JPH11132797A - Water quantity measuring method for rainwater storage reservoir - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water quantity measuring method, of which measuring accuracy is improved, while simplifying the device constitution and operation. SOLUTION: A water gage 8 for measuring the water level of a rainwater storage reservoir 3 is provided, a process controller 5 incorporates water level measurement values at every time (n) from the water gage 8, finds a residual quantity A(n) at every time from the water level measuring value, find the difference B(n) between respective residual quantities of the previous time (n-1) and the present time (n), integrates it as a inflow C, when the difference B(n) increases, integrates it as the discharge D, when the difference B(n) decreases, the finds the integrated results as the inflow C and the discharge D.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring the amount of inflow and discharge of water (return amount) and the amount of residual rainwater in a rainwater reservoir.

[0002]

2. Description of the Related Art As a method of operating a rainwater storage tank, it is common to store rainwater during rainfall and return it to a sewage facility when the weather is fine, or to discharge (drain) water to a river. FIG. 3 is a schematic diagram showing the operation of the rainwater storage tank. The rainwater flowing into the rainwater pump well 1 is pumped into the rainwater storage tank 3 by the pump 2 and stored in the rainwater storage tank 3. And drain into rivers.

[0003] In order to properly operate this rainwater reservoir,
It is necessary to measure the amount of inflow and the amount of drainage in the rainwater reservoir, determine the residual amount of rainwater in the rainwater reservoir 3 from them, and control the pump 2 and the drain valve 4 from the residual amount and the like. To measure the inflow amount, the process controller 5 calculates the head H of the pump 2 from the measurement value of the water level gauge 6, and based on the calculated head amount H, the pumping amount (discharge amount: inflow amount of the reservoir) Q-H of the pump 2. Calculated from the curve. The amount of drainage is measured by a flow meter 7
I want more. These measurements are performed for each unit time, and the process controller 5 calculates for each unit time.

[0004]

In the conventional measuring method,
The amount of water flowing into the rainwater reservoir 3 is obtained from the QH characteristic of the pump 2, and the amount of drainage is obtained from the flow meter 7. This difference in the measurement method deteriorates the measurement accuracy of the residual rainwater amount, which is the difference between the inflow amount and the drainage amount, in the process controller.

Further, when trying to control the residual amount of rainwater to be constant, the total value of the inflow amount and the total value of the drainage amount should be equal. However, this is not the same, and the water level of the rainwater reservoir 3 is kept constant. Uncontrollable things happen.

[0006] Further, as a measuring device, a water level gauge 6 for a pump well and a flow meter 7 for a rainwater reservoir, and a converter for converting each measurement signal into a digital signal handled by the process controller 5 are required.

It is an object of the present invention to provide a water flow measuring method which has an improved measuring accuracy while simplifying the device configuration and calculation.

[0008]

SUMMARY OF THE INVENTION According to the present invention, a residual amount at each time is obtained from a water level of a rainwater reservoir, and an inflow amount and a drainage amount at each time period are obtained based on whether the difference of the residual amount at each time is positive or negative. By integrating these, the inflow amount and the drainage amount up to the current time are obtained, and the following method is characterized.

In measuring the inflow from the pump well into the rainwater reservoir, the drainage from the rainwater reservoir, and the residual amount of the rainwater reservoir, a water level meter for measuring the water level of the rainwater reservoir is provided. The water level measurement value at each time n is taken from the water level meter, and the residual amount A (n) at each time is obtained from the water level measurement value. A quantity difference B (n) is obtained at each time,
When the difference B (n) increases, it is integrated as the inflow amount C, and when the difference B (n) decreases, it is integrated as the drainage amount D, and the calculating means for obtaining the integrated result as the inflow amount and the drainage amount is provided. It is characterized by having.

[0010]

FIG. 1 is an apparatus configuration diagram showing an embodiment of the present invention. The rainwater reservoir 3 is provided with a water level gauge 8,
The process controller 5 calculates the inflow amount, the drainage amount, and the residual amount in the rainwater reservoir 3 from the measured water level signal of the water level gauge 8.

The operation flow of the process controller 5 is as shown in FIG. At a measurement time n, a water level measured value by the water level gauge 8 is fetched (S1), and a residual amount A (n) of the rainwater reservoir 3 at the time n is calculated from the measured value (S2). This calculation is obtained by previously obtaining a storage amount characteristic or table data determined from the shape and the water level of the rainwater storage reservoir 3 and applying the water level thereto. The residual amount A (n) is obtained as a residual amount at each time,
These data are stored in the process controller.

Next, at the time (n-1), the residual amount A (n-
The difference between 1) and the residual amount A (n) at time n, that is, the residual amount difference B (n) = A (n) -A (n-1) is calculated (S3). This difference B (n) corresponds to an increase, decrease or no change in the residual amount from the previous time (n-1) to time (n), and the increase in the residual amount may be regarded as an inflow into the rainwater reservoir. Yes, the reduction can be considered as drainage from the rainwater reservoir, and no change can be considered as no inflow and drainage to the rainwater reservoir.

It is determined whether the difference B (n) has increased or decreased (S4). When the difference B (n) increases, the difference B (n) is used as the inflow amount in the period (n- (n-1)). Integrate into C (S
5). When the difference B (n) decreases, the period (n-
The difference B (n) is used as the drainage amount D as the drainage amount in (n-1)).
(S6). When there is no change in the difference B (n), the integration is not performed.

This processing is performed by changing the residual amount A at each time n.
(N) (n = 1, 2, 3,... X) is repeated (S
7) As a result, the sum of the inflow amount or the drainage amount in each period can be obtained as the integrated value of the inflow amount C and the drainage amount D.

[0015]

As described above, according to the present invention, the residual amount at each time is obtained from the water level of the rainwater reservoir, and the inflow amount and the drainage amount for each period are determined by the sign of the difference of the residual amount at each time. Since the inflow and drainage up to the current time are obtained by integrating these, the total value of the inflow and the total value of the drainage are obtained from the residual amount that becomes one variable, and the residual amount is calculated from the water level. Since it is obtained with high accuracy, it is possible to obtain data of the inflow amount, the drainage amount, and the residual amount with high measurement accuracy.

Further, the apparatus can be simply constructed by a water level gauge and arithmetic processing means of a process controller.

[Brief description of the drawings]

FIG. 1 is an apparatus configuration diagram showing an embodiment of the present invention.

FIG. 2 is a calculation flow of a process controller in the embodiment.

FIG. 3 is a configuration diagram of a conventional apparatus.

[Explanation of symbols]

 1 pump well 2 pump 3 rainwater reservoir 4 5 process controller 6 8 water level gauge

Claims (1)

[Claims] Claims 1. An inflow from a pump well to a rainwater reservoir,
In measuring the drainage amount from the rainwater reservoir and the residual amount of the rainwater reservoir, a water level meter for measuring the water level of the rainwater reservoir is provided, and the process controller acquires the water level measurement value at each time n from the water level meter. , The residual amount A (n) at each time is obtained from the measured water level, and the previous time (n-1) and the current time n
The difference B (n) of each residual amount with respect to
When (n) increases, it is integrated as an inflow amount C, when the difference B (n) decreases, it is integrated as a drainage amount D, and there is provided a calculating means for obtaining the integrated result as the inflow amount and the drainage amount. A method for measuring the amount of water in a rainwater reservoir.