Atomic absorption spectrophotometer

Abstract

The atomic absorption spectrophotometer (1) of the present invention comprises a burner head (100) and a burner slit portion (110). The burner head (100) has a long side direction and a short side direction. The burner slit portion (110) is formed at the upper portion of the burner head (100) and extends along the long side direction. The burner slit portion (110) has a pair of curved surface portions (121), and the pair of curved surface portions (121) face each other with a gap in the short side direction in such a way that the width of the burner slit portion (110) in the short side direction is larger at the central portion (113) than at both ends (112) of the burner slit portion (110) in the long side direction when viewed from above.

Description

Technical Field

[0001] The invention relates to an atomic absorption spectrophotometer. Background Art

[0002] As a conventional document that discloses the structure of an atomic absorption spectrophotometer, there is Japanese Patent Laying-Open No. 11-153540 (Patent Document 1). The atomic absorption spectrophotometer described in Patent Document 1 includes a burner head having a fixed slit width.

[0003] [Prior art literature]

[0004] [Patent Document]

[0005] Patent Document 1: Japanese Patent Laid-Open No. 11-153540 Summary of the invention

[0006] [Problems to be solved by the invention]

[0007] When measuring a sample containing high concentrations of sugar or salt, precipitates may be generated inside the burner slit of the burner head. If the precipitates block a portion of the burner slit, the flame generated on the burner slit becomes uneven, reducing the reliability of the measurement result.

[0008] The present invention has been made to solve the above-mentioned problems, and an object thereof is to provide an atomic absorption spectrophotometer capable of ensuring the reliability of measurement results of samples containing high-concentration sugar or salt by suppressing the generation of precipitates inside a slit portion of a crater.

[0009] [Technical means to solve the problem]

[0010] The atomic absorption spectrophotometer according to the present invention includes a burner head and a burner slit portion. The burner head has a long side direction and a short side direction. The burner slit portion is formed at the upper portion of the burner head and extends along the long side direction. The burner slit portion has a pair of curved surface portions, and the pair of curved surface portions are spaced apart from each other in the short side direction and face each other in a manner such that the width of the burner slit portion in the short side direction is larger in the central portion than at both ends of the burner slit portion in the long side direction when viewed from above.

[0011] [Effects of the Invention]

[0012] According to the present invention, the reliability of the measurement result of a sample containing high-concentration sugar or salt can be ensured by suppressing the generation of precipitates inside the crater slit portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1It is a perspective view showing the structure of the atomic absorption spectrophotometer according to the first embodiment.

[0014] Figure 2 Observe from the direction of the arrow on line II-II Figure 1 A cross-sectional view of a burner head included in an atomic absorption spectrophotometer.

[0015] Figure 3 Observed from the direction of arrow III Figure 1 A plan view of an atomic absorption spectrophotometer.

[0016] Figure 4 This is a perspective view showing the structure of a burner nozzle included in the atomic absorption spectrophotometer according to the first embodiment.

[0017] Figure 5 It is a graph showing the width of the center portion and both end portions of each crater slit portion of the embodiment and the comparative example.

[0018] Figure 6 It is a cross-sectional view showing a pair of burner nozzles and a water cooling unit included in the atomic absorption spectrophotometer according to the second embodiment.

[0019] [Explanation of Symbols]

[0020] 1: Atomic absorption spectrophotometer

[0021] 10: Holding tube

[0022] 20: Fuel gas inlet

[0023] 30: Combustion-supporting gas inlet

[0024] 40: Sample introduction part

[0025] 50: Flame

[0026] 60: Cooling water

[0027] 100: Combustion head

[0028] 110: Fire mouth slit

[0029] 112, 122: Both ends

[0030] 113, 123: Central

[0031] 120: Burner nozzle

[0032] 121: Curved Face

[0033] 124: Plane

[0034] 125: concave part

[0035] 126, 131: Space

[0036] 130: Abutment

[0037] 240: Water cooling unit

[0038] 250: Pipeline DETAILED DESCRIPTION

[0039] Hereinafter, the atomic absorption spectrophotometer of each embodiment will be described with reference to the drawings. In the following description of the embodiments, the same or equivalent parts in the drawings are marked with the same symbols, and their description will not be repeated. In the drawings, the ratio of the actual size is not used for illustration, but in order to make the structure easier to understand, there are places where the ratio is changed for illustration. The X direction in the drawings is the long side direction of the burner head described below, and the Y direction is the short side direction of the burner head.

