JPH0455916A - Waste water pump controller - Google Patents

Abstract

PURPOSE:To keep the level of a waste water pump well within a prescribed range by correcting a target discharge flow rate based on the decision whether the target discharge flow rate is kept within a range of a stable supply amount or not and the decision whether the level of the waste water pump well is kept within a prescribed range or not and applying the velocity control to a waste water pump. CONSTITUTION:A discharge flow rate correction means 11 receives a target discharge flow rate from a discharge flow rate arithmetic means 3 and decides whether this flow rate is kept under a prescribed upper/lower discharge flow rate limit range for stable supply or not. Furthermore the means 11 decides whether the level of a waste water pump well is under a prescribed upper/lower limit range or not. Based on these deciding results, the target discharge flow rate and the upper/lower discharge flow rate limit range for stable supply are decided and given to a velocity control part. Thus the stable supply of the waster water is secured in principle to a waste water treating system. Furthermore the power variance of a waste water pump is kept within a fixed range.

Description

DETAILED DESCRIPTION OF THE INVENTION [Purpose of the Invention (Field of Industrial Application) The present invention relates to a sewage pump control device used in water purification plants and other sewage treatment facilities. This invention relates to improvement of a sewage pump control device that stably supplies sewage to a treatment system.

(Prior art) Generally, in a sewage treatment facility, sewage is temporarily stored in a sewage pump well, and at the same time, sewage is pumped out from the sewage pump well in order to maintain the water level of the sewage pump well at a nearly constant target water level. Since it is necessary to supply a subsequent sewage treatment system, such as a settling tank, a plurality of pumps are installed between the sewage pump well and the settling tank. A sewage pump control device is provided to increase or decrease the number of these pumps in operation and simultaneously control the speed of the pumps.

FIG. 3 is a diagram showing the configuration of such a conventional sewage pump control device. That is, in this device, the water level of the sewage pump well 1 is detected by the water level gauge 2 and introduced into the P1 calculation section 3. In this P■ calculation unit 3, the detected water level Lpv from the water level gauge 2
After determining the deviation from the target water level LSV, a PI calculation is performed based on this deviation to obtain a control request value, and this control request value is supplied to the number control unit 4 and the speed control unit 5 as the target discharge flow rate Qsv. do. Here, the number control unit 4 determines the number of operating sewage pumps 6 based on the target discharge flow rate Qsν and the pump capacity, and performs control to start or stop one pump according to the determined number.

On the other hand, the speed control unit 5 is configured to execute a PI calculation based on the deviation between the target discharge flow rate Qsv and the discharge flow rate detected by the discharge flow meter 7, and control the operating speed of each pump 6 according to the target discharge flow rate Qsv. It becomes.

8 is a settling basin.

(Problems to be Solved by the Invention) One of the roles of the sewage pump well 1 is to stably supply water to the subsequent sewage treatment system, such as the settling tank 8. This means that if sewage can be stably supplied, sewage treatment can also be carried out stably. Therefore, sewage pump well 1
serves as a buffer to some extent.

However, in the conventional sewage pump control device, the sewage pump well 1
The system relied solely on controlling the water level at a constant level, and did not have the ability to stably supply wastewater to the subsequent wastewater treatment system. As a result, there are problems, for example, that chemical control in the sedimentation tank cannot be performed stably and that driving power for the pump is wasted.

The present invention has been made in view of the above circumstances, and provides a sewage pump control device that can always store the water level in a sewage pump well within a specified range and can always stably supply sewage to the subsequent sewage treatment system. The purpose is to

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above problems, the present invention provides a method for discharging water based on the deviation between the water level signal from the sewage pump well water level detection unit and the set target water level. A discharge flow rate calculation means for calculating a target value of flow rate, a determination as to whether the target discharge flow rate obtained by the discharge flow rate calculation means is within a range of stable supply amount, and a judgment as to whether the sewage pump well water level is within a specified water level range. A discharge flow rate correction means for correcting a target discharge flow rate based on the above judgment, and a speed control section for controlling the speed of the sewage pump using the discharge flow rate correction value from the discharge flow rate correction means as a target value. be.

(Function) Therefore, in the present invention, by taking the above-mentioned measures, when the discharge flow rate correction means receives the target discharge flow rate from the discharge flow rate calculation means, this target discharge flow rate adjusts the predetermined stable supply of discharge. Determine whether the flow rate is within the upper and lower limit specified values, and further determine whether the water level of the sewage pump well is within the upper and lower limit specified values, and adjust the target discharge flow rate and stability according to these judgment results. Since the upper and lower limits of the supply discharge flow rate are selected and given to the speed control unit, a stable supply of sewage to the sewage treatment system can be ensured in principle, and power fluctuations of the sewage pump can be kept within a certain range. things become possible.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention, and the same parts as in FIG. 3 are given the same reference numerals, and detailed explanation thereof will be omitted. That is, in this device, a water level gauge 2 is provided in a sewage pump well 1, and the water level gauge 2 detects the water level in the pump well 1 and supplies the water level to a PI processing unit 3. This PII calculation part 3
executes a PI calculation based on the deviation between the detected water level Lpv of the water level gauge 2 and the target water level Lsv, and sets the output obtained by this PI calculation as the target discharge flow rate Qsv to the unit number control unit 4.
In addition, it is sent to the discharge flow rate correction section 11.

