JPH07146287A - Water quality monitoring device - Google Patents

Abstract

PURPOSE:To accurately measure residual nitrogen concentration by compensating a measurement error with a slight sample water. CONSTITUTION:In a water monitoring device 2 with a residual nitrogen meter 6 for measuring the residual nitrogen concentration of city water, etc., a bypass path 10 for directly delivering sample water without going through a mainstream path 5 separately from the mainstream path 5 for flowing the sample water to the side of the residual nitrogen meter 6 is provided and an electromagnetic valve 12 for breaking the flow of the sample water of the bypass path 10 is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water quality monitor for continuously measuring the concentration of residual chlorine in sample water such as tap water.

[0002]

2. Description of the Related Art Residual chlorine, which is used for examining disinfection effects, is one of the most important water quality measurements in waterworks. Since this residual chlorine is extremely unstable, accurate values cannot be obtained unless it is accurately measured on-site. Does not come out. However, since it is difficult to attach a water quality monitoring device directly to the water pipe or water supply pipe to be measured, a water quality monitoring device is usually installed near the water pipe, and the water is guided by a conduit to be installed in the monitoring device. The water quality is measured by various water quality meters. The polarographic method is generally employed to continuously and stably measure residual chlorine.

[0003]

By the way, since the sample water to be measured is discarded after the measurement, it is desirable that as little sample water as possible be supplied to the water quality monitoring device. However, the flow of sample water in the conduit becomes slow when the amount of water is small, which causes a decrease in the residual chlorine concentration, and the concentration of the pipeline to be measured and the concentration measured by the device are slightly different, and the residual chlorine concentration is There is a problem that it cannot be measured. In particular, when the residual chlorine concentration is low, this slight error becomes a problem.

The present invention has been made in order to solve such a conventional problem, and an object thereof is to provide a water quality monitoring device capable of accurately measuring the residual chlorine concentration by correcting the measurement error.

[0005]

A water quality monitoring device of the present invention comprises a main flow path for flowing sample water to a residual chlorine meter side, and a bypass passage for directly discharging the main water path without passing through a pressure reducing valve.
A valve for shutting off the flow of sample water in the bypass passage is provided.

[0006]

According to the present invention, in the steady state, the sample water is flowed only through the main flow path in order to suppress the consumption of the sample water in a steady state, but the flow of the sample water through the conduit at this time is slow and the residual chlorine concentration is It will decrease and will be different from the actual residual chlorine concentration of tap water. Therefore, if the valve of the bypass channel is opened for a short time and more sample water is allowed to flow through the conduit than usual, the sample water stays in the conduit for a shorter time, and the decrease in residual chlorine concentration is reduced. , Sample water close to tap water will flow into the water quality monitoring device. By measuring this sample water, the residual chlorine concentration in a state almost equal to tap water can be measured. Correcting the steady-state measured value from this measured value makes it possible to know the accurate residual chlorine concentration value of tap water.
However, since the amount of sample water intermittently flowing to the bypass channel is small, the amount of sample water wasted can be reduced.

[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 circuit diagram of a water quality monitoring device according to an embodiment of the present invention, in which 1 indicates a water distribution pipe and 2 indicates a water quality monitoring device. The water pipe 1 and the water quality monitoring device 2 are connected by a conduit 3, and the tap water flowing through the water pipe 1 is introduced into the water quality monitoring device 2.

The water quality monitoring device 2 is provided with a main channel 5 for flowing sample water to a residual chlorine meter 6 during steady measurement. A pressure reducing valve 7 for reducing the water pressure of the sample water and a flow meter 8 for measuring the flow rate of the sample water are provided upstream of the residual chlorine meter 6 in the main flow path 5.

Further, in the water quality monitoring device 2, a large amount of sample water is intermittently caused to flow through the conduit 3 to correct the measurement error of the residual chlorine concentration. A bypass flow path 10 is provided to flow directly to the drainage path 9 without passing through the total 6. This bypass channel 10
The valve that controls the opening and closing of the valve by the controller 11 (motorized valve 1
2) and the variable throttle valve 13 is provided downstream thereof.

A gate valve 14 is provided upstream of a branch point where the main flow path 5 and the bypass flow path 10 branch.
Next, the operation of the above configuration will be described.

