JPH09144663A - Pump number control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the follow-up property to water conveying quantity and pump discharge rate of flow, and stabilize water conveyance in a pump number control device for controlling the operating number of storage pumps in a purification plant. SOLUTION: This device has a comparison part 17 for determining the operating number of storage pumps so that the flow rate of conveying water never exceeds total flow rate of pumping water; a water level control part 15 for determining the operating number of pumps on the basis of the water level of a purification pond, and also increasing and decreasing the operating number of pumps on the basis of the change ratio of level of the purification pond; a comparison part 18 for controlling the operating number of pumps when the deviation between a main pipe pressure and a pressure control set P5 is large; and a comparison part 19 for controlling the operating number of storage pumps when the deviation between water conveying quantity and pump discharge rate of flow is the discharge quantity of one storage pump or more.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pump number control device for controlling the number of pumping pumps operating in a water purification plant.

[0002]

2. Description of the Related Art In a pumping pump for pumping water from a sand basin to a sedimentation basin during the process of pumping water from a water purification plant through a water purification basin, the number of pumping pumps that do not perform variable speed control is shown in FIG. As described above, the number of pumps is controlled only by the water level in the water purification pond.

FIG. 2 shows an example of a conventional control device.
Is a supervisory control device having a control water level setting device 2 and an operation sequence setting device 3. Reference numeral 4 denotes a sequence controller including a water level control unit 5 and a unit number control circuit 6, which is connected to the monitoring control device 1 by transmission. 7 sand basin, 8 sedimentation, 9 purified water reservoir, 10 water level gauge, P1 is pumping pump, P2 is a water pump, P _H is mains pressure gauge, V is a flow regulating valve.

The water level control unit 5 obtains the deviation between the output signals of the control water level setting device 2 and the water level gauge 10, and calculates the number of units control circuit 6
Is based on the deviation and the output signal of the operation sequence setting device 3,
The number of operating pumps P1 is determined and the operation is controlled.

[0005]

In the conventional apparatus as described above, the pumping to the water feeding is via the settling basin 8 and the water purification basin 9, and it takes several minutes from the start of the pump including the discharge valve to the pumping. Therefore, even if the pumping pump P1 is started after the water level of the water purification pond changes depending on the amount of water sent,
There was a problem that it was not possible to follow the fluctuations in the amount of water sent.

The present invention has been made in view of the above points, and an object of the present invention is to provide a pump number control device which stabilizes the water supply by improving the followability of the water supply amount and the pumped water amount.

[0007]

According to the present invention, in a pump number control device for controlling the number of pumping pumps operating in a water purification plant, the number of pumping pumps to be operated is determined so that the pumped water flow rate does not exceed the total pumped flow rate. No. 1 control unit, a second control unit that determines the operating number of pumping pumps based on the water level of the water purification pond, and third control that increases or decreases the operating number of pumping pumps according to the rate of change of the water level of the water purification pond. Section, a fourth control section that increases or decreases the number of pumped pumps operating when the deviation between the main pressure and the set pressure is large, and when the deviation between the pumped water quantity and the pumped water quantity is one pump pump discharge quantity or more A fifth control unit for increasing or decreasing the number of pumping pumps to be operated is provided, and the number of pumping pumps to be operated is controlled by the control outputs of the first to fourth control units.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. In the present invention, in order to improve the stability of the water supply amount, the water supply flow rate and the pumping flow rate are compared, and the change in the water level of the water purification pond is predicted to operate and stop the pumping pump. Also, considering the time delay from the stop of the pumping pump to the stop of rising of the water level of the water treatment pond, the water level of the water treatment pond is adjusted so as not to exceed the upper limit.

In FIG. 1, the same parts as those in FIG. 2 are designated by the same reference numerals. Reference numeral 11 is a monitoring control device including a control water level setting device 2, an operation sequence setting device 3, and a pressure control setting device 12. Reference numeral 14 is a sequence controller, which is configured as follows.

