JP2000140783A - Washing of water examination tank in continuous organic pollution monitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically wash an examination tank to prevent the adhesion or propagation of algae. SOLUTION: In a continuous org. pollution monitor using a two-wavelength measuring method wherein water to be examined from a water examination tank 30 is allowed to flow to a sample cell (optical cell) 12 and light is transmitted through the cell 12 and the absorbancies of ultraviolet rays and visible light are measured to measure the concn. of org. matter in water to be examined, the valve of a drain 38 of the water examination tank comprises a twoway electromotive ball valve MV1 and the absorbancy measured data of visible light is inputted to an apparatus control part and this control part always monitors the absorbancy of visible light, and the valve MV1 is repeatedly opened and closed for a predetermined time every definite time by a timer in the control part and the interior of the tank is washed with a water stream to prevent the adhesion of algae or the like. If algae propagate in the tank, the absorbancy of visible light rises. The control part opens and closes the valve MV1 repeatedly when this absorbancy exceeds a predetermined value to wash the interior of the tank with a water stream to enable measurement.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cleaning a water tank in a continuous organic pollution monitor using an ultraviolet absorption spectrophotometer for measuring the concentration of organic substances in water.

[0002]

2. Description of the Related Art In sewage treatment plants, rivers, lakes and marshes, water purification plants, etc., the concentration of organic substances in water is constantly measured.
There are various methods for measuring the concentration of organic substances, and there is an ultraviolet absorption method.

Conventionally, a continuous organic pollution monitor (hereinafter simply referred to as a UV meter) in which an ultraviolet absorption spectrophotometer is used as an apparatus will be described.

(1) Principle of measurement When ultraviolet rays pass through a sample containing an organic substance, a part of the ultraviolet rays is absorbed and the amount of transmission decreases. The organic pollutants in the sample are measured from the decrease (absorbance).

[0005] In order to reduce the influence of suspended substances, there are a correction method based on a two-wavelength measurement method for ultraviolet light and visible light, a scattered light measurement correction method, and the like.

As a light source in the ultraviolet region, a low-pressure mercury lamp is widely used, and the measurement wavelength is 254 nm.

(2) Principle of the two-wavelength measurement method FIG. 3 shows a principle diagram of the two-wavelength measurement method. Between the light source lamp 41 and the visible light detector 44, a condenser lens L 1, a sample cell 42 in which water flows, a condenser lens L 2, and a half mirror 43
And an ultraviolet detector 45 is provided on the reflection optical axis of the half mirror 43.

[0008] The outputs of the visible light detector 44 and the visible light comparison detector 46 are input to a logarithmic amplifier 51 to obtain a signal corresponding to the absorbance of the visible light. Also, the ultraviolet detector 45
The output of the UV detector 47 is input to a logarithmic amplifier 52 to obtain a signal corresponding to the UV water absorbance.

The absorbance signals from the logarithmic amplifiers 51 and 52 are input to a differential calculator 53 and subjected to a differential operation to obtain an organic matter concentration signal corresponding to the absorbance of ultraviolet light in which the influence of suspended substances in the sample is corrected.

This organic matter concentration signal is output to the outside via the measurement mode changeover switch S1.

(3) Water Test Tank FIG. 4 shows a water test flow path diagram of a water test tank for flowing water into an optical cell (sample cell). The water test tank 30 includes an outer tube 31 and an inner tube 32 having a lid 39, and water from a water sampling pump (not shown) is supplied from a manual valve V1 for adjusting the inflow amount to a water inlet 33.
And flows through the inner tube 32 from above to below, enters the lower part of the optical cell 12 from the cell inlet tube 34, flows from below to above inside the cell, enters the outlet tube 35 from above, and forms an upper hole 36 of the outlet tube 35.
, Overflows into the outer cylinder 31 and flows out of the tank from the bottom outlet 37 of the outer cylinder 31.

[0012] Water is supplied so that the flow rate in the optical cell 12 becomes constant. When the water level in the inner tank 32 increases, it overflows and flows out of the tank from the outlet 37. When the drain manual valve V2 is opened, the water sample in the inner tank 32 and the optical cell is discharged.

