JP3271459B2 - Immersion type optical sensor and its automatic calibration method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a sewage treatment plant,
The present invention relates to an immersion-type optical sensor used for a chemical plant and environmental measurement, and an automatic calibration method thereof.

[0002]

2. Description of the Related Art In an immersion type optical sensor, an optical sensor measuring section is directly immersed in a liquid to be measured, and a light beam from a light source is projected on the liquid to be measured, and is attenuated by being absorbed or scattered by components of the liquid to be measured. The measured light amount is measured. In addition, there is a flow cell type optical sensor that uses the optical sensor measurement unit without directly immersing it in the liquid sample, but in general, the optical sensor depends on the amount of transmitted light or the component of the liquid to be measured when the liquid to be measured is irradiated with light. Since the amount of light attenuated by absorption and scattering is measured, dirt on the optical windows on the light emitting side and the light receiving side causes a measurement error. Therefore, the optical sensor usually needs to be periodically calibrated as a measurement value correction, and it is desirable that the calibration operation is performed under the same conditions as in the measurement system of the liquid to be measured.

For example, calibration in a flow cell type optical sensor which is not a direct immersion type is performed as follows. FIG. 9 is a schematic view of the flow cell 27 viewed from the side for explaining the calibration method. In FIG. 9, the liquid to be measured 29 is switched to the calibration liquid 30 by using the three-way valve 28 during calibration. Calibration fluid 30 flows in the direction
The calibration liquid 30 is sent into the flow cell 27 to perform calibration. A thick arrow indicates an optical path passing through the inside of the flow cell 27.

However, it is difficult for a direct immersion type optical sensor used for measurement of a liquid to be measured whose components change rapidly with time or real-time measurement in an actual plant to directly perform automatic calibration in the liquid to be measured. Therefore, every time calibration is performed, the optical sensor measurement unit must be moved out of the measurement system to perform calibration.

[0005]

As described above, the direct immersion type optical sensor has the following problems because the optical sensor measurement section must be taken out of the measurement system during calibration. Since the calibration is performed outside the measurement system, the conditions during measurement and during use are different.

[0006] Every time calibration is performed, the operation of transferring the optical sensor measurement unit into the calibration liquid is complicated and time-consuming. SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and an object of the present invention is to automatically calibrate an optical sensor in a measurement system, and to simultaneously generate air bubbles in a liquid supply path and measure an optical sensor. It is an object of the present invention to provide an immersion type optical sensor capable of preventing air bubbles from entering a part and an automatic calibration method thereof.

[0007]

In order to solve the above problems, an immersion type optical sensor according to the present invention forms an optical path between an irradiation window and a light receiving window on an opposing surface in an optical sensor measuring section. It has a U-shaped sensor head having a notch or a cylindrical sensor head. The U-shaped sensor head has two L-shaped shielding plates that can be opened and closed, and the optical path is shielded by the operation thereof. The sensor head can be sealed by a shielding cylinder that slides over the side surface of the cylindrical sensor head, and the sensor head can be sealed when the immersion optical sensor is calibrated. After that, the calibration liquid is injected into this sensor head, and it is automatically detected that the sample liquid has been replaced with the calibration liquid, and the calibration is automatically performed while the optical sensor measurement unit is immersed in the sample liquid. Do It is intended.

[0008] The liquid supply path for injecting the calibration liquid is a first liquid supply pipe connected to the liquid supply pump for supplying the calibration liquid stored in the tank, a liquid supply pump and a calibration liquid inlet formed in the sensor head. And a branch pipe branching from a branch point of the second liquid feed pipe at a position distant from the liquid surface to be measured.
It consists of an on-off valve connected to this branch pipe. In addition to the above, the liquid feeding path includes a first liquid feeding pipe, a sealed container provided at a position distant from the liquid surface to be measured, and one end connected to the liquid feeding pump and the other end inserted into the sealed container. A second liquid supply pipe attached by
A third liquid feed pipe having one end inserted into the closed vessel and the other end connected to a calibration liquid inlet formed in the sensor head;
One end may be inserted into the closed vessel and attached to the other end, and may be constituted by a vent pipe provided with an on-off valve near the other end.In this case, the end face of each pipe inserted into the closed vessel is perpendicular to the floor surface. It is necessary to arrange the vent pipe, the second liquid feed pipe, and the third liquid feed pipe in the direction so as to be at higher positions in this order.

In order to control these on-off valves,
An arbitrary control standby time can be set between the operation of closing the valve and the operation of the driving unit closing the L-shaped shielding plate or the shielding cylinder of the sensor head, and the operation of the driving unit opening the L-shaped shielding plate. A sequence circuit capable of simultaneously opening the valve is provided in the sensor body.

