JPH04109320A - Controller for the number of pumps - Google Patents

Abstract

PURPOSE:To use the water feeding capacity of a pump 4 at its maximum, to reduce the number of operating pumps 4 and to reduce power consumption at the time of water feeding by finding out the discharging flow rate of each pump and switching the number of pumps. CONSTITUTION:When a discharge setting pressure value PSV1 is increased from a reference discharging flow rate in the state of water feeding operation from (n) sets of pumps 4, and the value PSV1 reaches 'PSVi+1', a microprocessor 5 in a control device 1 accesses a table 8 and reads out the reference flow rate Qn of n pumps 4 and a correction coefficient (k) corresponding to the value PSVi+1. These read values are multiplied by each other, whether the multiplied value Qn.k is larger than or not a measured value F of a flow meter 3 to which water is fed correspondingly to a water feeding setting flow rate value, and when F<=Qn.k, the water feeding operation based upon the (n) pumps 4 is continued. At the time of F>Qn.k, n+1 pumps 4 are driven and water feeding operation based upon the (n+1) pumps 4 is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a pump number control device used in water supply facilities, water supply facilities, and the like.

(Prior art) In pump number control devices used in water supply facilities, water supply facilities, etc., the required discharge pressure value P is normally determined as shown in Fig. 5.
Calculate the water flow rate per pump for Sv (unit water flow rate value), divide the required water flow rate set during operation by the unit water flow rate value Q to calculate the number of pumps in operation, and calculate the result of this calculation. Based on this, the number of pumps in operation is controlled to ensure the required water flow rate.

(Problem to be Solved by the Invention) However, in the conventional pump number control device described above, it is not considered that the water supply flow rate value of the pump changes depending on the value of the discharge pressure value PSV.
Since the pump is used at 0% to 35% or less, the efficiency of pump usage is poor, and even when the required water flow rate could be secured with LL 011 pumps, If n+ l 11
There was a problem in that the system had to run multiple pumps, consuming an extra amount of electricity for one pump when pumping water.

In view of the above circumstances, it is an object of the present invention to provide a pump number control device that can reduce the number of pumps in operation by maximizing the water supply capacity of the pumps, thereby reducing power consumption during water supply. The purpose is

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the pump number control device according to the present invention switches the number of pumps in operation according to the set water supply flow rate value, and adjusts the number of pumps to the water supply set flow rate value. In a pump number control device that sends water at a corresponding flow rate, the discharge flow rate of the pump at a reference discharge pressure and the discharge flow rate correction coefficient when the discharge pressure is increased and decreased based on the reference discharge pressure are stored. according to the discharge setting pressure value, based on the pump discharge flow rate at the reference discharge pressure obtained by accessing the table according to the discharge setting pressure value, and the discharge flow rate correction coefficient for the discharge setting pressure. a discharge flow rate calculation section that calculates the discharge flow rate of each pump, and a number of operating pumps that control the number of operating pumps based on the discharge flow rate of each pump obtained by this discharge flow rate calculation section and the set water supply flow rate value. It is characterized by comprising a control section.

(Function) In the configuration described in section 2, the table is accessed by the discharge flow rate calculation unit to calculate the discharge flow rate of each pump according to the discharge setting pressure value, and the number of operating units control unit calculates the discharge flow rate obtained by the discharge flow rate calculation unit. the discharge flow rate of each pump,
The number of operating pumps is controlled according to the set water supply flow rate value.

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

The pump number control device shown in this figure is equipped with a control device 1 and a pump sequence control circuit 2, and the water supply setting flow rate value and discharge setting pressure value set by a setting device (not shown), and the flow rate. Water supply amount F obtained by total 3
The number of operating pumps 4 is controlled based on the above, and each pump 4 is operated so that the pressure value and flow rate value of the water to be fed become the set water sending flow rate value and the set discharge pressure value set by the setting device. Control.

As shown in FIG. 2, the control device 1 includes a microprocessor 5 that performs various processes, a ROM 6 that stores programs describing the operations of the microprocessor 5, various constant data, etc., and a ROM 6 that stores the operations of the microprocessor 5. A RAM 7 used as an area etc., a discharge flow rate Q of the pump 4 at a standard discharge pressure, and a discharge flow rate correction coefficient K when increasing and decreasing the discharge pressure based on the standard discharge pressure are stored. It is equipped with a table 8 and a plurality of interfaces 9 that connect the microprocessor 5 and each part of the device, and it is equipped with a table 8 and a plurality of interfaces 9 that connect the microprocessor 5 and each part of the device, and the water supply set flow rate value and discharge set pressure value set by the setting device and the set discharge pressure value obtained by the flow meter 3. An operation control command for the pump 4 is generated by calculation based on the water supply amount, and is supplied to the pump sequence control circuit 2.