The sample water in the steady state enters the water quality monitoring device 2 from the water distribution pipe 1 through the conduit 3, and enters the residual chlorine meter 6 through the gate valve 14, the pressure reducing valve 7 and the flow meter 8 to remove residual chlorine. Is measured and discharged from the drainage channel 9. Since the motor-operated valve 12 is closed, no sample water flows in the bypass flow passage 10.

When the motor-operated valve 12 is opened by the controller 11, the sample water of the amount adjusted by the variable throttle valve 13 also flows into the bypass passage 10. That is, in a steady state, a small amount of water as the measurement water flows through the conduit 3, but by opening the motor-operated valve 12, a larger amount of sample water flows through the conduit 3 than usual.

Next, a method of measuring the residual chlorine concentration will be described. In order to carry out the measurement while suppressing the consumption of the sample water at a constant time, the motor-operated valve 12 is closed and the sample water is flowed only through the main flow path 5. At this time, the flow of the sample water flowing through the conduit 3 is slow, and the concentration of residual chlorine is expected to decrease. Therefore, the residual chlorine concentration of the tap water flowing through the water distribution pipe 1 and the residual chlorine concentration measured in the residual chlorine meter 6 are different.

Therefore, the motor-operated valve 12 is controlled by the controller 11 for a short time.
When the valve is opened and a larger amount of sample water is flowed into the conduit 3 than usual, the time for which the sample water stays in the conduit 3 is shortened, the residual chlorine concentration is reduced less, and tap water flowing in the water distribution pipe 1 is reduced. The sample water close to is flowing into the water quality monitoring device 2. By measuring this sample water, it is possible to measure the residual chlorine concentration in a state substantially equal to the tap water flowing in the water distribution pipe 1. By correcting the above-mentioned normal measurement value with this measurement value, it becomes possible to know the accurate residual chlorine concentration value of the tap water flowing through the water pipe 1. However, since the amount of the sample water intermittently flown to the bypass channel 10 is small, the amount of the sample water wasted can be reduced.

Further, the case where the measured value is corrected will be specifically described with reference to FIG. Fig. 2 is a state diagram when the residual chlorine concentration is continuously measured by this water quality monitoring device. The vertical axis shows the residual chlorine measurement value (mg / l) and the horizontal axis shows the time (1
Day). In this figure, A shows the numerical value of the steady-state residual chlorine concentration where the flow rate of the sample water flowing through the conduit 3 is small, and B shows the numerical value when the flow rate of the conduit 3 is increased by flowing the sample water through the bypass channel 10. Shows. The residual chlorine concentration of A is about 0.20 mg / l and that of B is 0.2
It is 4 mg / l. Therefore, 0.24 mg / l-0.20 mg / l =
If 0.04 mg / l is added to the measured value in the steady state and corrected, the accurate residual chlorine concentration of tap water in the water pipe 1 can be known.

In the above embodiment, only the residual chlorine meter 6 is shown inside the water quality monitoring apparatus 1, but it goes without saying that it may be equipped with a pH meter, a conductivity meter or the like.

Further, although the bypass flow passage 10 is connected to the drainage passage 9 which is common to the main flow passage 5, it may be separated from the main flow passage 5.

[0018]

As described above, according to the present invention, the bypass passage for discharging the sample water without passing through the main water passage is separately provided, and the valve is provided in the bypass passage. When the valve is opened for a short time and more sample water than usual is flowed through the conduit, the decrease in residual chlorine concentration in the sample water is reduced, and the residual chlorine concentration almost equal to tap water can be measured. If the measured value in the steady state is corrected from this measured value, the residual chlorine concentration value of tap water can be accurately measured without wasting sample water.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a water quality monitoring device according to an embodiment of the present invention.

FIG. 2 is a state diagram when the residual chlorine concentration is continuously measured.

[Explanation of symbols]

 2 Water quality monitoring device 5 Main flow path 6 Residual chlorine meter 10 Bypass passage 12 Motorized valve

Claims (1)

[Claims] 1. A water quality monitoring device equipped with a residual chlorine meter for measuring the residual chlorine concentration of tap water, etc., wherein a main flow path for flowing sample water to the residual chlorine meter side and a sample water flow without passing through this main water channel. A water quality monitoring device comprising a bypass passage for direct discharge and a valve for shutting off the flow of sample water in the bypass passage.