[0010]

As described above, the amount of light attenuated by the replaced calibration liquid is measured, and the state in which the inside of the sealed sensor head is filled with the calibration liquid is determined by the following equation. Alternatively, the end point of the replacement from the sample solution to the calibration solution can be clearly detected by making the determination based on the value set in advance. Further, after determining that the inside of the sensor head is filled with the calibration liquid, the variation coefficients of all attenuation rates obtained by the predetermined number of measurements are calculated, and the variation coefficient obtained as a result of the calculation is equal to or less than a predetermined set value. For example, the average value of the attenuation rates calculated from all the measured values is adopted as the calibration value, and when the coefficient of variation exceeds a predetermined set value, the standard deviation σ of all the measured values is calculated, and the average value ± By adopting the average value of the attenuation rates of all the measured values within the range of 3σ as the calibration value, it is possible to delete data due to the influence of bubbles or the like.

Further, regarding the configuration of the above-mentioned liquid feeding path,
If you leave the liquid supply tube filled with the calibration solution for a long time,
Fine bubbles are generated in the tube and adhere to the wall of the shite tube, and it is difficult to completely remove the adhered bubbles just by sending the calibration liquid.Therefore, there is a possibility that bubbles may enter the sensor head closed part during calibration. This is done for the following.

After the calibration is completed, the on-off valve provided on the branch pipe is opened, and the inside of the liquid supply pipe to the sensor head is replaced with air using the siphon effect. Then, at the time of calibration, the on-off valve is closed and the calibration liquid is sent again. This prevents the generation of microbubbles in the tube, and enables replacement of the calibration liquid with air. Also,
Since the inside of the pipe to the tank storing the calibration liquid and the feed pump and the branch point following it cannot be completely replaced with air, a closed vessel is provided and the three pipes as described above are inserted and installed in this, After making a difference in the height of the pipe end, open the on-off valve after the calibration is completed, use the siphon effect to replace the inside of the sealed container and the liquid feed pipe to the sensor head with air, and then close the on-off valve during calibration By sending the calibration liquid anew, it is possible to prevent the generation of microbubbles in the closed container and the tube, and to replace the calibration liquid with air.All air bubbles generated in the tube that cannot be replaced with air are removed by this closed container. It can be trapped and reliably prevent air bubbles from entering the sealed portion of the sensor head.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments. FIG. 1 is a schematic diagram showing a main part configuration of an immersion type optical sensor according to the present invention. In FIG. 1, the optical sensor measurement unit 1 is a liquid 2 to be measured.
FIG. 3 is a perspective view showing a state of being immersed in the inside, and the outside of the liquid 2 to be measured is an optical sensor
And a system diagram in which the electric circuit 4 is connected to the optical sensor main body 3. FIG. 1 will be described below together with the method of the present invention using this apparatus.

In FIG. 1, a portion of the optical sensor measuring section 1 which is immersed in the liquid 2 to be measured has a U-shaped sensor head 5 at a lower portion. An optical path 6a is formed between the irradiation window 8 and the light receiving window 9 through the notch 7 forming the opposing inner surface.
Further, two L-shaped shielding plates 1 provided on the sensor head 5 are provided.
The L-shaped shielding plate 10 allows the notch 7 of the sensor head 5 to be opened and closed from the side by two drive shafts 11 connected to each other by an auxiliary shaft 11a.

At a predetermined timing that requires calibration, the drive shaft 1 is controlled so as not to affect the measurement of the optical sensor.
When the two drive shafts 11 are moved up and down by a drive device (not shown here) that performs one-dimensional movement such as a solenoid coil or a piston-moving motor above the drive shaft 11, the drive shaft 11 and the L-shaped The ends of the auxiliary shafts 11a connecting the shielding plates 10 on the shielding plate 10 side move away from or approach the optical path 6a, and the ends of the two shielding plates 10 coincide with each other when they are closest to each other. That is, 2
The L-shaped shielding plates 10 are opened and closed with the mounting portion to the sensor head 5 as a fulcrum. During calibration, the side of the cutout 7 of the sensor head 5 is closed, and the surrounding liquid to be measured is wrapped around the optical path 6a. 2, the notch 7 of the sensor head 5 is closed. At this time, a smooth sealing material 12 is attached to each of the terminal surfaces where the two L-shaped shielding plates 10 come into contact with each other, and the liquid 2 to be measured enters the cutout 7 of the shielded sensor head 5. Sensor head 5
The leakage of the later-described calibration liquid 14 to the outside of the notch 7 is prevented.

Here, the calibration liquid 14 is separated from the liquid 2 to be measured by using the liquid pump 13 provided outside the optical sensor measurement section 1.
Is injected from the injection pipe 15 in the optical sensor measuring section 1 through the injection port 16 into the cutout 7 of the shielded sensor head 5. That is, the liquid 2 to be measured is replaced with the calibration liquid 14 in the cutout 7 of the shielded sensor head 5. At that time, the discharged liquid 17 generated by the replacement of the calibration liquid 14 is:
The liquid to be measured 2 is discharged from the discharge port 18 in the optical sensor measurement section 1 to the outside of the liquid 2 to be measured through the discharge pipe 19.

