JP3032633B2 - Dissolved gas component extraction tank of dissolved gas analyzer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an extraction tank for extracting a dissolved gas component from a liquid phase to a gas phase in an apparatus for analyzing dissolved gas in a liquid.

[0002]

2. Description of the Related Art As an apparatus for analyzing dissolved gas in a liquid, there is conventionally known an extraction tank shown in FIG. 9 for transferring a dissolved gas component to a gas phase. FIG. 9 is a schematic cross-sectional view showing the configuration of the extraction tank, in which directions in which liquid and gas flow are indicated by arrows. In FIG. 9, the extraction tank feeds the sample liquid 3 from the introduction pipe 2 on the side surface of the main body 1 to the main body 1 by a water pressure or a liquid feed pump (not shown), causes the sample liquid 3 to overflow by the discharge pipe 4, and naturally drops the main body 1. Discharged from On the other hand, a clean gas is sent from a carrier gas introduction pipe 7 to a head space portion 6 formed by a water sealing plate 5 in the main body 1 to capture a dissolved gas component in the sample liquid 3, and then the carrier gas is introduced. The tube 8 leads to a gas component detection unit (not shown). Problems in such a dissolved gas component extraction tank are as follows.

[0003]

In the extraction tank shown in FIG. 9, a discharge pipe 4 for overflowing the sample liquid 3 is provided in order to keep the water level of the sample liquid 3 constant.
When the flow rate of the sample liquid 3 increases, the sample liquid 3 swells around the upper end of the discharge pipe 4 due to surface tension, and as a result, the volume of the head space 6 fluctuates according to the flow rate of the sample liquid 3,
The output of the detecting unit is affected by the fluctuation of the liquid level, and lowers the S / N ratio. Therefore, if it is attempted to increase the size of the discharge pipe 4 to reduce the swelling of the sample liquid 3 around it, the entire extraction tank becomes large, which is inconvenient as a dissolved gas analyzer.

Further, it is known that in this extraction tank having a head space section 6 using a carrier gas, the output of the detection section generally increases as the flow rate of the sample liquid 3 increases, and the entire amount of the sample liquid 3 is known. Flows through the body 1,
The structure is such that the detection unit side is easily affected directly by fluctuations in the flow rate of the sample liquid 3. Therefore, using a liquid feed pump,
It is necessary to feed a constant flow of the sample liquid 3 into the main body 1.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object to suppress fluctuations in the flow rate in the head space portion and to measure the flow rate of the sample liquid without affecting the output of the detection section. An object of the present invention is to provide a dissolved gas component extraction tank of a dissolved gas analyzer that can improve accuracy.

[0006]

In order to solve the above-mentioned problems, a dissolved gas component extraction tank according to the present invention is provided between a first overflow section and a second overflow section having a lower water level in the tank. A first partition section and a second partition section are provided to interpose a water receiving section and keep the water level of each of these overflow sections constant, and sample liquid is received from the first overflow section through the first capillary section. It has a flow path that flows into the water part, and a flow path in which the sample liquid that has flowed into the water receiving part flows through the second capillary part to the second overflow part, and is formed by a pipe connection member attached to the upper part of the water receiving part. One end of a carrier gas inlet pipe and one end of a carrier gas outlet pipe that captures a gas component to be detected are arranged in a head space section in the water receiving section to be formed.

[0007]

As described above, in the dissolved gas component extraction tank of the present invention, a part of the sample liquid drawn into the tank from the sample liquid introduction port overflows the upper part of the first partition part of the first overflow part. And the water level in the first overflow section is maintained at a certain value, the remaining sample liquid flows into the water receiving section through the first capillary section, and the sample liquid accumulated in the water receiving section is discharged to the first It flows into the second overflow portion through the second thin tube portion having a larger cross-sectional area than the thin tube portion, overflows the second partition portion of the second overflow portion, and is discharged from the bottom of the tank body. At this time, the water level of the second overflow portion is also kept at a certain value.

