JP2005009329A - Operation control method of metering pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for controlling an operation of a metering pump which does not need to provide a metering tank causing a high cost, which can conduct an accurate constant flow rate operation even corresponding to the continuous change of water level in a flow rate regulation tank, and which can prevent retention or deposition of a foreign matter in a pipe in a constant flow rate transfer of a waste water from the flow rate regulation tank to a treatment tank in a waste water treatment facility. <P>SOLUTION: The method for controlling the operation of the metering pump includes feeding back of a signal from an electromagnetic flowmeter 3 to an inverter 2 for controlling a rotational speed of a pump 1 or an external controller 4, and automatically regulating of a rotating speed so as to become a constant discharge rate beforehand set to the inverter 2 or the external controller 4 by using together the inverter 2 and the electromagnetic flowmeter 3 for actually measuring the discharge rate. Also, the method includes conducting of a cleaning operation in which the rotating speed is raised immediately after or immediately before the start of the pump 1 or only for a limited preset constant time immediately after the start or immediately before the stop. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention mainly relates to an operation control method for a quantitative pump used for quantitatively transferring waste water from a flow rate adjustment tank to a treatment tank in a sewage treatment facility.
[0002]
As is well known, supplying water at a constant flow rate from a flow rate adjustment tank to a treatment tank in a sewage treatment facility is an indispensable requirement for keeping the load of the treatment tank constant and performing stable treatment. However, the water level in the flow adjustment tank always changes depending on the inflow of the raw water, and the pump water supply greatly fluctuates with the change, so it is difficult to quantitatively send water to the treatment tank.
[0003]
[Prior art]
In order to solve the above-mentioned problem, a technique of interposing a tank called a measuring tank between the flow rate adjusting tank and the processing tank and returning an excessive flow rate to the flow rate adjusting tank is known (for example, Patent Document 1). reference). As another method, a liquid level detector and a rotation speed control device are integrated into the pump, and the pump rotation speed is changed according to the water level, so that a substantially constant amount of water can be supplied regardless of the change in the head. There is also a proposal to do so (for example, see Patent Document 2).
[0004]
[Patent Document 1]
JP-A-7-241579 (0004)
[Patent Document 2]
JP-A-8-109894 (0009)
[0005]
[Problems to be solved by the invention]
The technique of Patent Document 1 has the disadvantages that it cannot cope with fluctuations in the amount of water in the pump, and that an increase in equipment cost due to installation of a measuring tank is inevitable. Further, in the method of Patent Document 2, although it is possible to cope with stepwise water level fluctuations by the liquid level detector, it is not possible to perform high-precision quantitative operation corresponding to stepless water level fluctuations, and constant. If the amount of water to be sent is very small, the flow rate in the pipe will be slow, and foreign matter mixed in the sewage will not be discharged and will stay and accumulate in the pipe, causing clogging and bad odor, or In order to maintain a constant flow rate, it must be restricted so that it does not operate below the discharge flow rate specified by the pipe diameter.
[0006]
The purpose of the present invention is to eliminate the need for measuring tank interposition that causes high costs for the quantitative transfer of wastewater from the flow adjustment tank to the treatment tank in the sewage treatment facility, and to provide stepless water level fluctuations in the flow adjustment tank. It is an object of the present invention to provide an operation control method for a quantitative pump that is capable of high-accuracy constant-flow operation and that can prevent foreign matter from staying and accumulating in a pipe.
[0007]
[Means for solving problems]
In the operation control method for a quantitative pump according to the first aspect of the present invention, an inverter for controlling the pump rotation speed and an electromagnetic flow meter for actually measuring the discharge amount are used together, and a signal from the electromagnetic flow meter is incorporated into the arithmetic unit. The feedback is fed back to the inverter or the external control device, and the inverter or the external control device is caused to automatically adjust the rotational speed so that the preset discharge amount is constant.
[0008]
