JP3783332B2 - Atomic absorption photometer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an atomic absorption photometer, and more particularly, to a flame type atomic absorption photometer using a flame in which a gas is burned as a heat source for atomizing a sample.
[0002]
[Prior art]
In a flame type atomic absorption photometer, a sample is burned by a burner to generate a flame on a slot provided in the burner head and perform atomic absorption analysis. FIG. 3 is a perspective view showing the structure of a conventional burner 1, 32 is a combustion gas introduction section for supplying acetylene (hereinafter abbreviated as C 2 H 2) as combustion gas, and 33 is air (hereinafter referred to as “combustion gas”). (Referred to as AIR) AIR introduction section 34, N2 O introduction section 34 for supplying dinitrogen monoxide (hereinafter abbreviated as N2 O), which is also an auxiliary combustion gas, 35, sample introduction section, 36, burner head, 37 Is a burner head attaching / detaching portion for connecting the burner head and the gas introducing portion, and 38 is a slot for generating a flame formed on the upper surface of the burner head.
[0003]
In an atomic absorption photometer, an AIR-C2 H2 flame is usually used. In this case, an AIR-C2 H2 flame burner having a long side (for example, 10 cm) having a long side of a slot 38 as a combustion gas outlet is attached. Measure by burning an AIR-C2 H2 flame.
[0004]
On the other hand, in order to obtain a higher temperature flame, an N2 O-C2 H2 flame is used, but at this time, the long side of the slot 38 is short (for example, 5 cm), and it is necessary to install an N2 O-C2 H2 flame burner. There is.
[0005]
The N2 O-C2 H2 flame is replaced with a burner head having a different slot in this way because the chemical reaction energy at the time of combustion is large and the combustion speed is fast, so the gas flow rate at the location where the flame is formed must be increased. This is because a flashback (which means that the flame passes through the slot and enters the burner). Backfire causes a gas explosion inside the device and is very dangerous.
[0006]
In the AIR-C2 H2 flame, since the burning rate is relatively slow, both the AIR-C2 H2 flame burner and the N2 O-C2 H2 flame burner can be used safely. However, the longer the slot length, the greater the absorbance, which is advantageous for measurement. Therefore, an AIR-C2 H2 flame burner is usually used.
[0007]
Therefore, the N2 O supply valve provided on the upstream side of the N2 O introduction part 4 is opened only when it is detected that the apparatus has a short slot N2 O-C2 H2 flame burner. Interlock function that can be installed for safety.
[0008]
However, there is no guarantee that the N2 O-C2 H2 flame burner is not installed when the N2 O-C2 H2 flame burner is not installed. Therefore, it was not a complete safety mechanism. Therefore, in order to avoid this problem, a double detection mechanism has been installed.
[0009]
[Problems to be solved by the invention]
In this way, the N2 O-C2 H2 flame burner detection sensor must be a reliable and expensive sensor, or the sensor must be mounted twice or more, both of which increase costs. Had brought.
[0010]
The present invention aims to provide an atomic absorption photometer that uses only one inexpensive sensor and has a complete safety mechanism.
[0011]
[Means for Solving the Problems]
The atomic absorption photometer of the present invention, which has been made to solve the above-mentioned problems, has an operating procedure that inevitably confirms that the N2 O-C2 H2 flame burner detection sensor is operating normally. It is characterized by adding.
[0012]
That is, the atomic absorption photometer of the present invention burned a N2 O-C2 H2 flame burner for using an N2 O-C2 H2 flame by a mixed gas of N2 O and C2 H2, and a mixed gas of AIR and acetylene. In an atomic absorption photometer configured to be detachable from an AIR-C2 H2 flame burner for use with an AIR-C2 H2 flame, an N2 O-C2 H2 flame attached to the N2 O-C2 H2 flame burner Burner identification section, N2 O-C2 H2 flame burner identification section recognition means for recognizing the N2 O-C2 H2 flame burner identification section, and first urging / removing the N2O-C2H2 flame burner The signal from the N2O-C2H2 flame burner recognition unit is changed to confirm whether the N2 O-C2 H2 flame burner recognition unit is normal, and then the N2 O-C2 H2 flame burner. Is installed When it is confirmed that the N2 O-C2 H2 flame burner is not mounted together with the display means for guiding the series of operations to be confirmed and the control for performing the display for guiding the series of operations. Comprises control means for performing control to prohibit the supply of N2 O to the burner.
[0013]
As the burner detection sensor functioning as the burner identification unit recognition means, a photo interrupter, a micro switch, or the like is usually used. When the N2 O-C2 H2 flame burner is mounted, the sensor is activated, and the output signal changes. At this time, if no change occurs in the output, it can be determined that the sensor has failed.
