JP3201420U - Flame atomic absorption photometer - Google Patents

Abstract

A flame atomic absorption photometer capable of reliably detecting the disappearance of a flame is provided. A sample mixing unit 16 for adjusting a mixed sample by atomizing and introducing a measurement sample into supplied fuel gas and auxiliary combustion gas, and igniting the fuel gas and auxiliary combustion gas in the mixed sample to form a flame. A combustion unit 2 that performs measurement, a light source 8 that emits measurement light to a measurement sample atomized by the flame 5, a measurement light detection sensor 13 that detects measurement light intensity, and a measurement unit 41 that calculates absorbance based on the measurement light intensity. The flame light detection sensor 14 for detecting the intensity of the flame light emitted from the flame 5, the ambient light detection sensor 15 for detecting the ambient light intensity, and the flame 5 based on the flame light and the light intensity of the ambient light. It is set as the structure provided with the flame monitoring part 42 which determines whether or not is formed. [Selection] Figure 1

Description

  The present invention relates to a flame type atomic absorption photometer, and more particularly to a flame type atomic absorption photometer that measures the absorbance of a measurement sample atomized by a flame.

The flame type atomic absorption photometer measures the light intensity of the measurement light from the atomized measurement sample by atomizing the measurement sample by atomizing the liquid measurement sample and introducing it into the flame. . At this time, the measurement light is emitted from the light source to the atomized measurement sample, and the light intensity of the measurement light that has passed through the measurement sample is detected by the measurement light detection sensor.
In such a flame type atomic absorption spectrophotometer, it is necessary to form a flame for atomizing the measurement sample, and therefore air (supporting gas) and acetylene gas (fuel gas) are supplied to the burner (combustion unit). A flame is formed on the burner head by igniting the mixed gas of supplied air and acetylene gas.

Some frame-type atomic absorption photometers include a phototransistor (flame light detection sensor) that detects the extinction of a flame (see, for example, Patent Document 1). As an example of the configuration, a phototransistor for detecting the light intensity of the flame light is provided so as to be close to the flame formed on the burner head, the emitter terminal of the phototransistor is grounded, and the collector terminal is connected with a load resistance. Pull up. As a result, when a flame is formed, a current flows through the phototransistor (phototransistor ON), and the collector terminal becomes about “L” level. On the other hand, when no flame is formed, no current flows through the phototransistor (phototransistor OFF), and the collector terminal becomes about “H” level. Therefore, the presence or absence of a flame is determined by comparing the potential of the collector terminal with a predetermined reference potential T ₁ (where H <T ₁ <L). That is, the extinction of the flame at the time of sample measurement is detected by the light intensity of the flame light detected by the phototransistor.

Further, in the flame type atomic absorption photometer, no flame is formed when the flame light detection sensor disposed at a position close to the flame formed on the burner head and the flame light intensity A is less than the threshold T _1. determining that, when the flame light intensity a is the threshold value above T ₁ is also one and a and determining flame monitor the flame is formed (for example, see Patent Document 2). Thus, when the flame light intensity A after the ignition is less than thresholds T _1, it is determined that extinction of the flame is generated, and stops the supply of acetylene gas.

By the way, in the flame type atomic absorption photometer, the flame light intensity A detected by the flame light detection sensor is greater than or equal to the threshold T ₁ even though no flame is formed by the ambient light entering the burner head. (See FIG. 3B).
Therefore, to confirm the light intensity of the ambient light detected by the flame light detection sensor before the ignition, when the ambient light intensity is the threshold value above T _1, by Avoid contact with "firing sequence" Flame The occurrence of the situation where the disappearance of the can not be detected is prevented.

Japanese Patent Laid-Open No. 11-23453 JP 2009-281770 A

However, in the flame atomic absorption photometer as described above, even if the flame light intensity A detected by the flame light detection sensor before ignition is less than the threshold T ₁ (see FIG. 2A), increased amount of ambient light, when the light intensity of the ambient light only becomes thresholds T ₁ or more (day inclined direct sunlight device (such as to be irradiated on the burner chamber)), the extinction of the flame is generated also, since the flame light detecting sensor at the detected flame light intensity a is a threshold value above T _1, the user can not detect the extinction of the flame, there is a problem in that acetylene gas continues to flow out (Fig. 3 (b)).

