate data at each location A (1) to A (N) can be obtained from the continuous water level data at each location A (1) to A (N) according to 2. And since the expensive surface velocity type flow meter 1 is carried around, for example, the investigation of a large number of locations A (1) to A (N) necessary for screening can be realized at a low cost. That is, it is possible to obtain a simple and inexpensive water level measurement with the water level sensor 2 and an average flow velocity measurement with an expensive but portable flow meter such as the surface velocity type flow meter 1, and in the Manning formula A device is devised so that necessary coefficients and the like can be known, whereby the flow rate Q of each of the locations A (1) to A (N) can be calculated.

  In addition, in order to improve the flow measurement accuracy, it is possible to investigate combinations with surface velocity flow meters and flume flow meters as necessary. It is also possible to investigate combinations with surface velocity flowmeters, flume flowmeters, and velocimeters. It is also possible to make corrections based on measured values of temperature and electrical conductivity in order to improve the accuracy of inundation in rainy weather and constant infiltration water amount. The present invention can be applied to a water level flow rate survey related to rainwater management, and can also be applied to a water level flow rate survey related to confluence improvement. Applications of this technology include, for example, rainwater management (measures for intrusion based on water level measurement during rainfall in rainwater pipes) and merging improvement (discharge management based on water level measurement of inflow pipes and intercepting pipes in confluence pipes). Is also possible.

1 Flow meter 2 Water level meter A (1) to A (N) Multiple locations of sewage pipeline facilities

Claims (3)

  In order to investigate unknown water at a plurality of locations of a sewer pipe facility, a method of creating flow rate data at the plurality of locations, which was temporarily measured by a flow meter or an anemometer at each of the plurality of locations. The flow rate data obtained by using the measurement data, Manning's formula, and the water level data continuously measured by the water level gauges installed at each of the plurality of locations. How to make.   The flow rate data creation method according to claim 1, wherein a surface velocity type flow meter is used as the flow meter. The flow rate data creation method according to claim 1, wherein a flume type flow meter is used as the flow meter.

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