JPH07270231A - Photoelectric photomater - Google Patents

Abstract

PURPOSE:To provide a submerge type photoelectric photometer having a simple structure for washing and calibrating. CONSTITUTION:A measurement cell 1 forms a light source chamber 3 and a light reception chamber 4 sealed water-tightly from inspection water with a pair of optical windows 7, 8 arranged vertically putting an inspection water stagnation part 2 between them. Also it sets a light path for monocolor light for measurement which introduces the light from a source 15 arranged in the light source chamber through the inspection water stagnation part to a light reception part 17 arranged in the light reception chamber. A slide block 9 has seal rings 10a, 10b used also as at least a pair of window wipers which are in water-tight contact with the pair of optical windows. A liquid chamber 22 having an end opening facing a pair of windows between a pair of seal rings is formed water-tightly to and separated from the inspection water stagnation part. And liquid paths 18a and 18b for washing water or pure water connecting to this liquid chamber are formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoelectric photometer which can be directly immersed in or communicated with a test water source.

[0002]

2. Description of the Related Art In today's society, from the standpoints of securing water resources and protecting the living environment, it is necessary to measure the water quality at each depth of a dam lake and to monitor real-time pollution at rivers, lakes or water treatment facilities at various places. It has come to be requested.

In response to these demands, as a method currently used, it is usual to carry out continuous measurement by a flow cell system in which a sample water is pumped from each measurement point and guided to a measuring instrument sensor. In the case of this flow cell method, there is a drawback that the signal delay due to the distance from the water sampling point to the sensor and the capacity, and the dissociation with the actual concentration due to diffusion occur, and there are various restrictions on the movement of the measurement point. was there.

Therefore, recently, a method has also been developed in which the sensor itself is directly put into a measuring point and an electric signal obtained by this is derived in real time. However, generally, in monitoring water pollution, a photoelectric photometer method that measures the amount of light transmitted through the sample according to the light absorption characteristics of the sample is common, and when performing long-term continuous measurement in the field-real time mode or in the test water environment. When it is used as a direct immersion type, there are the following various problems.

[0005]

In the photoelectric photometer method, the sample solution existing in a certain optical path interval is irradiated with light, and the amount of the target component dissolved in the sample is determined by the attenuation amount of the light of a specific wavelength passing through the interval. For determining the concentration, therefore, a pair of window plates is provided for specifying the optical path interval and isolating the sample solution. However, in the case of the conventional flow cell method, various pollutants existing in the sample are deposited on the window surface, the apparent output gradually increases, and it seems as if high-concentration components exist with the passage of time. It shows various measured values.

As a means for eliminating such contamination of the window surface, a method of jetting a jet water stream onto the window surface to forcibly remove the deposits, a method of mechanically scraping off with a wiper, or peeling by the ultrasonic cavity effect Although a method of doing so has been developed, the cleaning effect cannot be reliably obtained with a simple mechanism. In addition to these methods, there is also a method in which a cleaning solution such as hydrochloric acid is introduced into the flow cell to chemically decompose and clean it, but in this case, a large amount of a strongly acidic chemical solution such as hydrochloric acid is required. , Its disposal also causes a problem.

Further, as a method of measuring the pollution concentration irrespective of the pollution of the window, the so-called Lambert-Beer equation As = a.L.C (As: absorbance, a: molecular extinction coefficient, L: cell interval,
C: object density), a method (cell modulation method) in which the cell interval between a pair of windows is varied by a certain distance to obtain a density signal irrespective of the dirt on the windows is also in practical use. That is, ΔAs = a · ΔL · C, where ΔAs is the absorbance difference and ΔL is the moving distance of the cell interval.

However, even in this method, in the measurement of an actual sample, when the window is contaminated, the photoelectric output and the measurement accuracy are inevitably decreased due to the absolute increase in the absorbance.