[0014]
Therefore, before the operator ignites the N2 O-C2 H2 flame, in order to confirm the operation of the burner detection sensor, an indication that an N2 O-C2 H2 flame burner is mounted is displayed, and the N2 O-C2 H2 flame is displayed. A burner is installed, or if it is already installed, it is urged to remove it once and install it again. If the operator performs as instructed and confirms that the sensor is operating normally, the use of the N2 O-C2 H2 flame is permitted, and the N2 O-C2 H2 flame can be ignited in the subsequent ignition operation. It can be so. If the sensor is faulty, display that the sensor is faulty and prohibit the use of N2 O-C2 H2 flame until the normal operation of the sensor is confirmed by the next confirmation procedure. Prevent ignition. Further, when the operator ignores the confirmation of the operation of the burner detection sensor, the use is similarly prohibited.
[0015]
By adding the operation procedure as described above, it is possible to correctly detect that the N2 O-C2 H2 flame burner is mounted, and a complete safety mechanism can be configured with only one sensor.
[0016]
If the operator has only an AIR-C2 H2 flame burner, the use of N2 O-C2 H2 flame is naturally prohibited, but the use of AIR-C2 H2 flame is not prohibited. C2 H2 flame will not interfere with the measurement.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a configuration diagram of an atomic absorption photometer according to an embodiment of the present invention. In addition, the same thing as shown in FIG. 3 attaches | subjects the same code | symbol, and abbreviate | omits description. In this figure, 1 is a microprocessor, 2 is a storage device for storing operation flow programs, device status data, etc., 3 is a microprocessor input circuit, 4 is a microprocessor output circuit, and 5 is a message. It is a display device for doing. A general-purpose computer system is used for these. 11 is a C2 H2 solenoid valve, 12 is an AIR solenoid valve, and 13 is an N2 O solenoid valve, which are attached to a C2 H2 pipe 14, an AIR pipe 15, and an N2 O pipe 16, respectively. The opening / closing operation is performed by a signal. Reference numeral 17 denotes an N2 O-C2 H2 flame burner, and a pin 19 is connected to the burner via a chain 18. And the pin holder 20 is provided in the vicinity of the burner installation position of an atomic absorption photometer, and the pin 19 can be inserted here. A photo interrupter 21 is attached to the pin holder 19, and when the pin 19 is inserted, the optical path of the photo interrupter 21 is blocked and a signal is output. That is, the mounting of the N2 O-C2 H2 flame burner 17 is detected by inserting the pin 19. In this figure, the optical system required for the flow rate adjusting device, the ignition device, the pressure monitoring device, the sample introduction unit or the atomic absorption photometer is omitted.
[0018]
Next, the operation in this embodiment will be described. The microprocessor 1 controls the C2 H2 solenoid valve 11, the AIR solenoid valve 12, and the N2 O solenoid valve 13 to burn the mixed gas with a burner. The operator selects either the AIR-C2 H2 flame or the N2 O-C2 H2 flame, and according to the instruction, the microprocessor 1 opens only one of the AIR solenoid valve 12 and the N2 O solenoid valve 13. The microprocessor 1 operates according to a program recorded in advance in the storage device 2. FIG. 2 shows an operation flow of the microprocessor 1.
[0019]
Before the operator ignites the N2 O-C2 H2 flame, an operation procedure for confirming the operation of the burner detection sensor is performed.
[0020]
The first half (st1 to st3) is an operation procedure for confirming whether or not a malfunction has occurred so as to recognize that the N2 O-C2 H2 flame burner 17 is installed, even though it is not installed. is there.
[0021]
An output signal from the photo interrupter 21 is transmitted to the microprocessor 1 through the input circuit 3. The status of the pin 19 is confirmed from this signal level (st1). If the pin 19 has already been inserted, the display device interactively displays “unplug” and instructs to prompt the operation of pulling out the pin (st2). This instruction repeats display and confirmation of the situation a plurality of times in order to allow an operator's operation mistake. Here, it is 3 times.
[0022]
If the microprocessor 1 can confirm that the burner detection sensor system, which is executed by the operator as instructed and reaches from the photo interrupter 21 to the input circuit 3, is operating normally, the information is stored in the storage device 2. Then, the process proceeds to the confirmation of the second half of the N2 O-C2 H2 flame burner 17 (st4).
[0023]
If the microprocessor 1 does not recognize that the output signal from the photo interrupter 21 has changed, it is a sensor failure, so that information is stored in the storage device 2 and "the sensor has failed". A message is displayed on the display device 5, and thereafter the use of the N2 O-C2 H2 flame is prohibited (st3). Also, if the operator ignores or forgets to confirm the operation of the burner detection sensor, the use is prohibited.
[0024]
The second half (st4 to st6) is a procedure for confirming whether or not the N2 O-C2 H2 flame burner 17 is actually mounted and the burner detection sensor detects this.