[0040] (Implementation Method 1)

[0041] Figure 1 It is a perspective view showing the structure of the atomic absorption spectrophotometer according to the first embodiment. Figure 2 Observe from the direction of the arrow on line II-II Figure 1 A cross-sectional view of a burner head included in an atomic absorption spectrophotometer. Figure 3 Observed from the direction of arrow III Figure 1 A plan view of an atomic absorption spectrophotometer. Figure 4 It is a perspective view showing the structure of a burner nozzle included in the atomic absorption spectrophotometer of Embodiment 1. In addition, in this embodiment, a combustion head including a burner nozzle having a shape capable of arranging a water cooling unit in Embodiment 2 described below will be described.

[0042] like Figure 1 to Figure 3 As shown in FIG. 1 , the atomic absorption spectrophotometer 1 of the first embodiment includes a burner head 100 and a burner slit portion 110. Figure 1 As shown, in this embodiment, the atomic absorption spectrophotometer 1 further includes a holding tube 10 , a fuel gas introduction part 20 , a combustion-supporting gas introduction part 30 , and a sample introduction part 40 .

[0043] like Figure 1 and Figure 2 As shown, a holding tube 10 is connected to the lower part of the combustion head 100. The sample introduced from the sample introduction part 40 and atomized by mixing the fuel gas introduced from the fuel gas introduction part 20 and the combustion-supporting gas introduced from the combustion-supporting gas introduction part 30 inside the holding tube 10 is introduced into the combustion head 100.

[0044] like Figure 1 to Figure 3As shown, the combustion head 100 has a long side direction (X direction) and a short side direction (Y direction). The combustion head 100 includes a pair of burner nozzles 120 and a base 130 .

[0045] A burner slit portion 110 is formed at an upper portion of the burner head 100. The burner slit portion 110 extends along the longitudinal direction (X direction) of the burner head 100. The burner slit portion 110 includes a pair of burner nozzles 120.

[0046] like Figure 1 to Figure 4 As shown, the pair of burner nozzles 120 each have a stepped shape when viewed from the long side direction (X direction) of the combustion head 100 so that a water cooling unit in Embodiment 2 described below can be arranged. However, when no water cooling unit is arranged, the pair of burner nozzles 120 can each have any shape such as a rectangle in the long side direction (X direction) of the combustion head 100.

[0047] like Figure 4 As shown, a pair of burner nozzles 120 include a curved surface portion 121 and a flat surface portion 124 on the inner side surfaces facing each other. In the long side direction (X direction) of the burner head 100, the flat surface portion 124 is located at both ends, and the curved surface portion 121 is located between the flat surface portions 124. The curved surface portion 121 is recessed relative to the flat surface portion 124 in the short side direction (Y direction) of the burner head 100.

[0048] like Figure 4 As shown, the curved surface portion 121 is located above the burner nozzle 120. In the burner nozzle 120, a recessed portion 125 is formed below the curved surface portion 121 and is farther from the flat surface portion 124 than the curved surface portion 121 in the short side direction (Y direction) of the combustion head 100.

[0049] like Figure 4 As shown, the thickness dimension t1 of the burner nozzle 120 at the portion where the two end portions 122 of the curved surface portion 121 in the longitudinal direction (X direction) of the burner head 100 are located is greater than the thickness dimension t2 of the burner nozzle 120 at the portion where the central portion 123 of the curved surface portion 121 is located. The curved surface portion 121 has an arc shape when viewed from above. In addition, the thickness dimensions t1 of the pair of burner nozzles 120 may be different from each other, and the thickness dimensions t2 may be different from each other.

[0050] The surface roughness (Ra) of the curved surface portion 121 of each of the pair of burner nozzles 120 is 0.1 μm or less. The curved surface portion 121 is, for example, polished. Each of the pair of burner nozzles 120 is made of stainless steel or titanium.