Further, in the direct immersion cell system for measuring pollutants in the ultraviolet region, an oil film, which is often present on the water surface of the measurement water area, usually adheres to the window surface immediately after being immersed in the water surface. There have been many problems that the amount of light absorption increases and a true measured value cannot be obtained.

Further, in the case of continuous measurement in the direct immersion method, the zero-point fluctuation and the sensitivity change with the passage of time of the entire system cannot be ignored.

Therefore, according to the present invention, in order to solve the above-mentioned various problems, mechanical wiping of the window surface and cleaning with a cleaning liquid containing a necessary minimum amount of hydrochloric acid and the like are performed in parallel, and at the start of measurement. An object of the present invention is to provide means for preventing oil film contamination of the optical window (during cell immersion).

The present invention also intends to provide means for performing zero point calibration or sensitivity calibration for each measurement in combination with the above means.

[0013]

In order to achieve the above object, the present invention provides a measuring cell of a photoelectric photometer having a test water retention part which can be directly immersed in or communicated with a test water source, wherein A light source chamber and a light receiving chamber that are watertightly sealed from the water to be detected are formed by a pair of optical windows that are vertically arranged with the water retention part interposed therebetween. It has a set of optical paths for monochromatic light measurement that reach the light receiver arranged in the light receiving chamber through the sample water retention part, and a seal ring that also serves as at least a pair of window wipers that make watertight contact with the pair of optical windows. Then, a liquid chamber having an open end facing the pair of windows between the pair of seal rings is formed in a watertight and separated manner from the test water retention part, and a cleaning liquid or pure water communicating with the liquid chamber is formed. To form a liquid passage for In the calibration block, the liquid chamber surrounds the optical path at the calibration or cleaning position, and the test water retention part between the pair of windows is released at the measurement position retracted from the calibration or cleaning position. A photoelectric photometer is provided, which is configured to communicate with a test water source.

[0014]

According to the above construction, the measuring cell is immersed in the test water source while the pair of optical windows are watertightly sealed from the test water by setting the slidable block to the calibration or cleaning position, and after the immersion, the sludge is moved. By moving the moving block back to the measurement position, the test water outside the sliding block enters the test water retention part between the pair of windows for the first time, and at this time, when the cell is dipped, the tip surface of the sliding block is The attached oil film moves as it is together with the sliding block and hardly contaminates the pair of optical windows, and does not substantially affect the measured values.

When the measuring cell is immersed, a calibration liquid such as pure water is introduced into the liquid chamber of the sliding block while the sliding block is in the calibration or cleaning position, whereby zero calibration of the measured value and sensitivity are performed. You can make adjustments.

Further, even during the immersion measurement, by switching the sliding block to the cleaning position, in addition to the cleaning action of the seal ring when the sliding block slides, the cleaning liquid filled in the liquid chamber can be used to chemically deposit Can be removed, and long-term continuous measurement can be expected in combination with these effects.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a measurement state in a basic embodiment of the present invention, and FIG. 2 shows a calibration or cleaning state thereof. In this embodiment, the measuring cell 1 is composed of a frame body having a test water retention portion 2 penetrating vertically, and a light source chamber 3 and a light receiving chamber 4 which are sealed on both sides thereof. Openings 5 and 6 are formed on the lower facing surfaces of the light source chamber 3 and the light receiving chamber 4, respectively, and a pair of optical windows 7 and 8 are attached to the facing wall surfaces of both chambers 3 and 4 so as to close them. It is in contact with the test water retention unit 2. The facing surfaces of the windows 7 and 8 are on the same surface as the inner ends 7a and 8a of the bottom walls of the light source chamber 3 and the light receiving chamber 4, and the side surfaces of the sliding block 9 are slidably pressed against the windows 7 and 8, respectively. A pair of seal rings 10a and 10b that also serve as window wipers are provided so that the inside of the test water retention section 2 can be slid up and down. The cross section of the test water retention part 2, and hence the cross section of the sliding block 9 is rectangular as shown in the plan view of FIG. 3 a, and the other two side edges 11, 12 of the sliding block 9 are There is a slight gap between the side walls 13 and 14 adjacent to the windows 7 and 8 of the test water retention portion in the cell 1 to facilitate the sliding movement of the sliding block 9. The seal rings 10a and 10b are liquid chambers 22 that penetrate through both side walls at the lower end of the sliding block 9.
Surrounds the opening. The diameter of the liquid chamber 22 is the measuring cell 1
2a corresponding to the diameters of the openings 5 and 6, and when the slidable block 9 occupies the calibration or cleaning position at the lower end of the slidable process, as shown in FIG.
The measurement optical path leading to the opening 6 is allowed.
The light source lamp 15 is provided at a position corresponding to the opening 5 in the light source chamber 3.
And optical filter / monochromator 1 for selecting specific wavelength
6 is arranged, and an appropriate light receiver 17 is arranged at a position corresponding to the opening 6 in the light receiving chamber 4.

