JPH0455746A - Apparatus for monitoring chemical feeder - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a monitoring device for a chemical dosing device, and in particular, to ensure that a chemical dosing device that injects a chemical solution such as a flocculant or a neutralizing agent into an aqueous system is operating normally. This invention relates to a device for automatically monitoring whether or not

[Prior art] When injecting chemicals using a chemical dosing pump, it is necessary to inject the specified amount of the chemical, so it is necessary to ensure that the dosing pump operates correctly and that the specified amount of chemical solution is actually injected into the water system, etc. If the prescribed amount of medicine is not being injected, it is necessary to promptly restore the normal amount of medicine.

In other words, if the specified amount of medicine is not being injected, and the chemical dosing device is operating in a state where the prescribed amount of medicine is not being injected, and the medicine is being injected insufficiently or excessively, the following specific problems will occur, resulting in a rise in costs, equipment failure, etc. cause.

In case of insufficient chemical injection: ■ Hardness components in the cooling water cause scale (calcium carbonate scale, magnesium silicate scale) to adhere to the heat transfer surfaces of heat exchangers, chillers, etc., reducing thermal efficiency and reducing power consumption. Increase etc. occur.

■ Similarly, biofouling such as slime occurs, resulting in a decrease in thermal efficiency and an increase in power consumption.

In the case of excessive chemical injection: ■ The pH of the treated water system increases (alkaline chemical solution),
On the other hand, it may deteriorate (acidic chemical solution), making anti-corrosion treatment difficult, and in severe cases, the materials in the system will corrode.

■ Medicinal solutions are wasted and the cost of chemical solutions increases.

Therefore, conventionally, in various types of equipment equipped with chemical injection devices, the following method has been adopted to monitor the amount of chemical injection.

■ Regular visual measurement of the remaining amount of chemical solution (l) by the administrator.
Calculate the injection rate by dividing by the operating time of the drug injection pump during that time.

■ If the chemical dosing pump is in operation, calculate the discharge amount by dividing it by the measurement time.

■ Install a flow meter on the discharge side of the chemical dosing pump and extract its signal. With this method, the amount of chemical liquid that has passed through can be directly measured.

[Problems to be Solved by the Invention] Among the above conventional methods, method (3) has the following problems.

(i) In order to measure the change in the volume of the drug solution in units of minutes or hours, expensive measuring instruments (such as a weighing scale, an ultrasonic liquid level needle, etc.) are required, which is disadvantageous in terms of equipment cost and maintenance.

(if) If there is a leak due to a crack in the chemical tank itself or a leak due to a poor connection between the chemical tank and the chemical injection pump, correct measurement cannot be performed.

In addition, method (2) requires expensive measuring equipment to empty the measuring tank at the start of measurement or to measure the initial volume by some method, which reduces processing operation and equipment costs. It is disadvantageous.

When implementing the above methods ■ and ■ manually, it is necessary for workers to actually go to the site and take measurements on the spot for a certain period of time. If approved, it is necessary to notify that fact. Also,
Even if methods ① and ③ are carried out using expensive equipment and with some labor saved, it is still necessary to perform calculations by applying the measured values to a predetermined formula, and to judge whether or not there is an abnormality. If an abnormality is found, it is necessary to notify the staff to that effect.
It still requires a considerable amount of manpower, and a sufficient labor-saving effect cannot be obtained.

Even the method (2) above similarly requires expensive equipment and manpower for determining abnormalities and making connections, and cannot be said to be an industrially advantageous method.

The present invention solves the above-mentioned conventional problems and provides a chemical dosing device that can automatically and quickly monitor whether the amount of chemical liquid discharged from a chemical dosing pump is correct or not without requiring an expensive device. The purpose is to provide a monitoring device.

[Means for Solving the Problems] A monitoring device for a drug feeding device of the present invention is a device for monitoring whether a specified amount of drug solution is being discharged from a drug feeding pump, 18 from the pump operation detection means and a signal from the flow rate detection means are input. calculation means;
Comparison means is provided to receive the calculated value from the calculation means and compare it with the set value.