This discharge flow rate correction unit 11 includes a prescribed value storage means for storing upper and lower limit prescribed values of stable supply discharge flow rate and upper and lower limit prescribed values of water level, and a target discharge flow rate that is within the upper and lower limit prescribed values of stable supply discharge flow rate. In addition to the discharge flow rate determining means for determining whether or not the pump well water level is within the upper and lower limit prescribed values for the pump well, the discharge flow rate correction value is determined based on the determination results by these determining means. The target discharge flow rate determination means and the like determine the target discharge flow rate.

Reference numeral 12 denotes a speed control section, which controls the discharge flow rate correction value Q determined by the target discharge flow rate determination means of the discharge flow rate correction section 1].
'sv, for example, PI calculation is executed based on the deviation between this discharge flow rate correction value Q'sv and the discharge flow rate detected by the discharge flow meter 7, and the speed of each sewage pump 6 is controlled according to this PI calculation output. do.

Next, the operation of the above device will be explained. First, the PI calculation unit 3 calculates the detected water level Lpv of the water level gauge 2 and the target water level Lsv.
After calculating the deviation from the
It is supplied to the number control section 4 and the discharge flow rate correction section 11 as sv. Here, the number control unit 4 controls the target discharge flow jlQs
The optimum number of operating sewage pumps 6 is determined based on v and the pump capacity, and control is performed to start or stop one pump according to the determined number.

On the other hand, the discharge flow rate correction section 11 calculates the discharge flow rate correction value Q'sv according to the flowchart shown in FIG. Specifically, when a start command is received, the stable supply discharge flow rate upper limit specified value Q IIax and lower limit specified value Q win are read from the specified value storage means, and these specified values Q max
, Compare Q win and target discharge flow rate Qsv5.
TI), this target discharge flow JitQsv is Q mi
When there is a relationship of n<Qsv<Qa+ax, this target discharge flow rate Qsv is output as a discharge flow rate correction value Q'sv (Sr1). Said step S
At TI, QSV is less than Q ll1n or Q I
When it is equal to or higher than Iax, the process moves to the next step ST3, where the water level lower limit specified value L win and water level upper limit specified value L l1aX are read from the specified value storage means, and the current sewage pump well water level Lpv is determined to be L win < L pv < L.
It is determined whether there is a saw relationship. Here, when the pump well water level Lpv is not between the specified values L win and L wax, the target discharge flow rate Qsv is set to the discharge flow rate correction value Q's.
Output as v (Sr1).

When the pump well water level Lpv is between the specified value L+ain and Lmax in step ST3, Q win and Qsv are compared in the next step ST5. here,
When Qsv is smaller than QIIljn, Qwin is output as the discharge flow rate correction value Q'sv to ensure stable supply (5T6). Conversely, when Qsv is larger than Qmin, Ql1ax is output as Q'SV.

(Sr1).

It should be noted that similar effects can be obtained even if the order of STI and Sr1 processing is reversed.

Therefore, according to the configuration of the embodiment as described above, when the target discharge flow rate does not exceed the stable supply discharge flow rate limit value, the water level constant control for the target water level is performed (Sr1
), and if the target discharge flow rate exceeds the stable supply limit value and the water level of the pump well is within the specified water level range, the target discharge flow rate is corrected to the stable supply upper limit value Qwax or lower limit value Qll1n. (S7.S6). Also, in case
When the sewage pump well water level is outside the specified range, that is, at a dangerous water level, the target discharge amount is not corrected and the water level is controlled to be constant at the target water level (S4). . As a result, the water level conditions under which a stable supply can be made are significantly expanded compared to the conventional method, and in turn, wastewater treatment such as chemical control in the subsequent wastewater treatment system can be carried out stably and reliably.

Note that the present invention can be implemented with various modifications without departing from the gist thereof.

[Effects of the Invention] As explained above, according to the present invention, wastewater can be stably supplied even in situations where conventional control devices could not stably supply wastewater. This basically ensures a stable supply to water treatment facilities, reduces the burden on water treatment facilities, and makes it possible to keep power fluctuations for sewage pumps within a certain range.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of a sewage pump control device according to the present invention, Fig. 2 is a flowchart for explaining correction of the discharge flow rate in the present invention, and Fig. 3 is a diagram showing a conventional sewage pump control device. FIG. 1...Sewage pump well, 2...Water level gauge, 3...P■
Arithmetic unit, 4... Number control unit, 5... Speed control unit, 6
. . . Sewage pump, 7. Discharge flow meter, 8. Sedimentation basin, 11. Discharge flow rate correction unit. Applicant's agent Patent attorney Takehiko Suzue

Claims (1)

[Claims] Control the water level of the sewage pump well to a target water level by controlling the number of operating pumps and controlling the speed of the pumps at least according to the water level of the sewage pump well. In a sewage pump control device, a discharge flow rate calculation means calculates a target value of a flow rate to be discharged based on a deviation between a water level signal from a sewage pump well water level detection unit and a set target water level; A discharge flow rate correction means for correcting the target discharge flow rate based on a determination as to whether the obtained target discharge flow rate is within a range of stable supply amount and a determination as to whether the sewage pump well water level is within a specified water level range; A sewage pump control device comprising: a speed control section that controls the speed of the sewage pump using the discharge flow rate correction value from the discharge flow rate correction means as a target value.