JPH06195102A - Pump controller - Google Patents

Abstract

PURPOSE:To select and control a distribution pump having capacity corresponding the demand quantity in the morning and evening in which the demand quantity increases, and in a midnight time zone in which it decreases by determining the operation priority of the distribution pump, based on a variation rate of the pump discharge flow rate, the control day and the control time. CONSTITUTION:By a water level gage 3, a water level of a clean water reservoir 1, a measured value is inputted to subtracter 4, and by a difference to a water distribution pressure target value PSV set in advance, the pump head is derived. Subsequently, when the present pump discharge flow rate measured by a flow meter 6 is smaller than a stop flow rate QOFF derived by an actuation/stop computing element 5, the number of sets of the pumps is decreased by one set. On the other hand, when it is larger than an actuation flow rate QON, the number of sets of the pumps is increased by one set, and they are decided by a set number increase/decrease deciding device 7, respectively. On the other hand, in an actuation/stop classification deciding device 22, in accordance with whether a control day is a weekady, a holiday or a special day, an optimal next actuation pump or next stop pump is determined from the data set in advance, and a variation rate of the pump discharge flow rate measured by the flow meter 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, in a water purification plant facility, a pump control for distributing water in a water purification pond to each customer using a plurality of variable speed distribution pumps and a plurality of fixed speed distribution pumps of different capacities. The present invention relates to an apparatus, and more particularly to a pump control apparatus capable of performing stable pump control by reducing the frequency of controlling the number of operating distribution pumps in response to a sudden change in water demand.

[0002]

2. Description of the Related Art Generally, for example, in a water purification plant, as a pump control device for distributing water in a water purification pond to each customer by combining a plurality of variable speed water distribution pumps and fixed speed water distribution pumps having different capacities. It is well known that the priority of the pump is manually set from the outside or is fixed in a predetermined fixed order. 6 and 7
FIG. 3 is a block diagram showing a configuration example of a pump control device in this type of water purification plant equipment.

In FIGS. 6 and 7, a plurality of units of water stored in the water purification reservoir 1 are composed of variable-speed water distribution pumps and fixed-speed water distribution pumps having large capacity, medium capacity, and small capacity (see FIG. In this case, the water is distributed to each customer by four (4) water distribution pumps 2.

On the other hand, the distribution pressure target value PSV and the water purification tank 1
The difference from the measured water level from the water level gauge 3 installed in the above is used to obtain the head using the subtractor 4. Also, from the value of this head,
The next start flow rate and the next stop flow rate in the current number of operating machines are calculated using the start / stop flow rate calculator 5 by applying the QH characteristic curve showing the relationship between the pump discharge flow rate and the head.

Next, if the current pump discharge flow rate measured by the flow meter 6 installed on the discharge side of the water distribution pump 2 is equal to or higher than the start flow rate determined by the start / stop flow rate calculator 5, the number of operating machines is changed. The increase / decrease judging device 7 judges whether the number of operating machines is decreased by one when the number of operating machines is increased by one or less than the stop flow rate.

On the other hand, the priority of pump starting and stopping is shown in FIG.
In the pump control device shown in No. 2, the unit No. set externally for each unit is set. This is the content of the priority setting unit 8. That is, for example, the operator manually sets the priority for each machine, for example, the first machine has the first priority and the second machine has the second priority. And this machine No. Next, it is judged whether the machine with the priority set by the priority setter 8 can be started or stopped next. If the machine cannot be started or stopped because the condition is not satisfied, the judgment of the machine with the next priority is made.
This is performed by the priority determiner 9.

Further, the priority of starting and stopping the pump is shown in FIG.
In the pump control device shown in FIG. There is no priority setter 8, and the internal fixed priority determiner 10 has a predetermined priority as a fixed value.

Next, when the increase / decrease judging unit 7 judges whether the increase or decrease is made, the unit No. Priority determiner 8
(In the case of FIG. 6) or according to the start or stop priority from the internal fixed priority determiner 10 (in the case of FIG. 7), start / stop
The stop command device 11 starts or outputs a stop command to the corresponding water distribution pump 2.