[Function] In the monitoring device for a chemical injection device of the present invention, when the cumulative operation of the chemical injection pump within a predetermined time is multiplied by the discharge amount of the chemical injection per unit time, the actual discharge amount discharged within the predetermined time is determined. is calculated.

By comparing the calculated actual discharge amount with a preset set water discharge amount, it is possible to detect whether the chemical injection pump is working well or not, whether or not water leaks from the piping, and the like.

For example, if the actual discharge rate is lower than the set discharge rate, there may be air trapped in the pump, damage to important parts such as the diaphragm, or the chemical tank may be empty or water may be leaking from the piping. It is possible to detect abnormalities such as

If the actual discharge amount is greater than the set discharge amount, it is detected that, for example, the check valve has broken and the chemical solution has been injected due to siphon action even though the chemical injection pump has stopped.

Note that if the flowmeter is a pulse type flowmeter, the actual discharge amount can be detected by the number of pulses without multiplying the discharge amount per unit time to obtain the actual discharge amount.

For example, the number of pulses of the pulse type flowmeter to be counted within the predetermined time period is determined from the cumulative pump operating time and the cumulative number of pulses within the predetermined time period. Therefore, by comparing the obtained number of pulses with a preset number of pulses within a predetermined time period, abnormality diagnosis can be performed in the same manner as described above.

[Example] FIG. 1 is a system diagram of a chemical dosing device according to an embodiment of a monitoring device for a chemical dosing device of the present invention, in which a chemical dosing pump 3 is connected to a chemical tank 1 via a pipe 2. . The discharge side of the chemical dosing pump 3 is connected to a water system via a pipe 4, and a pulse flowmeter 5 is provided on the pipe 4. Power can be supplied to the chemical dosing pump 3 from the power supply device 6, and the chemical dosing pump 3
When powered, it releases water quantitatively.

A detection pulse signal from the pulse flowmeter 5 is input to a monitoring circuit 7. A power supply signal indicating that the power supply device 6 is supplying power to the drug injection pump 3 is also input from the power supply device 6 to the monitoring circuit 7 .

The monitoring device is provided with a pulse counter 8 and a timer counter 9 that adds up the M constant time to the chemical injection pump 3. In addition, by dividing the number of pulses 8 counted by the pulse counter 8 by the cumulative operating time T of the drug injection pump determined by the timer counter 9, the number of pulses counted within a predetermined time (actual number of pulses) is calculated. (The calculation formula is a/
The monitoring device 7 is provided with a calculation circuit 10, which is a calculation means for calculating T). The monitoring device 7 is provided with a comparison circuit 11 that compares the actual number of pulses with a preset number of pulses.

In this embodiment, a memory 12 for setting and storing the number of pulses is provided in the monitoring device 7, and the set number of pulses in the memory 12 can be compared with the actual number of pulses in the comparison circuit 11. There is.

Furthermore, in this embodiment, the communication circuit 1 notifies the host computer of an abnormality based on the comparison result of the comparison circuit 11.
3 is installed. 14 is a public communication line.

The operation of the monitoring device configured as described above will be explained with reference to the flowchart shown in FIG. 1982.

First, a lock for measuring the above-mentioned "predetermined time" is started (step 21).

The operating time of the chemical dosing pump 3 and the output pulses of the pulse flowmeter 5 are counted until this predetermined time elapses (
Steps 22, 23, 24, 25).

When a predetermined period of time has elapsed (step 26), the counted cumulative pulse number and cumulative operating time T are read from the memory (step 27.28), and a/T is calculated based on the cumulative working time T1 and cumulative pulse number a. The number of pulses (actual number of pulses) to be counted within this predetermined time is calculated (step 29).

It is determined whether the calculation result is O or calculation is impossible (step 30).

If the chemical dosing pump 3 is not activated even once within this measurement time (abnormality 1), or if the flow meter does not detect any flow rate (abnormality 2), this means that some abnormality has occurred. Each abnormality is reported to the host computer (steps 31 and 32).

