JP6079574B2 - Luminescence analyzer - Google Patents

Description

  The present invention relates to an emission analyzer, and more particularly, to an igniter circuit that causes discharge in an emission analyzer.

  In a spark discharge type optical emission spectrometer, energy stored in a capacitor is applied to a discharge electrode to generate a spark discharge between the discharge electrode and a metal sample, evaporating the elements in the metal sample, and this by discharge plasma. Excites the element. Since an element excited in plasma emits light at a specific wavelength, the element can be quantified by measuring the light intensity at the wavelength by spectroscopically analyzing the emitted light. In addition, when the contained element is unknown, qualitative analysis can be performed by obtaining an emission spectrum in a predetermined wavelength range and examining the wavelength at which the line spectrum exists.

In such an emission analyzer, for example, a capacitor connected between the discharge electrode and the sample is charged to a voltage of about several hundred volts by a charging circuit described in, for example, Patent Document 1, and then discharge is started by an igniter circuit. Let FIG. 10 shows an example of a schematic configuration of an igniter circuit in a conventional emission analyzer.
The igniter circuit 1 connected to the light-emitting stand 7 includes a primary capacitor 2, an ignition transformer 3, a switching element 4 such as an FET, a switching element driving circuit 5, and a secondary capacitor 6. The ignition transformer 3 includes a primary winding 3a and a secondary winding 3b. The light-emitting stand 7 includes a discharge electrode 7a and a sample 7b that is an analyte. The secondary capacitor 6 includes the stray capacitance of the secondary winding 3 b of the ignition transformer 3, the stray capacitance of the light emitting stand 7, and the stray capacitance of the cable connecting the ignition transformer 3 and the light emitting stand 7. In FIG. 10, description is omitted about the main capacitor | condenser which supplies the main energy for discharge to the discharge electrode 7a, and the charging circuit which charges this main capacitor | condenser.

  The primary capacitor 2 is charged to a predetermined voltage in advance (before light emission) by a capacitor charging circuit (not shown). When the switching element drive circuit 5 increases the voltage applied to the gate terminal of the switching element 4 in a stepwise manner, the switching element 4 is turned on. Then, the primary capacitor 2 and the primary winding 3a of the ignition transformer 3 are connected in series, and a current corresponding to the voltage stored in the primary capacitor 2 flows to the primary winding 3a. As a result, a high voltage corresponding to the turn ratio of the ignition transformer 3 is induced in the secondary winding 3 b of the ignition transformer 3. Thereby, a spark discharge is generated between the discharge electrode 7a and the sample 7b.

  Further, the spark discharge forms a current path including a main capacitor (not shown) and the light-emitting stand 7, and the energy stored in the main capacitor moves between the discharge electrode 7a and the sample 7b (gap) to form plasma. To do. The evaporated element is excited by electrons in the plasma. When the excited element returns to a stable state, light having a wavelength corresponding to the energy difference is emitted. A photometric unit (not shown) including a spectroscope and a photodetector measures emitted light having a wavelength peculiar to this element, and collects information on the element contained in the sample 7b.

  In the igniter circuit 1, when no discharge is generated in the light emitting stand 7 due to, for example, the interval between the discharge electrode 7 a and the sample 7 b being too large, all the energy stored in the primary capacitor 2 is transferred to the ignition transformer 3. Are consumed by the winding resistance of the primary winding 3 a and the secondary winding 3 b and the on-resistance of the switching element 4. Therefore, there has been a problem that the temperature rise of the ignition transformer 3 and the switching element 4 is remarkably higher than when the discharge occurs in the light-emitting stand 7. Similarly, when the discharge electrode 7a and the sample 7b are in contact with each other and the light-emitting stand 7 is in a short-circuited state, the total energy stored in the primary capacitor 2 is the primary winding 3a of the ignition transformer 3 and Since it is consumed by the winding resistance of the secondary winding 3b and the on-resistance of the switching element 4, there is a problem that the temperature of the ignition transformer 2 and the switching element 4 is remarkably increased.