Liquid passages 18a, 18b for the cleaning liquid or pure water, which communicate with the liquid chamber 22, are formed in the sliding block 9. A supply pipe and a discharge pipe for the cleaning liquid or pure water are connected to the openings at the upper end of the slide block 9 of the liquid passages 18a and 18b by a suitable method. In FIGS. 1a and 2a, a block 19 shown above the sliding block 9 represents a driving mechanism for the sliding block.

According to the above construction, the measuring cell 1 is immersed in the water surface of the water source 20 to be measured in the measuring position shown in FIG. 2, that is, in the state where the sliding block is maintained at the lowermost position. In this state, when calibrating the zero point, the liquid chamber 15 is filled with pure water through the liquid passage, generally 18,
In this state, the zero point is set on the basis of the amount of light reaching the light receiver 17 from the light source lamp 15 through the filter 16 and the liquid chamber 22 between the windows 7 and 8. In some cases, a solution having a monochromatic light transmittance corresponding to a certain pollutant concentration or turbidity (span value) is contained in the liquid chamber 15,
You can also perform span setting operations.

The sliding block 9 is shown in FIG.
When it is pulled up to the measurement position of 1, the test water retention section 2 is connected to the test water source 20, and the test water fills the retention section 2.
In this case, even if there is an oil film adhered to the lower end surface 21 of the sliding block 9 at the time of zero point calibration, this only rises as the sliding block 9 rises, and the optical window 7 , 8 has no substantial effect. Therefore, the light receiver 17 can accurately receive the amount of light attenuated according to the amount of contamination of the test water.

Even during the immersion measurement, if the sliding block 9 is lowered to the cleaning or calibration position, the seal ring 10 is moved.
When the a and 10b move, the dirt on the window can be wiped off, and by supplying an appropriate cleaning liquid containing hydrochloric acid or the like into the liquid chamber 22, the dirt on the optical window can be chemically dissolved.

In the basic embodiment shown in FIGS. 1 and 2, the case where the cross section of the test water retention portion and the sliding block is rectangular has been described. However, this is circular and the seal ring is accordingly formed. 10 'can be attached to the outer periphery of the cylindrical sliding block 9'as a pair of circular rings located above and below the liquid chamber 22. 3B is a plan view of this modified example as seen from above. Since the liquid chamber 22 'is formed to penetrate the cylindrical slidable block 9', although not shown, the light source side of the measurement cell 1'and Appropriate angle maintaining means should be provided to align with the aperture on the receiving side.