In FIGS. 6 and 7, the pump discharge pressure is based on the difference between the distribution pressure target value PSV and the pressure measurement value from the pressure gauge 12 installed on the discharge side of the distribution pump 2. It is designed to be controlled using the adjuster 13.

By the way, such a conventional pump control device has the following problems. That is, in general,
As shown in FIG. 8, the amount of water supply used in each household is large during the morning and evening hours of the day, and the amount of water used is relatively small during other hours, which causes temporal fluctuations.

On the other hand, in the above-mentioned pump control device, in order to increase or decrease the number of operating water distribution pumps according to a predetermined priority, a small amount of water is distributed during the time when the demand for water is high as described above. Start additional pumps,
The next water distribution pump may be increased in a short time. Also,
In the time when the water demand is small, the small capacity water distribution pump may be stopped and the next water distribution pump may be reduced in a short time.

Therefore, in the morning or evening time when the demand for water is extremely increased, or in the midnight time when the demand is small, when the demand for water changes suddenly, the distribution pump The frequency of controlling the number of operating machines becomes high and stable pump control cannot be performed.

[0013]

As described above, in the conventional pump control device, when the water demand suddenly fluctuates, the frequency of controlling the number of operating distribution pumps becomes high, and a stable pump is obtained. There was a problem that control could not be performed.

An object of the present invention is to reduce the frequency of controlling the number of operating water distribution pumps in response to a sudden change in water demand.
An object of the present invention is to provide an extremely reliable pump control device capable of performing stable pump control.

[0015]

In order to achieve the above object, the present invention provides a pump controller for distributing water stored in a water purification reservoir to each customer by a plurality of water distribution pumps having different capacities. , Start / stop flow rate calculation means for calculating the next start flow rate and the next stop flow rate in the current operating number of water distribution pumps based on the head obtained from the water level value of the water purification pond and the distribution pressure target value, and start / stop flow rate calculation Based on the next start flow rate and the next stop flow rate calculated by the means and the current pump discharge flow rate, the number increase / decrease judging means for judging the increase or decrease of the number of pumps operating the distribution pump, and the change amount or change of the pump discharge flow rate Based on the rate, control date, and control time, the start / stop type determination means for determining the optimum next start pump or the next stop pump and the increase / decrease by the number increase / decrease determination means Startup on the basis of the determination result, it outputs a start or stop command for the next start the pump or the next stop pump determined by the start / stop type determining means /
And a stopping means.

[0016]

Therefore, in the pump control device of the present invention,
Based on the rate of change of the pump discharge flow rate or the rate of change, the control date and the control time, the operation priority of the water distribution pump is determined (the next start pump or the next stop pump is automatically selected), so that the water demand In the morning and evening hours when there is an extreme increase, or in the late-night hours when demand is low, control is performed by selecting a water distribution pump with the capacity that matches the demand, based on the number of pumps operating based on the pump discharge flow rate. Is possible. As a result, it is possible to reduce the frequency of controlling the number of operating water distribution pumps, that is, avoid unnecessary fluctuations in the number of pumps, and perform extremely stable pump control.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram showing a structural example of a pump control device in a water purification plant according to the present invention.
7, the same parts as those in FIG. 7 are designated by the same reference numerals, and the description thereof will be omitted. Here, only different parts will be described.

That is, the pump controller of this embodiment is
The unit No. of FIG. The priority determiner 8 and the priority determiner 9 or the internal fixed priority determiner 10 of FIG. 7 are omitted, and instead, a discharge flow rate change rate detector 21 and a start / stop type determiner 22 are provided. It is added. The discharge flow rate change rate detector 21 detects the rate of change of the pump discharge flow rate from the flow meter 6.

Further, the start / stop type judging device 22 determines the change rate of the pump discharge flow rate detected by the discharge flow rate change rate detector 21, the control date of weekday, holiday, or special day, and the control time. The optimum next start pump or next stop pump is determined based on Next, the operation of the pump control device of the present embodiment configured as described above will be described using FIG. 2 to FIG.

