JPH07200014A - Operation control method for pump - Google Patents

Abstract

PURPOSE:To perform high-performance and highly reliable water level control without using a water gauge and to prolong the life time of a pump and a motor. CONSTITUTION:Control is performed so as to detect a motor current in the operation of the pump 1 driven by the motor 3, stopping the operation of the pump 1 by turning the motor 3 OFF when the detected value becomes a motor current lower limit value corresponding to the prescribed lower limit water level LWL of water W inside a basin, timing the required suspension time T of the motor 3 calculated from an estimated maximum flow-in rate Q for the basin and the capacity C of the basin from the point of time of stopping the pump, turning the motor 3 ON by the time-up of the time T and starting the operation of the pump 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pump operation control method applied to drainage pump equipment for water tanks such as manholes.

[0002]

2. Description of the Related Art Conventionally, in a drainage pump facility such as a manhole, the water level in the manhole is detected by a water level gauge,
When the water level detection value reaches a predetermined upper limit value, the pump is operated via the motor, and when the upper water level detection value reaches a predetermined lower limit value, the operation control is performed to stop the pump via the motor. Generally, the method is adopted.

[0003]

In the conventional pump operation control method as described above, a water level gauge is often used, which often causes a failure, and also causes a malfunction due to entanglement of foreign matters. Therefore, if the water level gauge malfunctions or malfunctions, for example, the pump is unnecessarily continued to operate, which is not preferable in terms of the service life of the pump and its driving motor, and the reliability of the water level control is high. Was also lacking.

The present invention has been made to solve the above problems, and can improve the performance and reliability of water level control, and also extend the useful life of pumps and motors. It is an object of the present invention to provide a method for controlling the operation of a pump that can be performed.

[0005]

In order to achieve the above object, the method of controlling the operation of a pump according to the present invention is a method of operating a pump driven by a motor so as to discharge water in a water tank. -When the motor current (load current of the motor) is detected and the detected value becomes the motor current lower limit value corresponding to the predetermined lower limit water level of the water in the water tank, the motor is turned off to operate the pump. When the pump is stopped, the required rest time of the motor calculated from the predicted maximum inflow amount into the water tank and the capacity of the water tank from the time when the pump is stopped is counted, and when the time is up, the motor Is turned on to start the pump operation.

[0006]

According to the present invention, the load current of the motor for driving the pump decreases when the water level in the water tank decreases with the operation of the pump. When the detected value of is the lower limit set value, the motor is turned off and the pump operation is stopped. Also,
The water level in the water tank gradually increases with the stop of the pump operation.However, when the required downtime of the motor obtained by dividing the water tank capacity by the predicted maximum inflow is increased, Is turned on and pump operation is started. In this way, it is possible to accurately control the pump operation and appropriately control the water level in the water tank without using a water level gauge that easily causes a failure or malfunction.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram for embodying a pump operation control method according to an embodiment of the present invention.

In FIG. 1, 1 is a pump installed in a water tank 2 such as a manhole and driven by a motor 3, and 4 is an operation control device for the pump 1.

Reference numeral 5 is a motor current detection circuit for detecting a motor current during operation of the pump 1, and reference numeral 6 is a circuit for setting a motor current lower limit value corresponding to a predetermined lower limit water level LWL in the water tank 1. , 7 are comparators for comparing the motor current detection value by the motor current detection circuit 5 and the lower limit setting value by the setting circuit 6. Reference numeral 8 is an arithmetic circuit for taking in the predicted maximum inflow amount Q of the water W flowing into the water tank 2 and the capacity C of the water tank 2 as input data, and calculating the required downtime T of the motor 3, and 9 is the above-mentioned. This is a timer circuit that starts a time counting operation in response to a command from the arithmetic circuit 8 and times up at the required rest time T. Reference numeral 10 stops the drive of the motor 3 when the detected value of the motor current reaches the lower limit value, and the timer circuit 9 keeps the motor 3 at the time-up when the required rest time T is counted. This is a motor driver circuit for driving.

Next, a method for controlling the operation of the pump having the above structure will be described. Now, assuming that the pump 1 is operated by driving the motor 2, the motor current is detected by the motor current detection circuit 5, and the motor current detection value and the motor current lower limit setting circuit are detected. The comparator 7 compares the lower limit set value preset in 6 with the lower limit set value. on the other hand,
In the arithmetic circuit 8, the required rest time T of the motor 3 is calculated by dividing the capacity C of the water tank 2 by the predicted inflow amount Q into the water tank 2.

When the water level in the water tank 1 is lowered by the operation of the pump 1 to reach a predetermined lower limit water level LWL, the impeller (not shown) of the pump 1 is idling and the motor load current is significantly reduced. When this motor current value reaches the lower limit,
The motor driver circuit 10 is provided by the output from the comparator 7.
The motor 3 is turned off via the, and the operation of the pump 1 is stopped (FIG. 2). That is, when the predetermined lower limit water level LWL is reached, the motor 3 is turned off and the operation of the pump 1 is stopped, so that unnecessary operation of the motor 3 and the pump 1 is prevented.

The timer circuit 9 starts measuring the required rest time T when the operation of the pump 1 is stopped. When the water level in the water tank 1 rises while the pump 1 is stopped and reaches the upper limit water level HWL, for example,
Corresponding to this, the above rest time T has been increased,
The timer 3 turns on the motor 3 through the motor driver circuit 10 to restart (start) the operation of the pump 1 (FIG. 2). Therefore, the above water level is the upper limit water level HWL
It will be ensured that:

As described above, since the operation of the pump 1 is controlled by increasing the required rest time T of the motor 3 and detecting the lower limit value of the motor current, it is necessary to use a water level gauge with many failures. In addition, it is possible to always realize stable and accurate water level control even during long-term use.

Also, the service life of the motor 3 and the pump 1 can be extended by setting the required rest time T of the motor 3 without fail. In other words, setting the above-mentioned rest time T means that a water tank 2 having an optimum capacity C that does not cause an abnormal water level should be prepared from the product of this rest time T and the predicted maximum inflow amount Q. Become.

[0015]

As described above, according to the present invention, when the motor current for driving the pump during operation reaches the lower limit set value corresponding to the lower limit value of the water level, the motor is turned off to start the pump operation. Since the pump operation is started when the motor is stopped and the required downtime of the motor is up, without using a water level gauge that is likely to cause failure or malfunction,
By properly operating and stopping the pump according to the water level, it is possible to perform predetermined water level control accurately and reliably for a long period of time, and eliminate unnecessary operation of the motor and pump. This has the effect of extending their useful life.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating a method of controlling an operation of a pump according to an exemplary embodiment of the present invention.

FIG. 2 is a time chart in the embodiment.

[Explanation of symbols]

 1 Pump 2 Water Tank 3 Motor 5 Motor Current Lower Limit Setting Circuit 6 Motor Current Detection Circuit 7 Comparator 8 Arithmetic Circuit 9 Timer Circuit 10 Motor Driver Circuit C Water Tank Capacity T Required Rest Time Q Predicted Maximum Inflow W water

Claims (1)

[Claims] 1. A motor current is detected during operation of a pump driven by a motor so as to discharge water in the water tank, and the detected value corresponds to a predetermined lower limit water level of the water in the water tank. When the motor current lower limit value is reached, the motor is turned off to stop the pump operation, and the motor calculated from the predicted maximum inflow amount into the water tank and the water tank capacity from the time when the pump operation is stopped. A pump operation control method characterized in that the motor is turned on to start the pump operation when the required rest time of the motor is measured and the time is up.