Analysis device
The analytical apparatus stabilizes sample introduction into the combustion tube by using a tube holding part with a through-hole and fixing mechanism, addressing variability and clogging issues to enhance reproducibility.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- SHIMADZU CORP
- Filing Date
- 2025-11-06
- Publication Date
- 2026-05-28
AI Technical Summary
The reproducibility of sample introduction into a combustion tube in analytical devices is affected by the variability in the fixing state of the tube to the tube holding portion, which depends on the operator's skill, and the potential for sample scattering and clogging due to inaccurate cutting of the tube end, leading to inconsistent analysis results.
The analytical apparatus includes a tube holding part with a through-hole for vertical ejection and a fixing mechanism that secures the sample injection tube, fluidly connecting the tube end to the through-hole, ensuring stable sample introduction regardless of operator skill, with a detachable nozzle for easy cleaning and maintenance.
Stabilizes sample introduction into the combustion tube, reducing variability and clogging issues, thereby enhancing the reproducibility of analysis results.
Smart Images
Figure JP2025038872_28052026_PF_FP_ABST
Abstract
Description
Analytical device
[0001] The present invention relates to an analytical device equipped with a combustion tube, such as a combustion-type total organic carbon measuring device (hereinafter referred to as a TOC meter).
[0002] There is known a combustion oxidation type TOC meter that introduces a liquid sample into a combustion tube heated and temperature-controlled by an electric furnace, burns and oxidatively decomposes the carbon component in the sample, guides it to a detector, and measures the amount of total organic carbon (TOC) (see Patent Document 1).
[0003] International Publication No. 2019 / 078265
[0004] In the TOC meter as described above, a tube is fixed to a tube holding portion located above the combustion tube, and the sample supplied from a syringe pump is ejected from the tip of the tube into the combustion tube. When performing maintenance on the device, the tube may be removed from the tube holding portion. In that case, it is necessary to fix the tube to the tube holding portion. However, if the fixing state of the tube to the tube holding portion is not constant, the sample may not be ejected well from the tip of the tube, and the introduction state of the sample into the combustion tube may not be constant, resulting in deterioration of the reproducibility of the analysis results. Therefore, it is necessary to fix the tube to the tube holding portion with good reproducibility, but there is a problem that the fixing state of the tube to the tube holding portion tends to vary depending on the skill of the operator.
[0005] Also, in maintenance, the end portion of the tube may be cut when there is clogging at the end portion of the tube. However, if the tube is not cut accurately, such as when the cut surface of the tube is inclined, the sample ejected from the tip of the tube may scatter obliquely, and the introduction state of the sample into the combustion tube may not be constant, resulting in deterioration of the reproducibility of the analysis results.
[0006] The present invention has been made in view of the above problems, and an object thereof is to stabilize the introduction state of a sample into a combustion tube regardless of the skill of an operator performing maintenance.
[0007] The analytical apparatus according to the present invention is an analytical apparatus for analyzing a sample by combustion, comprising: a combustion tube for burning a sample in an internal space; a sample supplyer for supplying a sample to the combustion tube; a sample injection tube for guiding the sample supplied from the sample supplyer to the combustion tube; a tube holding part located above the combustion tube, having a holding hole for holding the end portion of the sample injection tube, and a through-hole located below the holding hole and penetrating vertically to eject the sample supplied from the sample supplyer through the sample injection tube vertically downward; and a fixing member that fixes the end portion of the sample injection tube in the holding hole and fluidly connects the opening on the end face of the end portion of the sample injection tube to the through-hole of the ejection part.
[0008] In other words, the analytical apparatus according to the present invention does not have a structure in which the sample is directly ejected into the combustion tube from the end of the sample injection tube. Instead, an ejection part with a through hole for ejecting the sample into the combustion tube is provided on a tube holding part located above the combustion tube, and the end portion of the sample injection tube is fixed to the tube holding part with a fixing member, thereby fluidly connecting the opening at the end of the sample injection tube to the through hole of the ejection part, and the sample supplied from the sample supplier is ejected into the combustion tube from the ejection part of the tube holding part.
[0009] According to the analytical apparatus of the present invention, instead of a structure in which the sample is directly ejected into the combustion tube from the tip of the sample injection tube, an ejection part with a through hole for ejecting the sample into the combustion tube is provided on a tube holding part located above the combustion tube, the end portion of the sample injection tube is fixed to the tube holding part with a fixing member, and the opening at the end of the sample injection tube is fluidly connected to the through hole of the ejection part, and the sample supplied from the sample supplier is ejected into the combustion tube from the ejection part of the tube holding part. As a result, the structure of the part in which the sample is ejected into the combustion tube is stable regardless of the skill of the worker performing maintenance on the tube holding part, and the introduction of the sample into the combustion tube is stable.