A pump sequence control circuit 2 controls the operation of each pump based on an operation control command supplied from the control device 1.

Next, the operation of switching the number of pumps in this embodiment will be explained with reference to the flowcharts shown in FIGS. 3(a) and 3(b).

First, in a state where water is being fed by atn71 pumps 4, the discharge set pressure value PSV+ is lowered from the reference discharge flow rate as shown in FIG. 3(a), and the discharge set pressure value becomes (l P S V , -, II (step 5TI), the microprocessor 5 of the control device 1 accesses the table 8 and calculates the reference flow rate Q.-1 when the "n"''th pump 4 is stopped, and the discharge Set pressure value PSV
After reading out the correction coefficient corresponding to +-+ (step ST2.5T3), these are multiplied (step 5
T4), check whether this multiplication result Qn-1k is larger than the measured value F of the flowmeter 3 that is sending water corresponding to the set flow rate value for water feeding; step S T5) +
F>Qn-t7. When tt nu pump 4
When F≦Q n -1, (1nt first unit 0 pump 4 is stopped and II nl
"The water supply operation is carried out by the pump 4 of the stand (Step 5)
T6).

In addition, when water is being fed by 'n' pumps 4, the discharge set pressure value P is as shown in Fig. 3(b).
When SVI is increased from the reference discharge flow rate and the discharge set pressure value is set to "PSV++t" (step 5TIO), the microprocessor 5 of the control device 1 accesses the table 8 and determines the reference flow rate Q0 by the It017 pumps 4. After reading and the correction coefficient corresponding to the discharge setting pressure value PSv+1 (steps 5T11 and 5T12), these are multiplied (step 5T13), and this multiplication result Qnk
In step 5T14), check whether the value F is larger than the measured value F of the flow meter 3 that is feeding water in accordance with the set flow rate value for water feeding. When F≦Qn3, the water feeding operation is continued by the pump 4 of the it ntr level. , when F〉Qok, it starts the pump 4 at the inlet of it n+ I N, and performs the water supply operation by "n+1" pumps 4 (
Step 5T15).

In this way, in this embodiment, when the discharge setting pressure value is changed, the discharge flow rate of each pump 4 is determined and the number of pumps is switched, so that the water supply capacity of the pump 4 is used to the maximum. Reduce the number of pumps 4 in operation,
Power consumption during water supply can be reduced.

In addition, in the embodiment described above, when switching the number of operating pumps 4, the number of operating pumps 4 is switched by non-systeresis control, but as shown in FIG. 4, the number of operating pumps 4 is switched. At this time, the number of operating pumps 4 may be changed by applying hysteresis control.

〔Effect of the invention〕

As explained above, according to the present invention, the water supply capacity of the pump can be used to the maximum, the number of pumps in operation can be reduced, and the power consumption during water supply can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of the pump number control device according to the present invention, Fig. 2 is a block diagram showing a detailed circuit example of the control device shown in Fig. 1, and Fig. 3 is the operation of the same embodiment. FIG. 4 is a flowchart showing an example, FIG. 4 is a schematic diagram showing another embodiment of the same embodiment, and FIG. 5 is a surface showing an example of characteristics of a pump used in water supply facilities and water supply facilities. 1...Control device 2...Pump sequence control circuit 3...Flowmeter 4...Pump 5...Discharge flow rate calculation section, number of operating units control section (microprocessor) 8...Table H (m ) Early Figure 4

Claims (1)

[Claims] (1) In a pump number control device that switches the number of pumps in operation according to a set water supply flow rate value and sends water at a flow rate corresponding to the water supply set flow rate value, the pump discharge flow rate at a reference discharge pressure; A table that stores discharge flow rate correction coefficients when increasing and decreasing the discharge pressure based on the reference discharge pressure, and a reference discharge obtained by accessing the table according to the discharge setting pressure value. a discharge flow rate calculation section that calculates the discharge flow rate of each pump according to the discharge set pressure value based on the discharge flow rate of the pump at the time of pressure and the discharge flow rate correction coefficient for the discharge set pressure, and the discharge flow rate obtained by the discharge flow rate calculation section. A pump number control device comprising: an operation number control section that controls the number of pumps in operation based on the discharge flow rate of each pump and a set water supply flow rate value.