  In order to avoid such a problem of heat generation, conventionally, the ignition transformer 3 and the switching element 4 are cooled using a heat sink, a cooling fan, or the like, or a protection element such as a temperature fuse, a temperature sensitive switch, and a thermistor is used to ignite the ignition transformer. 3 and a method of preventing overheating of the switching element 4 has been adopted. However, all of these methods increase the size and cost of the igniter circuit 1. Moreover, in order to suppress the temperature rise of the ignition transformer 3 and the switching element 4, although the method of reducing a discharge repetition frequency is also considered, there exists a problem that analysis time will become long if it does so.

Japanese Patent No. 4919104

  The present invention has been made to solve the above-mentioned problems, and the object of the present invention is that no discharge occurs in the light-emitting stand even when the discharge start operation is performed, or the light-emitting stand is short-circuited. Even in such a case, it is an object to provide an emission analyzer using an igniter circuit capable of preventing overheating of an ignition transformer and a switching element.

An emission analysis apparatus according to a first aspect of the present invention, which has been made to solve the above-mentioned problems, includes an ignition transformer, a primary capacitor and a switching element connected to a primary winding of the ignition transformer, and driving the switching element. And an igniter circuit provided with a drive circuit, a secondary capacitor on the secondary winding side of the ignition transformer and including at least a stray capacitance of the secondary winding, and a discharge generated by the igniter circuit A light emitting stand including an electrode and a sample, the switching element is turned on in a state where the primary capacitor is charged to a predetermined voltage, and the primary capacitor and the 2 are connected to a primary winding of the ignition transformer. LC resonance current is caused to flow due to the combined capacitance in series with the secondary capacitor and the leakage inductance of the ignition transformer. In optical emission spectrometer to generate discharge by generating a high voltage to the emission stand with the secondary winding of the ignition transformer and,
After the switching element is turned on, the driving circuit switches a pulsed driving signal that turns off the switching element during a period in which the polarity of the current flowing in the primary winding of the ignition transformer is reversed. It is characterized by being supplied to the element.

  In the emission analyzer according to the first aspect, when the drive circuit turns on the switching element, the resonance frequency in the LC resonance circuit formed by the parallel combined capacitance of the primary capacitor and the secondary capacitor and the excitation inductance of the ignition transformer. An alternating current having a current flows through the primary winding of the ignition transformer. That is, the direction of the current flowing through the primary winding of the ignition transformer, that is, the polarity is inverted every 1/2 of the resonance period. In the conventional igniter circuit, since the switching element is kept on, current continues to flow through the primary winding of the ignition transformer for a while. On the other hand, in the emission spectrometer according to the first aspect of the present invention, the drive circuit turns off the switching element during one period after the half of the resonance period has elapsed. Thereby, the resonance in the LC resonance circuit is completed in one period of the resonance period. As a result, power loss caused by the ignition transformer and the switching element can be reduced.

An emission analysis apparatus according to a second aspect of the present invention, which has been made to solve the above-described problems, includes an ignition transformer, a primary capacitor and a switching element connected to a primary winding of the ignition transformer, and driving the switching element. And an igniter circuit provided with a drive circuit, a secondary capacitor on the secondary winding side of the ignition transformer and including at least a stray capacitance of the secondary winding, and a discharge generated by the igniter circuit A light emitting stand including an electrode and a sample, the switching element is turned on in a state where the primary capacitor is charged to a predetermined voltage, and the primary capacitor and the 2 are connected to a primary winding of the ignition transformer. LC resonance current is caused to flow due to the combined capacitance in series with the secondary capacitor and the leakage inductance of the ignition transformer. In optical emission spectrometer to generate discharge by generating a high voltage to the emission stand with the secondary winding of the ignition transformer and,
A damping circuit is provided in parallel with the primary winding of the ignition transformer, in which a diode and a resistor are connected in series in a direction to turn on when the current flowing through the primary winding due to resonance has a reverse polarity. .

  In the emission analyzer according to the second aspect, when the drive circuit turns on the switching element, the alternating current in the LC resonance circuit flows in the primary winding of the ignition transformer, but the polarity of the voltage across the primary capacitor is When negative, the diode of the damping circuit becomes conductive. For this reason, a part of the current flows through the resistance of the damping circuit, and power is consumed in the resistance to reduce the primary winding current. Thereby, the power loss which arises with an ignition transformer and a switching element can be reduced.