[0051] like Figure 1 to Figure 3As shown, a pair of burner nozzles 120 are assembled so as to be attachable and detachable to each other. The burner nozzles 120 are connected to each other by a known connection method such as bolt fastening.

[0052] The burner slit 110 is formed by assembling a pair of burner nozzles 120 so that the curved surface portions 121 face each other. Figure 3 As shown, the burner slit portion 110 has a pair of curved surface portions 121, and the pair of curved surface portions 121 are separated from each other and face each other in the short side direction (Y direction) of the burner head 100 in such a manner that the width of the burner slit portion 110 in the short side direction (Y direction) of the burner head 100 is larger in the central portion 113 than at both end portions 112 of the burner slit portion 110 in the long side direction (X direction) of the burner head 100 when viewed from above.

[0053] Regarding the width of the burner slit portion 110, the width dimension w2 of the central portion 113 is larger than the width dimension w1 of each of the two end portions 112. In the present embodiment, the width dimension w2 of the central portion 113 of the burner slit portion 110 in the long side direction (X direction) of the burner head 100 is 120% or more of the width dimension w1 of each of the two end portions 112 of the burner slit portion 110 in the long side direction (X direction) of the burner head 100.

[0054] From the viewpoint of suppressing the occurrence of tempering in the burner slit portion 110, the width dimension w2 of the central portion 113 is preferably 120% or more and 150% or less of the width dimension w1 of each of the two end portions 112. For example, the width dimension w1 of each of the two end portions 112 is 0.5 mm, and the width dimension w2 of the central portion 113 is 0.6 mm. The length of the burner slit portion 110 in the longitudinal direction (X direction) of the burner head 100 is, for example, 50 mm or more and 100 mm or less.

[0055] In addition, the crater slit portion 110 is not limited to the case where it includes a pair of burner nozzles 120, and may be formed by providing an opening in one block-shaped burner nozzle.

[0056] like Figure 2 As shown, the pair of burner nozzles 120, when assembled together, have a tapered shape with the burner slit portion 110 side being thinner when viewed from the long side direction (X direction) of the burner head 100. A space 126 communicating with the burner slit portion 110 is formed between the assembled burner nozzles 120.

[0057] like Figure 1 and Figure 2 As shown, a pair of burner nozzles 120 are supported by bases 130. The bases 130 have a rectangular parallelepiped shape. Figure 2As shown, the base 130 is connected to the holding tube 10 and has a space 131 inside which a sample can flow. The pair of burner nozzles 120 are connected to the base 130 by a known connection method such as bolt fastening.

[0058] The sample in the combustion head 100 is introduced into the space 126 between the burner nozzles 120 through the space 131 inside the base 130 , and is released from the burner slit portion 110 .

[0059] like Figure 1 As shown, the sample released from the burner slit portion 110 is excited by the flame 50 on the burner slit portion 110. In addition, as the flame 50, for example, an acetylene-air flame or a nitrous oxide-air flame can be used. By detecting the absorbance of light passing through the flame along the long side direction (X direction) of the burner head 100 using a spectrophotometer, the sample components are analyzed.

[0060] Here, an experimental example for verifying the relationship between the shape of the burner slit and the occurrence of blockage in a portion of the burner slit is described. In this experimental example, an atomic absorption spectrophotometer of an embodiment including a burner slit 110 similar to Embodiment 1 and an atomic absorption spectrophotometer of a comparative example in which the width of the burner slit is substantially uniform are used to measure a sample containing high concentrations of sugar or salt to verify whether blockage occurs in a portion of the burner slit.

[0061] Figure 5 Graph showing the width of the central portion and both end portions of the crater slit portion of each embodiment and comparative example. Figure 5 In FIG. 1 , the vertical axis represents the width (mm) of the burner slit portion, and the horizontal axis represents the position of the burner slit portion in the longitudinal direction (X direction) of the burner head 100 .

[0062] like Figure 5 As shown, in the atomic absorption spectrophotometer of the embodiment, the width dimension w2 of the central portion 113 of the burner slit portion 110 in the long side direction (X direction) of the burner head 100 is 120% or more of the width dimension w1 of each of the two end portions 112. In the atomic absorption spectrophotometer of the comparative example, the width dimension of the central portion of the burner slit portion in the long side direction (X direction) of the burner head 100 and the width dimension of each of the two end portions are substantially the same as the width dimension w1 of each of the two end portions 112 of the burner slit portion 110 of the embodiment.