FIGS. 4 and 5 show the measurement position in the embodiment of the box type structure in which the measurement cell 41 seals the test water retention section 42,
And the calibration or cleaning position, respectively. In FIG. 4a shown in a vertical section, the test water retention part 42 is a rectangular parallelepiped closed space, and, for example, the test water introduced from the test water introducing port 43 formed in the upper right corner of the front wall is at the lower left. It is adapted to be discharged from the test water discharge port 44 formed in the corner. Similarly, the light source lamp 15 and the light receiver 17 are provided in the light source chamber 45 and the light receiving chamber 46 on both sides of the test water retention section 42.
Are arranged respectively, and the openings 5 and 6 for setting the optical path are provided on the inner side walls thereof, as in the basic embodiment. In this embodiment, a condenser lens 47 is arranged in front of the light source lamp 15, and a filter 16 is arranged in front of the light receiver 17, so that monochromatic light is selected on the light receiving side. The difference in the arrangement of the optical elements from the basic embodiment is properly selected according to the design specifications. Quartz windows 7 and 8 similar to those in the previous embodiment are provided in the test water retention section 42.
A similar circular seal ring 10a that slidably presses against
A cylindrical slidable block 48 having 10b at both ends is housed. From the upper end of the slidable block 48, connecting pipes 49a and 49b that form a liquid supply passage and a liquid discharge passage are projected, and these pipes 49a and 49b are formed in wall holes formed in the top wall 50 of the cell 41. It is fitted and guided to the outside of the cell. A seal ring 51 is also provided between these pipes 49a and 49b and the wall surface hole.
It is watertightly sealed by.

Also in this embodiment, the test water inlet port 43
And as long as the discharge port 44 is connected to the test water source and the test water is introduced into the retention part 42, the operation is similar to that of the basic embodiment described above. In this case, the test water retention is performed. Part 4
Since 2 is a closed chamber type, it is suitable for performing stable continuous measurement regardless of the state of the water source.

The embodiment shown in FIGS. 6 and 7 uses an open type measuring cell 61 similar to that of the basic embodiment shown in FIG. 1, in which the same reference numerals as those of the basic embodiment are attached. The description of the items is omitted. In the cell 61, the element specific to this embodiment is a span calibration plate 62 that can cross the optical path in front of the optical receiver 17. As its name implies, the span calibration plate 62 is composed of a semi-transparent plate having a light transmittance corresponding to a certain contaminant concentration or turbidity (span value) of the test water.

In the sliding block 63 of this embodiment, the sliding chamber 9 for the calibration liquid and the liquid chamber 65 for the cleaning liquid are vertically adjacent to each other and are watertightly separated from each other. Is different from 66a, 66
Reference numerals b, 67a, and 67b are liquid passages that communicate with the calibration liquid chamber 64 and the cleaning liquid chamber 65, respectively. In this case, the cleaning liquid chamber 65 is located below the calibration liquid chamber 64.

FIGS. 7a, 7b and 7c respectively show the cleaning position, the zero calibration position and the span calibration position. When the measuring cell 61 is dipped in the water source to be measured, the slidable block 63 is moved to these (a). ), (B), or (c). Cleaning position (a) and zero calibration position (b)
1 is similar to that in the basic embodiment of FIG. 1, but in the span calibration (c) operation, the span calibration plate 62 is lowered to the front of the optical receiver 17 and is kept stationary in the liquid chamber 64. The inside is filled with pure water, and the amount of light transmitted from the light source lamp 15 through the filter 16 and the windows 7 and 8 and the span calibration plate 62 is measured. When the calibration is completed, the cell 61 is moved to the position shown in FIG. 6 and the test water is measured.

In this embodiment, a calibration liquid chamber which only supplies pure water during calibration and a cleaning liquid chamber which supplies a chemical liquid such as hydrochloric acid are divided in order to obtain a strict measurement value.
Moreover, in addition to zero calibration, span calibration is also performed to maintain accuracy in the entire measurement scale.

[0029]

As described above, according to the present invention, the water quality can be accurately measured without being affected by the oil film on the water surface to be detected, and the mechanical window by the cleaning liquid supply mechanism and the seal ring that also serves as the wiper can be used. Provided is a flow cell type photoelectric photometer which reliably prevents contamination of a window surface by wiping the surface and is suitable for continuous monitoring of water pollution and the like. For example, according to the present invention, a low pressure mercury lamp is used as a light source, and selective wavelengths of 254 nm and 546 are selected.
An ultraviolet absorptiometer based on a continuous measurement method of two wavelengths and three optical paths of nm is configured, and the measurement range is set to three ranges of absorbance 0 to 0.5, 1.0 and 2.0, and the measurement optical path length is 10 mm.
, The linearity is within ± 5% of full scale,
Repeatability is within ± 2% of full scale, and zero drift and span drift are ± 2% of full scale.
It was within. This indicates that extremely stable continuous measurement is possible as compared with the photoelectric photometer using the conventional direct immersion type flow cell.

