JPH0658323B2 - COD measuring device for water - Google Patents

Description

TECHNICAL FIELD The present invention relates to a device for measuring the state of organic pollution of water, and more particularly to a COD measuring device for water.

(Prior art) As the dam lake is polluted with organic substances, the need for continuous monitoring of water quality is increasing from managers.
At the same time, the total amount of water quality is being regulated.

In the total amount regulation, COD (Chemical Oxygen Demand) is designated as one pollution index, and the designated measurement method is "JIS.
K0102 Industrial wastewater test method ", page 13," Oxygen consumption by potassium permanganate at 100 ° C (CO
D) ”is adopted.

COD is the amount of oxygen (mg / or ppm) consumed when an oxide in test water is oxidized by an oxidizing agent such as potassium permanganate, and chemically oxidizes organic substances using chemicals. And much data has already been accumulated.

However, it is difficult to measure continuously in, for example, a dam lake by the method of chemically processing and calculating.
Therefore, other methods have been studied, and since some organic substances absorb ultraviolet light well, ultraviolet absorption has come to be used for the qualitative quantification of the organic substances. Many data confirm that this UV absorbance serves as an index of COD.

Although the ultraviolet absorbance is considered to be effective as an indicator of water pollution, conventionally, there has not been a device that continuously measures without maintenance for a long period of time while being installed by a method of immersing it in a site such as a dam lake or lake.

(Problems to be Solved by the Invention) The present invention provides an apparatus capable of automatically and continuously measuring COD up to a depth of about 100 m from a water surface in a dam lake or the like for a long period without maintenance. is there.

(Means for Solving the Problems) The present invention is directed to an ultraviolet light emitting body that sucks and introduces water to be measured by a wiper that reciprocates in the cylinder into a transparent cylinder, cleans the surface of the cylinder, and transmits the light through the cylinder. Measurement of the attenuation value of ultraviolet light and the attenuation value of visible light that passes through the cylinder, and subtracting the attenuation value of visible light from the attenuation value of ultraviolet light determines the ultraviolet absorbance to measure COD in water. It has a feature.

(Function) The UV absorbance of inorganic substances cannot be ignored for nitrate ions, sulfite ions, and bromine ions at a wavelength of 220 nm.
Almost not seen at wavelengths above 50 nm. Therefore, absorption at wavelengths of 250 nm and above is mostly based on organic substances. That is, the COD and the absorbance at a wavelength of 250 nm have a good correlation. The UV emitters used in the present invention are 25
It emits light having a wavelength of 0 nm or more, and a commercially available low-pressure mercury lamp satisfies this. Alternatively, a normal light emitting body may be used and only the ultraviolet rays may be passed through the filter.

The device of the present invention is installed by being suspended by a cable in, for example, a dam lake. The cylindrical body is housed in a case that is sealed so that water does not enter except for a portion where the water sucked and introduced into the cylindrical body is discharged.

For the measurement, water is sucked into the transparent cylinder with a wiper and the water to be inspected is introduced into the cylinder. The ultraviolet light from the ultraviolet light emitter is absorbed by the contaminants of the sample water introduced into the cylinder and scattered by the floating substances to be attenuated. The attenuation is detected by comparing this with the original brightness. This attenuation also includes scattering by suspended matter as described above.
The present invention also measures the attenuation caused by scattering by a floating substance due to visible light that is not absorbed by an organic substance, and subtracts it by a calculator. This allows the present invention to measure UV absorbance, that is, the COD of water.

This measurement is continuously performed every time the sample water is sucked into the cylinder with the wiper. When placed in water for a long period of time, dirt adheres to the inner surface of the cylinder and adversely affects the measured value.However, in the present invention, the wiper moves in contact with the inner surface of the cylinder. The inner surface of the cylinder is wiped so that the inner surface of the cylinder can be kept clean and accurate measurement can be performed. Since the outer surface of the cylinder is housed in a closed case, there is no risk of getting dirty.

In addition, the wiper stops for a long time while being installed in water during intermittent measurement, which is about once a day, but microorganisms adhere when sunlight and oxygen are freely supplied.
Although there is a possibility of breeding, in the present invention, the inside of the cylinder is shielded from light and it is difficult to supply oxygen, so that the cylinder can be kept clean even if the wiper is intermittently operated.

In addition, since the lid provided at the opening of the cylinder is made of copper, which microorganisms dislike, it is possible to prevent the microorganisms from entering the cylinder through the water inlet while the wiper is stopped, thus keeping the cylinder clean. .

(Embodiment) FIG. 1 is a configuration diagram of the present invention, FIG. 2 is a minute cylinder for accommodating sample water, A is a sectional view showing a suction state, B is a discharge state, and FIG. It is a block diagram which shows the electric constitution of a circuit.

