Flame type atomic light absorption photometer

Abstract

The present invention is a flame-type atomic absorption photometer provided with: a burner (110) for forming a flame by burning a mixture of an atomized sample liquid and a mixed gas of a fuel gas and a combustion-supporting gas; a fire light detection unit (181) and a fire light detection unit (182) that detect light emitted from the fire light; and a midway extinguishment determination unit (162) that determines that the fire has occurred when the intensity of the light detected by the fire light detection unit is lower than a predetermined threshold value, and in the flame atomic absorption photometer, the fire light detection unit selectively detects light having a wavelength of 290 nm or more and 330 nm or less.

Description

Technical Field

[0001] The invention relates to a flame atomic absorption photometer. Background Art

[0002] The flame atomic absorption spectrophotometer mixes the sample liquid atomized by a nebulizer with the combustion gas in a chamber, and causes the mixed gas to burn while blowing out from the slit opening of the burner head, thereby forming a flame. In the flame, the components in the sample are atomized, and when the flame containing the atomized sample components is irradiated with light, only the light of a specific wavelength corresponding to the type of atom (element) is absorbed. Therefore, by measuring the absorption of light by the sample atoms, the elements in the sample can be identified and quantified.

[0003] The combustion gas used to form the flame usually contains acetylene (C 2 H 2 ) and other hydrocarbon fuel gas and air or nitrous oxide (N 2 When the combustion gas burns normally, its combustion speed is balanced with the flow rate of the gas blown out from the burner head, thereby stably forming a flame at a position slightly floating upward from the upper surface of the burner head.

[0004] However, when the balance between the combustion speed and the gas flow rate collapses for some reason, or wind flows in from the outside, the flame may be extinguished at an unexpected time (i.e., it may be extinguished midway). Therefore, in the conventional flame atomic absorption photometer, there is a flame atomic absorption photometer with the following functions: a light sensor is provided near the flame, and the intensity of the light (flame light) emitted by the flame is monitored at any time, and when the intensity is less than the light amount during normal combustion, the flame is automatically extinguished and the supply of combustion gas is stopped (for example, refer to Patent Document 1).

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2010-127812 Summary of the invention

[0008] Problems to be solved by the invention

[0009] However, even in a flame atomic absorption photometer including a light sensor for flame light monitoring as described above, there is a possibility that, depending on the usage environment, external interference light such as sunlight or indoor lighting may enter the light sensor, and the light sensor may be mistakenly judged to be continuing to burn normally even though the amount of light from the flame is actually less than that during normal combustion.

[0010] In addition, when the balance between the burning speed of the burner and the flow rate of the gas blown out from the burner head breaks down, the flame may sometimes invade the inside of the burner and cause unstable combustion, i.e., backfire. In the past, in order to ensure the safety of flame atomic absorption photometers, various mechanisms for preventing such backfire have been proposed, but there is still room for improvement.

[0011] In addition, if the flow rate of the combustion-supporting gas becomes too small relative to the flow rate of the fuel gas, incomplete combustion may occur, generating toxic gases such as carbon monoxide, or the temperature of the flame may decrease, causing insufficient atomization of the sample. Therefore, a mechanism for reliably detecting incomplete combustion is required.

[0012] In addition, in a flame atomic absorption photometer, when the combustion state of the flame becomes unstable temporarily or continuously, soot is generated and the soot is accumulated on the burner head. The soot becomes a cause of deteriorating the stability of the flame, so it is necessary to remove it appropriately. However, in the past, the user confirmed the accumulation of soot by directly visually observing the burner head, so sometimes it is not necessarily possible to properly grasp the accumulation of soot.

[0013] The present invention is made in view of these aspects, and its purpose is to accurately detect abnormalities of the flame related to the stability of the combustion state in a flame atomic absorption photometer. More specifically, the first purpose is to provide a flame atomic absorption photometer that can reliably determine whether the flame continues to burn normally. In addition, the second purpose is to detect the occurrence of backfire in advance in the flame atomic absorption photometer. In addition, the third purpose is to reliably detect the occurrence of incomplete combustion in the flame atomic absorption photometer. In addition, the fourth purpose is that in the flame atomic absorption photometer, the user can reliably grasp the accumulation of soot on the burner head.

[0014] Technical means of solving problems

[0015] A flame atomic absorption spectrophotometer according to a first aspect of the present invention, which is designed to solve the above-mentioned problems, comprises:

[0016] A burner that generates flame by burning a mixture of a fuel gas and a combustion-supporting gas with an atomized sample liquid;

[0017] a flame light detection unit that detects light radiated from the flame; and

[0018] a flame extinguishing determination unit that determines that the flame has extinguished when the intensity of the light detected by the flame light detection unit is lower than a predetermined threshold value,

[0019] The flame light detection unit selectively detects light having a wavelength of 290 nm to 330 nm.

[0020] A flame atomic absorption spectrophotometer according to a second aspect of the present invention, which is designed to solve the above-mentioned problems, comprises:

[0021] A burner that generates flame by burning a mixture of a fuel gas and a combustion-supporting gas with an atomized sample liquid;

[0022] a flame light detection unit that detects light radiated from the flame and selectively detects light having a wavelength of 290 nm or more and 330 nm or less;

[0023] The swan belt light detection unit selectively detects C in the light emitted from the flame 2 The light from the swan band is detected; and

[0024] The backfire sign determination unit determines that there is a backfire sign when a ratio of the intensity of the light detected by the swan band light detection unit to the intensity of the light detected by the flame light detection unit is lower than a predetermined threshold value.

[0025] A flame atomic absorption spectrophotometer according to a third aspect of the present invention, which is designed to solve the above-mentioned problems, comprises:

[0026] A burner that generates flame by burning a mixture of a fuel gas and a combustion-supporting gas with an atomized sample liquid;

[0027] a flame light detection unit that detects light radiated from the flame and selectively detects light having a wavelength of 290 nm or more and 330 nm or less;

[0028] a flame detection unit that selectively detects light having a wavelength of 800 nm to 1100 nm, among the light emitted from the flame; and

[0029] The incomplete combustion determination unit determines that incomplete combustion has occurred when a ratio of the intensity of the light detected by the light flame detection unit to the intensity of the light detected by the flame light detection unit exceeds a predetermined threshold value.