  In order to solve the above problems, the present inventor examined a method that can reliably detect the disappearance of a flame. When attempting to detect ambient light using only a flame light detection sensor as in the past, the flame light intensity is dominant during ignition and the intensity of the ambient light is unknown, and the flame light intensity depends on the sample being measured. Difficult to change. Therefore, an ambient light detection sensor is provided separately from the flame light detection sensor at a location where no flame is observed, and the flame light intensity A detected by the flame light detection sensor and the ambient light intensity B detected by the environment light detection sensor are provided. Based on this, it has been found that it is determined whether or not a flame is formed on the burner head.

  That is, the flame type atomic absorption photometer of the present invention includes a fuel gas supply unit that supplies fuel gas, an auxiliary gas supply unit that supplies auxiliary gas, and a measurement sample atomized into the supplied fuel gas and auxiliary gas. Measurement light is emitted to the sample mixing part that adjusts the mixed sample, the combustion part that ignites the fuel gas and auxiliary combustion gas in the mixed sample to form a flame, and the measurement sample atomized by the flame A frame-type atom comprising: a light source that performs measurement; a measurement light detection sensor that detects a light intensity of measurement light that has passed through the measurement sample; and a measurement unit that calculates the absorbance of the measurement sample based on the light intensity of the measurement light An absorptiometer, a flame light detection sensor for detecting the light intensity of flame light emitted from the flame, and an ambient light for detecting the light intensity of ambient light without detecting the flame light emitted from the flame detection And capacitors, based on the light intensity and the light intensity of the ambient light of the flame light, so that and a determining flame monitoring unit whether a flame is formed.

  According to the flame type atomic absorption photometer of the present invention, when the surroundings become bright during ignition, the ambient light detection sensor determines that the flame extinction cannot be detected, and the flame monitoring unit automatically The user's safety can be ensured by digesting or presenting the user with a dangerous state.

(Means and effects for solving other problems)
Further, in the flame type atomic absorption photometer of the present invention, the flame monitoring unit, when the light intensity of the flame light is not less than a first threshold value and the light intensity of the environmental light is less than a second threshold value, It is determined that a flame is formed. On the other hand, when the light intensity of the flame light is less than the first threshold value or the light intensity of the ambient light is equal to or greater than the second threshold value, no flame is formed. You may make it determine with possibility.

Here, the “first threshold value” is a light intensity determined by a designer, a user, or the like in order to determine whether or not a flame is formed by the flame light detection sensor.
The “second threshold value” is a light intensity for determining whether or not excessive ambient light that interferes with the determination of the presence or absence of a flame is incident on the flame light detection sensor. Since the position and the position of the ambient light detection sensor are separated from each other, it is preferable that a designer, a user, or the like appropriately determine the positional relationship between the flame light detection sensor and the ambient light detection sensor.

The schematic block diagram which shows an example of the flame | frame type atomic absorption photometer which concerns on this invention. The figure explaining the relationship between the light intensity when environmental light intensity is small, and a threshold value. The figure explaining the relationship between the light intensity when environmental light intensity is large, and a threshold value.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments described below, and it goes without saying that various aspects are included without departing from the spirit of the present invention.

FIG. 1 is a schematic configuration diagram showing an example of a frame-type atomic absorption photometer according to an embodiment of the present invention. 2 and 3 are explanatory diagrams showing the relationship between the ambient light intensity and the threshold. FIG. 2 shows a case where the ambient light intensity is small, and FIG. 3 shows a case where the ambient light intensity is large.
The flame type atomic absorption photometer 1 emits measurement light, a burner (combustion unit) 2 that forms a flame 5, an auxiliary combustion gas supply unit 11 that supplies air, a fuel gas supply unit 12 that supplies acetylene gas, and the like. A light source 8, a measurement light detection sensor 13 for detecting the measurement light intensity, a flame light detection sensor 14 for detecting the flame light intensity A, an ambient light detection sensor 15 for detecting the ambient light intensity B, and the measurement sample are atomized. Are provided with a frame chamber (sample mixing unit) 16 for adjusting the mixed sample by being introduced, a burner chamber 17, and a control unit 20 constituted by a computer.

The auxiliary combustion gas supply unit 11 includes an electromagnetic valve 11a that opens and closes the air supply pipe 31, and an air flow rate adjustment unit 11b that adjusts the flow rate of air. Then, the auxiliary combustion gas supply unit 11 supplies air to the frame chamber 16 at a flow rate based on the control signal from the control unit 20.
The fuel gas supply unit 12 includes an electromagnetic valve 12a that opens and closes the fuel supply pipe 32, and a fuel gas flow rate adjustment unit 12b that adjusts the flow rate of acetylene gas. The fuel gas supply unit 12 supplies acetylene gas to the frame chamber 16 at a flow rate based on a control signal from the control unit 20.