At the same time that the calibration liquid 14 is injected, the optical sensor measurement section 1 mixes the two liquids of the measurement liquid 2 and the calibration liquid 14 in the cut-out portion 7 of the shielded sensor head 5 ( (Attenuation rate of light) is measured, and this signal is
0 to the optical sensor main unit 3, the output value of the light attenuation rate from the optical sensor measuring unit 1 is converted from the optical sensor main unit 3 to analog by the analog circuit 21, and furthermore, the data storage device via the CPU / digital circuit 22 23.
The fact that the inside of the cut-out portion 7 of the shielded sensor head 5 of the optical sensor measurement section 1 is filled with the calibration liquid 14 indicates that the time-dependent change rate ΔE / Δt of the obtained attenuation rate measurement value is 0, Or, when it falls below the preset value,
A predetermined number of attenuation rate measurement values are collected after the CPU 22 determines that the inside of the cutout portion 7 of the shielded sensor head 5 is filled with the calibration liquid 14, and all obtained attenuation rate measurement values are obtained. , The CPU 22 calculates the average value A _V , the standard deviation σ, and the variation coefficient CV. Here, based on the results of these calculations, if the variation coefficient is 1% or less, the average value _AV1 calculated from all the measured attenuation factors is used as the calibration value.

If the coefficient of variation exceeds 1%, A _V1
The average value A _V2 of all measured attenuation rates in the range of ± 3σ is recalculated and used as a calibration value. After the determination of the calibration value, the feeding of the calibration liquid 14 into the shielded notch 7 of the sensor head 5 by the liquid feeding pump 13 is stopped, and the driving shaft 11 is operated by a driving device (not shown) to operate the driving shaft 11. The L-shaped shielding plates 10 are opened, and the state of the liquid 2 to be measured is set.

FIG. 2 is a diagram showing the change over time of the attenuation rate at the time of calibration. In FIG.
Denotes a point at which the rate of change of the attenuation rate ΔE / Δt becomes equal to or less than a predetermined value, and c denotes a point at which the injection of the calibration liquid 14 ends. FIG. 3 is FIG.
FIG. 4 is a diagram showing, in an enlarged manner, a temporal change of an attenuation rate between bc in FIG. 3, and a calibration value can be determined by statistically calculating the attenuation rate between bc.

Next, the sensor head 5 of the optical sensor measuring section 1
A device having a cylindrical shape will be described. FIGS. 4A and 4B are external views mainly showing the configuration of the sensor head 5a of the device, wherein FIG. 4A shows a state at the time of measuring the liquid to be measured, and FIG. 4B shows a state at the time of calibration. The sensor head 5a of FIG.
Having the notch 7a and forming the optical path 6b therein is similar to the case of the sensor head 5 shown in FIG.
Here, at a predetermined timing that requires calibration, a shield cylinder which is installed inside the sensor head 5a and is generated by the solenoid coil 24 shown in a partially peeled state and is placed on one end of the sensor head 5a. The two drive shafts 26 connected to 25 are moved one-dimensionally. Thus, at the time of calibration, the shield cylinder 25 is slid in the direction of the notch 7a of the sensor head 5a, and the notch 7a is closed by the shield cylinder 25, whereby the entire sensor head 5a can be hermetically sealed. In this way, the state of the liquid to be measured shown in FIG. 4A is shifted from the open state of the sensor head 5a to the calibration state of FIG. 4B, that is, the sensor head 5a is closed. At this time, a smooth sealing material 12 is attached to the end surface of the shielding cylinder 25 to make the surface where the shielding cylinder 25 comes into contact with the partner dense, and the shielded sensor head 5 is closed.
The liquid 17 is prevented from penetrating into the notch 7a, and the leakage of the calibration liquid 14 to the outside of the sensor head 5a.

Next, a notch 7 of the sensor head 5a in which the calibration liquid 14 is shielded from the injection port 16a through the injection pipe 15a using a liquid feed pump (not shown).
a, and the drainage liquid 17 that is generated with the injection of the calibration liquid 14 is discharged from the measurement system via the discharge port 18a via the discharge pipe 19a. The subsequent operation of determining the calibration value is as described with reference to FIG. After determining the calibration value,
To return to the measurement of the liquid to be measured, the above procedure may be reversed.

As described above, when the U-shaped sensor head 5 is shielded by using the two L-shaped shielding plates 10 to form a closed state, the capacity of the shielded portion is relatively small. The measurement unit 1 can be made compact. On the other hand, when the cylindrical sensor head 5a is sealed using the shielding cylinder 25, the capacity of the shielding part is relatively large, Although the amount of use increases, the shielding cylinder 2
Since the moving range of the 5 itself is small, there is an advantage that its driving operation is very simple.

Further, only when the components of the calibration liquid do not affect the liquid to be measured, the liquid can be discharged from the shielded notch of the sensor head during calibration as follows. FIG. 5 is a schematic view showing, as an example, the device having the L-shaped shielding plate 10 of FIG. 1 described above, which discharges the discharge liquid 17 generated with the supply of the calibration liquid into the liquid to be measured. In FIG. 5, the driving mechanism (not shown)
After closing the L-shaped shielding plates 10 and shielding and sealing the optical path,
The calibration liquid 14 is continuously injected into the shielded notch 7 of the sensor head 5 through the injection pipe 15 from the injection port 16 until the liquid to be measured is replaced. And the effluent 17
Is discharged to the outside of the shielded sensor head 5 through a discharge port 18b opened in one L-shaped shielding plate 10.
By continuously injecting the calibration liquid 14 in this manner, the liquid to be measured can be prevented from entering the sensor head 5.