[0025]
If the pin 19 has been removed, or if the operator confirms that the pin has been removed according to the instruction, a message “please insert the pin” is displayed on the display device 5 (st4), and the operator When the C2 H2 flame burner 17 is attached and the pin 19 is inserted into the pin holder 20, the fact that the output signal from the photo interrupter 21 has changed is transmitted to the microprocessor 1 through the input circuit 3 (st5). Since the N2 O-C2 H2 flame burner 17 is installed and the burner detection sensor system from the photo interrupter 21 to the input circuit 3 is operating normally according to the procedure so far, the microprocessor 1 Permits the use of the N2 O-C2 H2 flame (st6) and stores the information in the storage device 2.
[0026]
If the microprocessor 1 does not recognize that the output signal from the photo interrupter 21 has changed, the N2 O-C2 H2 flame burner 17 is not installed or the sensor is faulty, so that information is stored. The message is stored in the device 2 and a message “Sensor is broken” is displayed on the display device 5, and the use of the N2 O-C2 H2 flame is prohibited thereafter (st3).
[0027]
Thereafter, when the operator performs the ignition operation of the N2 O-C2 H2 flame, the microprocessor 1 is based on the information in the storage device 2 and only when the use is permitted, the C2 H2 solenoid valve 11 and the N2 O The solenoid valve 13 is controlled to burn the mixed gas with the N2 O-C2 H2 flame burner 17. If the use is not permitted, the display unit 5 will display a message saying "Nothing can be done because the sensor is faulty or the N2O-C2H2 flame burner is not installed". To do.
[0028]
By adding the operation procedure as described above, it is possible to correctly detect that the N2 O-C2 H2 flame burner 17 is mounted, and a complete safety mechanism can be configured with only one sensor. .
[0029]
In this embodiment, every time before the N2 O-C2 H2 flame is ignited, a procedure for confirming the operation of the burner detection sensor is performed. The portion from st1 to st3 in FIG. You can check only once. This is because a sensor that has once operated normally rarely fails during use. In this method, the operator's confirmation operation can be limited to one time during the operation of the apparatus.
[0030]
In this embodiment, the photo interrupter is used as the burner detection sensor. However, the present invention is not limited to this, and a micro switch that mechanically determines the presence or absence of a pin may be used.
[0031]
【The invention's effect】
The N2 O-C2 H2 flame burner must be installed by adding an operating procedure that inevitably confirms that the N2 O-C2 H2 flame burner detection sensor is operating normally. Can be detected correctly, and a complete safety mechanism can be configured with only one sensor.
[0032]
Even if the operator has only an AIR-C2 H2 flame burner, the use of the AIR-C2 H2 flame is not prohibited, so that the measurement with the AIR-C2 H2 flame is not hindered.
[0033]
The N2 O-C2 H2 flame burner detection sensor can be used with high reliability and high price, or it is not necessary to attach more than two sensors. Therefore, cost reduction and downsizing of the apparatus can be realized.
[0034]
The N2 O-C2 H2 flame burner is equipped with a sensor that detects that a burner is installed, so the atomic absorption photometer can be handled by changing the software. Can be easily implemented without causing any changes
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of an atomic absorption photometer according to an embodiment of the present invention.
FIG. 2 is an operation flowchart of an atomic absorption spectrophotometer according to an embodiment of the present invention.
FIG. 3 is a perspective view showing a configuration of a burner portion of an atomic absorption photometer.
[Explanation of symbols]
1: Microprocessor 2: Storage device 5: Display device 11: Solenoid valve for C2 H2 12: Solenoid valve for AIR 13: Solenoid valve for N2 O 14: Piping for C2 H2 15: Piping for AIR 16: Piping 17 for N2 O : N2 O-C2 H2 flame burner 18: Chain 19: Pin 20: Pin holder 21: Photo interrupter

Claims (1)

An N2O-C2H2 flame burner for using an N2O-C2H2 flame with a mixed gas of N2O and C2H2, and an AIR-C2H2 flame burner for using an AIR-C2H2 flame burned with a mixed gas of AIR and acetylene In the detachable atomic absorption photometer, the N2O-C2H2 flame burner identification unit attached to the N2O-C2H2 flame burner and the N2O-C2H2 flame burner identification unit for recognizing the N2O-C2H2 flame burner identification unit The N2O-C2H2 flame burner is urged to attach and detach the N2O-C2H2 flame burner at first, and the signal from the N2O-C2H2 flame burner identification unit changes at that time, thereby changing the N2O-C2H2 flame burner. A series of operations for guiding whether or not the identification unit recognition means is normal and subsequently confirming whether or not the N2O-C2H2 flame burner is attached are guided. In addition to the display means for performing display for display and the control for performing display for guiding the series of operations, when it is confirmed that the N2O-C2H2 flame burner is not mounted, the supply of N2O to the burner is prohibited. An atomic absorption photometer comprising control means for performing control.

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