JP2939832B2 - Liquid measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid measuring apparatus in which a sample liquid is supplied from a pump to a sample container via a pipe, and the component concentration of the sample liquid flowing in the sample container is measured.

[0002]

2. Description of the Related Art For example, measuring the component concentration of a sample solution 1
As one method, an absorption spectrophotometry is well known. In this absorptiometry, a sample solution is irradiated with light of a specific wavelength, the absorbance is measured from the transmitted light, and the measured data is used, for example, in a Lambertian method.
The component concentration is calculated by applying a conversion formula such as the Lambert-Beer's law. When such a measurement is performed on a sample liquid whose component concentration changes every moment, the sample liquid is supplied to a flow cell, which is a transparent sample container, by a pump while irradiating the flow cell with light of a specific wavelength. Will be

As another method for measuring the component concentration of a sample solution, there is a method using a sensor such as an electrode. Even in this case, when the measurement is performed on a sample solution whose component concentration changes every moment, a pump is used. A sample liquid is supplied to the flow cell.

[0004]

However, simply supplying the sample liquid to the flow cell with the pump in a monotonous manner as in the prior art described above causes not only the sample liquid but also the bubbles to pass through the flow cell, or the bubbles to the flow cell. As a result, the measurement becomes inaccurate or impossible due to the air bubbles. That is, for example, when measuring by the above-mentioned absorption spectrophotometry, if air bubbles are mixed in the sample solution, light scattering or irregular reflection occurs. Accurate component concentration cannot be calculated even if applied. Also, when the component concentration is measured by a sensor such as an electrode, if air bubbles adhere to the surface of the sensitive part of the sensor, the sensitivity is changed, which hinders the measurement. As a countermeasure to remove such obstacles due to bubbles, measures such as stirring the sample liquid or applying vibration to prevent air bubbles from adhering to the flow cell and the like have been performed so far. In some cases, the generation of air bubbles is promoted by physical stimuli such as vibrations. In such a case, the effect is adverse.

In view of the above-mentioned drawbacks, the present invention has as its object to provide a liquid measuring apparatus which can accurately measure a sample liquid while avoiding bubbles.

[0006]

According to a first aspect of the present invention, there is provided a pump for supplying a sample solution to a sample container via a pipe, and the operation of the pump is periodically stopped for a predetermined time. Pump control means for performing the measurement, and a measuring means for measuring the sample liquid in the sample container when the operation of the pump is stopped , further, the width of the flow path of the sample container, from the pump
It is characterized in that it is set narrower than the diameter of the pipe to the sample container .

[0007]

According to a second aspect of the present invention, there is provided a pump for supplying a sample liquid to a sample container via a pipe, a measuring means for measuring the sample liquid in the sample container, and a middle part of the pipe. together and a degassing for sealed vessel was placed an opening and the overflow opening of the pump-side conduit at a position higher than the opening position of the sample container side conduit provided in the sample liquid in the degassing for sealing vessel An overflow opening / closing valve that opens the overflow opening each time it is filled is in the middle of the overflow pipeline.
And further along a conduit connected to the outlet of the sample container.
An on-off valve for supplying sample liquid is provided inside, and the sample is
The overflow on-off valve is closed until the liquid is full
State, and the sample liquid supply on-off valve is opened.
On the other hand, when the sample liquid is full, the overflow
Close the valve and close the sample liquid supply on-off valve
It is characterized in that it is configured to be in a state.

[0008]

According to the structure of the first aspect of the present invention, even if air bubbles flow into the sample container with the supply of the sample liquid by the pump, the surge pressure generated in the pipe when the operation of the pump is periodically stopped is provided. The bubbles are pushed out of the sample container. During this time, the measurement of the sample liquid by the measurement means is performed, so that there is no measurement error or measurement failure due to bubbles.