[0063] In the atomic absorption spectrophotometer of the comparative example, precipitates are generated inside the crater slit, and the precipitates clog a portion of the crater slit. In the atomic absorption spectrophotometer of the embodiment, precipitates are not generated inside the crater slit, and a portion of the crater slit 110 is not clogged by precipitates.

[0064] The experimental example confirms that the generation of precipitates inside the burner slit 110 can be suppressed by making the width dimension w2 of the central portion 113 of the burner slit 110 in the long side direction (X direction) of the burner head 100 larger than the width dimension w1 of each of the two end portions 112 .

[0065] In the atomic absorption spectrophotometer 1 of the first embodiment, the burner slit portion 110 has a pair of curved surface portions 121, and the pair of curved surface portions 121 are spaced apart from each other in the short side direction (Y direction) of the burner head 100 in such a manner that the width of the burner slit portion 110 in the short side direction (Y direction) of the burner head 100 is larger at the central portion 113 than at both ends 112 of the burner slit portion 110 in the long side direction (X direction) of the burner head 100 when viewed from above. Thus, the generation of precipitates inside the burner slit portion 110 can be suppressed, and the uniformity of the flame generated on the burner slit portion 110 can be maintained, thereby ensuring the reliability of the measurement results of samples containing high concentrations of sugar or salt. In addition, a high concentration sample can be measured without dilution, so that the reduction in measurement sensitivity can be suppressed. Furthermore, the frequency of cleaning for removing precipitates can be reduced.

[0066] In the atomic absorption spectrophotometer 1 of the first embodiment, the width w2 of the central portion 123 of the burner slit portion 110 in the longitudinal direction (X direction) of the burner head 100 is 120% or more of the width w1 of each of the two end portions 122. Thus, the generation of precipitates inside the burner slit portion 110 can be stably suppressed.

[0067] In the atomic absorption spectrophotometer 1 of the first embodiment, the surface roughness (Ra) of each of the pair of curved surface portions 121 is 0.1 μm or less, thereby suppressing fluctuations of the flame 50 generated on the crater slit portion 110 and ensuring reliability of the measurement result.

[0068] In the atomic absorption spectrophotometer 1 of the first embodiment, the pair of burner nozzles 120 constituting the crater slit portion 110 are assembled so as to be detachable from each other, whereby the pair of burner nozzles 120 can be disassembled, cleaned, and assembled again.

[0069] (Implementation Method 2)

[0070] The atomic absorption spectrophotometer of Embodiment 2 is described below. The atomic absorption spectrophotometer of Embodiment 2 differs from the atomic absorption spectrophotometer of Embodiment 1 only in the structure of the combustion head, and therefore the same structure as that of the atomic absorption spectrophotometer 1 of Embodiment 1 will not be described repeatedly.

[0071] Figure 6FIG. 2 is a cross-sectional view showing a pair of burner nozzles and a water cooling unit included in the atomic absorption spectrophotometer of Embodiment 2. Figure 6 As shown, the burner head included in the atomic absorption spectrophotometer of the second embodiment further includes a water cooling portion 240 for cooling the pair of curved surface portions 121 .

[0072] The water cooling part 240 is arranged in parallel with the burner slit part 110 in the short-side direction (Y direction) of the combustion head 100 in each of the pair of burner nozzles 120. The water cooling part 240 is provided so as to sandwich the tapered shape of the pair of burner nozzles 120.

[0073] The water cooling unit 240 includes a pipe 250 that allows the cooling water 60 to flow through a circulation flow path (not shown). In the pair of burner nozzles 120, heat is exchanged with the cooling water 60 via the pipe 250, so that the pair of curved surface portions 121 are cooled.

[0074] In the atomic absorption spectrophotometer of the second embodiment, a water cooling portion 240 for cooling the pair of curved surface portions 121 is provided in the burner head to suppress a temperature rise of the pair of curved surface portions 121 , thereby suppressing the generation of precipitates inside the crater slit portion 110 .

