JP3002069B2 - Pump control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pump control system for distributing water from a water purification tank to each customer using, for example, a variable speed water pump and a plurality of fixed speed water pumps of different capacities in a water treatment plant. More particularly, the present invention relates to a pump control device capable of reducing the frequency of controlling the number of water distribution pumps operated in response to a rapid change in water demand and performing stable pump control.

[0002]

2. Description of the Related Art In general, for example, in a water purification plant, a pump control device for distributing water from a water purification tank to each customer by combining a plurality of variable speed water distribution pumps and fixed speed water distribution pumps with different capacities is known. It is well known that the priorities of the pumps are manually set from outside or according to a predetermined fixed order. 6 and 7
FIG. 1 is a block diagram showing a configuration example of a pump control device in this type of water purification plant equipment.

In FIG. 6 and FIG. 7, water stored in a water purifying reservoir 1 is divided into a plurality of units each comprising a variable-speed water distribution pump, and fixed-speed water distribution pumps having different capacities of large, medium, and small capacities. In this case, four water distribution pumps 2 distribute water to each customer.

[0004] On the other hand, the distribution pressure target value PSV and the water purification tank 1
The difference from the measured water level value from the water level gauge 3 installed at the above is calculated using the subtractor 4 to obtain the head. Also, from the value of this head,
Pump delivery rate - by applying the Q-H characteristic curve showing the relationship between the lift, additional in current number of operating start flow rate value and
Request stop flow value Start / using stop flow calculator 5.

[0005] Next, the current total pump discharge flow rate measured by the installed flow meter 6 to the discharge side of the water distribution pump 2, in the case of additional activation or flow rate value determined by the start / stop flow calculator 5 Is determined by the increase / decrease determiner 7 to increase the number of operating units by one and to decrease the number of operating units by one when the flow rate is equal to or less than the stop flow rate value .

On the other hand, the priority of pump start and stop is shown in FIG.
In the pump control device shown in FIG. This is the contents of the priority setting device 8. That is, for example, the operator manually sets the priority for each of the units such that the first unit has the first priority and the second unit has the second priority. And this unit No. A determination is made as to whether the unit having the priority set by the priority setting unit 8 can be started or stopped next, and if the unit cannot be started or stopped due to the condition not being satisfied, the determination of the unit having the next priority is performed.
This is performed in the priority decision unit 9.

[0007] The priority of starting and stopping the pump is shown in FIG.
In the pump control device shown in FIG. There is no priority setting device 8 and the internal fixed priority determining device 10 has a predetermined priority as a fixed value.

Next, when the increase / decrease determination is issued from the number increase / decrease determiner 7, if the number of the machine is 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).
The stop commander 11 outputs a start or stop command to the water distribution pump 2.

In FIG. 6 and FIG. 7, the pump discharge pressure is determined based on the difference between the target water distribution pressure value PSV and the actually measured pressure value from the pressure gauge 12 installed on the discharge side of the water distribution pump 2. The control is performed using the controller 13.

However, such a conventional pump control device has the following problems. That is, in general,
As shown in FIG. 8, the amount of water used by each household increases in the morning and evening hours of the day, and temporal fluctuations occur in other time periods in which the usage amount is relatively small.

On the other hand, the above-described pump control device increases or decreases the number of operating water distribution pumps in accordance with a predetermined priority. Start additional pumps,
The next distribution pump may be increased in a short time. Also,
There is a case where a small-capacity water distribution pump is stopped during a time period when the water demand is small, and the next water distribution pump is reduced in a short time.

Therefore, when the water demand fluctuates abruptly in the morning or evening hours when the water demand extremely increases, or in the late night hours when the water demand is small, the water supply pump is not used. The frequency of controlling the number of operating units increases, and stable pump control cannot be performed.

[0013]

As described above, in the conventional pump control apparatus, when the water demand suddenly fluctuates, the frequency of controlling the number of operating water distribution pumps increases, and a stable pump control is performed. 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 rapid 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, according to the present invention, a plurality of water pumps having different capacities connected in parallel can supply water stored in a water purification tank to each demand. in the pump control apparatus for water distribution in the house, based on the lift obtained from the water level value of the purified water reservoir and the water distribution pressure target value currently added in the number of operating units start flow rate value and stop <br/> stop flow value of distribution pump Start / stop flow rate calculating means for calculating
The additional start flow rate value calculated by the stop flow rate
Beauty stop flow rate value and on the basis of the current of the total pump discharge flow rate,
Number increase / decrease determination means for determining increase or decrease of the number of operating water distribution pumps, a change direction obtained from a change amount or change rate of the total pump discharge flow rate, and a preset value for each of a plurality of control days
Demand-current demand calculated from time data
Optimal capacity preset in relation to the direction of change in required quantity
Start / stop type determining means for determining the water distribution pump as an additional start pump or stop pump, and start / stop based on the increase / decrease determination result by the number increase / decrease determination means.
The additional start pump determined by the stop type determination means or
It is constituted by a start / stop means for outputting a start or stop command for stopping the pump.