According to the second aspect of the present invention, the air bubbles mixed with the sample liquid float on the surface of the sample liquid in the sealed defoaming tank provided in the middle of the pipe and are separated from the sample liquid. . Also,
When the sample solution is filled in the degassing closed tank, the overflow opening / closing valve opens the overflow opening, so that air bubbles do not flow into the opening of the sample container side pipe. Therefore, bubbles are removed from the sample liquid supplied to the sample container, and there is no possibility that a measurement error or measurement failure occurs due to the bubbles.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a first embodiment of the liquid measuring apparatus according to the present invention. The liquid measuring device of this embodiment is a device for measuring the component concentration of a hydrogen peroxide / ammonia mixture 1 as a sample liquid by an absorption spectrophotometer. The sample is supplied to a flow cell 4 as a sample container via a pipe 3.
The flow cell 4 is branched into two flow paths 4a and 4b in the middle. A specific wavelength 31 obtained from the first light source 5 through the interference filter 6 is provided in one flow path 4 a of the flow cell 4.
Ultraviolet UV of 3 nm is irradiated, and the ultraviolet UV transmitted through the flow path 4 a is received by the first detector 7. In addition, a diffraction grating 9 is provided from the second light source 8 to the other flow path 4 b of the flow cell 4.
Near infrared with a specific wavelength of 2209.8 nm obtained through
The near-infrared NIR irradiated with the NIR and transmitted through the flow path 4b is received by the second detector 10. The amount of ultraviolet light UV received by the first detector 7 is converted into a voltage signal,
After that, the signal is converted into a digital signal by the first A / D converter 12 and input to the arithmetic processing unit 13. Also, the second
The amount of near-infrared NIR received by the detector 10 is also converted into a voltage signal and amplified by the second amplifier 14, and then the second A / A
The signal is converted into a digital signal by the D converter 15 and the arithmetic processing unit 13
Is input to The voltage signal input to the arithmetic processing unit 13 is data indicating the amount of transmitted ultraviolet light UV and near-infrared NIR in the hydrogen peroxide / ammonia mixture 1, and the arithmetic processing unit 13 converts these data into absorbance. Thereafter, for example, an arithmetic process is performed which is applied to an ammonia concentration conversion formula and a hydrogen peroxide concentration conversion formula which are derived in advance by a multiple regression analysis.
The concentration of each component in the ammonia mixture 1 is determined. That is, the light sources 5 and 8, the interference filter 6, the detector 7,
10, diffraction grating 9, amplifiers 11, 14, A / D converters 12, 15,
The arithmetic processing unit 13 constitutes a measurement system 16 for measuring the concentration of each component from the ammonia / hydrogen peroxide mixed liquid 1 which is a sample liquid. The pump drive circuit 17 is a circuit having a control function of periodically stopping the operation of the liquid feed pump 2. The acquisition of data from the A / D converters 12 and 15 by the arithmetic processing unit 13 is performed in synchronization with the pump drive circuit 16. That is, assuming that the time during which the operation of the liquid sending pump 2 is stopped is T1, the absorbance is measured in a certain period in the latter half of the time T1.

In the liquid measuring apparatus thus configured, the liquid supply pump 2 is operated intermittently as described above, and when the operation of the liquid supply pump 2 is stopped, the sample liquid in the pipe 3, Since a surge pressure is generated in the hydrogen / ammonia mixture 1, bubbles that have flowed into or adhered to the flow paths 4 a and 4 b of the flow cell 4 before being stopped are pushed out of the flow paths 4 a and 4 b due to the surge pressure, and UV and infrared NI
Deviates from the optical path of R. And after the bubbles are removed,
An absorbance measurement is taken. Normally, the flow path width of the flow cell 4 is narrower than the diameter of the pipe line 3 from the liquid feed pump 2 to the flow cell 4, so that even if the surge pressure fluctuates slightly, the flow paths 4a, 4b of the flow cell 4 Has a great effect on
Bubbles can be sufficiently removed. In this way, the absorbance is measured under the condition from which bubbles are removed, so that the component concentration can be accurately measured. The operation stop time T1 of the liquid sending pump 2 and the timing of the start of measurement during stoppage may be set to appropriate values according to conditions such as the flow rate of the sample liquid.

FIG. 2 shows a liquid measuring apparatus using a hydrogen peroxide / ammonia mixed liquid 1 having an ammonia concentration of 5 wt% and a hydrogen peroxide concentration of 5 wt% as a sample liquid.
FIG. 3 is a graph showing the results of measuring the near-infrared NIR absorbance in the flow path 4b of the flow cell 4. FIG.
It is a graph which shows the result of having measured the light absorbency of NIR. However, the stop time T1 when the liquid feed pump 2 is operated intermittently,
The operation time T2 is 2 minutes, the material of the cell window of the flow cell 4 is sapphire, the optical path length is 1 mm, and the transmitted light output from the detector 10 is indicated by a voltage value as a value corresponding to the absorbance. As is clear from the comparison between FIG. 2 and FIG. 3, the measurement data at the time of the continuous operation has noise continuously generated, and the accurate absorbance cannot be measured. In the figure, the data level becomes flat every two minutes while the operation is stopped, and the noise is removed. In this measurement, the level of the flat portion of the data gradually increased with the passage of time. This was due to the fact that the same sample solution was circulated and supplied to the flow cell 4, and the component concentration changed due to volatilization. It is.