The configuration of the first aspect and the configuration of the second aspect can be used in combination. That is, in the emission spectrometer according to the first aspect,
A damping circuit may be provided in parallel with the primary winding of the ignition transformer, in which a diode and a resistor that are turned on in series when the current flowing through the primary winding due to resonance has a reverse polarity and a resistor are connected in series.

  When the light-emitting stand is in a short-circuited state, the secondary capacitor including the stray capacitance of the light-emitting stand is short-circuited, so that the resonance characteristics change, and the resonance period becomes longer than when the light-emitting stand is not short-circuited. The resonance current is also increased. As described above, in the emission analyzer according to the first aspect, the resonance in the LC resonance circuit can be terminated by one period of the resonance period, but the resonance period is smaller than that in the case where the light-emitting stand is not short-circuited. As the resonance current increases as the length increases, the power loss increases accordingly. On the other hand, by using the damping circuit as in the second aspect, the current flowing through the primary winding and the secondary winding of the ignition coil when the light-emitting stand is in a short-circuited state can be quickly attenuated. Therefore, the power loss generated in the ignition transformer and the switching element can be reduced more effectively.

When a damping circuit is used as described above, the resistance in the damping circuit is 1 to 4 times the resistance value at which the LC resonance circuit formed by the primary capacitor and the leakage inductance of the ignition transformer becomes critical braking. It is preferable that the resistance value be in the range.
Thereby, the resonance itself can be appropriately attenuated, and the current itself flowing through the primary winding of the ignition coil can be suppressed as small as possible.

  According to the emission analyzers of the first and second aspects according to the present invention, it is possible to reduce the power loss caused by the ignition transformer and the switching element as compared with the conventional case. As a result, the temperature rise of the ignition transformer and the switching element due to power loss can be suppressed, and even if there is no discharge in the light emitting stand or the light emitting stand is in a short-circuited state, Overheating can be prevented. As a result, cooling means such as a heat sink and a cooling fan, and overheat protection means using a temperature fuse, a temperature sensitive switch, a thermistor, and the like are not required, and the igniter circuit can be reduced in size, weight, and cost. Moreover, since it is not necessary to lower the discharge repetition frequency in order to prevent overheating, the discharge repetition frequency can be increased to shorten the analysis time.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic block diagram of the igniter circuit in the emission spectrometer which is 1st Example of this invention. The figure which shows the operation | movement waveform of the igniter circuit by 1st Example. The equivalent circuit diagram of the igniter circuit in the state which the light emission stand short-circuited. The figure which shows the operation | movement waveform in the state which the light emission stand short-circuited in the igniter circuit of 1st Example. The schematic block diagram of the igniter circuit in the emission spectrometer which is 2nd Example of this invention. FIG. 6 is an equivalent circuit diagram in a state where a damping diode is turned on in the igniter circuit according to the second embodiment. The figure which shows the operation | movement waveform in the state which the light emission stand short-circuited in the igniter circuit of 2nd Example. The figure which shows the relationship between the damping resistance in the state where the light emission stand was short-circuited in the igniter circuit of 2nd Example, and the energy loss of an ignition transformer and a damping circuit. The figure which shows the simulation result of the energy loss in the ignition transformer in the igniter circuit of a present Example, and the conventional igniter circuit. The schematic block diagram of the conventional igniter circuit. The equivalent circuit diagram in the state which turned on the switching element in the conventional igniter circuit. The figure which shows an example of the operation | movement waveform in the conventional igniter circuit. The figure which expanded the time axis of the waveform diagram shown in FIG.

Hereinafter, an embodiment of an emission analyzer according to the present invention will be described with reference to the accompanying drawings.
First, in the conventional igniter circuit 1 shown in FIG. 10, power loss in the ignition transformer 3 and the switching element 4 when no discharge occurs in the light-emitting stand 7 will be considered.