[Brief description of drawings]

1A is a front sectional view showing a measurement position of a direct immersion photoelectric photometer in a basic embodiment, and FIG. 1B is a sectional view taken along line AA at a calibration or cleaning position thereof.

2A is a front sectional view in the calibration or cleaning position of the embodiment of FIG. 1, and b is B in the calibration or cleaning position.
It is a -B sectional view.

3A is a plan view of the basic embodiment shown in FIG. 1, and FIG. 3B is a plan view showing a modification thereof.

FIG. 4A is a vertical cross-sectional view showing a measurement position of an embodiment of the closed type flow cell as seen from the front direction, and b is a CC cross-sectional view thereof.

5 is a vertical sectional view of FIG. 4 in a calibration or cleaning position, and b is a DD sectional view thereof.

6A is a front sectional view at a measurement position of an embodiment in which a liquid chamber dedicated to a calibration liquid and a liquid chamber dedicated to a cleaning liquid are separately formed in a slide block, and b is a side sectional view thereof.

7 is a vertical sectional view showing a cleaning position in the embodiment of FIG. 6, b is a vertical sectional view showing a zero calibration position, and c is a vertical sectional view showing a span calibration position.

[Explanation of symbols]

 1 Measurement Cell 2 Test Water Retaining Part 3 Light Source Room 4 Light-receiving Room 5, 6 Opening 7, 8 Optical Window 7a, 8a Inner End of Bottom Wall of Light-receiving Room 9 Sliding Block 10a, 10b Seal Ring 11, 12 Sliding Block Other 2 sides 13 and 14 Side wall 15 Light source lamp 16 Filter / monochromator 17 Light receiver 18 Liquid passage 19 Block 20 Test water source 21 Lower end surface of sliding block 22 Liquid chamber

Claims (3)

[Claims] 1. A measuring cell of a photoelectric photometer having a test water retention part that can be directly immersed in or communicated with a test water source, wherein a pair of optical windows are arranged vertically with the test water retention part interposed therebetween. To form a light source chamber and a light receiving chamber that are water-tightly sealed from the test water by means of a light source arranged in the light source chamber, and a light receiver arranged in the light receiving chamber via a water-to-be-tested portion between the pair of windows. With an optical path for monochromatic light measurement up to and having a seal ring that also serves as at least a pair of window wipers in water-tight contact with the pair of optical windows, and faces the pair of windows between the pair of seal rings. A slidable block which is formed by water-tightening and separating a liquid chamber having an open end from the test water retention part, and forming a liquid passage for the cleaning liquid or pure water in communication with the liquid chamber. The calibration or cleaning position. The liquid chamber surrounds the optical path, and at the measurement position retracted from the calibration or cleaning position, the test water retention part between the pair of windows is opened to communicate with the test water source. A photoelectric photometer characterized in that. 2. The test water retention part is formed in a closed chamber having a test water inlet and a test water outlet provided in the measurement cell, and the sliding block is arranged in the closed chamber, 2. The photoelectric photometer according to claim 1, wherein a connection pipe extending from the sliding block and forming the liquid passage is fitted into a wall hole of the closed chamber and guided to the outside thereof. . 3. The first and second liquid chambers are adjacent to each other in the sliding direction of the sliding block and are watertight and separated from each other.
And the first liquid chamber is a calibration liquid chamber communicating with the pure water passage, and the second liquid chamber is a cleaning liquid chamber communicating with the cleaning liquid passage. Item 2. The photoelectric photometer according to Item 1.