FIG. 4 is a graph showing the results obtained by measuring the absorbance of ultraviolet rays UV in the flow path 4a of the flow cell 4 using the same hydrogen peroxide / ammonia mixture 1 as the sample liquid in the liquid measuring apparatus. FIG. 5 is a graph showing the result of measuring the absorbance of the same ultraviolet ray UV by continuously operating the liquid feed pump 2 for comparison with the above. Other conditions are the same as in the case of near-infrared NIR. Also in this case, it can be seen that the noise is removed during the operation stop time T1 due to the intermittent operation of the liquid feed pump 2.

Depending on the object to be measured and the measuring method, the method of collecting the optical signal is not limited to the transmission type described above,
There are a reflection type and a scattering type, but the same effect can be expected in any case. The same effect can be expected not only in the case of using the optical measurement method but also in the case of using an electrode sensor or the like when bubbles interfere with the measurement.

FIG. 6 is a schematic structural view showing a second embodiment of the liquid measuring apparatus according to the present invention. The liquid measuring apparatus of this embodiment is also an apparatus for measuring the component concentration and the like of the sample liquid 21 by, for example, an optical measuring method. It is supplied to a flow cell 24 which is a sample container via a pipe 23b. The liquid supply pump 22 side pipe 23a has an opening 25a above the defoaming closed tank 25, and the flow cell 24 side pipe 23b has an opening 25b below the defoaming closed tank 25. is there. Separately, an overflow opening 25c for allowing the filled sample liquid 21 to escape is formed at a position above the degassing closed tank 25.
25c is communicated with the downstream pipe 27 via the overflow pipe 26, and in the middle of the overflow pipe 26,
An electromagnetic valve 28 for opening and closing the pipe 26 is provided. The outlet of the flow cell 24 is connected to the downstream pipe 27 via a pipe 29, and an electromagnetic valve 30 for opening and closing the pipe 29 is provided in the middle of the pipe 29. Sample solution for flow cell 24
21 is measured by an optical measuring means 35 including a light source 32, an interference filter 33, a detector 34 and the like. Solenoid valve control device
Reference numeral 31 denotes a device for controlling the opening and closing of the solenoid valves 28 and 30. The solenoid valve 28 is closed and the solenoid valve 30 is opened until the sample liquid 21 is filled in the degassing closed tank 25, and the sample liquid is opened. On the other hand, when 21 is full, the solenoid valve 28 is opened and the solenoid valve 30 is closed.

The opening and closing times of the solenoid valves 28 and 30 controlled by the solenoid valve control device 31 can be set, for example, as follows. Now, let the flow rate of the sample liquid 21 be x
(Ml / min), and the amount occupied by bubbles in the flow rate is represented by y (m
1 / min), the period during which the solenoid valve 28 is open and the solenoid valve 30 is closed is t1
(Minutes), the period during which the solenoid valve 28 is closed and the solenoid valve 30 is open is t2.
(Minutes), and assume that each pipeline uses a small-diameter pipe, and that the volume of the pipeline is ignored.
Liquid amount Q1 (ml) accumulated in the defoaming closed tank 25 during (minutes)
Is

Q1 = (xy) × t1 (m1)

## EQU1 ## Further, the liquid amount Q2 stored in the defoaming closed tank 25 during the period t2 (minute) is

Q2 = (xy) × t2-x × t2 = −y × t2 (m1)

That is, the liquid volume in the degassing closed tank 25 is reduced by y × t2 (ml). Therefore, the solenoid valve
In order not to empty the degassing closed tank 25 during the opening and closing cycle of 28 and 30, the capacity of the defoaming closed tank 25 must be y × t2 or more. Conversely, it is necessary to set the period t2 so as to satisfy the above relationship with the capacity of the degassing closed tank 25. On the other hand, the amount of liquid (Q that accumulates in the defoaming closed tank 25 during one cycle of opening and closing the solenoid valves 28 and 30 (t1 + t2).
1 + Q2) is

Q1 + Q2 = (xy) × t1-y × t2

In the middle of the cycle, the degassing closed tank 25 is used.
The value of this expression must be positive to avoid emptying. From this relationship, the ratio between the period t1 and the period t2 is determined. By setting the time periods t1 and t2 under the above-described conditions, the sample solution 21 is necessarily set in the degassing closed tank 25 while the open / close cycle of the solenoid valves 28 and 30 is repeated.
Overflows from the overflow pipe 26.