[0016]

Therefore, in the pump control device of the present invention,
Based on the change rate or change rate of the total pump discharge flow rate and the control date and control time, the operation priority of the water distribution pump is determined, that is, the change amount or the change rate of the total pump discharge flow rate is determined.
The direction of change obtained from the
Demand volume-demand volume at the current time obtained from time data
Distribution of the optimal capacity set in advance according to the
Determine water pump as additional start or stop pump
(Automatic selection of additional start pump or stop pump
That) by the time zone of morning and evening demand for water increases excessively or demand is small midnight time zone, to the pump operation number based on the pump delivery rate, the capacity commensurate with demand It becomes possible to select and control the water distribution pump. This will reduce the frequency of controlling the number of operating water distribution pumps, that is, avoid unnecessary fluctuations in the number of operating pumps,
Extremely stable pump control can be performed.

[0017]

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

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

That is, the pump control device of the present embodiment
The unit No. of FIG. The priority determiner 8 and the priority determiner 9 or the internal fixed priority determiner 10 in FIG. 7 are omitted, and instead, a discharge flow rate change rate detector 21 and a start / stop type determiner 22 are provided. The configuration is added .
Here, the discharge flow rate change rate detector 21 is for detecting the current total pump discharge flow rate of change from the flow meter 6.

The start / stop type determiner 22 determines the rate of change of the pump total discharge flow rate detected by the discharge flow rate change rate detector 21, the control day of weekday, holiday, or special day, and
On the basis of the control time, also optimal additional boot pump is to determine the stop <br/> stop pump. That is, the total discharge of the pump
The direction of change determined from the amount or rate of change
Is the demand-time data preset for each of several control days?
And the direction of change in demand at the current time
Add a water distribution pump with the optimal capacity set in advance.
Pump or stop pump (additional start pump or
Or automatically select a stop pump).

In FIG. 1, the water level of the water purification tank 1 is measured by a water level meter 3, and the measured water level is input to a subtractor 4,
The head is determined from the difference from the predetermined distribution pressure target value PSV. Based on the value of the head, the stop flow Q _OFF from the current pump operation head and the value of the required flow Q _ON increase by one pump are activated by a head-discharge flow relationship curve as shown in FIG. / Stop flow rate calculator 5.

[0022] Next, the current pump, which was measured by the flow meter 6
When the total discharge flow rate is smaller than the stop flow rate value Q _OFF obtained by the start / stop calculator 5, the number of pumps is reduced by one, and when the total discharge flow rate is larger than the additional start flow rate value Q _ON , The determination is made by the number increase / decrease determiner 7 so as to increase the number of pumps by one. Here, FIG. 2 shows two units.
-Flow characteristics when two water distribution pumps are operated in parallel
Shows the total discharge of the pump measured by the flow meter 6.
The output flow rate is higher than the additional startup flow rate value Q _ON calculated .
If there are many pumps, start one additional pump as described above
If the stop flow value Q _OFF is less than
Is stopped. Of course, one additional pump was started
When three units are operated in parallel, additional start-up is performed as is well known.
The head-flow characteristics of the pump
Additional start and stop flow values are determined.

On the other hand, in the start / stop type determiner 22, any one of the demand amounts and time data shown in FIGS. 3, 4, and 5 is determined according to whether the current control day is a weekday, a holiday, or a special day. select. Here, the weekdays, holidays, and special days are set in advance by an operator manually or by a date controller.

Then, in the start / stop type determiner 22,
From the set control date, control time, and the rate of change of the current pump discharge flow rate measured by the flow meter 6, the optimal next starting pump or next stopping pump is determined.

That is, for example, if the control date is a day using weekday data, the demand data at the time shown in FIG. When the discharge flow rate is determined by the discharge flow rate change rate detector 21 and is in the ascending direction, the next starter is determined to be a large-capacity water distribution pump.

In this case, the first water distribution pump to be started is a variable speed water distribution pump. In addition, the water distribution pump that stops last is also a variable speed water distribution pump.
Accordingly, hereinafter, the types of the additional or reduced pumps described above or below will be described only for fixed-speed water distribution pumps for large capacity, medium capacity, and small capacity.

That is, in the determination of the ascending direction, the rate of change from the value before the specified time is calculated, and only when the value is equal to or more than the specified value, it is determined to be ascending. Also in the determination of the descending direction, similarly, it is determined to be descending only when the rate of change is equal to or greater than a specified value. In other words, change from the rate of change of the pump total discharge flow rate
You are looking for a direction.