[0030] A flame atomic absorption spectrophotometer according to a fourth aspect of the present invention, which is designed to solve the above-mentioned problems, comprises:

[0031] A burner that generates flame by burning a mixture of a fuel gas and a combustion-supporting gas with an atomized sample liquid;

[0032] a flame light detection unit that detects light radiated from the flame and selectively detects light having a wavelength of 290 nm or more and 330 nm or less;

[0033] A bandpass filter selectively transmits light having a wavelength of 800 nm or more and 1100 nm or less;

[0034] an image sensor having a plurality of light detecting elements arranged two-dimensionally, and receiving light radiated from the burner and passing through the bandpass filter;

[0035] a soot accumulation determination unit that obtains, for each of the plurality of light detection elements, a ratio of the intensity of light detected by the light detection element to the intensity of light detected by the flame light detection unit, and determines that soot is accumulated in the burner when a predetermined number or more of the plurality of light detection elements have the ratio exceeding a predetermined threshold value; and

[0036] The notification unit notifies a user of the fact when the soot accumulation determination unit determines that soot is accumulated on the burner.

[0037] Effects of the Invention

[0038] The flame atomic absorption photometer of the first form can reliably determine whether the flame continues to burn normally. The flame atomic absorption photometer of the second form can detect the occurrence of backfire in advance. The flame atomic absorption photometer of the third form can reliably detect the occurrence of incomplete combustion. The flame atomic absorption photometer of the fourth form allows the user to reliably grasp the accumulation of soot. Therefore, the flame atomic absorption photometers of the first to fourth forms can accurately detect abnormalities of the flame related to the stability of the combustion state. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] [ Figure 1 ] is a diagram showing the main structure of the flame atomic absorption photometer according to the first embodiment of the present invention.

[0040] [ Figure 2 ] is a diagram showing the main structure of a flame atomic absorption spectrophotometer according to a second embodiment of the present invention.

[0041] [ Figure 3 ] is a diagram showing the main structure of a flame atomic absorption photometer according to a third embodiment of the present invention.

[0042] [ Figure 4 ] is a diagram showing the main structure of a flame atomic absorption spectrophotometer according to a fourth embodiment of the present invention.

[0043] [ Figure 5 ] is a diagram showing the main structure of a flame atomic absorption photometer according to the fifth embodiment of the present invention. DETAILED DESCRIPTION

[0044] [Implementation Method 1]

[0045] Below, refer to Figure 1 A flame atomic absorption spectrophotometer according to a first embodiment of the present invention will be described. Figure 1 1 is a structural diagram of the main parts of the flame atomic absorption photometer of this embodiment, which includes a burner 110 , a gas supply unit 120 , a sample supply unit 130 , a light source 140 , a spectroscopic unit 150 , and a control / processing unit 160 .

[0046] The burner 110 includes an atomizer 111 for atomizing the sample liquid, a chamber 112 for mixing the atomized sample liquid with a combustion gas, and a burner head 114 for blowing the mixed gas upward and burning it to form a flame 113. In addition, an ignition unit (not shown) for igniting the gas is attached to the burner 110. A mixed gas is supplied from a gas supply unit 120 to the chamber 112 as a combustion gas, and the mixed gas is a mixed gas of acetylene as a fuel gas and air or nitrous oxide as a combustion-supporting gas.

[0047] The gas supply unit 120 includes: a fuel gas supply pipe 122, which guides the fuel gas from a fuel gas source 121 such as a gas cylinder to the burner 110; a fuel gas pipe on-off valve 123 and a fuel gas flow regulating valve 124, which are arranged on the fuel gas supply pipe 122; a combustion-supporting gas supply pipe 126, which guides the combustion-supporting gas from a combustion-supporting gas source 125 such as a gas cylinder or an air compressor to the burner 110; a combustion-supporting gas pipe on-off valve 127 and a combustion-supporting gas flow regulating valve 128, which are arranged on the combustion-supporting gas supply pipe 126; and a valve driving unit 129, which drives the valves 123, 124, 127 and 128.

[0048] The light source 140 is arranged on the side of the area for forming the flame 113 (hereinafter referred to as the flame forming area). The spectroscopic unit 150 includes a spectroscope 151 and a photodetector 152, and is arranged at a position opposite to the light source 140 across the flame forming area. Light having a bright line spectrum containing a resonance line of a target element is emitted from the light source 140, and the light passes through the atomic vapor in the flame forming area. The light after passing through the atomic vapor is spectroscopically split by the spectroscope 151, and light of a specific wavelength corresponding to the bright line (usually a resonance line) with the highest absorbance based on the target element is extracted. The light of the specific wavelength is introduced into the photodetector 152, thereby outputting a detection signal corresponding to the amount of incident light. The detection signal is amplified by an amplifier not shown in the figure, and is converted into a digital signal by an analog to digital (A / D) converter not shown in the figure and input into the control / processing unit 160. The analysis data processing unit 161 , which is a functional block provided in the control / processing unit 160 , calculates the absorbance of light with a specific wavelength based on the digital signal, and further performs a quantitative analysis by performing a predetermined calculation process.

[0049] The control / processing unit 160 is constructed with a computer including a central processing unit (CPU) and a memory as the center, performs various calculations, and outputs control signals for the operation control of each unit. In addition to the analysis data processing unit 161, the control / processing unit 160 also includes a midway extinction determination unit 162, a gas supply control unit 163, and a display control unit 164 as functional blocks. In addition, an operation unit 171 such as a keyboard and a display unit 172 such as a liquid crystal display are connected to the control / processing unit 160, and instructions from the user are input to the control / processing unit 160 via the operation unit 171, and analysis results are displayed on the display unit 172.

[0050] Furthermore, an OH source light detection photosensor 182 is disposed near the flame formation area. The OH source light detection photosensor 182 is a photosensor for detecting light originating from OH radicals (hereinafter referred to as OH) in the flame 113. Between the OH source light detection photosensor 182 and the flame formation area, an OH source light transmission bandpass filter 181 is disposed as a bandpass filter that selectively transmits light having a wavelength of around 310 nm (these OH source light transmission bandpass filters 181 and OH source light detection photosensor 182 are equivalent to the flame light detection unit in the present invention). Here, the so-called around 310 nm refers to, for example, a range of 290 nm to 330 nm, and ideally 300 nm to 320 nm. The OH source light detection photosensor 182 is ideally configured to receive light from the entire flame 113, but may also be configured to receive light from only a portion of the flame 113. In addition, in Figure 1 In the figure, for the convenience of drawing, the OH source light detection optical sensor 182 is arranged obliquely above the flame 113, but the position of the OH source light detection optical sensor 182 is not limited to this (hereinafter, the same applies to Embodiments 2 to 5). As the OH source light detection optical sensor 182, for example, a phototransistor can be preferably used, but it is not limited to this, and any device such as a photodiode, a phototube, or a photomultiplier tube can also be used.

