JP2001343360A - Measuring device for ion quantity in gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a measuring device for ion quantity which can measure correctly the ion concentration in a gas to be measured containing some kinds of ions of different mobility without being affected by a surrounding noise or humidity and also can measure only the ion concentration of an ion having targeted polarity correctly excluding an ion having unwanted polarity. SOLUTION: This measuring device for ion quantity is provided with an ion converting electrode which removes the charge from ions existing in a gas, a supplying means for the gas to be measured which supplys a gas containing ions to the ion converting electrode, an electricity quantity processing part which process the quantity of electricity generated in the ion converting electrode, an electricity quantity measuring part which measures the quantity of the processed electricity, and an ion guiding means which returns the ions unable to be converted in the ion converting electrode back to the ion converting electrode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas ion amount measuring apparatus for measuring the concentration of ions existing in an atmosphere such as air.

[0002]

2. Description of the Related Art An apparatus for measuring the ion concentration in a gas is well known, and is disclosed, for example, in Japanese Patent Application Laid-Open No. 6-194340. In this apparatus, as shown in FIG. 19, a spherical electrode 1 is arranged in an atmosphere to be measured, the number of ions colliding with the spherical electrode 1 per unit time is detected as an ion current, and the ion current is detected by an operational amplifier. A method of converting and amplifying the voltage and measuring the ion concentration as the voltage is adopted.

[0003] With respect to the spherical electrode 1, the ions carry charges to the electrode 1 by diffusion of the ions almost independently of the direction of the ions, whereby an ion current flows. When the electrode 1 is spherical, current I ⁺ is due to the positive ions are absorbed by the spherical electrodes, the following formula ^{I + = 4πR · e · n} + · κ + · C · U - is determined by. Where R is the radius of the spherical electrode, e is the basic charge, n ⁺ is the number of positive ions, κ ⁺ is the mobility of the positive ions, C is the spherical capacitance to the environment, and U ^- is the spherical voltage to earth potential ( In this case, a negative voltage)
It is. For the current I ⁻ caused by the negative ions, the sign is reversed, resulting in a voltage U ^{+ at the} spherical electrode.

In this example, the electrode 1 is connected to the inverting input of the operational amplifier 3, and the output of the operational amplifier 3 is negatively fed back to the inverting input of the operational amplifier 3 via the resistor 4. Acting as a converter, the AC component of the output of the operational amplifier 3 is passed through a capacitor 5 connected in parallel with the resistor 4 to
Negative feedback has been received. The output of the operational amplifier 3 is
The output of the evaluation circuit 10 is connected to a display 11, a comparison circuit 12, and an alarm unit 13.

The non-inverting input of the operational amplifier 3 is connected to a reference potential 14 via a switch 8 controlled by a control unit 9.
(Ground potential), connected to the positive voltage source 6 or the negative voltage source 7,
The electrodes are biased to a ground potential, a positive potential, or a negative potential accordingly, and the concentration of positive and negative ions, the concentration of only negative ions, Alternatively, the concentration of only positive ions can be measured. This is because, when the control unit 9 controls to selectively connect to the positive or negative voltage sources 6, 7, a positive or negative voltage is applied to the non-inverting input of the operational amplifier 3, and the electrode is changed depending on the characteristics of the operational amplifier. 1 is set to this positive or negative voltage. Of the ions at the potential set for the spherical electrode, only negative ions or positive ions respectively collide with the electrode 1 and pass the charge to the electrode, so that it is possible to separate the positive and negative ions and measure the concentration. it can.

As can be seen from the above equation, the current does not depend on the velocity of the gas. The current flowing from the electrode 1 forming the sensor via the switch 2 is compensated by the operational amplifier 3 and the resistor 4 functioning as a current / voltage converter,
The output voltage of the operational amplifier is the product of the resistance 4 and the input current from the electrode 1. The voltage at the electrode 1 always becomes the applied potential of the non-inverting input of the operational amplifier 3 without depending on the input current.

The current / voltage converter has a low-pass characteristic due to negative feedback via the capacitor 5, and interference caused on the electrode 1 by, for example, an ion generator is suppressed. Such electrical spurious signals are
Through the capacitance, it is coupled to the interference source as an interference current. The spurious AC voltage is attenuated by the ratio of the sensor capacitance to the interference source to the negative feedback capacitance 5 and appears at the output of the operational amplifier 3. In the evaluation circuit 10, the voltage supplied by the operational amplifier 3 is temporarily stored, evaluated by Rieck's equation to determine the number of existing ions, and the determined number of ions is displayed on the display 11. You.

Another example of the prior art is disclosed in Japanese Patent Application Laid-Open No. 8-45.
No. 453 discloses an apparatus for measuring the amount of ions in gas.
FIG. 20 shows the outline of this device. A positive voltage and a negative voltage are applied to a pair of electrode plates 21a and 21b opposed at a constant interval, and the pair of electrode plates 21a and 21b are applied between the electrode plates 21a and 1b. A predetermined electric field is formed, and a gas to be measured 24 containing ions is supplied between the electrode plates. Positive and negative ions accelerated by the electric field are attracted to each electrode and collide, and ion current flows, and by measuring this current respectively,
The amount of positive and negative ions can be measured.

[0009]

The conventional ion measuring apparatus in gas using the above-mentioned spherical electrode has an error in the ion concentration in the gas when the gas contains several kinds of ions having different mobilities. And the lower the mobility, the lower the collection efficiency.