In this liquid measuring apparatus, a flow cell 22 is connected to a flow cell via a pipe 23a, a degassing closed tank 25, and a pipe 23b.
When the sample solution 21 is supplied to 24, a degassing closed tank 25
In, air bubbles are separated from the sample liquid 21, and only the sample liquid 21 containing no air bubbles is supplied to the flow cell 24. That is, in the degassing closed tank 25, the bubbles in the sample liquid 21 float and are separated. When the sample solution 21 is filled in the defoaming closed water tank 25, separation of bubbles is hindered and the sample solution 21 containing bubbles flows into the flow cell 24 from the line 23b. Is opened, the liquid level of the defoaming closed tank 25 drops to some extent during this time. Also, during this time, the other electromagnetic valve 30 is closed, so that the sample liquid 21 containing bubbles does not flow into the flow cell 24.

The sample liquid 21 is supplied to the flow cell 24 during the period t2 when the solenoid valve 30 is opened.
Since 28 is closed, the degassing closed tank 25 and the flow cell
Regardless of the arrangement of the 24, the inflow pressure of the sample liquid 21 is transmitted to the flow cell 24 as it is, and the sample liquid 21 can be easily supplied to the flow cell 24 having a narrow flow path. Also, the flow cell
Bubbles adhering to 24 etc. also flow cell by the above inflow pressure
Can be pushed out of 24 light paths. In this way,
Since the measurement of the sample liquid 21 is performed under the condition from which bubbles are removed, the measurement can be performed accurately. The solenoid valve 2
The opening and closing of 8, 30 is performed during the period t1, as in the above embodiment.
In addition to setting t2 in advance, a sensor for detecting the liquid level may be provided in the closed tank 25 for defoaming, and the opening and closing may be controlled based on the detection signal of the sensor.

[0025]

According to the first and second aspects of the present invention, the pump for supplying a sample liquid is operated intermittently, and
Air bubbles in the sample container are pushed out by the surge pressure generated when the operation is stopped, and air bubbles are removed from the sample liquid by a degassing closed tank provided in the middle of the pipeline from the pump to the sample container. The liquid can be measured accurately without being hindered by bubbles.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a configuration of a liquid measuring apparatus according to a first embodiment of the present invention.

FIG. 2 is a graph showing a result of measuring a near-infrared transmitted light output with respect to a mixed solution of hydrogen peroxide and ammonia by the liquid measuring apparatus of the first embodiment.

FIG. 3 is a graph showing the results of measuring the transmitted light output of the same near-infrared ray by continuously operating the pump.

FIG. 4 is a graph showing the results of measuring the transmitted light output of ultraviolet rays with respect to a mixed solution of hydrogen peroxide and ammonia by the liquid measuring device of the first embodiment.

FIG. 5 is a graph showing the result of measuring the transmitted light output of the same ultraviolet ray by continuously operating the pump.

FIG. 6 is a schematic configuration diagram of a liquid measuring device according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sample liquid 2 Pump 3 Pipe line 4 Sample container 16 Measuring means 17 Pump control means 21 Sample liquid 22 Pump 23a Pipe line 23b Pipe line 24 Sample container 25 Sealing tank for defoaming 25a Pump side pipe opening 25b Sample container side pipe Opening 25c Overflow opening 28 Overflow on-off valve 35 Measuring means

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroo Matsumoto 2 Higashi-cho, Kichijoin-miya, Minami-ku, Kyoto Co., Ltd. Inside HORIBA, Ltd. (56) References JP-A-59-148850 (JP, A) JP-A-48-100181 (JP, A) JP-A-56-99470 (JP, U) JP-A-61-161740 (JP, U) (58) Fields surveyed (Int. Cl. ⁶ , DB name) G01N 21/00-21/61

Claims (2)

(57) [Claims] 1. A pump for supplying a sample liquid to a sample container via a pipe, a pump control means for periodically stopping the operation of the pump for a predetermined time, and a sample in the sample container when the operation of the pump is stopped. comprising a measuring means for measuring the liquid, further
The width of the channel of the sample container is changed from the pump to the sample volume.
A liquid measuring apparatus characterized in that it is set narrower than the diameter of a pipe to a vessel . 2. A pump for supplying a sample liquid to a sample container via a pipe, a measuring means for measuring the sample liquid in the sample container, and a sample container side pipe provided in the middle of the pipe. It is provided with a degassing closed tank in which an opening of the pump side pipe and an overflow opening are arranged at a position higher than the opening position.
In addition , an overflow opening / closing valve that opens the overflow opening every time the sample solution is filled in the degassing closed tank is opened.
-Provided in the middle of the bar flow conduit, and further comprising the sample container
An on-off valve for supplying sample liquid is installed in the middle of the line connected to the outlet of
Until the sample liquid fills the degassing closed tank.
Close the on-off valve for bar flow and supply the sample liquid.
While the supply on-off valve is open, when the sample liquid is full,
The overflow on-off valve is opened, and
A liquid measuring apparatus characterized in that the sample liquid supply on-off valve is configured to be closed .