(4) Block Configuration of UV Meter FIG. 5 shows a block configuration diagram of a conventional UV meter. Numeral 11 denotes a sample water supply unit comprising a water test tank (FIG. 4), and 12 denotes a sample water supply unit 11
Is a sample cell through which water is sampled, 13 is a light source, 14 is a detector that detects ultraviolet light absorbance and visible light absorbance by the two-wavelength measurement method (FIG. 3), and 15 is an automatic washer that cleans the sample cell 12. .

Numeral 16 denotes an operational amplifier for calculating an ultraviolet absorbance (organic substance concentration) obtained by correcting the visible light absorbance from the ultraviolet light absorbance signal and the visible light absorbance signal from the detector 14.
Reference numeral 7 denotes an organic concentration indicator, reference numeral 18 denotes an external output unit, and reference numeral 19 denotes a control unit that controls the automatic washer 15 and outputs a device abnormality signal to the external output unit. The automatic cleaning device 15 performs cleaning of the sample cell using a wiper and a chemical solution.

(5) Regarding the maintenance management Stain on the sample cell window greatly affects the measurement, so that periodic cleaning is required.

The light source lamp is replaced periodically (every 3.000 hours).

[0017] Measurement is periodically performed by the designated measurement method.
Check the phase with the UV meter reading.

If necessary, the conversion formula is verified to ensure measurement accuracy.

(Supervision of the Sewerage Department of the City Bureau of the Ministry of Construction and the Water Environment Department of the Ministry of Health and Welfare, Ministry of Health and Welfare, Japan Water Works Association, Sewage Test Methods, Vol. 1, 1997 edition, pages 346 to 347). P
147-154.

Here, those relating to the ultraviolet absorption method are as follows:
It is described in P154.

Algae easily adheres to the test tank, and when the algae grows, the flow of the test water deteriorates or the algae enters the sample cell, which affects the measurement. Therefore, cleaning is performed frequently or periodically. There is a need.

[0022]

As shown in FIG. 4, the water test tank has many stagnant portions, so that adhesion and propagation of algae are frequently observed. Conventionally, maintenance personnel frequently or regularly perform cleaning of algae attached to the water test tank, so that the labor is large.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to provide a continuous organic pollution monitor capable of minimizing the adhesion and propagation of algae in a test tank without requiring any human labor. An object of the present invention is to provide a method for cleaning a water test tank.

[0024]

SUMMARY OF THE INVENTION According to the present invention, water is supplied to a sample cell in an apparatus using a test tank having a valve for adjusting the amount of inflow of test water and a valve for drain, and light from a light source is supplied to the sample cell. In a continuous organic pollution monitor using a two-wavelength measurement method that measures the absorbance of ultraviolet light and visible light by transmitting the sample to measure the concentration of organic matter in the sample, the drain valve of the test tank is electrically operated on-off valve And, the visible light absorbance measurement data is input to the device control unit, and the control unit constantly monitors the visible light absorbance measurement data, and repeatedly opens and closes the electric open / close valve for a predetermined time every predetermined time to open the water test tank. Washing, and when the visible light absorbance measurement data exceeds a predetermined level, the electric open / close valve is repeatedly opened and closed so that the data is within the predetermined level to wash the water test tank.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a water test flow path of a water test tank, which differs from the conventional water test tank in that the valve of the drain 38 is a two-way electric ball valve MV1. FIG. 2 shows a block configuration of a UV meter, which is different from the conventional one shown in FIG. 5 in that measurement data is input to the control unit 19 from the operational amplification unit and that the control unit 19 supplies the sample water supply unit 11.
(Temperature tank) is different in that the control signal is output. The other parts of FIGS. 1 and 2 correspond to those of FIGS.
Therefore, the same components are denoted by the same reference numerals, and the description thereof will not be repeated.