[0051] The combustion flame of hydrocarbons such as acetylene contains a light emission spectrum derived from OH. The light emission spectrum derived from OH exists in multiple regions in the ultraviolet region, but the 310 nm band ( The intensity of the band spectrum of the system is strong, the transmittance of the optical element is also high, and the detection sensitivity based on the general light sensor is also high. On the other hand, the ambient light such as sunlight, incandescent lamps, fluorescent lamps or white light emitting diodes (LEDs) that become external interference light has low intensity in the 310nm band. Therefore, according to the flame atomic absorption photometer of this embodiment, by providing an OH source light transmission bandpass filter 181 that selectively allows light with a wavelength of around 310nm as described above to pass before the OH source light detection light sensor 182, the OH source light detection light sensor 182 can be prevented from being affected by external interference light.

[0052] The light emitted from the flame 113 and passed through the OH source light transmission bandpass filter 181 is incident on the OH source light detection optical sensor 182, and the OH source light detection optical sensor 182 outputs a detection signal corresponding to the amount of the incident light. The detection signal is amplified by an amplifier (not shown), converted into a digital signal by an A / D converter (not shown), and then input to the midway extinguishing determination unit 162. The midway extinguishing determination unit 162 compares the intensity of the digital signal with a predetermined threshold value T 1 When the digital signal is below the threshold value T 1 In the case of , it is determined that the flame 113 is extinguished midway. 1 The setting may be performed before the device is delivered to the user or during the installation of the device, or may be performed by the user.

[0053] When the midway extinction determination unit 162 determines that the flame 113 is midway extinct, the gas supply control unit 163 controls the valve drive unit 129 to close the fuel gas pipe on-off valve 123 and the combustion-supporting gas pipe on-off valve 127 .

[0054] After the fuel gas pipe on-off valve 123 and the combustion-supporting gas pipe on-off valve 127 are closed, the display control unit 164 controls the display unit 172 to display a specified message on its screen, thereby notifying the user that the gas supply has been stopped due to the occurrence of midway extinction. In addition, it is also possible to display a message on the screen of the display unit 172 to notify the user that the flame 113 has been extinguished before or while the fuel gas pipe on-off valve 123 and the combustion-supporting gas pipe on-off valve 127 are closed. Alternatively, it is also possible to not perform such notification and only close the fuel gas pipe on-off valve 123 and the combustion-supporting gas pipe on-off valve 127. In addition, it is also possible to configure a structure in which the fuel gas pipe on-off valve 123 and the combustion-supporting gas pipe on-off valve 127 are not closed and only a notification that the flame 113 has been extinguished midway is performed.

[0055] [Implementation Method 2]

[0056] Then, refer to Figure 2 A flame atomic absorption photometer according to a second embodiment of the present invention will be described. Figure 2 FIG. 1 is a structural diagram of the main parts of the flame atomic absorption photometer of this embodiment. Figure 1 The same or corresponding components as those shown in FIG. 1 are denoted by reference numerals having the same last two digits, and the description thereof is omitted as appropriate.

[0057] The flame atomic absorption photometer of this embodiment includes the same structure as the flame atomic absorption photometer of the first embodiment, and further includes: 2 Source light transmission with bandpass filter 283 and C 2 The light sensor 284 for detecting the source light is arranged near the flame forming area; and the backfire sign determination unit 265 is a functional block arranged in the control / processing unit 260. 2 Source light transmission with bandpass filter 283 and C 2 The source light detection optical sensor 284 corresponds to the swan band light detection unit in the present invention. In addition, in the present embodiment, the gas supply control unit 263 corresponds to the backfire avoidance unit in the present invention.

[0058] Generally, in the burner 210 of the flame atomic absorption photometer, the ratio of the combustion-supporting gas flow rate to the fuel gas flow rate (i.e., the air-fuel ratio) is set to be significantly smaller than the theoretical air-fuel ratio (the air-fuel ratio at which the combustion-supporting gas in the combustion gas reacts moderately with the fuel gas and the combustion speed becomes the highest). However, when the air-fuel ratio approaches the theoretical air-fuel ratio for some reason, the combustion reaction is promoted, the region of the outer flame portion where the emission spectrum of OH origin is prominent in the flame 213 is expanded, and the C-containing gas in the transition process of the reaction is increased. 2The area of ​​the inner flame portion of the luminescence spectrum of the (diatomic carbon) source is reduced. In this state, if the air-fuel ratio is further increased and the combustion speed becomes excessive relative to the supply speed of the combustion gas, the flame 213 cannot continue to form outside the burner 210, but invades the inside of the burner 210, resulting in unstable combustion, i.e., backfire. In order to prevent the occurrence of such backfire in advance, the flame atomic absorption photometer of this embodiment has the following functions: respectively detecting the light from the outer flame portion and the light from the inner flame portion, and detecting the backfire sign based on the intensity ratio of the two.

[0059] As the C 2 The luminescence spectrum of the source is known to be C 2 Swan Series (C 2 Swan System) band spectrum. 2 The source light is transmitted by a bandpass filter 283 to selectively allow the C 2 The light transmission of the swan series in the wavelength band of the spectrum. 2 The swan series has multiple spectral bands in the visible light region, and the emission near 517nm is particularly prominent. 2 The source light transmission bandpass filter 283 is preferably configured to selectively transmit light with a wavelength of 507 nm to 527 nm (ideally 512 nm to 522 nm). 2 The transmission wavelength range of the source light transmission bandpass filter 283 is not limited to this, and may be set to selectively use C 2 The Swan series contains other spectral wavelength ranges, namely, light transmission in the range of 464nm to 484nm (ideally 469nm to 479nm) or 554nm to 574nm (ideally 559nm to 569nm). 2 The light sensor 284 for detecting the source light is used to detect the light emitted from the flame 213 and passing through C 2 The source light is transmitted through the light sensor using the bandpass filter 283. As C 2 The light sensor 284 for detecting the source light can preferably use a phototransistor, but is not limited thereto, and any device such as a photodiode, a phototube, or a photomultiplier tube can also be used. 2 The light sensor 284 for detecting the source light can be set to receive light from the entire flame 213, but it is most effective to receive light from C 2 The light of only the lower area of ​​the flame 213 is locally present. Figure 2 In order to facilitate drawing, C 2 The light sensor 284 for detecting the source light is arranged obliquely above the flame 213, but the C 2 The position of the source light detecting optical sensor 284 is not limited thereto.