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

[Table] Discharge flow rate change rate Demand-time data Increased capacity Decreased capacity Up Rise Large Small 小 No change Large Small 小 Descending Medium Medium No change Rise Large Small 〃 No change Small Small 〃 Descend Small Large Descend Ascend Medium Medium な し No change Small Large 下降 Descent Small Large

Accordingly, when the increase / decrease determination result is obtained from the number increase / decrease determiner 7, the start / stop type determiner 2
For additional activation or stop Unit was determined by 2, start or stop command is output.

During the start or stop of the water distribution pump 2, since the discharge pressure and the discharge flow rate fluctuate greatly, the increase / decrease of the number is not determined. Also, the determination method can be freely changed by changing the capacity determination result shown in the above pump capacity determination table.

As described above, in the present embodiment, the water stored in the water purification tank 1 in the water purification plant is supplied to a variable speed water distribution pump, a fixed speed water distribution pump having different capacities of large, medium and small volumes. A pump control device that distributes water to each customer by a plurality of water distribution pumps 2 comprising
Based on the control day and the control time and the total pump delivery rate of the rate of change of the special date, etc., the optimum type additional boot pump <br/> or stop pump (volume), i.e. the change in the total pump delivery rate
Change direction obtained from quantity or change rate and multiple control dates
Current time obtained from demand-time data set in advance for each
Preset according to the relationship between the demand
Add the optimal capacity water distribution pump to start pump or stop
The pump is automatically selected and controlled.

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

With this arrangement, the frequency of controlling the number of operating water distribution pumps 2 can be reduced in response to sudden fluctuations in water demand, and an extremely stable pump utilizing the pump discharge capacity to the maximum by avoiding unnecessary fluctuations in the number of pumps. Control can be performed.
It should be noted that the present invention is not limited to the above-described embodiment, and can be similarly implemented in the following manner.

[0035] (a) In the above embodiment, as one element in determining the optimum additional boot pump or stop pumping, has been described for detecting the rate of change of the total pump delivery rate is not limited thereto Even if the amount of change in the pump total 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 a variable speed water distribution pump,
A case has been described in which water is distributed to each customer by a plurality of water distribution pumps 2 including fixed-speed water distribution pumps having different small capacities and different capacities. 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.

[0037] (c) In the above embodiment describes the case of measuring the total pump delivery rate by the flow meter 6 which is disposed on the discharge side of the water distribution pump 2 directly, not limited to this, the distribution pump 2 rpm ( Alternatively, the total pump discharge flow rate may be obtained indirectly from the speed) and the head.

[0038]

According to the present invention as described above, according to the present invention, port
Change rate or change rate of pump discharge flow rate, control date and control time
The operation priority of the distribution pump based on the
That is, it is calculated from the change amount or change rate of the pump total discharge flow rate.
Direction and the demand set in advance for each of multiple control days
Change in demand at current time obtained from quantity-time data
A water distribution pon with an optimal capacity set in advance according to the direction
The pump as an additional start or stop pump
(Automatic selection of additional start pump or stop pump)
Having urchin, against sharp fluctuations in demand for water aims to reduce the number of operating units control the frequency of the distribution pump, stable and highly reliable pump controller capable of performing a pump control can be provided.

[Brief description of the drawings]

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

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

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

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

FIG. 5 is a diagram showing an example of a relationship between a demand amount and a 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 ... Water purifier, 2 ... Water distribution pump, 3 ... Water gauge, 4 ... Subtractor, 5 ... Start / stop flow calculator, 6 ... Flow meter, 7 ... Number increase / decrease determiner, 8 ... Unit No. Priority setting device, 9: priority determining device, 10: internal fixed priority determining device, 11: activation /
Stop commander, 12 ... pressure gauge, 13 ... pressure regulator, 21 ...
Discharge flow rate change rate detector, 22... Start / stop type determiner.

Claims (1)

(57) [Claims] 1. A pump control device for distributing water stored in a water purification tank to each customer by a plurality of parallel-connected water distribution pumps having different capacities, wherein a water level value of the water purification tank is provided. Based on the head obtained from the distribution pressure target value and
Additional starting flow rate value Oyo and start / stop flow rate calculation means for calculating a beauty stop flow value, the start / stop flow rate calculating means is calculated by adding start flow rate value and stop flow value and the total current pump discharge based on the flow rate, the volume increase / decrease determining means for determining an increase or decrease in the distribution pump operation number, obtained from the amount of change or rate of change of the total pump delivery rate
Change direction and demand amount preset for each of multiple control days
-How the demand volume changes at the current time obtained from the time data
Distribution pump with optimal capacity set in advance according to direction
A start / stop type determining means for determining as an additional start pump or stop pumping on the basis of the increase or decrease of the determination result by the number increase / decrease determination means, the start / stop type determining means additional boot pump determined by or pump control apparatus characterized in that it comprises a start / stop means for outputting a start or stop command to stop the pump, the.