In addition, the above-described measuring apparatus using a pair of opposed electrodes requires the ion to collide with the electrodes with high efficiency.
It is necessary to increase the electric field strength between the electrodes as much as possible,
If the distance between the electrodes is shortened, the pressure loss of the gas flowing between the electrodes increases, and the gas containing ions cannot be efficiently supplied between the electrodes. On the other hand, when the distance between the electrodes is increased, the voltage applied to the electrodes must be increased. Furthermore, in the conventional apparatus for measuring the amount of ions in gas, when measuring a minute current converted by ions, there is a problem that the minute current cannot be accurately measured due to the influence of ambient noise and humidity.

SUMMARY OF THE INVENTION In view of the above problems, the present invention provides a gas capable of efficiently collecting ions in a gas to be measured and accurately measuring the amount of current generated by converting the ions. It is an object of the present invention to obtain a medium ion amount measuring device and a gas ion amount measuring method.

[0012]

According to the present invention, there is provided an apparatus for measuring the amount of ions in a gas, comprising: an ion conversion electrode for removing charges from ions present in the gas; It comprises a measuring gas supply means, an electric quantity processing section for processing the electric quantity generated in the ion conversion electrode, and an electric quantity measuring section for measuring the magnitude of the processed electric quantity.

That is, the apparatus of the present invention comprises an ion conversion electrode for receiving charges of ions present in a gas to be measured in a wind tunnel forming an atmosphere gas flow, and a gas supply for supplying the gas to the ion conversion electrode. Means are arranged, the gas taken into the wind tunnel by the gas supply means is brought into contact with the ion conversion electrode, and the electric charge of the ions is input as a current to the electric quantity processing unit, and the electric charge proportional to the ion electric charge amount is provided. It is output as a signal.

In the present invention, a metal porous body disposed in a wind tunnel and through which gas can flow can be used for the ion conversion electrode, and more preferably, a metal net is used for the metal porous body. .

The electric quantity processing section of the present invention preferably includes a current-voltage conversion circuit for converting an electric quantity into a voltage signal, and a noise removal filter circuit for the voltage signal. After removal, a voltage signal is obtained.

[0016] At least the inner surface of the wind tunnel is formed of an electrical insulator, thereby preventing consumption of ions in the wind tunnel air flow and preventing a decrease in measurement accuracy. The wind tunnel
Further, it may be made of a conductor, and in this case, a wind tunnel in which the wind tunnel is electrically insulated from the ground can be employed.

In the measuring device of the present invention, it is preferable that the ion conversion electrode is insulated from the wind tunnel via an insulating support. Further, it is preferable to provide a potential adjusting means capable of arbitrarily changing the reference potential of the ion conversion electrode. This reference potential is ground potential (or space potential)
By setting to a more positive or negative potential, only negative ions or positive ions can selectively pass charges to the ion conversion electrode, respectively, and the ion concentration of that polarity can be measured from the amount of electricity. it can.

In this case, the ion conversion electrode is connected to the inverting input of the differential operation unit of the current-voltage conversion circuit, and the potential adjusting means is connected to the non-inversion of the differential operation unit of the current-voltage conversion circuit. A DC power supply circuit that can be switched between a positive potential and a negative potential connected to the input can be used.

According to the present invention, an ion guiding means for guiding ions in the airflow in the wind tunnel to the ion conversion electrode can be employed in the wind tunnel. The ion inducing means is a means for preventing a measurement error from passing through the ion conversion electrode without passing an electric charge, and the ion inducing means is a metal conductor arranged in an air flow. A DC power supply for applying a DC voltage is included. As the ion inducing means, an ion repelling electrode arranged on the downstream side of the ion conversion electrode and an ion inducing electrode arranged on the upstream side can be used, and both have a potential of the same polarity as the charge of the ion to be measured. You.

The ion repelling electrode is preferably a metal mesh, and is disposed at the rear. The ions to be measured that have passed through the ion conversion electrode are repelled to the upstream side to increase the efficiency of capture at the ion conversion electrode. As the other ion induction electrode, a metal conductor having an opening area ratio of 80% or more can be used, and the ions to be measured passing through are converged on the ion conversion electrode to increase the capture efficiency.

One or two or more conductors can be used in which the ion conversion electrode is arranged in the airflow direction in a wind tunnel having an opening through which gas can be sucked. A measuring device in which a conduit is arranged so as to allow gas flow and a potential having a polarity opposite to the ionic charge to be measured is applied can also be used. The metal conduit to which the DC potential is applied acts as an ion repulsion electrode or an induction electrode, and captures a target ion in a conducting wire, that is, a metal wire, and detects an ion current.

In the present invention, the gas supply means is preferably a suction fan disposed downstream of the ion conversion electrode. In particular, a DC motor is employed as a motor for driving the fan, thereby stabilizing the rotational speed, making the suction speed of the gas to be measured constant, and improving the measurement accuracy.

It is preferable that the diameter of the opening of the wind tunnel is larger than the diameter of the wind tunnel at the position where the ion conversion electrode is disposed, so that the input amount in the laminar flow is increased. Conversely, the opening of the wind tunnel is smaller than the diameter of the wind tunnel at the position of the ion converter, reducing the flow velocity near the ion conversion electrode, thereby increasing the ion capture efficiency and increasing the measurement sensitivity. be able to.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. Embodiment 1 FIG. In FIG. 1, this embodiment is an example in which an ion exchange electrode 31 using a wire mesh is used as an ion conversion electrode. The ion exchange electrode 31 is used to guide a gas to be measured 24 containing ions therein. A measured gas supply unit 33 for supplying the measured gas 24 to the ion exchange electrode 31 is disposed in the wind tunnel 32,
That is, a blower is arranged.