[0060] Emitted from flame 213 and passed through C 2 The source light is incident on C through the bandpass filter 283. 2 Source light detection using light sensor 284, from C 2 The light sensor 284 for detecting the source light outputs a detection signal corresponding to the incident light amount. The detection signal is amplified by an amplifier (not shown), converted into a digital signal by an A / D converter (not shown), and then input into the backfire sign determination unit 265 (hereinafter referred to as "C 2 On the other hand, the detection signal from the OH source light detection optical sensor 282 is amplified and digitally converted in the same manner as in Embodiment 1, and then input to the control / processing unit 260 (hereinafter referred to as the "OH source light detection signal"). The OH source light detection signal is input to the midway extinction determination unit 262 in the same manner as in Embodiment 1 to determine whether the flame 213 is midway extinguished, and is also input to the backfire sign determination unit 265. The backfire sign determination unit 265 converts C 2 The intensity of the source light detection signal is divided by the intensity of the OH source light detection signal (i.e., to find C 2 The ratio of the source light detection signal to the OH source light detection signal) and compares its value with a predetermined threshold value T 2 And, in C 2 The value obtained by dividing the intensity of the source light detection signal by the intensity of the OH source light detection signal is lower than the threshold value T 2 In the case of , it is determined that there is a backfire sign. In addition, the threshold T 2 The setting may be made before the device is delivered to the user or during the installation of the device, or may be made by the user. 2 The ratio of the source light detection signal to the OH source light detection signal is used to determine whether there is a backfire sign, which can eliminate the C caused by the shaking of the flame 213. 2 The intensity of the source light changes, allowing for accurate judgment.

[0061] When the backfire sign determination unit 265 determines that there is a backfire sign, the gas supply control unit 263 controls the valve drive unit 229 to reduce the air-fuel ratio of the combustion gas supplied to the burner 210. Specifically, the opening of the fuel gas flow control valve 224 is gradually increased, or the opening of the combustion-supporting gas flow control valve 228 is gradually decreased, or both are performed until the backfire sign determination unit 265 determines that the backfire sign disappears (that is, until it is determined that C 2 The ratio of the source light detection signal to the OH source light detection signal becomes the threshold value T 2So far).

[0062] After adjusting the opening of the fuel gas flow control valve 224 and / or the opening of the combustion-supporting gas flow control valve 228 (hereinafter referred to as gas flow adjustment), the display control unit 264 controls the display unit 272 to display a specified message on its screen, thereby notifying the user that the gas flow has been adjusted due to a sign of backfire. In addition, it is also possible to display a message notifying the existence of a sign of backfire on the screen of the display unit 272 while or before adjusting the gas flow. Alternatively, it is also possible to not make such a notification and only adjust the gas flow. In addition, it is also possible to have a structure in which the gas flow is not adjusted and only a notification to the effect that a sign of backfire exists is made.

[0063] Alternatively, when the backfire sign determination unit 265 determines that there is a backfire sign, a mechanism for reducing the combustion speed of the flame 213 by reintroducing the exhaust gas from the burner 210 into the burner 210 may be provided in addition to or instead of the above-mentioned adjustment of the gas flow rate. A flame atomic absorption photometer (a flame atomic absorption photometer according to a third embodiment of the present invention) including such a mechanism will be described below.

[0064] [Implementation method 3]

[0065] Figure 3 3 is a diagram showing the main structure of a flame atomic absorption photometer according to a third embodiment of the present invention. In this embodiment, components identical to or corresponding to those shown in Embodiment 1 or Embodiment 2 are denoted by the same reference numerals with the same last two digits, and description thereof is omitted as appropriate.

[0066] The flame atomic absorption photometer of this embodiment includes, in addition to the same structure as the flame atomic absorption photometer of the second embodiment, an exhaust gas re-introduction pipe 315 for returning a portion of the exhaust gas generated from the burner 310 to the burner 310; an on-off valve (hereinafter referred to as the exhaust gas on-off valve 316) and a flow rate regulating valve (hereinafter referred to as the exhaust gas flow rate regulating valve 317) provided on the exhaust gas re-introduction pipe 315; an exhaust gas valve driving unit 318 for driving the valves 316 and 317; and an exhaust gas re-introduction control unit 366, which is a functional block provided in the control / processing unit 360 and controls the exhaust gas valve driving unit 318. The exhaust gas re-introduction pipe 315, the exhaust gas on-off valve 316, the exhaust gas flow rate regulating valve 317, the exhaust gas valve driving unit 318 and the exhaust gas re-introduction control unit 366 are equivalent to the exhaust gas introduction unit in the present invention. The exhaust gas reintroduction pipe 315 is a pipe branched from an exhaust pipe 391 for discharging exhaust gas from a burner chamber 390 containing the burner 310 to the outside, and its front end is connected to the chamber 312 of the burner 310. In addition, the burner chamber 390 and the exhaust pipe 391 are also provided in the flame atomic absorption photometer of Embodiment 1 and Embodiment 2, but for the sake of simplicity, they are omitted from the illustration in these embodiments (the same is true in Embodiment 4 and Embodiment 5 described later).

[0067] In the flame atomic absorption photometer of the present embodiment, when the backfire sign determination unit 365 determines that there is a backfire sign, the exhaust gas re-introduction control unit 366 controls the exhaust valve drive unit 318 to recirculate the exhaust gas generated in the burner 310 to the chamber 312 of the burner 310. Specifically, at the time point when it is determined that there is a backfire sign, the exhaust on-off valve 316 is first opened, and then the opening of the exhaust flow rate regulating valve 317 is gradually increased until it is determined in the backfire sign determination unit 365 that the backfire sign disappears. In this way, the combustion speed of the flame 313 can be suppressed to avoid the occurrence of backfire.