In FIG. 1, the water level of the water purification tank 1 is measured by the water level meter 3, and the measured water level is input to the subtractor 4,
The head is obtained from the difference between the preset distribution pressure target value PSV. Then, based on the value of this head, the stop flow rate Q _OFF from the current pump operating head, and the value of the required flow rate Q _ON for increasing one pump are started according to the relation curve of the head-discharge flow rate as shown in FIG. / Determined by the stop flow rate calculator 5.

Next, the current pump discharge flow rate measured by the flow meter 6 is the stop flow rate Q determined by the start / stop calculator 5.
If less than _OFF , reduce the number of pumps by one,
If the starting flow rate is more than Q _ON , set the number of pumps to 1
The number of vehicles is increased and the number of vehicles is increased / decreased by the determination unit 7.

On the other hand, in the start / stop type judging device 22, one of the demand amount and the time data shown in FIGS. 3, 4 and 5 is selected depending on whether the current control day is a weekday, a holiday or a special day. select. Here, the weekday, the holiday, and the special day are set in advance by the operator manually or in the date controller.

Then, in the start / stop type judging device 22,
The optimum next start pump or next stop pump is determined from the set control date, control time, and the change rate of the current pump discharge flow rate measured by the flow meter 6.

That is, for example, if the control day is the day on which weekday data is used, the demand data at the time shown in FIG. If the discharge flow rate is determined by the discharge flow rate change detector 21 and is in the ascending direction, the next starting machine is determined to be a large capacity water distribution pump.

In this case, the first water distribution pump is a variable speed water distribution pump. The water distribution pump that will be stopped at the end will also be a variable speed water distribution pump.
Therefore, in the following, the types of the addition or reduction pumps described above or later will be described only for large capacity, medium capacity, and small capacity fixed-speed water distribution pumps.

That is, in the determination of the rising direction, the rate of change from the value before the specified time is calculated, and only when it is equal to or more than the specified value, it is determined to be the rising. Similarly, the downward direction is also determined only when the rate of change is equal to or greater than the specified value.

Therefore, the demand quantity-time data depending on whether the control day is a weekday, a holiday, or a special day, and the priority judgment of the fixed speed water distribution pump based on the pump discharge flow rate change rate are as follows. Performed by.

[Table] Rate of change in discharge flow rate Demand-time data Increase capacity Decrease capacity Rise Rise Large Small 〃 No change Large Small 〃 Falling Medium Medium No change Rise Large Small 〃 No change Small Small 〃 Lower Small Large Large Down rising Medium Medium 〃 No change Small Large 〃 Downward Small Large

Therefore, when the increase / decrease judging device 7 gives a judgment result of increase or decrease, the start / stop type judging device 2
The start or stop command is output to the next start or stop machine determined in 2. In this way, the optimum water distribution pump can be determined in the morning and evening hours when the water demand is drastically increased or decreased, or when the demand suddenly changes.

Since the discharge pressure and the discharge flow rate fluctuate drastically while the water distribution pump 2 is being started or stopped, the increase / decrease of the number of units is not determined. Further, the determination method can be freely changed by changing the displacement determination result shown in the pump displacement determination table.

As described above, in this embodiment, the water stored in the water purification reservoir 1 in the water purification plant is supplied with a variable speed water distribution pump, a fixed capacity water distribution pump having a large capacity, a medium capacity, and a small capacity. In a pump control device that distributes water to each customer by a plurality of water distribution pumps 2 consisting of
Based on the control date such as a special day, the control time, and the rate of change of the pump discharge flow rate, the next start pump or the next stop pump of the optimum type (capacity) is automatically selected and controlled. .

Therefore, in the morning and evening hours when the water demand increases extremely, or in the midnight time when the water demand is low,
With respect to the number of pumps operating based on the pump discharge flow rate, it is possible to select and control the water distribution pump 2 having the capacity corresponding to the demand amount.

As a result, the frequency of controlling the number of operating distribution pumps 2 is reduced in response to a sudden change in water demand, avoiding wasteful changes in the number of pumps, and making an extremely stable pump that maximizes pump discharge capacity. Control can be performed.
The present invention is not limited to the above embodiment, but can be implemented in the same manner as described below.