As the ion exchange electrode 31, a metal net having appropriate flow holes is used. The metal mesh also includes a mesh formed by forming a suitable mesh with woven or knitted metal wires or bands, or a perforated metal plate. Here, a wire mesh in which a metal wire is plain woven is used. The outer edge of the ion-exchange electrode 31 is insulated in the wind tunnel through a support base 34, and the mesh surface is arranged substantially perpendicular to the axial direction of the wind tunnel, and the mesh is used for gas flow, Use metal wires as electrodes.

The ion exchange electrode 31 is provided with an electric quantity processing unit 35.
And converts the ion current generated in the electrode into an electric quantity signal of a level that can be easily measured.
5 is connected to the electric quantity measuring unit 36 and the electric quantity processing unit 3
From the electric quantity signal output from the ion exchange electrode 31
To calculate the quantity of electricity of the ions that collided with.

In the wind tunnel, a gas 24 containing ions in the atmosphere to be measured is sucked at a constant flow rate from a blower 33 and guided to the ion exchange electrode 31, and the ions in the gas 24 collide with the ion exchange electrode 31. . At this time, the shape of the ion exchange electrode 31 is determined according to the cross-sectional shape of the wind tunnel 32 so that the gas 24 taken in from the atmosphere to be measured can be uniformly supplied to the ion exchange electrode 31.

Charge is supplied to the ion exchange electrode 31 by collision of ions. Since the ion exchange electrode 31 is insulated from the wind tunnel by the support plate 34, the electric charge of the ion exchange electrode 31 flows as a current only toward the electric quantity processing unit 35. Since the level of the current flowing from the ion exchange electrode 31 to the electric quantity processing unit 35 is at most the nA level, it is converted into a signal level that can be easily measured by the electric quantity processing unit 35. That is, when converting to a current, the current is converted to a current of several mA to several A, and when converting to a voltage, it is converted to a voltage of several mV to several V. The signal converted by the electric quantity processing unit 35 in this manner is output to the electric quantity measurement unit 3.
In step 6, the current flowing from the ion exchange electrode 31 to the electric quantity processing unit 35 is determined. Assuming that the current flowing from the ion exchange electrode 31 to the electric quantity processing unit 35 is I [A], the ion concentration n [ions / cm ³ ] in the gas to be measured can be represented by n = I / (eQ). . Here, e is the elementary charge [C] of the ion, and Q is the flow rate of the gas to be measured supplied to the ion exchange electrode 31 [cm ³ / s].

In this embodiment, as shown in FIG. 1B, the electric quantity processing unit 35 includes a current-voltage converter 351.
, A buffer amplifier 352, and a voltage-current converter 353.
It is comprised including. Current-voltage converter 351
Is a high input impedance operational amplifier D and a super high resistance R
And performs a current-voltage conversion with a very large gain, and functions as a low-pass filter by providing a capacitor C for determining a cutoff frequency in the feedback system. This current-voltage converter D
The pA to nA level current output from the ion exchange electrode 31 is amplified to a voltage level of several mV to several V, and at the same time,
Removes noise superimposed on the input current. As a result, a current corresponding to only the ion concentration is accurately converted into a voltage.

Although not shown, the buffer amplifier 352
It consists of an operational amplifier with low output impedance,
After the output voltage of the voltage converter is buffer-amplified to generate a sensor voltage, the sensor voltage is converted to a voltage-current converter 353.
And outputs it to the electric quantity measuring unit 36. The voltage-current converter 353 is configured by a dedicated analog integrated circuit, and measures a sensor current of several mA to several tens mA generated by performing voltage-current conversion of a sensor voltage buffer-amplified by a buffer amplifier. Output to the unit 36.

In the example shown in FIG. 1B, the inverted input terminal P of the high input impedance operational amplifier D constituting the current-to-voltage converter 31 in the electric quantity processing unit 35 is grounded. The reference potential of the operational amplifier D is set to zero potential. Thereby, the ion exchange electrode 31
It is at zero potential.

As described above, in this embodiment, the ion amount measuring device in the gas includes the ion exchange electrode 31 composed of the wire mesh electrode disposed in the wind tunnel, and the wind tunnel 32 from the external environment.
Blower 3 which draws gas into ion exchange electrode 31
3, an electric quantity processing unit 35 for processing the electric quantity generated by the ion exchange electrode 31 with a filter circuit, and an electric quantity measuring unit 36 for measuring the magnitude of the electric quantity. Only the amount of electricity obtained by the conversion can be accurately measured without being affected by ambient noise and the like, and the ion concentration can be accurately measured. Also, since the gas to be measured 24 is forcibly sent to the ion exchange electrode 31 efficiently,
Even if several types of ions having different mobilities are included, the ion concentration in the gas to be measured can be clarified.

The wind tunnel 32 is a cylinder or a conduit for guiding the gas 24 containing ions from the atmosphere to be measured to the ion exchange electrode 31. Preferably, at least the inner surface is formed of an insulating material, and Is done.

When ions in the gas collide with an object, they transfer charges to and from the object. Therefore, when accurately measuring the ion concentration in the gas to be measured 24, the ions in the ion conversion electrode It is important to efficiently supply the gas to be measured 24 to the exchange electrode 31. When the material of the wind tunnel 32 is made of a non-conductor (insulator), the ions collide with the inner surface of the wind tunnel 32 and charge the inner surface of the wind tunnel 32, reaching the saturated charge amount of the non-conductor forming the inner surface. Since only the surface portion of the conductor is charged, the time to reach the saturated charge amount is short, and the measurement of ions can be started. In the case of a non-conductor, no current flows in the thickness direction of the wind tunnel 32. Therefore, by increasing the thickness of the non-conductor forming the wind tunnel 32, leakage current from the contact portion of the outer wall surface of the wind tunnel 32 is eliminated. be able to.