[0068] In addition, in the flame atomic absorption photometer of the present embodiment, when the backfire sign determination unit 365 determines that there is a backfire sign, the flow rate of the combustion-supporting gas and / or the fuel gas can be adjusted in the same manner as in Embodiment 2 on the basis of the exhaust gas recirculation as described above. The method for determining the backfire sign and the method for adjusting the flow rate of the combustion-supporting gas and / or the fuel gas in the present embodiment are the same as those in Embodiment 2, and therefore, description thereof is omitted here.

[0069] [Implementation Method 4]

[0070] Next, refer to Figure 4 A flame atomic absorption spectrophotometer according to a fourth embodiment of the present invention will be described. Figure 42 is a block diagram of the main part of the flame atomic absorption photometer of this embodiment. In this embodiment, components identical to or corresponding to those shown in Embodiment 1 are denoted by the same reference numerals with the same last two digits, and description thereof is omitted as appropriate.

[0071] The flame atomic absorption photometer of this embodiment includes the same structure as the flame atomic absorption photometer of the first embodiment, and further includes: a bandpass filter 485 for light flame transmission and a light sensor 486 for light flame light detection, which are arranged near the flame formation area; and an incomplete combustion determination unit 467, which is a functional block arranged in the control / processing unit 460. Among them, the bandpass filter 485 for light flame transmission and the light sensor 486 for light flame light detection are equivalent to the light flame detection unit in the present invention. In addition, in this embodiment, the gas supply control unit 463 is equivalent to the incomplete combustion elimination unit in the present invention.

[0072] The flame light transmission bandpass filter 485 is a bandpass filter that selectively transmits the light (flame) emitted from the soot (coal ash) in the flame 413, and specifically, selectively transmits the entire or a portion of the wavelength range of 800nm ​​to 1100nm. The flame light detection optical sensor 486 is a sensor that detects the light that is emitted from the flame 413 and passes through the flame light transmission bandpass filter 485. As the flame light detection optical sensor 486, a phototransistor can be preferably used, but it is not limited to this, and any device such as a photodiode, a phototube or a photomultiplier tube can also be used. In addition, the flame light detection optical sensor 486 is ideally configured to receive light from the entire flame 413, but it can also be configured to receive light from only a portion of the flame 413. In addition, in Figure 4 In the figure, for the convenience of drawing, the flame light detecting optical sensor 486 is arranged obliquely above the flame 413, but the position of the flame light detecting optical sensor 486 is not limited to this.

[0073] In the burner 410, if the air-fuel ratio becomes too small, incomplete combustion will occur and soot will be generated in the flame 413. The light emitted from the soot heated to a high temperature, that is, the light flame, is a high-brightness, thermally balanced continuous spectrum. The continuous spectrum generated by the soot at the temperature of the flame 413 (~3000K) has almost no energy in the 310nm band of the OH luminescence. Therefore, the OH source light detection light sensor 482 with the OH source light transmission bandpass filter 481 that selectively transmits the 310nm band can monitor whether the flame 413 continues to burn without being affected by the light flame.

[0074] The light radiated from the flame 413 and passed through the light flame light transmission bandpass filter 485 is incident on the light flame light detection optical sensor 486, and the light flame light detection optical sensor 486 outputs a detection signal corresponding to the incident light amount. The detection signal is amplified by an amplifier (not shown), and converted into a digital signal by an A / D converter (not shown) and then input into the incomplete combustion determination unit 467 (hereinafter referred to as the "light flame detection signal"). On the other hand, the detection signal from the OH source light detection optical sensor 482 is amplified and digitally converted in the same manner as in Embodiment 1, and then input into the control / processing unit 460 (hereinafter referred to as the "OH source light detection signal"). The OH source light detection signal is input into the midway extinction determination unit 462 in the same manner as in Embodiment 1 to determine whether the flame 413 is extinguished midway, and is also input into the incomplete combustion determination unit 467. The incomplete combustion determination unit 467 divides the intensity of the flame detection signal by the intensity of the OH source light detection signal (i.e., finds the ratio of the flame detection signal to the OH source light detection signal), and compares the value with a predetermined threshold value T 4 And, when the value obtained by dividing the intensity of the flame detection signal by the intensity of the OH source light detection signal exceeds the threshold value T 4 In the case of , it is determined that incomplete combustion has occurred in the burner 410. In addition, the threshold T 4 The setting can be made before the device is delivered to the user or during the installation of the device, or can be made by the user. In this way, by determining whether incomplete combustion has occurred based on the ratio of the light flame detection signal to the OH source light detection signal, the intensity change of the light flame light caused by the shaking of the flame 413 can be eliminated, thereby making an accurate determination.

[0075] When the incomplete combustion determination unit 467 determines that incomplete combustion has occurred, the gas supply control unit 463 controls the valve drive unit 429 to increase the air-fuel ratio of the combustion gas supplied to the burner 410. Specifically, the opening of the fuel gas flow control valve 424 is gradually reduced, or the opening of the combustion-supporting gas flow control valve 428 is gradually increased, or both are performed until the incomplete combustion determination unit 467 determines that incomplete combustion has not occurred (that is, until it is determined that the ratio of the light flame detection signal to the OH source light detection signal becomes less than the threshold value).

[0076] After the fuel gas flow control valve 424 and / or the combustion-supporting gas flow control valve 428 are adjusted (hereinafter referred to as the adjustment of the gas flow), the display control unit 464 controls the display unit 472 to display a specified message on its screen, thereby notifying the user that the gas flow has been adjusted due to incomplete combustion. In addition, it is also possible to display a message on the screen of the display unit 472 to notify the user that incomplete combustion has occurred while or before the gas flow is adjusted. Alternatively, it is also possible to not make such a notification and only adjust the gas flow. In addition, it is also possible to have a structure in which the gas flow is not adjusted and only a notification that incomplete combustion has occurred is made.

[0077] [Implementation method 5]

[0078] Then, refer to Figure 5 A flame atomic absorption photometer according to a fifth embodiment of the present invention will be described. Figure 5 2 is a block diagram of the main part of the flame atomic absorption photometer of this embodiment. In this embodiment, components identical to or corresponding to those shown in Embodiment 1 are denoted by the same reference numerals with the same last two digits, and description thereof is omitted as appropriate.