FIG. 11 is an equivalent circuit diagram in which the ignition transformer 2 is replaced with a T-type equivalent circuit when the switching element 4 is on in the igniter circuit 1 shown in FIG. In FIG. 11, C ₁ is a primary capacitor, C ₂ is a secondary capacitor (primary conversion), L ₁ is a primary leakage inductance, L ₂ is a secondary leakage inductance (primary conversion), and L ₃ is an excitation inductance. is there. The initial voltage of the primary capacitor C ₁ is Vi, and the initial voltage of the secondary capacitor is 0. Primary capacitor C ₁ and the secondary capacitor (primary conversion) a series combined capacitance of C ₂ Cs, primary capacitor C ₁ and the secondary capacitor (primary equivalent) parallel combined capacitance of C ₂ Cp, the leakage inductance L _s = L ₁ + L _2, when the exciting inductance and _{L p = L 1 + L 3} , the current I ₁ flowing through the primary capacitor C ₁ is
_{I 1 = {C 1 / (} C 1 + C 2)} Vi · {C 1 / (C 1 + C 2)} √ (C p / L p) sinω p t + Vi√ (C s / L s) sinω s t
It becomes. The current I ₂ (primary conversion) flowing through the secondary capacitor C ₂ is
_{I 2 = {C 1 / (} C 1 + C 2)} Vi · {C 2 / (C 1 + C 2)} √ (C p / L p) sinω p t + Vi√ (C s / L s) sinω s t
It becomes. However,
ω _p = 1 / √ (L _p C _p )
ω _s = 1 / √ (L _s C _s )
It is. Further, voltages V ₁ across the primary capacitor C ₁ is
_{V 1 = {C 1 / (} C 1 + C 2)} Vi · cosω p t + {C 2 / (C 1 + C 2)} Vi · cosω s t
It becomes. The voltage across the secondary capacitor C ₂ (primary conversion) V ₂ is
_{V 2 = {C 1 / (} C 1 + C 2)} Vi · cosω p t + {C 1 / (C 1 + C 2)} Vi · cosω s t
It becomes.

In FIG. 12, the initial voltage of the primary capacitor 2 is Vi = 300 [V], the turn ratio of the ignition transformer 3 is 1:40, and the capacitance of the primary capacitor 2 is C ₁ = 160 [nF], the secondary capacitor 6 Is a waveform showing the result of simulating the primary capacitor voltage V ₁ , the secondary capacitor voltage V _2, and the primary winding current I _L1 of the ignition transformer, which is observed when the capacitance of the capacitor is C ₂ = 100 [pF]. FIG. 13 is an enlarged view of the time axis of FIG.
When a discharge occurs in the light-emitting stand 7, LC resonance stops at that moment, and the resonance current flowing through the ignition transformer 3 becomes zero. On the other hand, when no discharge occurs in the light-emitting stand 7, the vibration due to the LC resonance continues, and all the energy stored in the primary capacitor 2 immediately before the switching element 4 is turned on is all the resistance component of the circuit (1 of the ignition transformer 3). The winding resistance of the secondary winding 3a and secondary winding 3b and the on-resistance of the switching element 4). For this reason, the power loss of the ignition transformer 3 and the switching element 4 at this time is significantly larger than that in the case where discharge occurs in the light-emitting stand 7. As a result, there is a problem that the temperatures of the ignition transformer 3 and the switching element 4 rise excessively.

  FIG. 1 is a schematic configuration diagram of an igniter circuit 10 in an emission analyzer according to a first embodiment of the present invention. The same components as those in the conventional igniter circuit 1 shown in FIG. As apparent from a comparison between FIG. 1 and FIG. 10, the basic components are the same, and the igniter circuit 10 in the first embodiment is different from the conventional circuit 1 in that the switching element 4 is driven. It is the switching element drive part 15 to do. That is, the switching element driving unit 5 in the conventional igniter circuit 1 is a step voltage in which the voltage increases in a step shape at a certain time and is maintained. On the other hand, in this embodiment, the switching element drive unit 15 turns on the switching element 4 so that the resonance current flows through the ignition transformer 3 and the switching element 4 only during the first one period of the LC resonance. Is limiting. That is, the drive signal for driving the switching element 4 is a pulse signal whose on-time is a predetermined time.