The frame chamber 16 includes the nebulizer 3 and the sample suction pipe 4. Thus, when the measurement sample is introduced from the sample suction pipe 4 into the nebulizer 3 by the user, the measurement sample, acetylene gas, and air that are atomized are mixed in the frame chamber 16 and sent to the burner 2. When the measurement sample is not introduced into the sprayer 3, only acetylene gas and air are mixed in the frame chamber 16 and sent to the burner 2. That is, when the measurement sample is not introduced, a mixed gas not containing the measurement sample is sent to the burner 2.
The burner 2 discharges the mixed gas supplied from the frame chamber 16 from the elongated slit of the burner head and ignites the mixed gas based on a control signal from the control unit 20 to form a flame 5 on the burner head. Or extinguish the formed flame 5. Therefore, when the flame 5 is formed when the mixed sample containing the measurement sample is supplied from the frame chamber 16, the measurement sample in the mixed sample is atomized by the flame 5 to become atomic vapor.

  The measurement light detection sensor 13 is arranged so as to face the light source 8 and spectrally separates the measurement light that has passed through the measurement sample atomized by the flame 5 with a spectroscope (not shown) to detect the spectroscopic measurement light intensity. Then, a detection signal indicating the measurement light intensity is output to the measurement unit 41 of the control unit 20 described later.

The flame light detection sensor 14 is a phototransistor that is not opposed to the light source 8 and is disposed at a position close to the flame 5 formed on the burner head. The emitter terminal of the phototransistor is grounded and the collector terminal is Pulled up with load resistance. Thereby, the flame light detection sensor 14 detects the flame light intensity A emitted from the flame 5 and outputs a detection signal indicating the flame light intensity A to the control unit 20.
Similarly to the flame light detection sensor 14, the ambient light detection sensor 15 is a phototransistor that does not oppose the light source 8 and is disposed at a position far from the flame 5 formed on the burner head. The emitter terminal of the phototransistor Is grounded and the collector terminal is pulled up with a load resistor. Thereby, the ambient light detection sensor 15 detects only the ambient light intensity B incident in the burner chamber 17 instead of the flame light emitted from the flame 5, and sends a detection signal indicating the ambient light intensity B to the control unit 20. Output.

The control unit 20 includes a CPU 21 that performs various types of control and arithmetic processing, and an input device 22, a display device 23, and a memory 24 are connected to each other. The processing executed by the CPU 21 will be described separately for each functional block. The measurement unit 41 calculates the absorbance of the measurement sample, and the flame monitoring unit 42 determines whether or not the flame 5 is formed. Further, the memory 24 stores in advance a first threshold value T ₁ of the flame light intensity A and a second threshold value T ₂ of the light intensity of the ambient light B for determining whether or not the flame 5 is formed. Yes.

The measurement unit 41 outputs a control signal to each of the burner 2, the light source 8, the auxiliary combustion gas supply unit 11, and the fuel gas supply unit 12 based on an operation signal indicating measurement start / end of measurement from the input device 22 or the like. Thereafter, based on the detection signal from the measurement light detection sensor 13, control is performed to calculate the absorbance of the measurement sample atomized by the flame 5.
For example, when an operation signal indicating the start of measurement is received from the input device 22 or the like, the detection signal from the flame light detection sensor 14 is received. Then, the flame light intensity A is when it is determined that the first less than a thresholds T ₁ enters the "ignition sequence", of controlling the combustion aid gas supply unit 11 air flow rate 15.0 L / min (measurement start for The flow rate of acetylene gas is adjusted to 2.0 L / min (set flow rate for starting measurement) by controlling the fuel gas supply unit 12 (see FIG. 2A). Then, the burner 2 is controlled to ignite a mixed gas of air and acetylene gas, and the light source 8 is controlled to emit measurement light. Thereafter, the detection signal from the measurement light detection sensor 13 is received, and the absorbance of the measurement sample atomized by the flame 5 is calculated.
When an operation signal indicating the end of measurement is received from the input device 22 or the like, the auxiliary combustion gas supply unit 11 is controlled to adjust the air flow rate to 0.0 L / min (set flow rate for measurement end), and the fuel. The gas supply unit 12 is controlled to adjust the flow rate of the acetylene gas to 0.0 L / min (set flow rate for measurement end). Then, the burner 2 is controlled so that the flame 5 is extinguished, and the light source 8 is controlled to stop the emission of the measurement light.