On the other hand, when the material of the wind tunnel 32 is a conductor such as a metal, ions in the gas collide with the inner surface of the wind tunnel 32 and transfer electric charges to the inner surface of the wind tunnel 32. In the case where the wind tunnel 32 is grounded, the electric charge flows to the ground without staying, so that the ions are constantly eliminated in the wind tunnel 32 before reaching the electrodes, resulting in a large measurement error.

On the other hand, if the wind tunnel 32 is not grounded, the charge loses its destination and the wind tunnel 32 is gradually charged. The extinction on the wall surface 32 stops, and the ions are supplied to the ion exchange electrode 31. However, since the metal wind tunnel 32 has a large charging capacity, it takes a considerable amount of time to measure ions. Since the entire metal is charged, if there is a leakage current from the contact portion, the ions are continuously consumed.

As described above, by forming the inner surface of the wind tunnel 32 with a non-conductor, the amount of ions in the gas to be measured 24 can be accurately measured, and the ion measurement time can be shortened. The effect is obtained that the ions in the gas to be measured 24 existing in the space can be measured online.

In FIG. 2, the wind tunnel 32 can be made of a metal conductor. In this case, the wind tunnel 32 is supported by a non-conductive support 37 to insulate it from the ground potential. It is preferable to supply a constant voltage from the DC power supply 38 with the same polarity as the polarity of the ions to be measured. If a direct current is applied by the direct current power supply 38, a constant charge can be immediately applied from the outside, so that the time for charging the inner surface of the wind tunnel 32 is not required, and the amount of ions in the gas 24 can be measured immediately. effective.

The blower 33 guides the gas to be measured 24 to the ion exchange electrode 31. In order to accurately measure the ion concentration in the gas to be measured 24, the efficiency of the ion exchange electrode 31, which is an ion conversion electrode, is increased. It is important to supply the measured gas 24 at a constant rate. Therefore, the blower 33 for guiding the gas to be measured 24 to the ion exchange electrode 31 is also
It is one of the important components of a gas ion amount measuring device for accurately measuring ion concentration.

The blower 33 is preferably disposed downstream of the ion exchange electrode 31, which is an ion conversion electrode. The sucked gas 24 is supplied to the blower 33 first.
Can be supplied to the ion-exchange electrode 31 without passing through, so that the annihilation of ions in the blower 33 can be avoided. In this case, the ion exchange electrode 31
Since the gas from which ions have been removed is sucked, the blower 33
Irrespective of the presence or absence of grounding, malfunction due to charging of the blower 33 can be prevented, and a fixed amount of gas to be measured can be supplied to the ion exchange electrode 31.

On the other hand, when the blower 33 is disposed upstream of the ion exchange electrode 31 which is an ion conversion electrode, ions in the gas to be measured 24 collide with the blower 33 and
, The ions are constantly extinguished by the blower 33, so that ions cannot be supplied to the ion exchange electrode 31 at a constant air volume, resulting in an error in the ion amount measurement. Alternatively, when the blower 33 is not grounded, the electric charges may charge the blower 33 and cause the electric circuit of the blower 33 to malfunction.

As described above, by installing the blower 33 downstream of the ion exchange electrode 31, which is an ion conversion electrode, the amount of ions in the gas to be measured 24 can be accurately measured. Can be supplied to the ion exchange electrode 31 at a constant air volume, and the concentration of ions present in a constant volume can be measured.

Next, the blower 33 determines the ion concentration in the gas 24 by dividing the current flowing into the ion exchange electrode 31 by the product of the elementary charge and the air flow. It is preferable that the blowing amount of the gas 24 be constant. For this purpose, the amount of electric power supplied to the blower 33 is maintained constant, and the pressure loss in the gas ion content measuring device is maintained constant.

As the blower 33, a rotary pump of continuous blade rotation type, that is, a fan can be preferably used. Although a reciprocating pump can be used, since the gas to be measured 24 is pulsated and transported to the ion exchange electrode 31, the stability of the flow rate of the gas 24 supplied to the ion exchange electrode 31 is higher than that of the continuously rotating fan. Will be lower.

The fan-type blower 33 is mainly divided into an AC condenser run motor, an AC bear motor, and a DC brushless motor depending on a difference in the motor. The DC brushless motor (Hall element motor) is
It is excellent in that there is no electric noise, stable control of rotation speed, and prevention of generation of unnecessary ions.

As shown in FIG. 3, the DC brushless motor preferably performs DC conversion from an AC commercial power supply 39 by an AC / DC converter 40 to drive a DC brushless motor provided inside the blower 33. . This is because the blower 33 can be operated without being influenced by the input power source, the measured gas 24 having a constant air volume can be stably supplied to the ion exchange electrode 31, and the ion amount in the measured gas 24 can be reduced. Can be measured accurately.

As described above, by using a suction fan as the blower 33 and using a DC brushless motor (Hall element motor) as the drive motor, the gas to be measured 24 can be supplied to the ion exchange electrode 31 at a constant air flow rate. The effect is obtained that the concentration of ions present in the volume can be accurately measured.

Regarding the structure of the wind tunnel 32, as described above, the ion concentration in the gas to be measured 24 is measured by causing the ions in the gas to be measured 24 to collide with the ion exchange electrode 31. It is important that the gas to be measured 24 flow uniformly to the ion exchange electrode 31.
For this purpose, the flow of the gas to be measured 24 in the wind tunnel 32 is preferably a laminar flow.