  Specifically, when the switching element driving unit 15 turns on the switching element 4, a resonance current starts to flow through the ignition transformer 3 and the switching element 4, but in the first half of the resonance period, the positive polarity (primary A current having a polarity corresponding to the polarity of the initial voltage of the capacitor 1 flows, and a negative current flows in a half period of the latter half of the resonance period. In FIG. 1, a positive current is a current that flows from the top to the bottom of the primary winding 3a, and a negative current is a current that flows from the bottom to the top of the primary winding 3a. After switching element 4 is turned on, switching element driver 15 turns switching element 4 off during the half period of the latter half of the resonance period. Even after the switching element 4 is turned off, the resonance current continues to flow through the built-in diode (also referred to as a body diode) of the switching element 4, but at the moment when the polarity of the negative resonance current becomes positive again, the built-in diode turns off and resonates. The current stops.

FIG. 2 shows the initial voltage Vi = 300 [V] of the primary capacitor 2 in the igniter circuit 10 of the first embodiment, the turns ratio of the ignition transformer 3 is 1:40, and the capacitance of the primary capacitor 2 is C ₁ = 160. [nF] The primary capacitor voltage V ₁ , the secondary capacitor voltage V _2, and the primary winding current I _{L1 of the} ignition transformer observed when the capacitance of the secondary capacitor 6 is C ₂ = 100 [pF] It is a waveform which shows the result of having simulated. In this example, the switching element 4 is turned off immediately before the resonance period becomes one period. If the switching element 4 is turned off while a positive current flows through the switching element 4, a back electromotive force is generated in the primary winding 3 a of the ignition transformer 3, thereby applying an excessive surge voltage to the switching element 4. The device may be damaged. On the other hand, if the switching element 4 is turned off from on during the period in which the current flowing through the primary winding 3a of the ignition transformer 3 is negative, an excessive surge voltage is prevented from being applied to the switching element 4. be able to.
Even if no discharge occurs in the light-emitting stand 7, the resonance current flowing through the primary winding 3a and secondary winding 3b of the ignition transformer 3 and the switching element 4 is a maximum of one resonance period. The power loss generated in the primary winding 3a and secondary winding 3b of the ignition transformer 3 and the switching element 4 can be small, and heat generation can be suppressed.

Next, consider a case where the discharge electrode 7a and the sample 7b are short-circuited in the light-emitting stand 7.
FIG. 3 is an equivalent circuit in which the secondary capacitor C ₂ of the equivalent circuit shown in FIG. 11 is short-circuited and the excitation inductance L ₃ is omitted.
In FIG. 3, the primary capacitor current I ₁ is
I ₁ = Vi√ (C ₁ / L _s ) sinω ₀ t
The primary capacitor voltage V ₁ is
V ₁ ≒ Vicosω ₀ t
It becomes. However,
ω ₀ = 1 / √ (L _s C ₁ )
It is.
The peak value of the current flowing through the ignition transformer 3 and the switching element 4 and the resonance period are larger than when the light emitting stand 7 is not short-circuited, and becomes {square root} {(C ₁ + C ₂ ) / C ₂ }.

In the conventional igniter circuit 1 shown in FIG. 10, as in the case where the light-emitting stand 7 is not short-circuited, all the energy stored in the primary capacitor 2 is the primary winding of the ignition transformer 3 which is a resistance component of the circuit. 3a and the secondary winding 3b and the on-resistance of the switching element 4 are consumed.
On the other hand, in the igniter circuit 10 in the first embodiment shown in FIG. 1, the time during which the resonance current flows through the ignition transformer 3 and the switching element 4 is only the first cycle of the LC resonance, and the primary winding of the ignition transformer 3 The power loss caused by the winding resistance of the wire 3a and the secondary winding 3b and the switching element 4 is [√ {(C ₁ + C ₂ ) / C ₂ }] ² × √ { (C ₁ + C ₂ ) / C ₂ } times, that is, {(C ₁ + C ₂ ) / C ₂ } ^3/2 times.