In the operation control method of the quantitative pump according to claim 2 according to the present invention, an inverter for controlling the pump rotation speed and an electromagnetic flow meter for actually measuring the discharge amount are used in combination, and a signal from the electromagnetic flow meter is incorporated into the arithmetic unit. Is fed back to the inverter or external control device, and the inverter or external control device automatically adjusts the rotational speed so that the preset discharge amount is constant, and is set to a predetermined constant immediately after the pump starts or immediately before the stop. A cleaning operation with an increased rotational speed is performed for a limited time, or a cleaning operation with an increased rotational speed is performed for a predetermined time immediately after starting and immediately before stopping the pump.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
The embodiment of the present invention will be described below with reference to FIGS.
[0010]
According to the operation control method of the quantitative pump of the present invention, for the quantitative transfer of waste water from the flow rate adjustment tank to the treatment tank in the sewage treatment facility, the inverter 2 for controlling the rotational speed of the pump 1 and the electromagnetic flowmeter for actually measuring the discharge amount 3 is used in combination. Then, the analog signal from the electromagnetic flow meter 3 is fed back to the inverter 2 or the external control device 4 in which the arithmetic device is incorporated in the manner illustrated in FIGS. By automatically adjusting the rotational speed of the pump 1 so that the set discharge amount becomes constant, a highly accurate constant flow rate operation corresponding to stepless water level fluctuation in the flow rate adjustment tank is possible. It goes without saying that a conventional measuring tank is not required between the flow rate adjusting tank and the processing tank.
[0011]
Even if the rotation speed is adjusted in this manner and the fixed amount operation is performed, if the target flow rate is too small, the flow velocity in the pipe is slowed down, and foreign matters in the sewage are not discharged and stay in and accumulate in the pipe. It will be. Therefore, the cleaning operation is performed at a higher rotational speed for a predetermined time period immediately after the start of the pump 1 or immediately before the stop, or as shown in FIGS. 4 and 5, it is set in advance immediately after the start of the pump 1 and immediately before the stop. By performing a cleaning operation with an increased rotational speed for a certain period of time, foreign matter stays and accumulates.
[0012]
【The invention's effect】
According to the operation control method of the quantitative pump according to the present invention, the quantitative transfer of wastewater from the flow rate adjustment tank to the treatment tank in the sewage treatment facility eliminates the need for a measuring tank that causes a high cost, Therefore, there is an advantage that high-precision constant flow operation corresponding to stepless water level fluctuation is possible, and that foreign matter can be prevented from staying or accumulating in the pipe.
[Brief description of the drawings]
FIG. 1 is a system block diagram according to the present invention, showing an example in which a constant discharge amount control function and a cleaning operation function are incorporated in an arithmetic unit in an inverter.
FIG. 2 is a system block diagram according to the present invention, and shows an example in which a constant discharge amount control function is applied to an external control device, and a cleaning operation function is incorporated in an arithmetic device in an inverter.
FIG. 3 is a system block diagram according to the present invention, showing an example in which a constant discharge amount control function and a cleaning operation function are provided to an external control device.
FIG. 4 is an operation flowchart of the pump according to the present invention.
FIG. 5 is a diagram showing rotational speed characteristics during pump operation according to the present invention.
[Explanation of symbols]
1 Pump 2 Inverter 3 Electromagnetic flow meter 4 External controller

Claims (2)

Combined use of an inverter that controls the pump rotation speed and an electromagnetic flow meter that actually measures the discharge amount, the signal from the electromagnetic flow meter is fed back to the inverter or external control device with a built-in arithmetic unit, and the inverter or external control device A method for controlling the operation of a quantitative pump, wherein the rotation speed is automatically adjusted so that a predetermined discharge amount is constant. Combined use of an inverter that controls the pump rotation speed and an electromagnetic flow meter that actually measures the discharge amount, the signal from the electromagnetic flow meter is fed back to the inverter or external control device with a built-in arithmetic unit, and the inverter or external control device The rotation speed is automatically adjusted so that the preset discharge amount is constant, and the cleaning operation is performed with the rotation speed increased immediately after starting the pump or immediately before stopping, or immediately after the pump is started. And a method for controlling the operation of the quantitative pump, wherein a cleaning operation with an increased rotational speed is performed for a predetermined time immediately before stopping.

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