FIG. 4 shows the relationship between the diameter of the wind tunnel and the gas flow rate for the gas flow to become a laminar flow. all right. Therefore, assuming that the diameter of the wind tunnel is D [cm], the gas flow rate Q [cm ³ / sec] that can maintain the laminar flow state is the viscosity μ [g / cm / sec] of the measured gas and the density ρ of the measured gas. As [g / cm ³ ], Q = 1.9 × 10 ³ × μ / ρ × D. By setting the flow rate of the gas to be measured smaller than the value of the gas flow rate calculated by this equation, It was found that ions could be efficiently converted to electric current.

As shown in FIG. 5, even if the enlarged diameter wind tunnel 41 is provided at the inflow portion of the wind turbine 32 for taking in the gas to be measured, there is an effect of suppressing the generation of turbulence due to external disturbance. I understood. As a result, the flow rate of the gas to be measured that can be taken into the wind tunnel can be increased, so that the specifications of the microcurrent measurement circuit, such as the amplification factor of the buffer amplifier can be reduced, can be reduced. This has the effect of reducing costs.

FIG. 6 shows another example of laminar flow, in which a blower 3 is provided behind an ion exchange electrode 31 which is an ion conversion electrode.
Before 3, a passage for a current plate, for example, a perforated plate 42 (a plate material having many through holes) or a honeycomb plate 43 may be provided. The baffle plate suppresses the generation of turbulence on the upstream side due to the rotation of the blades of the fan. Thus, similarly to the case where the enlarged diameter portion 41 of the wind tunnel is attached, the laminar flow state is maintained. The flow rate of the gas that can be sucked into the body 32 can be increased, the amplification factor of the buffer amplifier can be reduced, and the specification of the microcurrent measurement circuit can be reduced, and the cost of the microcurrent measurement circuit can be reduced. effective.

As described above, the wind tunnel 3 for taking in the gas to be measured
2, the opening, that is, the inflow portion is provided with an enlarged portion 41,
Further, by providing the perforated plate guide 42 and the honeycomb-shaped rectifying plate 43 behind the ion exchange electrode 31 which is an ion conversion electrode, the amount of gas 24 taken in can be increased in a laminar state from the atmosphere. A relatively small and stable ion measurement device can be provided.

The structure of the ion exchange electrode 31 is such that the relationship between the aperture ratio of the ion exchange electrode 31 and the ion collection rate of the ion exchange electrode 31 is shown in FIG.
It can be understood that when the aperture ratio of the sample gas is set to 10% or less, ions in the gas to be measured 24 sucked into the wind tunnel 32 can be collected at a collection rate of almost 100%. When measuring the ion concentration, the aperture ratio of the ion exchange electrode 31 is set to at least 10% or less at a practical wind speed in the wind tunnel 32,
Can be designed. As described above, by setting the aperture ratio of the ion exchange electrode 31 to 10% or less, an effect of accurately measuring the ion concentration in the gas to be measured 24 can be obtained.

The material of the ion exchange electrode 31 is made of a metal having a low electric resistance. For example, gold, silver, copper, platinum, palladium, aluminum, cobalt, nickel, iron or steel, particularly stainless steel is used. .

Since the ion concentration in the gas to be measured 24 is measured by colliding the ions in the gas to be measured 24 with the ion exchange electrode 31, the charge deprived of the colliding ions is transferred from the ion exchange electrode 31 to the electric quantity converter. 35, without attenuation
And it is important to supply as soon as possible. For this purpose, it is necessary to use a metal having a low electric resistance for the ion exchange electrode 31. However, gold, silver, platinum, palladium, etc. are expensive, copper, aluminum,
Iron and the like are easily oxidized and corroded, and may be particularly damaged depending on the corrosiveness of the measurement atmosphere gas. The resistance value may change with the passage of time, and the performance of the ion exchange electrode 31 may not be guaranteed for a long period of time.

Therefore, it is most practical to use stainless steel for the ion exchange electrode 31 in consideration of low cost, low electric resistance and corrosion resistance. It is also possible to suppress the oxidative corrosion of the ion exchange electrode 31 while reducing the metal resistance value of the surface of the ion exchange electrode 31 by plating the surface of a base metal such as copper, aluminum, and iron with gold.

As described above, since the ion exchange electrode 31 is made of a metal material such as stainless steel or gold-plated copper, aluminum, or iron, the amount of ions in the gas 24 can be accurately measured over a long period of time. In addition to this, it is possible to provide a low-cost gas ion amount measuring device.

Since an extremely small current flows through the electric wire connected from the electrode to the electric quantity processing unit 35, the electric shield wire whose electric wire portion is electrostatically shielded so as not to be affected by noise from the surroundings. It is desirable to use.

It is particularly preferable that the electric quantity processing section 35 is electromagnetically shielded. In this example, each component is mounted on a printed circuit board for mounting components, and the printed circuit board is built in a storage case. Specifically, the storage case is formed of stainless steel in the shape of a box having an upper surface opening, and a plurality of columns are erected at the bottom thereof.
Further, the printed circuit board is built in a state of being separated from the bottom of the storage case by being screwed to the support. Since the electric quantity processing unit 35 is shielded by the storage case, the occurrence of malfunction due to external noise is reliably prevented.

