JP2621707B2 - Method and apparatus for controlling chemical injection amount - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for controlling a chemical injection amount, and more particularly to a method and an apparatus for controlling a chemical injection amount in the fields of water supply and sewerage and industrial water treatment.

[0002]

2. Description of the Related Art Conventionally, this kind of chemical injection amount is controlled by a pulsating flow type pump (plunger pump), but the actual injection amount of the chemical is not measured, and the stroke and rotation of the plunger pump are not measured. The medicine injection amount is adjusted based on the value multiplied by the number. In addition, a combination of a water cutoff relay and a timer is used to check the presence or absence of chemical injection.

[0003]

However, in the conventional chemical injection amount control, it is necessary to manually adjust the stroke and the number of revolutions of the plunger pump every time the injection amount is changed. is there. Also,
The conventional medicine injection amount control has a disadvantage that the medicine injection amount cannot be accurately controlled.

[0004] The present invention has been made in view of such circumstances, and the amount of medicine to be injected can be accurately controlled without the need for troublesome and accurate control of the amount of medicine to be delivered by a pulsating flow type pump. An object of the present invention is to provide a control method and an apparatus therefor.

[0005]

In order to achieve the above object, the present invention provides a method for controlling the amount of liquid medicine to be injected by a pulsating flow type pump. The injection amount of the liquid medicine which is sucked and sent out in a pulsating flow is intermittently measured, and the average flow rate without pulsation is calculated by the calculation based on the intermittently measured medicine injection amount. The set injection amount is intermittently compared with the set injection amount, and the number of revolutions and the stroke of the pulsating flow type pump are feedback-controlled so that the obtained injection amount of the chemical is equal to the set injection amount. And Further, in order to achieve the above object, the present invention provides a chemical injection amount control device for controlling an injection amount of a liquid chemical injected by a pulsating flow type pump. An electromagnetic flow meter for intermittently measuring the injection amount of a liquid chemical to be obtained, an average calculation device for calculating an average flow rate without pulsation based on the chemical injection amount measured intermittently by the electromagnetic flow meter, and A comparison operation device that intermittently compares and calculates a medicine injection amount and a preset injection amount, based on a signal from the comparison operation device, so that the obtained medicine injection amount is equal to the set injection amount. And control means for performing feedback control on the rotation speed and stroke of the pulsating flow type pump, respectively.

[0006]

According to the present invention, first, the injection amount of the liquid medicine sucked by the pulsating flow type pump and sent out by the pulsating flow is intermittently measured by the electromagnetic flow meter. Next, a signal indicating the chemical injection amount measured by the electromagnetic flow meter is electrically averaged by the averaging device. Next, the comparison calculation device intermittently performs a comparison calculation between the medicine injection amount averaged by the averaging device and the preset injection amount. Then, the control unit feedback-controls the rotation speed and the stroke of the pulsating flow pump based on a signal from the comparison arithmetic unit. This makes it possible to accurately control the amount of the chemical to be delivered in a pulsating flow by the pulsating flow pump without trouble.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a method and an apparatus for controlling a chemical injection amount according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 shows a control device 10 for controlling the amount of injected chemical according to the present invention.
The liquid medicine 14 stored in the chemical liquid tank 12 operates a pulsating flow type pump 16 such as a plunger pump, so that the liquid medicine 14 is supplied to the injection point 20 via the electromagnetic flow meter detector 18 in a pulsating flow. It is sent.

An electromagnetic flowmeter amplifier 22 having a damper function is connected to the electromagnetic flowmeter detector 18, and a controller 26 is connected to the electromagnetic flowmeter amplifier 22 via a cable 24. The controller 26 includes a moving average operation circuit 28, a sampling control circuit 30, and a PI
A D operation circuit 32 is provided therein, and a set injection amount 34 of the medicine 14 is stored in the PID operation circuit 32 in advance.
The set injection amount 34 can be appropriately changed.

The PID operation circuit 32 is connected to a rotation speed control device 38 and a stroke control device 40 provided outside the controller 26 via a cable 36, and the pulsating flow type pump 16 is connected to the rotation speed control device. The number of revolutions and the stroke are controlled by a stroke control device 38 and a stroke control device 40. Next, a control method of the chemical injection amount control device 10 configured as described above will be described.