As described above, according to the present invention, the measurement liquid can be replaced with the calibration liquid while the optical sensor measurement section is immersed in the measurement liquid, and the calibration value can be automatically adjusted. Can start to be measured. By the way, in the liquid supply path for injecting the calibration liquid of this immersion type optical sensor, if the liquid supply pipe is left for a long time with the calibration liquid filled, fine bubbles generated in the pipe adhere to the pipe wall surface, It is difficult to completely remove the generated bubbles only by sending the liquid, and there is a possibility that bubbles may be mixed into the sealed part of the sensor head during calibration, causing a measurement error,
An immersion-type optical sensor according to the present invention which has been made to deal with this will be described with reference to FIG.

FIG. 6 is a schematic diagram mainly showing the configuration of a calibration solution sending path of this apparatus. The immersion type optical sensor of the present invention having a branch pipe provided with an on-off valve in the calibration solution sending path is shown in FIG. It represents. 6 are denoted by the same reference numerals, but the optical sensor measuring unit 1 and the electric circuit 4 connected to the optical sensor main body 3a in FIG. 6 are the same as those in FIG. Therefore, it is simplified.

In FIG. 6, a calibration liquid 14 is stored in a calibration liquid tank 31 outside the liquid 2 to be measured, and a first liquid supply pipe 32 in the liquid supply path of the calibration liquid 14
The second liquid feed pipe 3 connected from the inside of the calibration liquid tank 31 to the liquid feed pump 13 and serving as a liquid feed path after the liquid feed pump 13
3 is connected to the inlet 16 of the calibration liquid 14 belonging to the U-shaped sensor head 5 immersed in the liquid 2 to be measured. Second
The liquid supply pipe 33 corresponds to the one shown as the injection pipe 16 in FIG. A branch pipe 35 is provided at a branch point 34 located in the middle of the second liquid feed pipe 33 at a location not immersed in the liquid 2 to be measured.
A controllable on-off valve 36 is provided in this path, and the on-off valve 36 closes the valve to change the liquid supply path of the calibration liquid 14 to the U-shaped sensor head 5 and the branch pipe 35.
Can be changed from the two directions to only the U-shaped sensor head 5 in one direction. Further, by opening the on-off valve 36, the inside of the liquid sending pipe can be opened to the atmosphere.

The optical sensor measuring section 1 having the U-shaped sensor head 5, the mechanism for shielding the notch 7 of the sensor head 5, the optical sensor main body 3a, and the electric circuit 4 connected thereto are as shown in FIG. Therefore, although the description is omitted here, the opening / closing control of the opening / closing valve 36 can be automatically performed at a later-described timing by the sequence circuit 37 in the optical sensor main body 3a.

Here, the automatic calibration method of the present invention using the apparatus shown in FIG. 6 will be described with reference to FIG.
7 (a) to 7 (d) are schematic diagrams showing a time series of the state of the calibration liquid 14 in the liquid supply path. The hatched portion in the liquid supply pipe is filled with the calibration liquid 14. This indicates that the area has been set. First, FIG. 7A shows a normal measurement state of the liquid 2 to be measured. At this time, in the liquid feed path of FIG. 6, the liquid feed pump 13 is in a stationary state, and the on-off valve 36 in the middle of the branch pipe 35 is in an open state.
The calibration liquid 14 includes the first liquid supply pipe 32 and the second liquid supply pipe 3
The state has reached the position of the branch point 34 in the middle of three.

FIG. 7B shows a state in which the calibration operation is started at the timing of the calibration. At this time, in the liquid feeding path shown in FIG.
, The calibration liquid 14 is gradually fed from the branch point 34 in two directions of the U-shaped sensor head 5 and the branch pipe 35. Accordingly, the second liquid feed pipe 33 and the branch pipe 3
The air in 5 is supplied to the inlet 16 of the calibration liquid 14 and the branch pipe 3.
From the end of 5, the liquid is gradually fed out of the liquid feeding path.

Further, as shown in FIG.
4, the air in the branch pipe 35 is all sent to the on-off valve 36, and at the same time, the calibration liquid 14 is supplied.
Has reached the opening / closing valve 36. At this time, FIG.
In the liquid supply path, the on-off valve 36 is closed by the control signal of the sequence circuit 37 in the optical sensor main body 3a, and the supply of the calibration liquid 14 is switched only from the branch point 34 to the U-shaped sensor head 5. The calibration solution 1
By the liquid feeding of 4, the air in the second liquid feeding pipe 33 is completely sent out from the inlet 16 of the calibration liquid 14.