[0079] In addition to including the same structure as the flame atomic absorption photometer of the first embodiment, the flame atomic absorption photometer of this embodiment also includes: a burner head photographing unit 588, which photographs the burner head 514; a bandpass filter 587 for flame light transmission, which is arranged between the burner head photographing unit 588 and the burner head 514; and an ash accumulation determination unit 568, which is a functional block provided in the control / processing unit 560.

[0080] When the combustion state of the flame 513 in the burner 510 becomes unstable temporarily or continuously, soot is generated and the soot is accumulated in the burner head 514. The soot accumulated in the burner head 514 becomes a cause of damage to the stability of the flame, so it is necessary to remove it appropriately. The flame atomic absorption photometer of this embodiment has a function of monitoring the accumulation of soot in the burner head 514.

[0081] The burner head imaging unit 588 is an image sensor including a plurality of light detecting elements arranged in a two-dimensional matrix. The burner head imaging unit 588 is preferably configured to capture the entire burner head 514, but is not limited thereto and may be configured to capture only the peripheral portion of the slit opening where soot is easily accumulated. Figure 5In order to facilitate drawing, the burner head photographing unit 588 is arranged obliquely above the flame 513, but the position of the burner head photographing unit 588 is not limited to this. The light flame light transmission bandpass filter 587 is a bandpass filter that selectively transmits light (light flame) emitted from the soot heated to a high temperature, and selectively transmits light in the same wavelength region as the light flame light transmission bandpass filter 485 in the fourth embodiment.

[0082] In the flame atomic absorption photometer of the present embodiment, the detection signals from the light detection elements of the burner head imaging unit 588 are amplified by amplifiers (not shown), converted into digital signals by A / D converters (not shown), and then input into the soot accumulation determination unit 568 of the control / processing unit 560. On the other hand, the detection signal from the OH source light detection optical sensor 582 is amplified and digitally converted in the same manner as in the first embodiment, and then input into the control / processing unit 560 (hereinafter, the signal is referred to as "OH source light detection signal"). The OH source light detection signal is input into the midway extinction determination unit 562 in the same manner as in the first embodiment to determine whether the flame 513 is midway extinct, and is also input into the soot accumulation determination unit 568. The soot accumulation determination unit 568 divides the intensity of the detection signal from each light detection element by the intensity of the OH source light detection signal (i.e., finds the ratio of the detection signal from each light detection element to the intensity of the OH source light detection signal), and compares the value with a predetermined threshold value T. 5 In addition, the threshold T 5 The prescribed number N may be set before the device is delivered to the user or during the installation of the device, or may be set by the user. Furthermore, when the value obtained by dividing the intensity of the detection signal of the plurality of light detection elements provided in the burner head photographing unit 588 by the intensity of the OH source light detection signal exceeds the threshold value and the number of light detection elements is greater than the prescribed number N (N is an integer greater than 1), the soot accumulation determination unit 568 determines that soot is accumulated on the burner head 514. In this way, by determining the accumulation of soot based on the ratio of the intensity of the detection signal from each light detection element to the intensity of the OH source light detection signal, the intensity change of the flame light caused by the shaking of the flame 513 can be eliminated, thereby making an accurate determination.

[0083] When the soot accumulation determination unit 568 determines that soot is accumulated on the burner head 514, the display control unit 564 controls the display unit 572 to display a specified message on its screen, thereby notifying the user of the fact that soot is accumulated on the burner head 514. The display control unit 564 and the display unit 572 are equivalent to the notification unit in the present invention. In addition, it is also possible to display an image showing the area where soot is accumulated on the burner head 514 on the screen of the display unit 572 in addition to or instead of the message. In this case, the soot accumulation determination unit 568 determines that the value obtained by dividing the detection signal by the OH source light detection signal among the plurality of light detection elements exceeds the threshold value T 5 The burner head 514 is provided with one or more light detecting elements, and the radiation position of the light flame on the burner head 514 (i.e., the position where the soot is accumulated) is determined based on the position of the light detecting element on the burner head photographing unit 588. Then, under the control of the display control unit 564, the image of the burner head (or an illustration representing the burner head) captured in advance is displayed on the screen of the display unit 572, and a specific color is added to the area corresponding to the accumulation position of the soot on the image, or a prescribed graphic (for example, a line surrounding the area, etc.) is added, thereby displaying the accumulation area of ​​the soot on the burner head 514. In addition, in this case, the soot accumulation determination unit 568, the display control unit 564 and the display unit 572 are equivalent to the soot accumulation area prompting unit in the present invention.

[0084] As mentioned above, although the form for implementing this invention was demonstrated using a specific example, this invention is not limited to the said embodiment, It allows suitable change within the range of the meaning of this invention.

[0085] For example, the flame atomic absorption spectrophotometer of embodiments 1 to 5 is configured to, after the flame 113 is ignited, always monitor whether any abnormality related to the stability of the combustion state, such as the flame 113 being extinguished midway, signs of backfire, incomplete combustion, or accumulation of soot, occurs, and notify the user at the time when it is determined that an abnormality occurs. However, instead of this, it may be configured to determine whether the abnormality has not occurred at a time indicated by the user or a pre-set time, and notify the user of the determination result regardless of the result.