[0010] This is a schematic diagram showing one embodiment of the analytical apparatus. This is a cross-sectional view showing an example of the structure of the tube connection portion to the combustion tube in the same embodiment. This is a cross-sectional view showing another example of the structure of the tube connection portion to the combustion tube in the same embodiment. This is a cross-sectional view showing yet another example of the structure of the tube connection portion to the combustion tube in the same embodiment.
[0011] Hereinafter, embodiments of the analytical apparatus according to the present invention will be described with reference to the drawings.
[0012] Figure 1 shows a schematic configuration of a combustion oxidation type TOC meter, which is one type of analytical instrument equipped with a combustion tube.
[0013] The TOC meter in this embodiment mainly comprises a combustion tube 2, an electric furnace 4, a sample injection mechanism 6, a switching valve 14, a syringe pump 16, a dehumidification unit 20, and a detection unit 22.
[0014] The combustion tube 2 is made of, for example, quartz glass and has an oxidation catalyst placed inside. The combustion tube 2 is heated to a high temperature (for example, 680°C) by the electric furnace 4 and is used to burn the liquid sample injected inside to generate a sample gas. A sample injection mechanism 6 is provided at the top of the combustion tube 2.
[0015] The sample injection mechanism 6 is equipped with a slider 8 (tube holder) that moves horizontally. The upper surface of the slider 8 is provided with a tube holder hole 9 for holding the end portion of one end of the sample injection tube 12, and the end portion of one end of the sample injection tube 12 is fixed to the tube holder hole 9.
[0016] The other end of the sample injection tube 12 is connected to one of the selection ports of the switching valve 14. The switching valve 14 has one central port and multiple selection ports. In addition to the sample injection tube 12, the multiple selection ports of the switching valve 14 are connected to a flow path leading to the sample tank, a flow path leading to the dilute hydrochloric acid container, a flow path leading to the washing solution container, and a flow path leading to the drain. The suction / discharge port of the syringe pump 16 is connected to the central port of the switching valve 14, and the destination of the suction / discharge port of the syringe pump 16 can be switched by the switching valve 14.
[0017] The injection of the sample into the combustion tube 2 is performed by connecting the syringe pump 16 to the sample tank, collecting the sample from the sample tank into the syringe pump 16, and then, if necessary, adding acid to the sample or aeration being performed inside the syringe pump 16, after which the slider 8 of the sample injection mechanism 6 is slid to the second position, the nozzle 10 is connected to the sample injection port 3, and the sample is discharged from the syringe pump 16.
[0018] A carrier gas is supplied to the combustion tube 2. The outlet of the combustion tube 2 is connected to the detection unit 22 via the sample gas flow path 18. The detection unit 22 is for measuring the carbon dioxide concentration in the sample gas generated inside the combustion tube 2, and is, for example, an NDIR. A dehumidification unit 20 is provided on the sample gas flow path 18, and moisture in the sample gas that flows out from the outlet of the combustion tube 2 is removed in the dehumidification unit 20.
[0019] Figure 2 shows an example of the structure of the sample injection mechanism 6.
[0020] The sample injection mechanism 6 in the example shown in Figure 2 is equipped with a ejection nozzle 10 below the tube holding hole 9 of the slider 8. The ejection nozzle 10 has a flat upper surface that forms the bottom surface of the tube holding hole 9, and a through hole 26 for ejecting the sample supplied through the sample injection tube 12 held in the tube holding hole 9 vertically downward. A recess 28 is provided on the lower surface of the slider 8 where the ejection nozzle 10 is located, and the portion of the bottom surface of the recess 28 where the through hole 26 is located protrudes vertically downward to form a nozzle 24. The tip of the nozzle 24 is located above the lower surface of the slider 8 so as not to obstruct the horizontal movement of the slider 8.
[0021] The portion of the lower surface of the ejection section 10 where the through-hole 26 is provided does not necessarily need to protrude to form a nozzle 24. However, by protruding toward the combustion tube 2 to form a nozzle 24, the sample ejected from the lower end of the through-hole 26 is less likely to diffuse into the surroundings, the injection of the sample into the combustion tube 2 can be stabilized, and this contributes to improving the reproducibility of the analysis results.
[0022] In this example, the end of the sample injection tube 12 on the combustion tube 2 side is a flange 13, and the end face is a circular flat surface. A fixing member 30 is provided at the end portion of the sample injection tube 12. The fixing member 30 has an inner diameter slightly larger than the outer diameter of the sample injection tube 12, and its tip surface (bottom surface in the figure) engages with the flange 13 at the end of the sample injection tube 12. The tip side of the fixing member 30 has a threaded portion with a screw that screws into a screw provided on the inner circumferential surface of the tube holding hole 9.