The UV meter of FIG. 2 measures the absorbance of ultraviolet light and visible light by a two-wavelength measurement method (FIG. 3), similarly to the conventional UV meter of FIG. This visible light absorbance data is input to the control unit 19. The control unit 19 has an internal timer, and repeatedly outputs an opening / closing control signal to the two-way electric ball valve MV1 of the water test tank 30 (FIG. 1) at fixed time intervals. Also,
The two-way electric ball valve MV1 of the water detection tank 30 is also used when the input visible light absorbance data becomes higher than a predetermined level.
Repeatedly outputs the open / close control signal.

The two-way electric ball valve MV1 is a control unit 1
Opening / closing is controlled by the opening / closing control signal from 9. When the valve MV1 is opened, the inside of the inner cylinder 32 of the water test tank and the cell 12
The test water inside is immediately discharged from the drain 38, and when closed, the test water flowing from the manual valve V1 accumulates in the inner cylinder 32 and flows in the direction of the arrow. By repeatedly opening and closing the valve MV1, the inside of the water test tank 30 is washed, and adhesion and propagation of algae can be suppressed as much as possible.

Normally, the opening and closing of the valve MV1 is repeatedly controlled at regular intervals by a timer in the control section 19, so that the growth of algae in the test tank 30 is suppressed, but the growth of algae in the tank occurs. When the sample cell 12 is affected by algae, the absorbance of visible light increases, and the control unit 19 repeatedly outputs an opening / closing control signal to the valve MV1 to clean the water tank 30.
Returns to a measurable state.

[0029]

Since the present invention is configured as described above, the following effects can be obtained.

(1) It is possible to suppress the adhesion and propagation of algae in the test tank.

(2) Maintenance work of the UV meter is reduced.

(3) Since the drain valve of the water test tank is an electric open / close valve that is controlled by the control unit to open and close, the configuration is simple.

[Brief description of the drawings]

FIG. 1 is a diagram of a water test flow path of a water test tank according to an embodiment.

FIG. 2 is a block configuration diagram of a UV meter main body according to the embodiment.

FIG. 3 is a principle diagram of a UV meter using a two-wavelength measurement method.

FIG. 4 is a diagram showing a water test flow path of a water test tank according to a conventional example.

FIG. 5 is a block diagram of a conventional UV meter main body.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... UV meter main body 11 ... Sample water introduction part (water test tank) 12 ... Sample cell 13 ... Light source (low-pressure mercury lamp) 14 ... Detector 15 ... Automatic cleaning device 16 ... Operational amplification part 17 ... Indicator 18 ... External output part 19 ... Control unit 20 ... Optical cell (including light source, detector, sample cell, etc.) 30 ... Test tank 31 ... Outer cylinder 32 ... Inner cylinder V1, V2 ... Manual valve MV1 ... Two-way electric ball valve (electric open / close valve).

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Nagatake Nagatake 2-1-1-17 Osaki, Shinagawa-ku, Tokyo F-term in Meidensha Co., Ltd. (reference) 2G059 AA01 AA05 BB04 CC20 DD12 EE01 EE11 GG10 HH02 HH03 JJ02 JJ11 JJ22 KK03 MM01 3B116 AA33 AB51 BB62 CD42 CD43 3B201 AA33 AB51 BB62 BB92 CB01 CD42 CD43

Claims (1)

[Claims] 1. A test cell having a test sample inflow rate adjusting valve and a drain valve is used to flow test water through a sample cell in the apparatus, and light from a light source is transmitted through the sample cell to generate ultraviolet light from the test sample. In a continuous organic pollution monitor using a two-wavelength measurement method of measuring the absorbance of visible light and measuring the concentration of organic matter in a test water, the drain valve of the water test tank is an electric open / close valve, and the visible light is transmitted to a device control unit. The control unit monitors the absorbance measurement data of the visible light at all times, and repeatedly opens and closes the electric open / close valve for a predetermined period of time for a predetermined period of time to wash the test tank, and inputs the light absorption measurement data. If the data exceeds a certain level,
A method for cleaning a water test tank in a continuous organic pollution monitor, wherein the electric open / close valve is repeatedly opened and closed to clean the water test tank.