Further, it is preferable that the electric quantity processing unit 35 is protected by a moisture proof material. For the purpose of preventing moisture, the interior space of the storage case is filled with a filler (ie, a moisture barrier) such as urethane resin for electrical insulation. In addition, since the filler prevents water droplets from adhering to each component during the dew condensation, the electric quantity processing unit 35 prevents the gain fluctuation due to the dew condensation, so that the current-voltage conversion process can be performed accurately and reliably. Will be

As a connection cable for connecting the electric quantity processing unit 35 and the electric quantity measuring unit 36, for example, an electric shield wire such as a coaxial cable is used. The superposition of noise on the sensor current is prevented. With the above configuration, the electric quantity measuring unit 36 can accurately measure the ion concentration in the gas without being affected by external noise or fluctuation of environmental conditions.

Embodiment 2 FIG. 8 is a configuration diagram showing an apparatus for measuring the amount of ions in gas according to Embodiment 2 of the present invention. A DC voltage adjusting device 51 is provided for changing the reference potential of the operational amplifier D having a high input impedance, which constitutes the current-voltage converter 351 in the electric quantity processing unit 35.

The DC voltage regulator 51 is not shown,
A positive voltage and a negative voltage are connected to a non-inverting input terminal P of a high input impedance operational amplifier D constituting a current-voltage converter 351 through a selection switch (FIG. 1).
(B)), applying a positive voltage or a negative voltage. When the potential of the non-inverting input terminal P of the operational amplifier D is set to a positive potential, the ion exchange electrode 31 is charged to a positive polarity. Gas to be measured 24
Since the negative ions therein are of a different polarity from the ion exchange electrode 31, they are attracted and moved toward the ion exchange electrode 31, and finally collide with the ion exchange electrode 31 to supply negative charges to the ion exchange electrode 31. I do. In this case, since the positive ions have the same polarity as the ion exchange electrode 31,
1 and is emitted to the outside of the wind tunnel 32 through the blower 33 without repelling and colliding. By doing so, it is possible to collect only the negative ions in the gas to be measured 24 and to know the ion concentration.

Since the ion-exchange electrode 31 is insulated by the support plate 34, the negative charge supplied to the ion-exchange electrode 31 flows as a current only toward the electric quantity processing unit 35. Since the level of the current flowing from the ion exchange electrode 31 toward the electric quantity processing unit 35 is at most the nA level, it is converted by the electric quantity processing unit 35 into an easily measurable electric quantity level. That is, when converting to a current, the current is converted to a current of several mA to several A, and when converting to a voltage, it is converted to a voltage of several mV to several V. The signal converted by the electric quantity processing unit 35 in this manner is output to the electric quantity measurement unit 3.
6, the amount of electricity per unit time which is converted into the amount of electricity and flows from the ion exchange electrode 31 to the amount of electricity processing unit 35 is obtained.
The negative ion concentration in the gas is calculated.

When the reference potential of the operational amplifier having high input impedance constituting the current-voltage converter in the electric quantity processing unit 35 is set to a negative potential by the DC voltage adjusting device 51, the ion exchange electrode 31 is turned off. Is negatively charged. Since the positive ions in the gas to be measured 24 have a different polarity from the ion exchange electrode 31, the positive ions move toward the ion exchange electrode 31, and finally collide with the ion exchange electrode 31 to generate a positive charge. To supply. On the other hand, since the negative ions have the same polarity as the ion exchange electrode 31,
The air does not collide with 1 and passes through the blower 33 and is discharged outside the wind tunnel 31. By doing so, the measured gas 2
Only the positive ions in 4 can be collected and the ion current can be measured.

As described above, the current-
Since the DC voltage adjusting device for changing the reference potential of the high input impedance operational amplifier constituting the voltage converter is provided, the positive ion amount and the negative ion amount in the gas under measurement 24 are provided. Can be separately measured, only the ions of the polarity to be measured can be collected, and the concentration of the ions of the polarity to be measured in the gas to be measured 24 can be accurately measured.

Embodiment 3 This embodiment shows an example in which a repulsion electrode 61 is arranged as ion guiding means as shown in FIG. The repulsion electrode 61 is for guiding ions that have passed through the ion exchange electrode 31 serving as an ion conversion electrode into the wind tunnel again to the ion exchange electrode 31, and is disposed behind the ion exchange electrode 31. As the repulsion electrode, a metal mesh is used. A voltage of the same polarity as the ion species to be measured is applied to the repulsion electrode 61 by the DC power supply 38.
More applied. The repulsion electrode 61 is provided on an insulating support base 61.
Is insulated and attached to the wind tunnel 32 by utilizing the above.

The ions to be measured in the gas to be measured 24 collide with the wire mesh electrode when passing through the ion exchange electrode 31 together with the gas flow, and give the charge to the ion exchange electrode 31. It passes through the mesh of the ion exchange electrode 31 and enters the space between the ion exchange electrode 31 and the repulsion electrode 61. Since a voltage having the same polarity as the ion to be measured is applied to the repulsion electrode 61, ions passing through the ion exchange electrode 31 are repelled by the repulsion electrode and returned to the original ion exchange electrode. Since the charge is transferred to the ion exchange electrode 31, the ion trapping efficiency is high, the current is high,
Measurement accuracy can be increased.

A positive voltage is applied to the repelling electrode 61 when measuring positive ions, and a negative voltage is applied to the repelling electrode 61 when measuring negative ions. As a result, an electric field from the repulsion electrode 61 toward the ion exchange electrode 31 during positive ion measurement and an electric field from the ion exchange electrode 31 toward the repulsion electrode 61 during negative ion measurement are generated between the ion exchange electrode 31 and the repulsion electrode 61. appear. Therefore, the ions that have entered between the ion exchange electrode 31 and the repulsion electrode 61 move toward the ion exchange electrode 31 under the force of the electric field, and eventually collide with the ion exchange electrode 31 to transfer the charge to the ion exchange electrode 31. 31. Since the ion-exchange electrode 31 is insulated and installed by the support plate 34, the electric charge supplied to the ion-exchange electrode 31 flows as a current only toward the electric quantity processing unit 35.