First, the injection amount of the medicine 14 sucked by the pulsating flow pump 16 and sent out in a pulsating flow is intermittently measured by the electromagnetic flow meter detector 18. Next, a signal indicating the medicine injection amount measured by the electromagnetic flow meter detector 18 is amplified by a predetermined amount by the electromagnetic flow meter amplifier 22, and the signal indicating the amplified medicine injection amount is subjected to a moving average operation circuit 28 of the controller 26. Output to Next, upon receiving the signal, the moving average calculation circuit 28 averages the injection amount measured by the electromagnetic flow meter detector 18.

Next, a plurality of signals indicating the injection amount averaged by the moving average operation circuit 28 are sampled by the sampling control circuit 30, and a signal indicating the sampled injection amount is output to the PID operation circuit 32. PID
When a signal indicating the injection amount is input to the arithmetic circuit 32,
The PID operation circuit 32 performs a comparison operation between the signal indicating the injection amount and a preset injection amount 34. And PI
The D operation circuit 32 controls the pulsating flow pump 16 so that the signal indicating the injection amount of the medicine 14 intermittently input from the sampling control circuit 30 becomes equal to the set injection amount 34.
Is controlled by the rotation speed control device 38 and the stroke is controlled by the stroke control device 40, respectively.

Therefore, in the present embodiment, the pulsating flow pump 16 is feedback-controlled based on the delivery amount of the medicine 14 intermittently measured by the electromagnetic flow meter detector 18, so that the pulsating flow pump 16 is controlled. At 16, the injection amount of the medicine 14 delivered by the pulsating flow can be accurately and feedback-controlled without trouble.

[0013]

As described above, according to the method and the apparatus for controlling the injection amount of a medicine according to the present invention, the injection amount of the liquid medicine sucked by the pulsating flow type pump and sent out in a pulsating flow is determined by the electromagnetic flow rate. A signal indicating the amount of chemical injection measured intermittently by the meter and the amount of chemical injection measured by the electromagnetic flowmeter is electrically averaged by the averaging device, and the averaged amount of chemical injection by the averaging device and the predetermined injection The amount of the pulsating flow pump is intermittently compared with the amount of the pulsating flow type pump based on a signal from the comparing and calculating device. The injection amount of the medicine delivered by the pulsating flow by the mold pump can be accurately controlled without trouble.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an embodiment of a drug injection amount control device according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Control device of chemical injection amount 12 ... Chemical liquid tank 14 ... Chemical 16 ... Plunger pump 18 ... Electromagnetic flow meter detector 22 ... Electromagnetic flow meter amplifier 26 ... Controller 28 ... Moving average operation circuit 30 ... Sampling control circuit 32 ... PID operation Circuit 38: Revolution control device 40: Stroke control device

Claims (2)

(57) [Claims] 1. A liquid chemical injected by a pulsating flow pump.
In chemical injection amount control method for controlling the injection amount of the is sucked by the pulsatile flow pump intermittently measuring the injection amount of the liquid medicine delivered by pulsatile flow, the dosing amount of the intermittently measured No pulsation based on
Obtained by calculation an average flow rate, the intermittently comparing calculated the dosing amount and a preset injection amount calculated as chemical injection amount which the obtained becomes equal to the set injection amount, the pulsating flow A method for controlling a chemical injection amount, wherein the number of revolutions and the stroke of a mold pump are feedback-controlled, respectively. 2. A liquid chemical injected by a pulsating flow pump.
Of the control device for dosing the amount of controlling the injection quantity, an electromagnetic flowmeter for intermittently measuring the injection amount of the liquid medicine delivered by pulsatile flow is sucked by the pulsatile flow pump, intermittent in the electromagnetic flow meter Based on the chemical injection amount measured
Calculation device that calculates the average flow rate without pulsation by calculation
When the comparison operation unit for intermittently comparison operation and dosing amount and a preset injection volume the obtained, based on a signal from the comparison operation unit, the obtained pharmaceutical Note
Control means for feedback-controlling the number of revolutions and the stroke of the pulsating flow pump so that the amount of injection becomes equal to the set amount of injection , respectively.