JPH0826873B2 - Automatic pump controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to automatic pump control when the amount of inflow sewage is predicted by some means in rainwater and sewage pump equipment at sewage treatment plants and relay pump stations. It relates to the device.

[Conventional technology]

FIG. 2 is a system diagram showing a conventional automatic pump control device, for example, published in “Sewerage Facility Resource Saving Energy Manual (Draft)” P46-47, Japan Sewer Association, 1982, where 1 is a pump. Masu 2 is an inflow pipe, 3a, 3
b is a pump, 4a and 4b are motors, 5 is a flow meter, 6 is a lower-level computer that performs nonlinear proportional and derivative control, and 7 is a water level H-flow rate Q
A high-level computer that performs non-linear correction of proportional gain to the deviation of the set water level based on a curve and the water level of pump masu 1, 8
Is an alarm device, 9 is a sequencer for controlling the number of pumps, 10 is a flow rate control device, 11 is a speed control device, 12 is a flow rate signal generator, and 13 is a water level detector of the pump tank 1.

Next, the operation will be described. A water level detector 13 detects the water level of the pump masu 1. Next, for the deviation between the water level set value and the water level given in advance, the lower-order computer 6 determines the non-linear proportionality and the differential control amount, and determines the number of pumps and the instruction value for speed control. The calculation of the nonlinear proportional gain is calculated based on the flow rate (Q) -water level (H) curve in the host computer 7. Next, the pump number control sequencer 9 operates based on the instruction value of the pump number control calculated by the low-order computer 6, and the pump 3a is controlled by the motor 4a. On the other hand, the flow rate adjusting device 10 adjusts the flow rate so that the flow rate information based on the flow meter 5 matches the instruction value of the speed control calculated by the low-order computer 6, and the speed control device 11
Is driven to control the pump 3b by the motor 4b. In this method, it is necessary to set in advance a QH curve corresponding to the fluctuation tendency of the inflow sewage amount and the pump operation time delay time. When the predicted value of the inflow sewage is obtained, the QH curve corresponding to the amount may be selected.

[Problems to be Solved by the Invention]

Since the conventional pump automatic control device is configured as described above, it is necessary to preset the Q-H curve according to the fluctuation tendency of the inflow sewage amount and the operation delay time of the pump. It is extremely difficult to create a QH curve that can keep the water level change of the pump masu 1 within a certain width against a sudden change of the inflow rate in rainy weather. For this reason, when it rains
That is, it is necessary to start a plurality of pumps, perform throttle operation, and perform manual operation such as fully opening operation when the water level rises, which imposes excessive strain on the operator and economically. However, there were many problems such as waste.

The present invention has been made to solve the above problems, and an object of the present invention is to obtain an automatic pump control device capable of highly reliable automatic control not only in fine weather but also in rainy weather.

[Means for solving the problem]

The pump automatic control device according to the present invention has the predicted sewage amount obtained by the inflow sewage amount prediction means accumulated by the predicted inflow sewage amount integration circuit from the present time to the predetermined time ahead and the sewage calculated by the sewage storage amount calculation circuit. A pump discharge amount basic planned value calculation circuit that inputs the stored amount and the pump discharge amount that has been integrated retroactively for a predetermined time in the pump discharge amount integration circuit, and the output from this pump discharge amount basic planned value calculation circuit And the target value of the pump discharge amount at the present time calculated by the pump discharge amount target value calculation circuit,
And a pump discharge amount optimum calculation circuit for calculating the optimum value of the pump discharge amount.

[Work]

In this invention, the integrated value that is the sum of the predicted inflow from the present time to the predetermined time, which is obtained by the estimated inflow sewage accumulation circuit, and the sewage storage amount calculation circuit, at the present time, the water level of the pump masu or inflow pipe, and The accumulated water area is calculated as the sum of the sewage storage amount calculated from the physical shape of the pump or the inflow pipe and the sum of the pump discharge amounts from the present time obtained by the past pump discharge amount integration circuit to the time point traced back in the past. It is input to the pump discharge amount basic plan value calculation circuit for maintaining the target sewage storage amount, and the basic plan value of the current pump discharge amount necessary for maintaining the target sewage storage amount is calculated.

Next, the pump discharge amount optimum calculation circuit uses the pump discharge amount target value calculated by the pump discharge amount target value calculation circuit and the pump discharge amount basic plan value calculated by the pump discharge amount basic plan value calculation circuit. The optimum amount of water is calculated so that the target sewage storage amount can be maintained even when the inflow changes suddenly.

Example of Invention

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention. In FIG. 1, 20 is an inflow sewage amount prediction means, 21 is an estimated inflow sewage amount integration circuit, The inflow sewage accumulated value 22 is output. Reference numeral 23 is a means for detecting the water level of the pump and the inflow pipe, 24 is a sewage storage amount calculation circuit, and this sewage storage amount calculation circuit 24 outputs the sewage storage amount 25. Reference numeral 26 is a past pump discharge amount detecting means, 27 is a past pump discharge amount integrating circuit, and this past pump discharge amount integrating circuit 27 outputs a past pump discharge amount integrated value 28. 29 is a target sewage storage amount detection means (a target water level detection means such as a pump or an inflow pipe can be substituted), and 30 is a time point of the last measurement (k-
Pump discharge amount detection means in 1), 31 is the last measurement time (k
-1) pump discharge amount target value detection means, 32 is a target setting parameter, 33 is a pump discharge amount target value calculation circuit, and this pump discharge amount target value calculation circuit 33 is the pump discharge amount target value at the current time point k. Output 34. 35 is a pump discharge amount basic plan value calculation circuit for maintaining the target sewage storage amount. This pump discharge amount basic plan value calculation circuit 35 is a pump discharge amount basic plan value
Outputs 36. 37 is a weighting coefficient section for maintaining the target storage amount, 38 is a weighting coefficient section for maintaining the pump discharge target value,
Reference numeral 39 denotes a pump discharge amount optimum value calculation circuit that considers both maintenance of the target storage amount and maintenance of the pump discharge amount target value, and this pump discharge amount optimum value calculation circuit 39 outputs the pump discharge amount optimum value 40.