Next, the ion exchange electrode 31 and the repulsion electrode 61
The strength of the electric field created between them is related to the ion collection efficiency. In both cases, an electric field strength is generated between the ion exchange electrode 31 which is a wire mesh electrode and the repulsion electrode 61. In FIG. The wind speed of the gas to be measured 24 is 1.4 m / s
In the case of (1), it is understood that 100% of ions can be collected by applying an electric field of 8 kV / m or more. Similarly, when the wind speed is 3.6 m / s, an electric field of 18 kV / m is applied, and when the wind speed is 4.9 m / s, an electric field of 25 kV / m is applied, whereby 100% of ions can be collected. .

FIG. 11 shows the relationship between the wind speed and the required minimum electric field strength when 100% of the ions are collected. As described above, the relationship between the wind speed v and the electric field strength E is as follows. It was found that the relationship of the formulas shown holds. E [V / m] = 5.5 × 10 ³ × v [m / s]

Therefore, when measuring the ions in the gas to be measured 24, the distance between the ion exchange electrode 31 and the repulsion electrode 61 and the voltage applied to the repulsion electrode 61 are designed so as to satisfy the above equation. Is preferred.

As described above, the repulsion electrode 61 is insulated and provided downstream of the ion exchange electrode 31 which is an ion conversion electrode.
By attaching to 2, the ion of the measured gas 24 can be collected 100%, and the ion concentration in the measured gas 24 can be accurately measured.

In the present embodiment, since only ions of the polarity to be measured can be moved by the force of the electric field between the ion exchange electrode 31 and the repulsion electrode 61 for measurement, the ion exchange electrode 31 By preventing collision of ions of a polarity that is not desired to be measured, it is possible to improve the accuracy of concentration measurement of ions of a polarity that are desired to be measured.

That is, as shown in FIG. 7, by setting the opening ratio of the wire mesh to at least 80% or more, the ion exchange electrode 31 is provided in the gas to be measured 24 taken into the wind tunnel 32 without depending on the wind speed. Nearly 100% of the ions can be passed. Therefore, in the ion amount measuring device provided with the repulsion electrode 61, the opening ratio of the wire mesh of the ion exchange electrode 31 is set to at least 80% or more, and the ion exchange electrode 3
Preferably, one is designed.

As described above, by increasing the opening ratio of the wire mesh of the ion exchange electrode 31, unintended ions in the gas to be measured 24 are passed, and the ions to be measured are repelled by the repulsion electrode, so that the ion exchange electrode 31 Therefore, ions can be selectively and efficiently collected, and the ion concentration in the gas to be measured 24 can be measured more accurately.

In the above embodiment, the potential of the ion exchange electrode 31 is set to zero, and a predetermined amount of positive or negative charge is applied to the repulsion electrode 61 so that the potential between the ion exchange electrode 31 and the repulsion electrode 61 is reduced. Although the case where an electric field is generated has been described, as shown in FIG.
A positive or negative voltage is switched by connecting to the inverted fluid force terminal P of the high input impedance operational amplifier D constituting the current-voltage converter in the electric quantity processing unit 35 (FIG. 1B). And the reference potential of the operational amplifier D is set to a positive or negative potential so that the ion exchange electrode 31 is charged to a positive or negative polarity. Thus, it is possible to prevent ions having a polarity different from the charge of the ions to be measured from colliding with the ion exchange electrode 31, and the gas to be measured 24
There is an effect that the ion concentration in the inside can be measured more accurately. Further, since the voltage value applied to the repulsion electrode 61 can be reduced and the capacity of the DC power supply 38 can be reduced, there is an effect that the cost can be reduced without deteriorating the performance of the ion amount measuring device.

Embodiment 4 This embodiment is shown in FIG.
As shown in FIGS. 14 to 14, one or more metal conduits 72 having both ends open in the direction of the air flow are arranged in the wind tunnel so as to allow gas flow, and the ion exchange electrode is coaxially arranged in the metal conduit 72. A metal conductor 61 stretched in a shape, a potential having the opposite polarity to the ion charge to be measured is applied to the conduit, and the electric quantity processing unit 35 is connected to the conductor.

This embodiment allows the repelling electrode to consist of a cylindrical metal conduit 72 which is insulated from the insulated wind tunnel 32 and
In the central portion of each flow path through which the gas to be measured 24 flows, a conductive wire, that is, a wire electrode 71 is supported via an insulating support plate, and a voltage having the same polarity as the ions to be measured is applied to the metal conduit 72 by DC. This is applied from the power supply 38.

With such a measuring device, the gas to be measured 24 taken in by the suction fan 33 from the atmosphere to be measured is
Is divided at a fixed rate into each flow path in the metal conduit 72 and penetrates into the flow path. A voltage having the same polarity as the ions being measured is applied to the metal conduit 72 as the repelling electrode from the DC power supply 38. That is, a positive voltage is applied to the metal conduit 72 during positive ion measurement, and a negative voltage is applied to the metal conduit 72 during negative ion measurement. Thus, the electric field from the metal conduit 72 toward the line electrode 71 is measured when measuring positive ions, and the electric field is measured when measuring negative ions.
An electric field is generated between the wire electrode 71 and the inner surface of the wind tunnel of the metal conduit 72 and the wire electrode 71. Therefore, the metal conduit 72
And the conducting wire, that is, the ions that have entered between the line electrodes 71 move toward the line electrode 71 under the force of the electric field, and eventually collide with the line electrode 71 to supply electric charges to the line electrode 71. Since the wire electrode 71 is insulated by the insulating support plate 73, the electric charge supplied to the wire electrode 71 flows out as a current only toward the electric quantity processing unit 35.