Here, the flow rate of the sample solution passing through the first capillary portion is a constant value determined by the water level difference (head pressure) between the first overflow portion and the water receiving portion, and the constant cross-sectional area of the first capillary portion A constant flow rate can be obtained from the product of Therefore, a stable head space portion having a constant volume can be secured without being affected by the sample liquid flow rate on the surface of the sample liquid in contact with the carrier gas. A carrier gas is introduced into the head space, the dissolved gas component dissolved in the sample solution is captured, and this can be sent to the detection unit at the same gas flow rate as the introduced carrier gas flow rate.

[0009]

1 to 4 are schematic views showing the configuration of a main part of a dissolved gas component extraction tank of the present invention used in a dissolved gas analyzer. 1 is a front view seen from above, FIG. 2 is a sectional view taken along line AA of FIG. 1, FIG. 3 is a sectional view taken along line BB of FIG. 1, and FIG.
FIG. 4 is a cross-sectional view taken along a line C, in which directions in which the liquid flows are indicated by arrows. However, FIG. 1 to FIG.
The illustration is omitted for convenience of explanation and will be described later. First, the present invention will be described mainly with reference to the cross-sectional views of FIGS.

[0010] In FIG. 2, from the sample liquid inlet 11 provided in the bottom surface of the tank body 10, is introduced into the first overflow portion 13 surrounds the sample solution 12 by the dotted line of the vessel main body 10. The sample liquid 12 overflows the upper part of the first partition part 14 provided in the first overflow part 13 and flows out to the outside from the outlet 15 opened at the bottom of the tank body 10 . Therefore,
The water level of the first overflow section 13 is the first partition section 14
Regulated by The remaining sample liquid 12 that does not overflow in the first overflow section 13 passes through a first thin tube section 17 below a partition 16 provided in the tank body 10 and is introduced into a water receiving section 18 surrounded by a dotted line. Water receiving section 18 samples introduced into the liquid 12 passes through the second narrow tube portion 19 thicker than the side surface and the first tube portion 17 provided in the lower portion of the water receiving portion 18, surrounded by a dotted line shown in FIGS. 3 and 4 It is introduced into the second overflow section 20 . The sample solution 12 which is introduced into the second overflow section 20, the upper portion of the second partition part 21 which is provided on the second overflow section 20 overflows, with the sample solution 12 which overflows the first overflow section 13,
It is discharged to the outside through the outlet 15 at the bottom of the tank body 10 .
Therefore, the water receiving section 18 and the second overflow section 2
The water level of 0 is regulated by the second partition 21.

As described above, the flow rate of the sample liquid 12 passing through the first capillary portion 17 becomes a constant value determined by the water level difference regulated by the first partition portion 14 and the second partition portion 21, and Since the first capillary portion 17 has a constant cross-sectional area, the sample liquid 12 flowing into the water receiving portion 18 has a constant flow rate.

[0012] The dissolved gas component extraction vessel of the present invention described with reference to sectional views of FIGS. 2-4, the positional relationship of the components is, as the front view shown in FIG. 1, the first overflow section 1
3 , water receiving section 18 , second overflow section 20 , drain port 1
5 are arranged so as to be substantially perpendicular to each other. Therefore, the dissolved gas component extraction tank of the present invention is easy to process for reducing the size and integrating the constituent members. further,
By providing the stoppers 22 and 23 shown in FIG. 1, the processing of the first thin tube portion 17 and the second thin tube portion 19 is facilitated, and when these thin tube portions are contaminated, the stopper plugs 22 and 23 are removed to remove the rod-like substance. Removal is also possible, and maintenance is improved.

Next, a dissolved gas component extraction tank according to the present invention to which a gas pipe connecting member not shown in FIGS. 1 to 4 is attached is shown in FIG. 5 as a sectional view taken along line AA of FIG. FIG. 5 corresponds to FIG. 2, but is shown slightly enlarged from FIG. 2, and the same parts as those in FIG. 2 are denoted by the same reference numerals. In FIG. 5, a gas pipe connection member 24 is attached to the upper part of the water receiving part 18 of the tank body 10 via, for example, an O-ring 25, and a water level surface regulated by the second partition part 21 of the water receiving part 18 ; A head space portion 26 is formed by the piping connection member 24. Then, one end of each of the carrier gas inlet pipe 29 and the carrier gas outlet pipe 30 is inserted and fixed from the outside to the head space portion 26 by penetrating the pipe connecting member 24 and using tube fittings 27 and 28, respectively. By flowing the carrier gas from the gas introduction pipe 29 into the head space portion 26, the gas component dissolved in the sample liquid 12 shifts to the gas phase. The carrier gas captures the gas component, and the captured gas is used as a carrier. The gas can be led to a detection unit (not shown) through the gas outlet pipe 30. The pipe connection member 24 also serves as a lid for the water receiving portion 18 at the same time.