 Next, the operation will be described.

In the estimated inflow sewage accumulation circuit 21, the estimated inflow sewage q _in (k), ..., q from the current time point k to the future time point k + L-1
_In (k + L-1) is integrated.

Ie However, L is the dead time of the pump control system, and the sewage storage amount calculation circuit 24 inputs the water level h (k) (or the water level of the inflow pipe) of the pump masu at the current time k as shown in the following equation (2). Then, the sewage storage amount v (k) is calculated based on the physical shape of the pump masu or inflow pipe.

v (k) = f (h (k)) (2) where f is a function for calculating the sewage storage amount from the water level,
It can be easily obtained if the physical shape is known. Further, in the past pump discharge amount integration circuit 27, the following (3)
As shown in the equation, of the pump discharge amount U (k-1), ..., U (k-L + 1) detected by the pump discharge amount detecting means 26 retroactively from the present time k to the past k- (L-1) time. Accumulated value U _past
Calculate (k).

In the pump discharge amount target value calculation circuit 33, as shown in the following equation (4), the pump discharge amount target value U at the current time point k
^* Determine _sub (k) as follows.

That is, U ^* _sub (k) = αU ^* _sub (k-1) + (1-α) U
(K−1) (4) where α: target setting parameter (0 ≦ α ≦ 1) At this time, if α = 0, U ^* _sub (k) = U (k−1), and Until now, this means setting the target value for this time. If α = 1, U ^* _sub (k) = U ^*
_It becomes _sub (k-1), which means that the previous target value of the pump discharge amount remains unchanged. This aims at a kind of flow rate stabilization control. That is, the equation (4) smoothes the past data of the pump discharge amount, and the pump discharge amount target value is given as one target value for stabilizing the pump discharge amount.

In the pump discharge amount basic plan calculation circuit 35 for maintaining the target sewage storage amount V ^* , the pump discharge amount basic plan value U ^* _pred is given by the following formula U ^* _pred (k ) = V (k) = V ^* + q _pred (k) -U _past
(K) (5) The pump discharge amount optimum calculation circuit 39 uses the following evaluation function as shown in the following expression (6). U (k) that minimizes

However, v (k + L) = v (k) + q _in (k) + ... + q _in (k + L
-1)-{U (k- (L-1)) + ... + U (k-1) + U
(K)} (7). The meaning of the above equation (6) considers both maintaining the sewage storage amount at the (k + L) time at the target value and maintaining the pump discharge amount at the target value, that is, stabilizing the pump discharge amount. It is a thing. Solving equation (6), Becomes That is, the pump discharge amount optimum calculation circuit 39 calculates the above equation (8). Here, if W _V = 0, U (k) = U ^* _sub (k) (pump discharge amount target value maintained)
(9) Moreover, when W _u = 0, U (k) = U ^* _pred (k) (maintaining target sewage storage amount)
Equation (10) is obtained, and equation (8) is an integrated equation.

〔The invention's effect〕

As described above, according to the present invention, the pump automatic control device is optimized to satisfy both the target sewage storage amount maintenance and the pump discharge amount target value maintenance in consideration of the change tendency of the inflow sewage amount and the waste time delay of the pump operation. Since the pump discharge amount can be determined, it is possible to obtain the one that has high reliability and safety and can reduce the operating power cost regardless of the rapid change of the inflow sewage amount.

[Brief description of drawings]

FIG. 1 is a block diagram showing an automatic pump control system according to an embodiment of the present invention, and FIG. 2 is a system diagram showing an example of a conventional automatic pump control system. Predicted inflow sewage amount integration circuit, 24 sewage storage amount calculation circuit, 27 pump discharge amount integration circuit, 33 pump discharge amount target value calculation circuit, 35 pump discharge amount basic plan value calculation circuit, 39 pump discharge amount optimum Calculation circuit.

Claims (1)

[Claims] 1. An inflow sewage amount predicting means for determining the amount of sewage flowing into a pump mast, and a predictive inflow sewage amount integrating circuit for integrating the predicted value obtained by the inflow sewage amount predicting means from a present time to a predetermined time ahead, A sewage storage amount calculation circuit that calculates the sewage storage amount stored in the pump masu, a pump discharge amount integration circuit that integrates the discharge amount of the pump retroactively for a predetermined time from the present, a pump discharge amount at the time of the previous measurement, and a previous measurement Pump discharge amount target value calculation circuit that inputs the pump discharge amount target value and target setting parameter at the time point and calculates and outputs the pump discharge amount target value, and the integrated predicted value integrated by the above-mentioned predicted inflow sewage amount integration circuit Input the sewage storage amount calculated by the sewage storage amount calculation circuit, the integrated discharge amount of the pump discharge amount integration circuit, and the target sewage storage amount to calculate and output the pump discharge amount basic plan value. The pump discharge basic plan value calculation circuit, the output from the pump discharge basic plan value calculation circuit, and the output of the pump discharge target value calculation circuit described above maintain the target value of the sewage storage amount and stabilize the pump discharge amount. A pump automatic control device including a pump discharge amount optimum calculation circuit for calculating the optimum value of the pump discharge amount in consideration of optimization.