When entering the “ignition sequence”, the flame monitoring unit 42 performs control to determine whether or not the flame 5 is formed based on the detection signals from the flame light detection sensor 14 and the ambient light detection sensor 15. .
For example, when a detection signal “flame light intensity A is less than the first threshold T ₁ ” is received from the flame light detection sensor 14, it is determined that no flame is formed (see FIG. 2C), and an error occurs. The message “The flame is gone” is displayed on the display device 23. The auxiliary combustion gas supply unit 11 is controlled to adjust the air flow rate to 0.0 L / min, and the fuel gas supply unit 12 is controlled to adjust the acetylene gas flow rate to 0.0 L / min.

Further, when a detection signal “environment light intensity B is equal to or greater than the second threshold T ₂ ” is received from the ambient light detection sensor 15, it is determined that a flame may not be formed (see FIG. 3), An error message “The flame may have disappeared” is displayed on the display device 23. The user who has confirmed this error message recognizes that the sun is tilted and direct sunlight has hit the burner chamber 17, and takes measures such as lowering the window blind.
On the other hand, the flame light intensity A is not less the first threshold value above T _1, when the ambient light intensity B is less than the second threshold value T ₂ are, determines that the flame 5 is normally formed (see FIG. 2 (b)) However, no message is displayed on the display device 23.

  As described above, according to the frame-type atomic absorption photometer 1 of the present invention, when the surroundings become bright during ignition, it is determined that the extinction of the flame 5 by the ambient light detection sensor 15 cannot be detected. The safety of the user can be ensured by the danger monitoring unit 42 presenting the danger to the user. As a result, it is possible to reliably detect the disappearance of the flame 5 as shown in FIG.

<Other embodiments>
(1) In the frame type atomic absorption photometer 1 described above, when the ambient light intensity B is greater than or equal to the second threshold T ₂ , an error message is displayed on the display device 23 to notify the user. Instead of this, the auxiliary combustion gas supply unit 11 and the fuel gas supply unit 12 may be automatically controlled to stop the supply of air and acetylene gas.

(2) In the flame atomic absorption photometer 1 described above, the memory 24 has a configuration in which the first thresholds T ₁ and the second threshold value T ₂ is stored in advance, the first thresholds T ₁ for each measurement second threshold value T ₂ and may be configured as the user sets the.

  The present invention can be used for a flame type atomic absorption photometer that measures the absorbance of a measurement sample atomized by a flame.

1: Flame type atomic absorption photometer 2: Burner (combustion part)
5: Flame 8: Light source 11: Auxiliary gas supply unit 12: Fuel gas supply unit 13: Measurement light detection sensor 14: Flame light detection sensor 15: Ambient light detection sensor 16: Frame chamber (sample mixing unit)
41: Measuring unit 42: Flame monitoring unit

Claims (2)

A fuel gas supply section for supplying fuel gas;
An auxiliary gas supply unit for supplying auxiliary gas;
A sample mixing section for adjusting the mixed sample by atomizing and introducing the measurement sample into the supplied fuel gas and auxiliary combustion gas;
A combustion part that ignites the fuel gas and the auxiliary combustion gas in the mixed sample to form a flame;
A light source that emits measurement light to a measurement sample atomized by the flame;
A measurement light detection sensor for detecting the light intensity of the measurement light that has passed through the measurement sample;
A frame-type atomic absorption photometer comprising a measurement unit that calculates the absorbance of the measurement sample based on the light intensity of the measurement light,
A flame light detection sensor for detecting the light intensity of the flame light emitted from the flame;
An ambient light detection sensor that detects the light intensity of ambient light without detecting the flame light emitted from the flame;
A flame type atomic absorption photometer comprising: a flame monitoring unit that determines whether or not a flame is formed based on the light intensity of flame light and the light intensity of ambient light. The flame monitoring unit determines that a flame is formed when the light intensity of the flame light is equal to or higher than a first threshold value and the light intensity of the ambient light is less than a second threshold value,
On the other hand, when the light intensity of the flame light is less than a first threshold value, or when the light intensity of the environmental light is equal to or greater than a second threshold value, it is determined that there is a possibility that no flame is formed. The flame type atomic absorption photometer according to claim 1.

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