Then, as shown in FIG. 7D, the air in the second liquid supply pipe 33 is completely replaced by the calibration liquid 14, and the air discharged from the inlet 16 of the calibration liquid 14 is The sensor head 5 is also completely removed from the notch 7. At this time, the time required from the start of the calibration operation to the time shown in FIG. 7D is set in the sequence circuit 37 in FIG. 6 in advance. 5 means for driving the L-shaped shielding plate 10 (not shown, the same applies hereinafter)
Operation is started. That is, the driving means operates in the direction in which the L-shaped shielding plate 10 of the sensor head 5 is closed, and the notch 7 of the sensor head 5 is closed. At the same time, the calibration liquid 14 is injected into the cutout 7 from the injection port 16 by the operation of the liquid feeding pump 13. The subsequent operations up to the completion of the replacement with the calibration liquid 14 in the notch 7 and the operation of automatically determining the calibration value are the same as those described with reference to FIG.

After the calibration value is determined in this manner, the liquid feed pump 13 is stopped, and the L-shaped shielding plate 1 of the sensor head 5 is stopped.
Activate the drive means in the direction to open 0. At this time, the on-off valve 36 is opened by the control signal from the sequence circuit 37, and the liquid feed path is opened to the atmosphere. Accordingly, the branch pipe 35
Due to the water level difference between the calibration liquid 14 and the liquid 2 to be measured, the calibration liquid 14 in the branch pipe 35 and the second
Is discharged into the liquid 2 to be measured, the inside of the branch pipe 35 and the inside of the second liquid supply pipe 33 are replaced with air, the calibration is completed, and the normal measurement state of the liquid 2 to be measured [FIG. Return to.

In addition, the liquid feeding path should be configured as follows.
Can also be. FIG. 8 shows a closed vessel in
Immersion type optical sensor of the present invention equipped with a vent pipe having an on-off valve
Is a schematic diagram showing the configuration of the calibration solution sending path
It is a figure, and the part common to FIG. 1, FIG. 6 uses the same code | symbol.
The sensor measurement section is immersed in the liquid to be measured.1
Is the same as FIGS. 1 and 6, and is not shown in FIG.
I have.

Referring to FIG. 8, this apparatus uses a closed container 39 into which three pipes described below are inserted, corresponding to the branch pipe 35 shown in FIG. That is, the calibration liquid 14 is stored in the calibration liquid tank 31 arranged outside the liquid 2 to be measured, and the liquid supply path of the calibration liquid 14 is such that the first liquid supply pipe 38 is connected to the inside of the calibration liquid tank 31. A part that is connected to the liquid feed pump 13 and that is not immersed in the liquid 2 to be measured in the middle of the path from the liquid feed pump 13 to the inlet 16 (not shown here) of the calibration liquid 14 of the U-shaped sensor head 5. A second liquid feed pipe 40 is a path from the liquid feed pump 13 to the closed vessel 39, and a third liquid feed pipe 41 is connected to the inlet 16 (not shown) from the closed vessel 39. It is a route to reach. Furthermore, a ventilation pipe 42 having a controllable on-off valve 36 is inserted and installed in the closed container 39.

Here, the vent pipe 42, the second liquid feed pipe 40, and the third liquid feed pipe 41 inserted into the closed container 39.
The free ends of the insertion portions of the three tubes occupy a high position in the direction perpendicular to the floor surface in this order, and when the calibration solution 14 is sent, it passes through the second solution sending tube 40 and is closed. The air bubbles mixed into the container 39 are surely captured by the closed container 39 so that the air bubbles cannot enter the third liquid supply pipe 41.

By closing the on-off valve 36 provided in the ventilation pipe 42, the liquid feeding path from the closed container 39 is moved from the third liquid feeding pipe 41 and the ventilation pipe 42 to the third liquid feeding pipe. 41
Only one direction can be changed, while the on-off valve 36
By opening, the inside of the liquid sending pipe can be opened to the atmosphere. It should be noted that the optical sensor measuring section 1 having the U-shaped sensor head 5 (not shown), the notch 7 of the sensor head 5
The mechanism for shielding the light, the optical sensor main body 3a, and the electric circuit 4 (omitted from the drawing) are the same as those in FIG. By the sequence circuit 37 provided in 3a,
This can be performed automatically at the timing described later.

The automatic calibration method of the present invention using the apparatus shown in FIG. 8 is almost the same as the method of the apparatus shown in FIG. 6 described above. For reference, only the differences between the two will be described. In the apparatus shown in FIG. 6, the inside of the liquid feed pipe from the calibration liquid tank 31 to the branch point 34 is always filled with the calibration liquid 14. Therefore, the fine bubbles generated in the pipe that cannot be replaced with air from the calibration liquid tank 31 to the branch point 34 are:
At the time of calibration, it may be mixed into the sensor head 5 in a closed state.