6 and 7 are schematic views showing the shape of the gas pipe connecting member 24. FIG. 6 is a plan view, and FIG.
It is sectional drawing of the A line. Referring to both figures, the gas pipe connecting member 24 having a U-shaped cross section when viewed from the side is provided with two through holes 31 and 32 in a thick portion on the upper surface. The carrier gas introduction pipe 29 shown in FIG.
This is for inserting and fixing using the tube fitting 27, and the through hole 32 is for inserting and fixing the carrier gas outlet pipe 30 similarly shown in FIG. 5 using the tube fitting 28. Reference numeral 26 corresponds to the head space section in FIG.

Next, the results of measuring the concentration of dissolved ozone in a sample liquid using a dissolved gas analyzer equipped with this dissolved gas component extraction tank will be described. The sample liquid was introduced into a fixed amount using a liquid pump. In addition, a semiconductor type ozone gas detector was used for a detection unit of the dissolved gas analyzer. Various measurement conditions are as follows. Flow rate of liquid feed pump for sample liquid introduction 300 ml / min Flow rate of carrier gas introduction pipe 29 30 ml / min

FIG. 8 shows the result obtained by this measurement. FIG. 8 is a diagram showing the relationship between the concentration of dissolved ozone in the sample liquid and the output of the ozone gas detector. FIG. 8 shows good linearity, confirming the effectiveness of the dissolved gas component extraction tank according to the present invention. Next, the same measurement was carried out while changing the flow rate of the sample liquid delivery pump from 155 ml / min to 665 ml / min. The carrier gas flow rate and the detector are the same as described above. Table 1 shows the obtained results.

[Table 1]

It can be seen from Table 1 that the output obtained does not change. In addition, the water level of the water receiving section 18 did not change. From this, it can be seen that the use of the dissolved gas component extraction tank according to the present invention did not affect the measurement due to fluctuations in the flow rate of the liquid feed pump for deriving the sample liquid. Furthermore, it is also possible to supply the sample liquid to the extraction tank using, for example, the water pressure of the ozone reaction tower without using a liquid feed pump.

The reproducibility was repeatedly examined using a sample solution having a dissolved ozone concentration of 0.6 mg / l. The flow rate of the sample liquid is 300 ml / min, and the carrier gas flow rate and the detector are the same as described above. When the conventional extraction tank shown in FIG. 9 was used, the CV value (coefficient of variation) was 3.8%, but the result of measurement using the extraction tank of the present invention was CV.
The value is 1.4%, which indicates that the measurement accuracy is improved because the sample liquid 12 is sent to the water receiving unit 18 at a constant flow rate through the first thin tube unit 17 in the present invention.

[0019]

As described in the embodiment, the dissolved gas component extraction tank according to the present invention divides the inside of the tank into two overflow sections, and sets different water levels by providing partitions in each of the overflow sections.
A water receiver is provided between the two overflow channels, and a constant flow rate of sample liquid obtained by the difference in water level is introduced into the water receiver through two narrow pipe channels with different diameters. The headspace formed by the member and the carrier gas captures the gas components dissolved in the sample liquid by the carrier gas, so that the output of the detection unit does not depend on the flow rate of the sample liquid, and the measurement accuracy is improved. Can be improved. Further, since the output is not affected by the flow rate of the sample liquid, the introduction of the sample liquid into the tank is performed by a hydraulic (head pressure)
Can be performed using In the case where bubbles containing oxygen gas are present in the sample water, in the conventional apparatus, the bubbles may be taken into the carrier gas, which may cause a detection output abnormality of the gas component detection unit. In the apparatus of the present invention, such bubbles are discharged before the sample water and the carrier gas come into contact with each other in the first overflow portion, so that occurrence of a detection output abnormality is prevented. Furthermore, since the introduction of the sample liquid into the water receiving portion having the head space portion is performed through the thin tube portion, the stirring effect is large, and from this point, there is also an advantage that a high sensitivity and stable output can be obtained. As in the case of introducing the carrier gas into the head space as described in the embodiment, it is needless to say that the method of blowing the carrier gas into the sample liquid in the water receiving section can be used.