The water purification pond water level control unit 15 supplies a water level control signal to the pump number control unit 16 based on the water level of the water purification pond (by the water level meter 10 in FIG. 2) and the signal of the control water level setting device 2. The comparison unit 17 compares the water supply amount (total) with the NP (N units × pumping pump discharge amount per unit) and outputs an operation command for N units to the pump number control unit 16. The comparison unit 18 outputs an increase / decrease control signal to the pump number control unit 16 when the deviation between the main pipe pressure (by the main pipe pressure gauge P _H in FIG. 2) and the main pipe pressure control setting P _S is large. The comparison unit 19 obtains a deviation between the pumped water amount and the pumped water amount, and when the pumped water amount is more than the pumped pumping amount by one pump (ΔQ) or more, the number of pumps control unit 16
Issue an increase control signal.

[0011]

EXAMPLE The concrete control in the apparatus of FIG. 1 was carried out as follows.

(1) The N pumps are operated in advance within the control water level such that the water supply flow rate is less than the total pumping flow rate (pumping pump discharge flow rate × N pumps).

(2) When the inflow rate is greater than the water supply rate, the water level of the water treatment pond is reduced by one when the water level exceeds M2.

(3) When N water tanks are operated as they are and the water level is below the water level M1, one water tank is added.

(4) The water level increased to M1
Below, when this continues for a certain period of time, or when the rate of change in water level falls, two units are additionally activated.

(5) In combination with the water level control of the above (1) to (4), the number of pumping pumps is increased or decreased at the following times.

A. Deviation in main pressure control setting is large (P
_{At S} ± ΔP) a. When the difference between the amount of pumped water and the amount of pumped water is one pump pump discharge amount or more (ΔQ).

[0018]

As described above, according to the present invention, the first control unit which determines the number of pumping pumps to be operated so that the flow rate of the pumped water does not exceed the total pumped flow rate, and the pumping pump based on the water level of the water purification pond. When the deviation between the main pressure and the set pressure is large, the second control unit that determines the number of operating pumps and the third control unit that increases or decreases the number of operating pumps according to the rate of change of the water level in the water purification pond And a fourth control unit for increasing / decreasing the number of pumping pumps to be operated, and a fifth control unit for increasing / decreasing the number of pumping pumps to be operated when the deviation between the water supply amount and the pumping amount is one pumping pump discharge amount or more. Since it is provided, the following excellent effects can be obtained.

(1) Since the change in the water level of the water purification pond is grasped earlier and the number of pumps for pumping is controlled, the stability of the water supply (the followability of the water supply and the pumped water) is improved.

(2) Since not only the water level change but also the main pipe pressure is taken into consideration, it is possible to cover the control of the flow rate adjusting valve which is separately combined and controlled.

(3) Since not only the fluctuation range of the water level of the water purification pond but also the rate of change is captured, it is possible to make adjustment so as not to exceed the upper limit of the water level of the water purification pond.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a block diagram showing an example of a conventional pump number control device.

[Explanation of symbols]

 1, 11 ... Monitoring and control device 2 ... Control water level setting device 4, 14 ... Sequence controller 5, 15 ... Water level control unit 10 ... Water level gauge 12 ... Pressure control setting device 16 ... Pump number control unit 17, 18, 19 ... Comparison unit

Claims (1)

[Claims] 1. A pump number control device for controlling the number of pumping pumps operating in a water purification plant, a first control unit for determining the number of pumping pumps operating so that the flow rate of the pumped water does not exceed the total pumped flow rate, and a water treatment pond. A second control unit that determines the number of pumping pumps to be operated based on the water level of
A third control unit that increases / decreases the number of operating pumps according to the rate of change of the water level in the water purification pond, and a fourth control that increases / decreases the number of operating pumps when the deviation between the main pressure and the set pressure is large. Section and a fifth control section for increasing or decreasing the number of pumping pumps operating when the deviation between the pumped water quantity and the pumped water quantity is one pump pump discharge amount or more, and the control outputs of the first to fourth control sections. The number-of-pumps control device is characterized by controlling the number of pumping pumps to be operated.