Therefore, in the apparatus shown in FIG. 8, during the period from the start of operation of the liquid feed pump 13 at the time of calibration to the determination of the calibration value, all air bubbles sent out of the pipe which cannot be replaced with air are removed. It is captured by the closed container 39. Further, at the timing when the calibration liquid 14 reaches the on-off valve 36, the on-off valve 36 is closed, and after the calibration value is determined, the on-off valve 3
By opening 6, the inside of the liquid sending pipe is opened to the atmosphere, and air enters through the vent pipe 42. Thereby, the closed container 39
The calibration liquid 14 in the third liquid supply pipe 41 is discharged from the inlet 16 (not shown) of the sensor head 5, and at the same time, the inside of the liquid supply path is replaced with air to complete the calibration.

As described above, in the present invention, the air in the liquid feeding path can be replaced with the calibration liquid every time calibration is performed, and the generated bubbles can be reliably captured. Therefore, when sending out the calibration liquid, by completely preventing air bubbles from entering the cutout part of the sensor measurement unit in the sealed state, the inside of the sealed part is effectively replaced with the calibration liquid, and extremely highly reliable. Calibration can be obtained.

[0040]

As described above, the immersion type optical sensor has a complicated problem that the optical sensor measurement unit is moved to another place every time calibration is performed.
Using the sensor head of the optical sensor measurement unit or its side surface, simple drive shaft operation, only at the time of predetermined calibration,
The sensor head of the optical sensor measurement unit including the optical path is shielded and sealed, and the optical sensor measurement unit is effectively and automatically replaced with the calibration liquid inside the shield while the optical sensor measurement unit is immersed in the liquid to be measured. be able to.

In calibrating the immersion type optical sensor, a calibration solution is injected into a cutout portion of the shielded and sealed sensor measurement section, and the solution to be measured in the shielded portion is replaced with the calibration solution. Can be clearly detected,
Statistical processing of light decay rate data in the state determined to be filled with the calibration solution eliminates abnormal values caused by bubbles and the like, and automatically determines a highly reliable calibration value. .

From the above, when the immersion optical sensor of the present invention is used, it is possible to perform calibration while being installed in a measurement system, which has been considered difficult, and as a result, every time calibration is performed, The complexity of transferring the sensor measurement unit to the outside has been eliminated, and the calibration can be performed efficiently and automatically with high reliability without requiring much time.

Further, in the liquid supply path for injecting the calibration liquid of the immersion type optical sensor, if the state in which the liquid supply pipe is filled with the calibration liquid is left for a long time, fine bubbles are generated in the pipe and fine bubbles adhere to the pipe wall surface. However, it is difficult to completely remove the generated air bubbles only by sending the calibration liquid, and the air bubbles may be mixed into the sealed portion of the sensor head being calibrated, thereby causing a measurement error. After determining the calibration value, open the on-off valve provided in the branch pipe in the liquid feed path, use the siphon effect to replace the inside of the liquid feed pipe to the sensor head with air, then close the open / close valve at the time of calibration, By sending the calibration liquid anew, the generation of microbubbles in the liquid supply tube was prevented, and the air in the tube was replaced with the calibration liquid.

In addition, since the inside of the liquid supply pipe to the calibration liquid tank, the liquid supply pump, and the branch point cannot be completely replaced with air, an airtight container is assumed to correspond to the branch point of the liquid supply path. And a liquid feed pipe inserted into the closed container is a vent pipe having an open / close valve, a liquid feed pipe connected to a liquid feed pump, and a liquid feed pipe connected to a calibration liquid inlet of a sensor head. By setting the free terminal of the closed container insertion part to the higher position in this order, after the calibration value is determined, the open / close valve provided in the ventilation pipe is opened, and the inside of the closed container and the sensor head are sent to the sensor head using the siphon effect. After replacing the liquid tube with air, the on-off valve is closed during calibration and the calibration liquid is sent again, preventing the generation of fine bubbles in the sealed container and the tube, and replacing the air in the tube with the calibration liquid. And put it in the air All air bubbles, including air bubbles generated in tubes that cannot be replaced, can be captured by this closed container, so that air bubbles can be reliably prevented from entering the closed part of the sensor head, and replacement of the calibration solution can be performed efficiently. You can now do it.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a configuration of a main part of an immersion type optical sensor according to the present invention.

FIG. 2 is a diagram showing a change with time of an attenuation rate at the time of calibration;

FIG. 3 is an enlarged diagram showing a change with time of the attenuation rate in FIG. 2;

FIGS. 4A and 4B show a main configuration of a sensor measuring unit having a cylindrical sensor head, wherein FIG.
Is an external view showing the state at the time of calibration

FIG. 5 is a side view of the sensor head showing a discharge means for discharging liquid different from FIG. 1;

FIG. 6 is a schematic diagram showing a configuration of a main part of an immersion optical sensor according to the present invention having a branch pipe in a liquid supply path of a calibration liquid.

FIGS. 7A and 7B show a time-series liquid supply state of the calibration liquid in the liquid supply path of FIG. 6, wherein FIG.
(B) is a state in which the calibration operation has been started, (c) is a state in which the calibration liquid has reached the position of the on-off valve, and (d) is a schematic view showing a state in which the air in the liquid supply pipe has been completely replaced with the calibration liquid.