[Brief description of the drawings]

FIG. 1 is a front view of a dissolved gas component extraction tank of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG. 1;

FIG. 3 is a sectional view taken along line BB of FIG. 1;

FIG. 4 is a sectional view taken along line CC of FIG. 1;

FIG. 5A of FIG. 1 when a gas pipe connection member is attached.
-A line sectional view

FIG. 6 is a schematic plan view showing the shape of a gas pipe connection member.

FIG. 7 is a sectional view taken along line AA of FIG. 6;

FIG. 8 is a graph showing the relationship between the dissolved ozone concentration measured using the dissolved gas component extraction tank of the present invention and the output of the ozone gas detector.

FIG. 9 is a schematic cross-sectional view showing a main configuration of a conventional dissolved gas component extraction tank.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Main body 2 Inlet pipe 3 Sample liquid 4 Drain pipe 5 Water seal plate 6 Head space part 7 Carrier gas inlet pipe 8 Carrier gas outlet pipe 10 Tank body 11 Sample liquid inlet 12 Sample liquid 13 First overflow part 14 First partition Part 15 Discharge port 16 Partition wall 17 First thin tube part 18 Water receiving part 19 Second thin tube part 20 Second overflow part 21 Second partition part 22 Stopcock 23 Stopcock 24 Pipe connection member 25 O-ring 26 Headspace part 27 Tube Fitting 28 Tube fitting 29 Carrier gas inlet tube 30 Carrier gas outlet tube 31 Through hole 32 Through hole

────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yoshitaka Taka 2-5-4 Mitsuyanaka, Yodogawa-ku, Osaka-shi Inside New Cosmos Electric Co., Ltd. (72) Inventor Hiromasa Tangami 2-5-5 Mitsuyanaka, Yodogawa-ku, Osaka-shi No. 4 Inside New Cosmos Electric Co., Ltd. (56) References JP-A-4-332844 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01N 1/00 101 G01N 1/22

Claims (5)

(57) [Claims] 1. A method according to claim 1, A water receiving part which is adjacent to both the first overflow part and the second overflow part provided in the tank body and is provided at a position where the first overflow part and the second overflow part are at right angles on the same bottom surface, b . A sample liquid inlet formed at the bottom of the tank body for flowing the sample liquid into the first overflow section; c. An outlet formed at the bottom of the tank body for allowing the sample liquid overflowing from the first overflow section and the second overflow section to flow out of the tank body; d. A partition wall provided on the tank body between the first overflow section and the water receiving section; e. A first partition for overflowing the sample liquid flowing into the first overflow section from the sample liquid inlet; f. A first thin tube portion formed in the partition wall for flowing the sample liquid in the first overflow portion to the water receiving portion; g. A second thin tube section for flowing the sample liquid in the water receiving section to the second overflow section; h. A second partition section for overflowing the sample liquid flowing from the second capillary section into the second overflow section; i. It has a carrier gas inlet for feeding a carrier gas from the outside of the tank body, and a carrier gas outlet for taking out the carrier gas capturing the detected gas component to the outside of the tank body, and is attached to the upper part of the water receiving part. A dissolved gas component extraction tank of a dissolved gas analyzer, comprising: a pipe connection member; 2. The dissolved gas component extraction tank of a dissolved gas analyzer according to claim 1, wherein the diameter of the first capillary portion is smaller than the diameter of the second capillary portion. . 3. The dissolved gas component extraction tank according to claim 1, wherein the position of the upper end surface of the first partition portion of the first overflow portion is changed to the upper end surface of the second partition portion of the second overflow portion. A dissolved gas component extraction tank of a dissolved gas analyzer, characterized in that the tank is higher than the position of (1). 4. A dissolved gas analyzer according to claim 1, wherein an upper end surface of said second partition is higher than a position of said second thin tube. Dissolved gas component extraction tank. 5. A dissolved gas analyzer according to claim 1, wherein said first thin tube portion and said second thin tube portion are located in directions perpendicular to each other. Gas component extraction tank.