[0023] When the end portion of the sample injection tube 12 is inserted into the tube holding hole 9, and the threaded portion at the tip of the fixing member 30 is tightened against the tube holding hole 9, the tip surface of the fixing member 30 presses downward against the flange 13 at the end of the sample injection tube 12, thereby pressing the end face of the end of the sample injection tube 12 against the upper surface of the ejection part 10 (the bottom surface of the tube holding hole 9). As a result, the opening at the end of the sample injection tube 12 and the through hole 24 of the ejection part 10 are fluidly connected while maintaining airtightness.
[0024] The slider 8 moves between a first position in which the ejection nozzle 10 is positioned directly above the combustion tube 2, and a second position in which the ejection nozzle 10 is positioned directly above the drain port 7. In Figure 1, the slider 8 is in the second position, and in Figure 2, the slider 8 is in the first position. When the slider 8 is in the first position (the state in Figure 2), a sample is supplied through the sample injection tube 12, and the sample is ejected from the tip of the nozzle 24 toward the internal space of the combustion tube 2. When the slider 8 is in the second position, the opening at the upper end of the combustion tube 2 is sealed.
[0025] Furthermore, if continuous analysis is performed over a long period, contamination and / or salt precipitation originating from the sample may occur upstream of the combustion tube 2. Such contamination and / or salt precipitation originating from the sample is more likely to occur at the sample ejection portion closest to the combustion tube 2. In conventional structures where the sample is ejected into the combustion tube 2 from the tip of the sample injection tube 12, clogging of the sample is likely to occur at the end of the sample injection tube 12 on the combustion tube 2 side. However, when such clogging occurs, it is difficult to clean the inner surface of the sample injection tube 12, which has a small inner diameter (e.g., 1 mm or less), so it is common to cut the end of the sample injection tube 12. However, the condition of the cut surface of the sample injection tube 12 can affect the ejection of the sample into the combustion tube 2, which can affect the reproducibility of the analysis results.
[0026] On the other hand, as shown in the example in Figure 2, if a nozzle 10 is provided on the slider 8 and the opening at the end of the sample injection tube 12 is fluidly connected to the through hole 26 provided in the nozzle 10, then sample clogging will almost always occur within the through hole 26 of the nozzle 10. When sample clogging occurs, it is necessary to clean the through hole 26, but since the through hole 26 is much shorter than the sample injection tube 12, cleaning the through hole 26 is easy.
[0027] In the example shown in Figure 2, the ejection part 10 is integrally formed with the slider 8, but as shown in Figure 3, the ejection part 10 can also be a sample injection tip that is detachably attached to the slider 8. Examples of materials for the sample injection tip include metal, fluoropolymer resins such as ETFE and PTFE, PEEK, and polyimide. As shown in the example in Figure 3, by making the ejection part 10 a detachable tip from the slider 8, the ejection part 10, which has a through-hole 26 prone to sample clogging, can be made disposable, further simplifying maintenance.
[0028] Furthermore, in the examples shown in Figures 2 and 3, the end of the sample injection tube 12 is a flange 13, and the flange 13 is pressed against the flat bottom surface of the retaining hole 9, but the present invention is not limited to this. Figure 4 shows an example of a slider 8 having a different structure from the examples in Figures 2 and 3.
[0029] The slider 8 in Figure 4 has a structure that uses a male nut to hold the end portion of the sample injection tube. The holding hole 9 of the slider 8 is designed to tighten and secure the male nut attached to the end portion of the sample injection tube, and the ejection part 10 is positioned below the end portion of the sample injection tube held in the holding hole 9 by the male nut. The ejection part 10 is provided with a through hole 26 for ejecting the sample flowing out from the opening at the end portion of the sample injection tube held in the holding hole 9 by the male nut vertically downwards. By tightening the male nut attached to the end portion of the sample injection tube against the holding hole 9, the opening at the end portion of the sample injection tube is fluidly connected to the through hole 26 while maintaining airtightness.
[0030] Furthermore, in the structure shown in Figure 4, similar to the example in Figure 3, the ejection part 10 can be made into a sample injection tip that can be attached to and detached from the slider 8.
[0031] In the examples shown in Figures 2 to 4, the carrier gas is depicted as being supplied into the combustion tube 2 from the side of the combustion tube 2. However, the present invention is not limited to this, and the carrier gas may be supplied into the combustion tube 2 through the sample injection mechanism 6.
[0032] Furthermore, the embodiments described above are merely examples of embodiments of the analytical apparatus according to the present invention. Embodiments of the analytical apparatus according to the present invention are as follows.