FIG. 4 shows the initial voltage Vi = 300 [V] of the primary capacitor 2 and the turns ratio of the ignition transformer 3 of 1:40 when the light-emitting stand 7 is in a short-circuit state in the igniter circuit 10 of the first embodiment. The primary capacitor voltage V ₁ , the secondary capacitor voltage V ₂ observed when the capacitance of the secondary capacitor 2 is C ₁ = 160 [nF], and the capacitance of the secondary capacitor 6 is C ₂ = 100 [pF] It is a waveform which shows the result of having simulated the primary winding current _IL1 of an ignition transformer.
As described above, in the igniter circuit 10 of this embodiment, by limiting the time for which the switching element 4 is turned on, the power loss generated in the ignition transformer 3 and the switching element 4 can be significantly reduced as compared with the conventional circuit. .
However, as described above, when the light-emitting stand 7 is short-circuited, the power loss increases by {(C ₁ + C ₂ ) / C ₂ } ^3/2 times as compared with the case where the light-emitting stand 7 is not short-circuited. In order to reduce this increase, the configuration of the second embodiment described below can be adopted.

  FIG. 5 is a schematic configuration diagram of an igniter circuit 20 according to a second embodiment of the present invention. In the igniter circuit 20 of the second embodiment, a damping circuit 8 is added to the igniter circuit 10 of the first embodiment. The damping circuit 8 includes a diode (damping diode) 8b having an anode connected between the primary winding 3a of the ignition transformer 3 and the switching element 4, a cathode of the diode 8b, and the primary winding 3a of the ignition transformer 3. And a resistor 8a connected to the other end. That is, the damping circuit 8 is connected in parallel with the primary winding 3 a of the ignition transformer 3. When the switching element 4 is turned on and a resonance current flows through the primary winding 3a of the ignition transformer 3, the diode 8b is turned on when the voltage across the primary capacitor 2 is reversed in polarity, and the resonance current (negative resonance current) Flows through the damping circuit 8. Thereby, the resonance current flowing through the primary winding 3a and the secondary winding 3b of the ignition transformer 3 can be quickly converged. As a result, the power loss generated in the ignition transformer 3 can be reduced as compared with the case where the damping circuit 8 is not provided.

FIG. 6 is an equivalent circuit diagram in a state where the polarity of the voltage across the primary capacitor 2 becomes negative and the diode 8b becomes conductive in the circuit shown in FIG. Since the diode 8b is conductive, it is short-circuited, and the excitation inductance of the ignition transformer 3 is omitted because it is sufficiently larger than the secondary leakage inductance (primary conversion).
The current I _p flowing through the equivalent circuit shown in FIG. 6 depends on the relationship among the resistor R ₁ , the inductances L ₁ and L ₂ , and the capacitor C ₁ . That is, the change in current is oscillatory (damped vibration) when R ₁ ² <L _s / 4C ₁ , critical braking when R ₁ ² = L _s / 4C ₁ , R ₁ ² > L _s / 4C ₁ Is logarithmic (overbraking).

FIG. 7 shows that in the igniter circuit 20 of the second embodiment, the initial voltage Vi of the primary capacitor 2 is 300 [V], the turns ratio of the ignition transformer 3 is 1:40, and the capacitance of the primary capacitor 2 is C ₁ = 160. [nF] The primary capacitor voltage V ₁ , the secondary capacitor voltage V _2, and the primary winding current I _{L1 of the} ignition transformer observed when the capacitance of the secondary capacitor 6 is C ₂ = 100 [pF] It is a waveform which shows the result of having simulated. As shown in the figure, in the critical braking, the primary winding current in the reverse direction does not flow unlike the damping braking, and the primary winding current quickly converges to 0 unlike the overbraking.
FIG. 8 shows an example of a result of simulation calculation of energy loss generated in the ignition transformer (winding resistance) 3 and the damping circuit 8 with respect to the resistance value of the resistor 8 a in the damping circuit 8. In this example, the resistance value of the damping resistor that minimizes the energy loss generated in the ignition transformer 3 is about 9Ω with respect to the resistance value (4.6Ω) of the damping resistor that becomes critical braking. At this time, the energy loss generated in the ignition transformer 3 is about 40% lower than that without the damping circuit.
Thus, by providing the damping circuit 8, energy loss caused by the winding resistance of the ignition transformer 3 when the light emitting stand 7 is short-circuited can be reduced. The resistance value of the damping resistor is preferably R ₁ ² = L _s / 4C ₁ which is critical braking, but practically, a sufficient effect can be obtained by setting the resistance value to a range four times that value. I can expect.