In these drawings, a case 1 is a sealed cylindrical container having a pressure resistant structure, and is formed by a first case 2 and a second case 3. A transparent cylindrical body 4 is installed in the first case 2 with its open end released from the bottom of the first case 2. The tubular body 4 is a container for containing a sample water and measuring COD, and a wiper 5 which moves up and down while contacting the inner surface of the tubular body is provided therein. A drive shaft 6 is attached to the wiper 5, and the drive shaft 6 is slidably projected from the base end of the cylindrical body 4. A screw shaft 9 is attached to a motor 7 installed in a second case 3 provided above the first case 2 via a coupling 8. Furthermore, a slide body 10 is screwed onto the screw shaft 9, and the drive shaft 6 is attached to the slide body 10. That is, the screw shaft 9 is rotated by the rotation of the motor 7,
The wiper 5 is moved up and down in the cylindrical body 4 by moving the sliding body 10 along the axis.

In FIG. 2, the tubular body 4 is provided with a transparent tubular body 42 made of glass or the like between the base die 40 and the tip die 41, and the wiper 5 moves up and down in the transparent tubular body 42.
The drive shaft 6 projects from the base cap 40. The tip base
41 is provided with a lid 43 made of copper, a groove 44 is formed on the inner peripheral edge of the lid 43, and a plurality of injection ports 45 opening toward the groove 44 are provided. . The inner wall forming the groove 44 is the tip cap.
It is attached with a gap between it and 41, so that it has a structure in which water enters the transparent cylinder 42 from the inlet 45 but blocks light, and the lid 43 is made of copper. Therefore, it has a structure that makes it difficult for organisms to attach.

In addition, the drain pipe 11 is connected to the base cap 40.

On the other hand, in the wiper 5, a hollow portion 52 having a tapered surface 51 inside is formed in a cylindrical plug body 50 having a diameter smaller than that of the transparent cylindrical body 42, and a shaft hole 53 reaching the tapered surface 51 is formed. Has been done. The tip of the drive shaft 6 has a shaft hole 53 of the plug 50.
It is accommodated in the cavity portion 52 via the inside, and a taper plug 60 is provided in the cavity portion 52. Also, the drive shaft 6 has the plug 50.
A flange 61 to be joined to the base end surface of the rod 61 is provided, and the diameter of the rod 62 between the flange 61 and the taper plug 60 is smaller than the diameter of the shaft hole 53, and thus the shaft hole 53 and the rod 62 are A gap is formed between them. Furthermore, stopper 50
A through hole 54 that opens toward the shaft hole 53 is provided in the.

When the drive shaft 6 is moved toward the wiper 5, the flange 61 is joined to the base end surface of the plug body 50, and at this time, the taper plug 60 enters the cavity 52 and leaves a gap between it and the taper surface 51. Is formed. Taper plug if drive shaft 6 is moved in the opposite direction
60 is sealed to the tapered surface 51.

A bowl-shaped wiper wheel 55 joined to the inner peripheral surface of the transparent cylinder 42 is fixed to the tip of the plug body 50 with a bolt screw 5b.
Further, the bolt screw 56 is provided with a guide hole 57 communicating with the hollow portion 52.

The first case 2 is provided with a drain pipe 11 for discharging the water in the tubular body 4 from the case 1, and the second case 3 is provided with a cable 12 for suspending the case 1. .

With reference to FIG. 3, a low-pressure mercury lamp 20 as an ultraviolet light emitter and a first photoelectric tube as an ultraviolet light detector sandwiching the cylindrical body 4 therebetween.
21 and 21 are provided. As shown in the figure, in the optical path from the low-pressure mercury lamp 20 to the first photoelectric tube 21, a lens 22, a rotary slit 24 which is rotationally driven by a motor 23 to alternately alternately pass and block light, a filter 25, and a lens 26 are arranged. Has been done. The filter 25 is for cutting light other than ultraviolet rays. Further, the ultraviolet light of the low-pressure mercury lamp 20 is further received by the second photoelectric tube 27 and is used as reference light for comparing attenuation.

Further, an LED 28 and a first light receiving element 29 as a visible light detector are arranged with the cylindrical body 4 sandwiched therebetween. A lens 30, a half mirror 31, and a red filter 32 are arranged in this optical path, and a second light receiving element 33 for receiving the light reflected by the half mirror 31 is separately prepared. This is a reference light for calculating the attenuation of visible light.