[0086] In the first to fourth embodiments, bandpass filters (i.e., OH source light transmission bandpass filter 181, OH source light transmission bandpass filter 281, OH source light transmission bandpass filter 381, OH source light transmission bandpass filter 481, C 2 Bandpass filter 283, C for source light transmission 2The light source light transmission bandpass filter 383, or the light flame light transmission bandpass filter 485) and the light sensor that detects the light that has passed through the bandpass filter (i.e., the OH source light detection light sensor 182, the OH source light detection light sensor 282, the OH source light detection light sensor 382, ​​the OH source light detection light sensor 482, and the C 2 Source light detection optical sensor 284, C 2 The structure has a light sensor 384 for detecting source light, or a light sensor 486 for detecting flame light), but it can also be set up without setting these bandpass filters and light sensors, and instead the spectrometer 151, spectrometer 251, spectrometer 351, spectrometer 451 and light detector 152, light detector 252, light detector 352, light detector 452 set in the spectrometer unit 150, spectrometer unit 250, spectrometer unit 350, spectrometer unit 450 have the functions of these bandpass filters and light sensors. In this case, the spectrometer 151, the spectrometer 251, the spectrometer 351, and the spectrometer 451 are used to select the same wavelength as the wavelength transmitted through the OH source light transmission band pass filter 181, the OH source light transmission band pass filter 281, the OH source light transmission band pass filter 381, and the OH source light transmission band pass filter 481 from the light incident on the spectrometer unit 150, the spectrometer unit 250, the spectrometer unit 350, and the spectrometer unit 450, and guide the selected wavelength to the photodetector 152 and the photodetector 2 52, photodetector 352, photodetector 452, the detection signal (OH source light detection signal) of the photodetector 152, photodetector 252, photodetector 352, photodetector 452 at this time is input to the midway extinction determination unit 162, midway extinction determination unit 262, midway extinction determination unit 362, midway extinction determination unit 462, thereby determining whether the combustion of the flame 113, flame 213, flame 313, flame 413 is maintained (that is, whether the midway extinction has not occurred). In addition, the spectrometer 251, spectrometer 351 is used to select the light that is incident on the spectrometer unit 250, spectrometer unit 350 and transmits the C 2 Bandpass filter 283, C for source light transmission 2 The source light is transmitted through the bandpass filter 383 with the same wavelength as the wavelength and is guided to the photodetector 252 and the photodetector 352. The detection signals (C 2The light source light detection signal (light source light detection signal) and the OH source light detection signal are input to the backfire sign determination unit 265 and the backfire sign determination unit 365, thereby determining whether there is no backfire sign. Alternatively, the spectrometer 451 is used to select the same wavelength as the wavelength transmitted by the light flame light transmission bandpass filter 485 from the light incident on the spectroscopic unit 450, and guide it to the light detector 452, and the detection signal (light flame detection signal) of the light detector 452 and the OH source light detection signal are input to the incomplete combustion determination unit 467, thereby determining whether incomplete combustion has not occurred. In addition, in these cases, it is set that the light detection for determining the presence or absence of abnormality and the light detection for sample analysis as described above are performed at different times. Specifically, for example, after igniting flame 113, flame 213, flame 313, flame 413, when no sample is supplied from sample supply section 130, sample supply section 230, sample supply section 330, sample supply section 430 to burner 110, burner 210, burner 310, burner 410, a determination is made as to whether flame 113, flame 213, flame 313, flame 413 is extinguished midway. If it is determined that no extinguishing midway has occurred (i.e., combustion of flame 113, flame 213, flame 313, flame 413 is maintained), a determination is then made as to whether there are signs of backfire or whether incomplete combustion has occurred, or both. When all determination results indicate that no abnormality has occurred, samples are supplied from sample supply sections 130 , 230 , 330 , and 430 to burners 110 , 210 , 310 , and 410 , and the samples are analyzed.

[0087] In addition, the flame atomic absorption photometer of embodiments 2 to 5 may also be configured to not include the midway extinction determination unit 162, the midway extinction determination unit 262, the midway extinction determination unit 362, and the midway extinction determination unit 462, and the OH source light detection signal is only used to determine whether there are signs of backfire, incomplete combustion, or ash accumulation.

[0088] Furthermore, the flame atomic absorption photometer of the present invention may be provided with two or more of a function of determining whether there is a backfire sign, a function of determining whether incomplete combustion has occurred, and a function of determining whether soot has accumulated.

[0089] [form]

[0090] It is obvious to those skilled in the art that the exemplary embodiments described above are specific examples of the following aspects.

[0091] (Item 1) The flame atomic absorption spectrophotometer of Item 1 has:

[0092] A burner that generates flame by burning a mixture of a fuel gas and a combustion-supporting gas with an atomized sample liquid;

[0093] a flame light detection unit that detects light radiated from the flame; and

[0094] a flame extinguishing determination unit that determines that the flame has extinguished when the intensity of the light detected by the flame light detection unit is lower than a predetermined threshold value,

[0095] The flame light detection unit selectively detects light having a wavelength of 290 nm to 330 nm.

[0096] The flame atomic absorption photometer of the first item can reliably determine whether the flame continues to burn normally without being affected by external interference light.

[0097] (Item 2) The flame atomic absorption spectrophotometer of Item 2 has:

[0098] A burner that generates flame by burning a mixture of a fuel gas and a combustion-supporting gas with an atomized sample liquid;

[0099] a flame light detection unit that detects light radiated from the flame and selectively detects light having a wavelength of 290 nm or more and 330 nm or less;

[0100] The swan belt light detection unit selectively detects C in the light emitted from the flame 2 The light from the swan band is detected; and

[0101] The backfire sign determination unit determines that there is a backfire sign when a ratio of the intensity of the light detected by the swan band light detection unit to the intensity of the light detected by the flame light detection unit is lower than a predetermined threshold value.

[0102] The flame atomic absorption photometer of the second item can detect the occurrence of backfire in advance.

[0103] (Item 3) The flame atomic absorption photometer of Item 3 further comprises:

[0104] a gas supply unit for supplying the fuel gas and the combustion-supporting gas to the burner; and

[0105] The backfire avoidance unit controls the gas supply unit so as to reduce a ratio of a flow rate of the combustion-supporting gas to a flow rate of the fuel gas when the backfire sign determination unit determines that there is a backfire sign.

[0106] (Item 4) The flame atomic absorption photometer of Item 4 further comprises the following in the flame atomic absorption photometer of Item 2 or Item 3:

[0107] The exhaust gas introduction unit introduces a part of the exhaust gas generated from the burner into the burner when the backfire sign determination unit determines that there is a backfire sign.

[0108] The occurrence of backfire can be automatically avoided by using the flame atomic absorption photometer of the third or fourth item.

[0109] (Item 5) The flame atomic absorption spectrophotometer of Item 5 has:

[0110] A burner that generates flame by burning a mixture of a fuel gas and a combustion-supporting gas with an atomized sample liquid;

[0111] a flame light detection unit that detects light radiated from the flame and selectively detects light having a wavelength of 290 nm or more and 330 nm or less;

[0112] a flame detection unit that selectively detects light having a wavelength of 800 nm to 1100 nm, among the light emitted from the flame; and

[0113] The incomplete combustion determination unit determines that incomplete combustion has occurred when a ratio of the intensity of the light detected by the light flame detection unit to the intensity of the light detected by the flame light detection unit exceeds a predetermined threshold value.

[0114] The occurrence of incomplete combustion can be reliably detected by the flame atomic absorption photometer of item 5.