[0033] In one embodiment of the analytical apparatus according to the present invention, the analytical apparatus is used to analyze a sample by combustion, and comprises: a combustion tube for burning a sample in an internal space; a sample supplier for supplying a sample to the combustion tube; a sample injection tube for guiding the sample supplied from the sample supplier to the combustion tube; a tube holding part located above the combustion tube, having a holding hole for holding the end portion of the sample injection tube, and a through-hole located below the holding hole and penetrating vertically to eject the sample supplied from the sample supplier through the sample injection tube vertically downward; and a fixing member that fixes the end portion of the sample injection tube in the holding hole and fluidly connects the opening on the end face of the end portion of the sample injection tube to the through-hole of the ejection part.
[0034] In the first aspect of the above embodiment, the fixing member has a threaded portion on its outer circumference, a screw that engages with the thread of the threaded portion is provided on the inner circumference of the retaining hole, and the opening on the end face of the sample injection tube is configured to be fluidly connected to the through hole by tightening the threaded portion of the fixing member into the retaining hole.
[0035] In the second aspect of the above embodiment, the upper surface of the ejection part forms the bottom surface of the holding hole, a flange is provided at the end portion of the sample injection tube, the fixing member engages with the flange from the side opposite to the end face of the end portion of the sample injection tube, and is fixed to the tube holding part from above while pressing the flange toward the bottom side of the holding hole, and the end face of the end portion of the sample injection tube is pressed against the upper surface of the ejection part so that the opening of the end face is fluidly connected to the through hole of the ejection part.
[0036] In the third aspect of the above embodiment, the ejection portion has a nozzle formed by the portion where the through hole is provided protruding vertically downward from the lower surface.
[0037] In the fourth aspect of the above embodiment, the ejection portion is composed of a sample injection tip that is detachably provided with respect to the tube holding portion.
[0038] In the fifth aspect of the above embodiment, the ejection portion is formed integrally with the tube holding portion.
[0039] In the sixth aspect of the above embodiment, the tube holding portion is configured to move between a first position in which the ejection portion is positioned directly above the combustion tube, and a second position in which the ejection portion is positioned away from the position directly above the combustion tube.
[0040] 2 Combustion tube 4 Electric furnace 6 Sample injection mechanism 7 Drain port 8 Slider 9 Tube holding hole 10 Discharge part 12 Sample injection tube 13 Flange 14 Switching valve 16 Syringe pump 18 Sample gas flow path 20 Dehumidification part 22 Detection part 24 Nozzle 26 Through hole 28 Recess 30 Fixing member
Claims
1. An analytical apparatus for burning and analyzing a sample, comprising: a combustion tube for burning the sample in an internal space; a sample supplier for supplying the sample to the combustion tube; a sample injection tube for guiding the sample supplied from the sample supplier to the combustion tube; a tube holding part located above the combustion tube, having a holding hole for holding the end portion of the sample injection tube, and a through-hole located below the holding hole and penetrating vertically to eject the sample supplied from the sample supplier through the sample injection tube vertically downward; and a fixing member that fixes the end portion of the sample injection tube in the holding hole and fluidly connects the opening on the end face of the end portion of the sample injection tube to the through-hole of the ejection part.
2. The analytical apparatus according to claim 1, wherein the fixing member has a threaded portion on its outer circumference, a screw that engages with the thread of the threaded portion is provided on the inner circumference of the retaining hole, and the opening on the end face of the sample injection tube is fluidly connected to the through hole by tightening the threaded portion of the fixing member into the retaining hole.
3. The analytical apparatus according to claim 1, wherein the upper surface of the ejection part forms the bottom surface of the holding hole, a flange is provided on the end portion of the sample injection tube, the fixing member engages with the flange from the side opposite to the end face of the end portion of the sample injection tube, and is fixed from above to the tube holding part while pressing the flange toward the bottom side of the holding hole, and the end face of the end portion of the sample injection tube is pressed against the upper surface of the ejection part so that the opening of the end face is fluidly connected to the through hole of the ejection part.
4. The analytical apparatus according to claim 1, wherein the ejection part has a portion where the through hole is provided protruding vertically downward from the lower surface to form a nozzle.
5. The analytical apparatus according to claim 1, wherein the ejection part is composed of a sample injection tip that is detachably provided with respect to the tube holding part.
6. The analytical apparatus according to claim 1, wherein the ejection part is integrally formed with the tube holding part.
7. The analytical apparatus according to claim 1, wherein the tube holding portion is configured to move between a first position in which the ejection portion is positioned directly above the combustion tube, and a second position in which the ejection portion is positioned away from the position directly above the combustion tube.