FIG. 8 is a schematic diagram showing a configuration of a main part of an immersion optical sensor according to the present invention having a closed vessel and a ventilation pipe in a passage for sending a calibration solution.

FIG. 9 is a side view of a flow cell type optical sensor.

[Description of Signs] 1 Sensor measuring section 2 Liquid to be measured 3 Sensor main body 3a Sensor main body 4 Electric circuit 5 Sensor head 5a Sensor head 6 Light 6a Optical path 6b Optical path 7 Notch section 7a Notch section 8 Irradiation window 9 Light receiving window 10 L V-shaped shielding plate 11 Drive shaft 11a Auxiliary shaft 12 Seal material 13 Liquid feed pump 14 Calibration liquid 15 Injection pipe 15a Injection pipe 16 Inlet 16a Inlet 17 Drain 18 Discharge 18a Discharge 18b Discharge 19 Drain 19a Discharge 20 Signal line 21 Analog circuit 22 CPU / digital circuit 23 Data storage device 24 Solenoid coil 25 Shielding cylinder 26 Drive shaft 27 Flow cell 28 Three-way valve 29 Sample liquid 30 Calibration liquid 31 Calibration liquid tank 32 First liquid supply pipe 33 Second transmission Liquid pipe 34 Branch point 35 Branch pipe 36 On-off valve 37 Sequence circuit 38 Feeding tube 39 sealed container 40 the second liquid supply pipe 41 of one third fluid feeding pipe 42 vent tube

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Kenji Harada 1-1-1, Tanabeshinda, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Inside Fuji Electric Co., Ltd. (56) References JP-A-56-16851 (JP, A) Sho 55-152444 (JP, A) Shokai Sho 56-79847 (JP, U) Shokai Sho 59-100251 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01N 21 / 00-21/61 Practical file (PATOLIS) Patent file (PATOLIS)

Claims (15)