If there is no such abnormality, in step 33, the set pulse number, that is, the target drug injection amount (in this example, it has a certain range, and the allowable target lower limit value and allowable target upper limit value are stored in the memory 1.
It is stored in 2. ) is read, this set number of pulses is compared with the actual number of pulses actually counted (step 34).

If the actual pulse number is between the upper limit and lower limit of the set pulse number, it is determined that there is no abnormality in the chemical injection pump 3 and the flowmeter 5. If there is a large discrepancy between the two pulse numbers, it is diagnosed that there is an abnormality.

If the actual number of pulses is smaller than the set value by more than the allowable width, abnormality 3 described below has occurred, and if the actual number of pulses is greater than the allowable width, abnormality 4 described later has occurred. (Steps 35.36).

Any anomalies are communicated to the host computer (step 32).

If there is no abnormality, the memory of the counter 8.9 is initialized (reset) in steps 37 and 38, and then the process returns to step 1.

The relationship between the pulse signal of the pulse type flowmeter and the operation signal of the chemical injection pump is as shown in FIG.

The leftmost region in FIG. 3 is a normal state.

Abnormality 1 is when the chemical liquid is flowing even though the chemical dosing pump is not operating, for example, when the chemical liquid flows due to the action of a siphon due to a malfunction in the check valve, and although a pulse is generated, The actuation of the dosing pump is not measured.

Abnormality 2 is when the chemical injection pump is operating but no chemical is being injected, such as when air is trapped in the pump, the diaphragm is malfunctioning, or the chemical tank is empty.Although no pulses are generated, The actuation of the dosing pump is measured.

Abnormality 3.4 is caused by the loosening or misalignment of the injection volume adjustment screw, causing the chemical injection pump to operate and the chemical solution to be flowing.
The amount of injection is too low (abnormality 3) or excessive (abnormality 4).
), in the case of abnormality 3 in the understate condition, the number of pulses is small relative to the operating time of the chemical dosing pump, and in the case of abnormality 4 in the excessive state
In this case, the number of pulses is large compared to the operating time of the drug injection pump.

In the embodiment described above, such an abnormality in the chemical injection device is notified to the host computer.

In addition, in the present invention, when such an abnormality occurs, an alarm device may be activated.

In addition, in the above embodiment, the number of pulses within a predetermined time (a/T)
is calculated and compared with the set number of pulses, but furthermore,
This is multiplied by the flow rate per pulse, and the actual discharge amount (a-
b/T) and may be compared with the set discharge amount.

[Effects of the Invention] As detailed above, according to the monitoring device for a chemical injection device of the present invention, it is possible to automatically check whether or not a predetermined amount of chemical is being injected using a simple and low-cost device. It can be detected accurately and quickly. Therefore, according to the monitoring device for a drug feeding device of the present invention, it is possible to significantly reduce personnel costs, reduce device costs,
It is possible to improve the efficiency of abnormality recovery processing and reliably prevent problems caused by under- or over-injection of chemicals.

[Brief explanation of drawings]

Fig. 1 is a system diagram showing one embodiment of the monitoring device for the chemical injection device of the present invention, Fig. 2 is a flowchart explaining the operation of the monitoring device shown in Fig. 1, and Fig. 3 is a flowchart showing pulse signals of the flow meter. It is a time chart which shows the relationship with the operation signal of a drug injection pump. 1... Chemical tank, 3... Chemical dosing pump, 5...
・Pulse flowmeter, 6...Power supply device, F...Monitoring circuit.

Claims (1)

[Claims] (1) A device for monitoring whether a prescribed amount of chemical liquid is being discharged from a chemical dosing pump, comprising pump operation detection means for detecting operation and stoppage of the chemical dosing pump; and a chemical dosing pump. a flow rate detection means for detecting the discharge amount of the pump, a calculation means into which the signal from the pump operation detection means and the signal from the flow rate detection means are input, and a calculation value from the calculation means is input and compared with a set value. A monitoring device for a chemical dosing device, comprising: a comparing means for comparing the information, and a monitoring device for a drug feeding device.