  9 shows the energy loss of the ignition transformer for the conventional igniter circuit shown in FIG. 10, the igniter circuit 10 in the first embodiment shown in FIG. 1, and the igniter circuit 20 in the second embodiment shown in FIG. It is an example of the result of having calculated (power loss). As is clear from this figure, according to the igniter circuits in the first and second embodiments of the present invention, compared with the conventional igniter circuit, when no discharge occurred in the light emitting stand or the light emitting stand was short-circuited. In this case, power loss caused by the ignition transformer or the switching element can be reduced. In particular, according to the igniter circuit in the second embodiment, the power loss caused by the ignition transformer and the switching element when the light-emitting stand is short-circuited is about ½ that of the igniter circuit in the first embodiment. Can be reduced.

  Therefore, in the emission analyzers of the first and second embodiments according to the present invention, the ignition transformer and the switching element are cooled using a heat sink, a cooling fan, etc., or a thermal fuse, a temperature sensitive switch, a thermistor, etc. Thus, it is not necessary to prevent overheating of the ignition transformer and the switching element, and the igniter circuit can be reduced in size and weight, and the cost can be reduced. Moreover, since it is not necessary to deliberately lower the discharge repetition frequency in order to avoid overheating, the discharge repetition frequency can be increased and the analysis time can be shortened.

  It should be noted that the above embodiment is an example of the present invention, and it is obvious that any modification, addition, or modification within the scope of the present invention is included in the scope of the claims of the present application.

DESCRIPTION OF SYMBOLS 10, 20 ... Igniter circuit 2 ... Primary capacitor 3 ... Ignition transformer 3a ... Primary winding 3b ... Secondary winding 4 ... Switching element 6 ... Secondary capacitor 7 ... Light emitting stand 7a ... Discharge electrode 7b ... Sample 8 ... Damping Circuit 8a ... resistor 8b ... diode 15 ... switching element driver

Claims (4)

An ignition transformer, a primary capacitor and a switching element connected to a primary winding of the ignition transformer, a drive circuit for driving the switching element, and a secondary winding side of the ignition transformer, the secondary winding An igniter circuit comprising at least a secondary capacitor including at least a stray capacitance, a discharge electrode for generating discharge by the igniter circuit, and a light emitting stand including a sample, wherein the primary capacitor is charged to a predetermined voltage. In this state, the switching element is turned on, and an LC resonance current due to a series combined capacity of the primary capacitor and the secondary capacitor and a leakage inductance of the ignition transformer is passed through the primary winding of the ignition transformer. High voltage on the light-emitting stand along with the secondary winding of the ignition transformer In optical emission spectrometer to generate discharge is generated,
After the switching element is turned on, the driving circuit switches a pulsed driving signal that turns off the switching element during a period in which the polarity of the current flowing in the primary winding of the ignition transformer is reversed. An emission analyzer characterized by being supplied to an element. An ignition transformer, a primary capacitor and a switching element connected to a primary winding of the ignition transformer, a drive circuit for driving the switching element, and a secondary winding side of the ignition transformer, the secondary winding An igniter circuit comprising at least a secondary capacitor including at least a stray capacitance, a discharge electrode for generating discharge by the igniter circuit, and a light emitting stand including a sample, wherein the primary capacitor is charged to a predetermined voltage. In this state, the switching element is turned on, and an LC resonance current due to a series combined capacity of the primary capacitor and the secondary capacitor and a leakage inductance of the ignition transformer is passed through the primary winding of the ignition transformer. High voltage on the light-emitting stand along with the secondary winding of the ignition transformer In optical emission spectrometer to generate discharge is generated,
A damping circuit is provided in parallel with the primary winding of the ignition transformer, in which a diode and a resistor are connected in series when the current flowing through the primary winding due to resonance has a reverse polarity and a resistor. Luminescence analyzer. The emission analyzer according to claim 1,
A damping circuit is provided in parallel with the primary winding of the ignition transformer, in which a diode and a resistor are connected in series when the current flowing through the primary winding due to resonance has a reverse polarity and a resistor. Luminescence analyzer. The emission analyzer according to claim 2 or 3,
The resistance in the damping circuit has a resistance value in the range of 1 to 4 times the resistance value at which the LC resonance circuit formed by the primary capacitor and the leakage inductance of the ignition transformer becomes critical braking. Emission analyzer.

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