The attenuated output from the first phototube 21 is amplified by the amplifier 34a and passed through the bandpass filter 35a to the rectifier circuit 36a.
To be entered. Similarly, the reference light is also amplified by the amplifier 34b and input to the rectifier circuit 36b via the bandpass filter 35b. The outputs of the rectifier circuits 36a and 36b are both input to the divider 37, and the ratio between the attenuated light and the reference light is output. Further, the output of the divider 37 is input to the logarithmic amplifier 38 and outputs the ultraviolet ray attenuation degree A _uv .

The pass band is limited by the band pass filter 35a by choppering with the rotary slit 24, which is for removing external light noise.

On the other hand, the visible light of the LED 28 is similarly amplified by the amplifiers 39a and 39b, and the bandpass filters 40a and 40b and the integer circuit 41 are used.
a, 41b and dividers 42a, 42b are input to the logarithmic amplifier 43 to output the visible light attenuation A _vis .

In the embodiment, each of them is output, and the difference A _uv -A _vis is output by the calculator 44. This A _uv -A _vis is the ultraviolet absorbance absorbed by the organic substance from which the attenuation due to the suspended matter is removed. This value is converted to COD.

The embodiment is arranged in a lake or marshes such as a dam lake and automatically operates continuously to monitor changes in water quality in real time.

Therefore, this device is suspended in water and arranged by the cable 12. Water is introduced into the cylindrical body 4 by raising the wiper 5 by the motor 7, and the above-mentioned measurement is performed to measure the COD. Each time the wiper 5 is lifted, the measurement is continuously performed. Organic substances and floating substances adhere to the inside of the transparent cylinder 4, but the reciprocating movement of the wiper 5 removes them, so that the wiper 5 can always be measured in a clean state.

(Effects of the Invention) According to the present invention, the absorbance of ultraviolet rays can be measured from the attenuation value of ultraviolet rays and the attenuation value of visible light by introducing sample water into the transparent cylindrical body while placing it in water. Therefore, COD of dam lakes, lakes and marshes can be automatically and continuously observed without maintenance for a long period of time.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an apparatus according to an embodiment of the present invention, FIG. 2 shows the details of a detection unit, A is a state in which water is sucked into the cylinder, and B is each cross-section showing a state in which water is discharged from the cylinder. 3 and 4 are block diagrams showing the electrical configuration of the measuring circuit. 1 …… Case 2 …… First case 3 …… Second case 4 …… Cylinder 5 …… Wipeer, 6 …… Drive shaft 7 …… Motor, 8 …… Coupling 9 …… Screw shaft , 10 ...... Sliding body 20 ...... Low pressure mercury lamp, 21 ...... First photoelectric tube 24 ...... Rotating slit, 27 ...... Second photoelectric tube 28 ...... LED, 29 ...... First light receiving element 33 ...... Second light receiving element

Front page continuation (72) Inventor Takaho Oike 2-22 Tsurumi Chuo, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture Tsurumi Seiki Co., Ltd. (56) References JP-A-56-106143 (JP, A) JP-A-55 -159140 (JP, A) JP-A-60-128333 (JP, A) JP-A-61-290345 (JP, A)

Claims (2)

[Claims] 1. A container for accommodating sample water and measuring COD, which has one end communicating with the outside and a transparent cylinder into which water is sucked and introduced, and emits ultraviolet rays with the cylinder interposed therebetween. An ultraviolet light emitter, a modulation mechanism that modulates the light from the ultraviolet light emitter at a constant frequency, an ultraviolet light detector that receives the ultraviolet light that has passed through the tubular body and converts it into an electrical signal, and the light received by the ultraviolet light detector. UV attenuation value detecting means for obtaining an ultraviolet attenuation value by comparing the light and the brightness of the ultraviolet light emitter, a visible light emitter modulated at a constant frequency with the tubular body sandwiched, and a visible light passing through the tubular body. A visible light detector that receives light, a visible light attenuation value detection unit that obtains a visible light attenuation value by comparing the light received by the visible light detector and the brightness of the visible light emitter, and the ultraviolet attenuation value. From the UV attenuation value obtained by the detection means, the visible And a calculator for subtracting the visible light attenuation value obtained by the attenuation value detecting means after converting it to absorbance, and the cylindrical body and the ultraviolet and visible light emitters and detectors are housed in a case and the case is connected by a cable. In a measuring device to be hung and installed in a dam lake or the like, the cylindrical body has one end communicating with the outside of the cylindrical body but is shielded so that external light does not enter the inside of the cylindrical body, and the peripheral surface of the cylindrical body. A COD measuring device for water, comprising: a wiper for reciprocating while contacting with, and sucking and introducing the sample water into the inside of the cylinder by the reciprocating motion, and at the same time cleaning the peripheral surface of the cylinder. 2. The water COD measuring device according to claim 1, wherein the water inlet of the cylindrical body is formed of a material such as copper which is less susceptible to microorganisms.