[0115] (Item 6) The flame atomic absorption photometer of Item 6 further comprises:

[0116] a gas supply unit for supplying the fuel gas and the combustion-supporting gas to the burner; and

[0117] The incomplete combustion elimination unit controls the gas supply unit to increase the ratio of the flow rate of the combustion-supporting gas to the flow rate of the fuel gas when the incomplete combustion determination unit determines that incomplete combustion has occurred.

[0118] Incomplete combustion can be automatically eliminated by the flame atomic absorption photometer of item 6.

[0119] (Item 7) The flame atomic absorption spectrophotometer of Item 7 has:

[0120] A burner that generates flame by burning a mixture of a fuel gas and a combustion-supporting gas with an atomized sample liquid;

[0121] a flame light detection unit that detects light radiated from the flame and selectively detects light having a wavelength of 290 nm or more and 330 nm or less;

[0122] A bandpass filter selectively transmits light having a wavelength of 800 nm or more and 1100 nm or less;

[0123] an image sensor having a plurality of light detecting elements arranged two-dimensionally, and receiving light radiated from the burner and passing through the bandpass filter;

[0124] a soot accumulation determination unit that obtains, for each of the plurality of light detection elements, a ratio of the intensity of light detected by the light detection element to the intensity of light detected by the flame light detection unit, and determines that soot is accumulated in the burner when a predetermined number or more of the plurality of light detection elements have the ratio exceeding a predetermined threshold value; and

[0125] The notification unit notifies a user of the fact when the soot accumulation determination unit determines that soot is accumulated on the burner.

[0126] Through the flame atomic absorption photometer of item 7, users can accurately grasp the accumulation status of soot in the burner.

[0127] (Item 8) The flame atomic absorption photometer of Item 8 further comprises in the flame atomic absorption photometer of Item 7:

[0128] The soot accumulation region presenting unit presents to a user a region on the burner corresponding to a light detecting element among the plurality of light detecting elements for which the ratio exceeds a predetermined threshold value as a region where soot is accumulated.

[0129] By using the flame atomic absorption photometer of the eighth item, the user can easily grasp the area on the burner where soot is accumulated.

[0130] Explanation of symbols

[0131] 110: Burner

[0132] 120: Gas supply unit

[0133] 130: Sample supply unit

[0134] 140: Light source

[0135] 150: Spectroscopic unit

[0136] 151: Spectrum Splitter

[0137] 152: Photodetector

[0138] 160: Control / Processing Department

[0139] 162: Midway Extinction Judgment Unit

[0140] 163: Gas supply control unit

[0141] 164: Display control unit

[0142] 172: Display unit

[0143] 181: Bandpass filter for OH source light transmission

[0144] 182: Optical sensor for OH source light detection

Claims

1. A flame atomic absorption photometer having: A burner that generates flame by burning a mixture of a fuel gas and a combustion-supporting gas with an atomized sample liquid; a flame light detection unit that detects light radiated from the flame; and a flame extinguishing determination unit that determines that the flame has extinguished when the intensity of the light detected by the flame light detection unit is lower than a predetermined threshold value, The flame light detection unit selectively detects light having a wavelength of 290 nm to 330 nm.

2. A flame atomic absorption photometer having: A burner that generates flame by burning a mixture of a fuel gas and a combustion-supporting gas with an atomized sample liquid; a flame light detection unit that detects light radiated from the flame and selectively detects light having a wavelength of 290 nm or more and 330 nm or less; a swan band light detection unit that selectively detects light of a C2 swan band among the light emitted from the flame; and The backfire sign determination unit determines that there is a backfire sign when a ratio of the intensity of the light detected by the swan band light detection unit to the intensity of the light detected by the flame light detection unit is lower than a predetermined threshold value.

3. The flame atomic absorption photometer according to claim 2, further comprising: a gas supply unit for supplying the fuel gas and the combustion-supporting gas to the burner; and The backfire avoidance unit controls the gas supply unit so as to reduce the ratio of the flow rate of the combustion-supporting gas to the flow rate of the fuel gas when the backfire sign determination unit determines that there is a backfire sign.

4. The flame atomic absorption photometer according to claim 2, further comprising: The exhaust gas introduction unit introduces a part of the exhaust gas generated from the burner into the burner when the backfire sign determination unit determines that there is a backfire sign.

5. A flame atomic absorption photometer having: A burner that generates flame by burning a mixture of a fuel gas and a combustion-supporting gas with an atomized sample liquid; a flame light detection unit that detects light radiated from the flame and selectively detects light having a wavelength of 290 nm or more and 330 nm or less; a flame detection unit that selectively detects light having a wavelength of 800 nm to 1100 nm, among the light emitted from the flame; and The incomplete combustion determination unit determines that incomplete combustion has occurred when a ratio of the intensity of the light detected by the light flame detection unit to the intensity of the light detected by the flame light detection unit exceeds a predetermined threshold value.

6. The flame atomic absorption photometer according to claim 5, further comprising: a gas supply unit for supplying the fuel gas and the combustion-supporting gas to the burner; and The incomplete combustion elimination unit controls the gas supply unit to increase the ratio of the flow rate of the combustion-supporting gas to the flow rate of the fuel gas when the incomplete combustion determination unit determines that incomplete combustion has occurred.

7. A flame atomic absorption photometer having: A burner that generates flame by burning a mixture of a fuel gas and a combustion-supporting gas with an atomized sample liquid; a flame light detection unit that detects light radiated from the flame and selectively detects light having a wavelength of 290 nm or more and 330 nm or less; A bandpass filter selectively transmits light having a wavelength of 800 nm or more and 1100 nm or less; an image sensor having a plurality of light detecting elements arranged two-dimensionally, and receiving light radiated from the burner and passing through the bandpass filter; a soot accumulation determination unit that obtains, for each of the plurality of light detection elements, a ratio of the intensity of light detected by the light detection element to the intensity of light detected by the flame light detection unit, and determines that soot is accumulated in the burner when a predetermined number or more of the plurality of light detection elements have the ratio exceeding a predetermined threshold value; as well as The notification unit notifies a user of the fact when the soot accumulation determination unit determines that soot is accumulated on the burner.

8. The flame atomic absorption spectrophotometer according to claim 7, further comprising: The soot accumulation region presenting unit presents to a user a region on the burner corresponding to a light detecting element among the plurality of light detecting elements for which the ratio exceeds a predetermined threshold value as a region where soot is accumulated.

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