(57) [Claims] 1. An optical sensor measuring section is immersed directly in a sample liquid, a light beam from a light source section is projected on the liquid to be measured, and the amount of light absorbed or scattered and attenuated by the components of the liquid to be measured is automatically measured. An immersion type optical sensor, wherein the optical sensor measuring unit is
A U-shaped sensor head having a notch that forms an optical path between the irradiation window and the light receiving window on the opposing surface, and a sensor head that is attached to this sensor head in parallel with the optical path to shield the optical path from the liquid to be measured and cut the sensor head Two openable and closable L-shaped shielding plates for closing the notch portion, and driving means having at least one drive shaft and an auxiliary shaft attached to each of the L-shaped shielding plates for opening and closing each of the L-shaped shielding plates. A liquid supply pump and a liquid supply path for injecting the calibration liquid into the cutout of the sealed sensor head from outside the liquid to be measured, passing through the optical sensor measurement unit, and a drainage liquid caused by the injection of the calibration liquid. And a discharge path for taking out the air from the cutout portion of the sealed sensor head to the outside. 2. An immersion type optical sensor according to claim 1, wherein the driving means is provided at a position separated from a measuring portion of the optical sensor to a stable measurable position. 3. An immersion type optical sensor according to claim 1, wherein at least one discharge port for sending out the discharge liquid is formed in an L-shaped shielding plate. 4. The immersion type optical sensor according to claim 1, wherein the liquid supply path is a first liquid supply pipe connected to the liquid supply pump to supply the calibration liquid stored in the tank, and a liquid supply pump. A second liquid feed pipe connecting the calibration liquid injection port formed in the sensor head, a branch pipe branched from a branch point of the second liquid feed pipe at a position distant from the liquid surface to be measured, and a branch pipe. An immersion-type optical sensor comprising a controllable on-off valve to be connected. 5. An immersion type optical sensor according to claim 1, wherein the control of the on-off valve is performed by an arbitrary control standby time between the operation of closing the valve and the operation of the drive means closing the L-shaped shielding plate. An immersion-type optical sensor characterized in that the immersion-type optical sensor is performed using a configurable sequence circuit. 6. The immersion type optical sensor according to claim 1, wherein the control of the on-off valve is performed using a sequence circuit capable of opening the valve simultaneously with the operation of the drive means for opening the L-shaped shielding plate. An immersion type optical sensor characterized by the following. 7. The immersion type optical sensor according to claim 1, wherein the liquid supply path is a first liquid supply pipe connected to a liquid supply pump to supply a calibration liquid stored in a tank, and a liquid surface to be measured. A sealed container provided at a position distant from the container, a second liquid feed pipe having one end connected to the liquid feed pump and the other end inserted into the sealed container and attached, and one end inserted and inserted into the sealed container. A third liquid feed pipe connected to a calibration liquid inlet formed in the sensor head, and a vent pipe provided with an open / close valve near the other end by inserting one end into a sealed container. Type optical sensor. 8. The immersion type optical sensor according to claim 1, wherein the end face of each pipe inserted into the closed container has a vent pipe and a second liquid feed pipe in a direction perpendicular to the floor surface. , An immersion type optical sensor which is located at a higher position in the order of the third liquid supply pipe. 9. The immersion type optical sensor according to claim 1, wherein the control of the on-off valve is performed between an operation of closing the valve and an operation of the driving means closing the L-shaped shielding plate. An immersion type optical sensor characterized in that the control standby time is set using a sequence circuit which can be set. 10. The immersion type optical sensor according to claim 1, wherein the on / off valve is controlled by a sequence circuit capable of opening the valve at the same time as the driving means opens the L-shaped shielding plate. An immersion type optical sensor characterized in that the immersion type optical sensor is used. 11. An optical sensor measuring section is immersed directly in a liquid to be measured, a light beam from a light source section is projected on a sample liquid, and an amount of light absorbed or scattered and attenuated by components of the liquid to be measured is automatically measured. An immersion type optical sensor, wherein the optical sensor measuring unit is
A cylindrical sensor head having a notch that forms an optical path between the irradiation window and the light receiving window on the opposing surface, and one end of the sensor head that covers one end of the sensor head and slides toward the other end in parallel with the optical path to be measured. A shielding tube that shields the optical path from the sensor head and seals the notch of the sensor head, at least one solenoid generating coil provided in the sensor head, and at least sliding the shielding cylinder by a solenoid attached to a side surface of the shielding cylinder. A liquid supply pump and a liquid supply path for injecting a calibration liquid into a cutout portion of a sealed sensor head that has two drive shafts and passes through the optical sensor measurement unit from outside the liquid to be measured, and injection of the calibration liquid And a discharge path for taking out a discharged liquid caused by the discharge from the cutout portion of the sealed sensor head to the outside. 12. When calibrating the immersion type optical sensor according to claim 1, the optical path of the optical sensor measuring section is shielded in the liquid to be measured, and the notch of the sensor head is sealed. Inject the calibration liquid into the notch of the sensor head, take out the drainage generated by the injection of the calibration liquid out of the sealed sensor head, replace the liquid to be measured with the calibration liquid, and then seal Automatically detects that the cut-out part of the sensor head is completely replaced with the calibration liquid, and automatically performs calibration while the optical sensor measurement part is immersed in the liquid to be measured. Automatic calibration method for immersion type optical sensors. 13. The method according to claim 12, wherein the state in which the notched portion of the sealed sensor head is filled with the calibration liquid is such that the change rate of the light attenuation rate over time is 0 or a predetermined value. , And then calculate the variation coefficient from the attenuation rates of all the lights obtained by the predetermined number of measurements. When the variation coefficient is equal to or less than the predetermined set value, the attenuation rate of the light calculated from all the measured values Is used as the calibration value, and when the variation coefficient exceeds a predetermined set value, the standard deviation σ of all the measured values is calculated, and the average value of the attenuation rates of all the measured values within the range of the average value ± 3σ is calculated. An automatic calibration method for an immersion optical sensor, wherein the calibration value is a calibration value. 14. When calibrating the immersion type optical sensor according to any one of claims 1 to 6, first, the liquid supply pump is operated to supply the calibration liquid from the branch point of the second liquid supply pipe to the sensor head and the branch pipe. To send out the air in the second liquid feed pipe and the branch pipe, replace the inside of the branch pipe with the calibration liquid, close the on-off valve, and completely send out the air in the second liquid feed pipe to cut out the notch of the sensor head. After removing the air, the driving means closes the L-shaped shielding plate, seals the notch, injects the calibration liquid into the notch, and takes out the discharged liquid accompanying this to the outside to remove the liquid to be measured in the notch. It is automatically detected that the liquid has been completely replaced with the calibration liquid, the calibration is automatically performed while the optical sensor measuring unit is immersed in the liquid to be measured, and then the operation of the liquid supply pump is stopped and the driving means is used. Open the L-shaped shielding plate Open closed, second by water level difference
An immersion type optical sensor characterized in that the calibration liquid in the branch pipe and the second liquid transmission pipe is discharged into the liquid to be measured until the level of the calibration liquid in the liquid feeding pipe and the level of the liquid to be measured are at the same level. Automatic calibration method. 15. In calibrating the immersion type optical sensor according to claim 1, first, a liquid feed pump is operated to cause a calibration liquid to pass through the first and second liquid feed pipes into a closed container. The air in the closed vessel and the third liquid feed pipe is sent out, and after the calibration liquid level in the closed vessel reaches the end face of the second liquid feed pipe, the on-off valve is closed, and the air in the third liquid feed pipe is further opened. And completely remove the air from the notch of the sensor head, close the L-shaped shielding plate by the driving means, seal the notch, and inject the calibration liquid into the notch. And automatically detect that the solution to be measured in the notch has been completely replaced with the calibration solution, and automatically calibrate the optical sensor measurement unit while it is immersed in the solution to be measured, and then send it. The operation of the liquid pump is stopped and the L-shaped shield is Open the on-off valve with opening the plate,
The calibration liquid in the closed vessel and the third liquid supply pipe is discharged into the liquid to be measured until the liquid level in the third liquid supply pipe and the liquid to be measured are at the same level due to the water level difference. Automatic calibration method for immersion type optical sensors.