(A) In the above embodiment, the case where the rate of change of the pump discharge flow rate is detected is described as one element for determining the optimum next start pump or next stop pump, but the present invention is not limited to this. Even if the change amount of the discharge flow rate is detected, the same effect as described above can be obtained.

(B) In the above embodiment, the water stored in the water purification tank 1 is supplied to the variable speed water distribution pump, large capacity, medium capacity,
The case where water is distributed to each customer by a plurality of water distribution pumps 2 composed of fixed-speed water distribution pumps having different small capacities has been described, but the present invention is not limited to this, and large capacities, medium capacities, and small capacities are different. The present invention can be similarly applied to a case where water is distributed to each customer by a plurality of water distribution pumps 2 including only fixed speed water distribution pumps.

(C) In the above embodiment, the case where the pump discharge flow rate is directly measured by the flow meter 6 installed on the discharge side of the water distribution pump 2 has been described, but the present invention is not limited to this. ) And the pump head, the pump discharge flow rate may be indirectly obtained. (D) In the above embodiment, the case where the present invention is applied to a water purification plant facility has been described, but the present invention is not limited to this.

[0038]

As described above, according to the present invention, the next start flow rate and the next stop flow rate in the current operating number of water distribution pumps are calculated based on the head obtained from the water level value of the water purification pond and the water distribution pressure target value. The number of start / stop flow rate calculation means to be calculated, and the number of operating water pumps for increase / decrease based on the next start flow rate / next stop flow rate calculated by the start / stop flow rate calculation means and the current pump discharge flow rate Increase / decrease determination means, start / stop type determination means for determining the optimum next start pump or next stop pump based on the change amount or change rate of the pump discharge flow rate, the control date and the control time, and the number increase / decrease Outputs a start or stop command to the next start pump or next stop pump determined by the start / stop type determination means based on the increase or decrease determination result by the decrease determination means Since it is equipped with a start / stop means for controlling the number of operating water distribution pumps in response to sudden fluctuations in water demand, stable pump control can be performed with extremely high reliability. A high pump controller can be provided.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a pump control device according to the present invention.

FIG. 2 is a diagram showing an example of a relation curve between a head and a start / stop flow rate in the same embodiment.

FIG. 3 is a diagram showing an example of a relationship between demand amount and time on weekdays.

FIG. 4 is a diagram showing an example of a relationship between a demand amount and time on a holiday.

FIG. 5 is a diagram showing an example of the relationship between the demand amount and time on a special day.

FIG. 6 is a block diagram showing a configuration example of a conventional pump control device.

FIG. 7 is a block diagram showing a configuration example of a conventional pump control device.

FIG. 8 is a diagram showing an example of a relationship between a general demand amount and a control time in a water purification plant.

[Explanation of symbols]

1 ... Purification basin, 2 ... Water distribution pump, 3 ... Water level gauge, 4 ... Subtractor, 5 ... Start / stop flow rate calculator, 6 ... Flowmeter, 7 ... Number increase / decrease judgment device, 8 ... Unit No. Priority setter, 9 ... Priority determiner, 10 ... Internal fixed priority determiner, 11 ... Start /
Stop commander, 12 ... Pressure gauge, 13 ... Pressure regulator, 21 ...
Discharge flow rate change rate detector, 22 ... Start / stop type determination device.

Claims (1)

[Claims] 1. A pump control device for distributing water stored in a water purification reservoir to each customer by a plurality of water distribution pumps having different capacities, which is obtained from a water level value of the water purification reservoir and a distribution pressure target value. A start / stop flow rate calculation means for calculating a next start flow rate and a next stop flow rate for the current operating number of the water distribution pumps based on the lift; and a next start flow rate and a next stop flow rate calculated by the start / stop flow rate calculation means. Based on the current pump discharge flow rate, the number increase / decrease determination means for determining an increase or decrease in the number of water distribution pumps operating, based on the change amount or change rate of the pump discharge flow rate, the control date and the control time, Based on the start / stop type determination means for determining the optimum next start pump or the next stop pump, and the increase / decrease determination result by the number increase / decrease determination means, / Stop type determining unit pump control device comprising a start / stop means for outputting a start or stop command to the determined next activated pump or the next stop pump, in that it comprises an a.