[0075] (form)

[0076] Those skilled in the art will appreciate that the above-described exemplary embodiments are specific examples of the following aspects.

[0077] (First Item)

[0078] Atomic absorption spectrophotometer includes:

[0079] A burner head having a long side direction and a short side direction; and

[0080] The burner slit is formed at the upper part of the burner head and extends along the long side direction.

[0081] The crater slit portion has a pair of curved surface portions, and the pair of curved surface portions face each other with a gap in the short side direction in such a way that the width of the crater slit portion in the short side direction is larger in the center than at both ends of the crater slit portion in the long side direction when viewed from above.

[0082] According to the atomic absorption spectrophotometer described in the first item, the reliability of the measurement result of the sample containing high concentration of sugar or salt can be ensured by suppressing the generation of precipitates inside the slit portion of the crater.

[0083] (Second Item)

[0084] In the atomic absorption spectrophotometer described in the first item,

[0085] The width of the center portion of the burner slit portion in the longitudinal direction is 120% or more of the widths of both end portions of the burner slit portion in the longitudinal direction.

[0086] According to the atomic absorption spectrophotometer described in the second aspect, the generation of precipitates inside the crater slit portion can be stably suppressed.

[0087] (Third Item)

[0088] In the atomic absorption spectrophotometer described in the first or second item,

[0089] The surface roughness (Ra) of each of the pair of curved surface portions is 0.1 μm or less.

[0090] According to the atomic absorption spectrophotometer described in the third item, the fluctuation of the flame generated on the slit portion of the burner can be suppressed, thereby ensuring the reliability of the measurement results.

[0091] (4th item)

[0092] In the atomic absorption spectrophotometer described in any one of the first to third items,

[0093] The combustion head includes a pair of burner nozzles, and the pair of burner nozzles are assembled in a manner that they can be attached and detached from each other.

[0094] The burner slit portion includes the pair of burner nozzles.

[0095] According to the atomic absorption spectrophotometer described in the fourth item, the pair of burner nozzles can be disassembled, cleaned, and reassembled.

[0096] (Fifth Item)

[0097] In the atomic absorption spectrophotometer described in any one of the first to fourth items,

[0098] The burner head is provided with a water cooling portion for cooling the pair of curved surface portions.

[0099] According to the atomic absorption spectrophotometer described in the fifth aspect, the temperature rise of the pair of curved surface parts can be suppressed, thereby suppressing the generation of precipitates inside the crater slit part.

[0100] In addition, the embodiments disclosed this time are illustrative in all aspects and are not the basis for restrictive interpretation. Therefore, the technical scope of the present disclosure is not interpreted only by the embodiments. Moreover, all changes within the meaning and scope equivalent to the scope of the claims are included. In the description of the above embodiments, structures that can be combined can be combined with each other.

Claims

1. An atomic absorption spectrophotometer, characterized in that: include: The combustion head has a long side direction and a short side direction; as well as The burner slit is formed at the upper part of the burner head and extends along the long side direction. In which, the crater slit portion has a pair of curved surface portions, and the pair of curved surface portions are separated from each other in the short side direction and face each other in a manner such that, when viewed from above, the width of the central portion of the crater slit portion in the long side direction in the short side direction is larger than the width of the two end portions of the crater slit portion in the long side direction in the short side direction.

2. The atomic absorption spectrophotometer according to claim 1, characterized in that: The width of the center portion of the burner slit portion in the longitudinal direction is 120% or more of the widths of both end portions of the burner slit portion in the longitudinal direction.

3. The atomic absorption spectrophotometer according to claim 1 or 2, characterized in that: The surface roughness (Ra) of each of the pair of curved surface portions is 0.1 μm or less.

4. The atomic absorption spectrophotometer according to claim 1 or 2, characterized in that: The combustion head includes a pair of burner nozzles, and the pair of burner nozzles are assembled in a manner that they can be attached and detached from each other. The burner slit portion includes the pair of burner nozzles.

5. The atomic absorption spectrophotometer according to claim 1 or 2, characterized in that: The burner head is provided with a water cooling portion for cooling the pair of curved surface portions.

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