Since the level of the current flowing from the line electrode 71 toward the electric quantity processing section 35 is at most the nA level, the electric quantity processing section 35 is set to an easily measurable electric level.
Is converted by That is, when converting to current, several meters
When converting to a current of A to several A levels into a voltage, several m
It is converted into a voltage of V to several V level. The electric quantity converted by the electric quantity processing unit 35 in this way is converted into an electric quantity measurement unit 36
And the current flowing from the wire electrode 71 to the electric quantity processing unit 35 is obtained.

Next, the relationship between the strength of the electric field created between the line electrode 71 and the metal conduit 72 and the ion collection efficiency will be described.
As described above, the ions that have entered the electric field between the line electrode 71 and the metal conduit 72 move toward the line electrode 71 due to the electric field created between the line electrode 71 and the metal conduit 72. Therefore, in order to efficiently collect ions on the line electrode 71, it is necessary to cause the ions to collide with the line electrode 71 while the ions are present in the electric field between the line electrode 71 and the metal conduit 72. Time t [s] during which ions are present in the electric field
Can be expressed as t = L / U, during which time the ions must collide with the line electrode 71. Here, L is the length [cm] of the line electrode 71, and U is the velocity [cm / s] of the measured gas 24 flowing in a direction parallel to the line electrode 71.

The maximum distance that ions that have entered the electric field between the wire electrode 71 and the metal conduit 72 must travel to collide with the wire electrode 71 is determined by the inner surface of the cylindrical hole of the metal conduit 72 and the wire electrode. The distance from the outer surface of the wire 71 to the outer surface of the wire 71 can be expressed by the difference between the radius R of the cylindrical hole of the metal conduit 72 and the radius r of the wire electrode 71.

On the other hand, the electric field intensity E [V / cm] between the line electrode 71 and the metal conduit 72 can be expressed by E = V / {(R + r) / 2 × ln (R / r)}. Here, V is a voltage [V] applied from the DC power supply 38 to the metal conduit 72. The speed D [cm / s] at which the ions move toward the line electrode 71 by this electric field can be expressed by D = μ × E. Here, μ is the ion mobility [c
m ² / V / s].

Therefore, the maximum time τ [s] required for ions entering the electric field between the line electrode 71 and the metal conduit 72 to collide with the line electrode 71 is: τ = (R−r) / D Can be represented by

In order to efficiently collect ions on the line electrode 71, the time τ required for the ions to collide with the line electrode 71 must be shorter than the time t during which the ions exist in the electric field. . That is, it is necessary to determine the voltage applied from the DC power supply 38 to the metal conduit 72 so that the following relational expression holds. V ≧ {(R ² −r ² ) × U × ln (R / r)} / (2 × L ×
μ)

As described above, the metal conduit 72 is constituted by the metal conduit 72 having a plurality of cylindrical through holes formed in parallel.
The line electrode 71 is supported by an insulating support plate at a central portion in each flow path through which the gas to be measured 24 flows, and a metal conduit 72 is provided.
Since the voltage of the same polarity as that of the ions to be measured is applied from the DC power supply 38, only the ions of the polarity to be measured are separated by one while separating the ions of the gas to be measured 24 by polarity.
Thus, there is an effect that the ion concentration in the gas to be measured 24 can be accurately measured.

In the above embodiment, the potential of the line electrode 71 is set to zero, and a predetermined amount of positive or negative charge is applied to the metal conduit 72 so that an electric field is applied between the line electrode 71 and the metal conduit 72. However, as shown in FIG. 14, the DC voltage regulator 51 corrects the reference potential of the high input impedance operational amplifier constituting the current-to-voltage converter in the electric quantity processing unit 35, as shown in FIG. Alternatively, the line electrode 71 may be charged to a positive or negative polarity by setting a negative potential. Accordingly, it is possible to prevent ions having a polarity different from the polarity desired to be measured from colliding with the line electrode 71, and it is possible to more accurately measure the ion concentration in the measured gas 24. Further, since the voltage value applied to the metal conduit 72 can be reduced and the capacity of the DC power supply 38 can be reduced, the cost can be reduced without deteriorating the performance of the ion amount measuring device.

Embodiment 5 FIG. 15 shows an apparatus for measuring the amount of ions in gas according to Embodiment 5 of the present invention, but shows an example in which the opening of the wind tunnel is smaller than the diameter of the installation part of the ion exchange electrode 31.

The different diameter wind tunnel 32 is provided with a different diameter wind tunnel 81 on the opening side.
Since the cross section becomes larger as approaching the ion exchange electrode 31 from above, the flow velocity of the gas to be measured 24 taken in becomes slower as approaching the ion exchange electrode 31. When the flow velocity is slow as described above, the moving speed of the ions is also slow, so that the probability that the ions collide with the ion exchange electrode 31 increases, the ion collection efficiency is high, and the charge can be supplied to the ion exchange electrode 31. become able to. In order to uniformly supply the gas 24 to be measured taken in from the space to the ion exchange electrode 31, the cross-sectional shape of the different diameter wind tunnel 81 and the shape of the ion exchange electrode 31 are circular. It is desirable that the exchange electrode 31 exist in a coaxial straight line.

As described above, the apparatus is provided with a different diameter wind tunnel in which the section of the ion exchange electrode 31 is larger than the section of the inlet of the gas to be measured 24, and traps ions in the gas to be measured. The efficiency of collection can be further increased, and the ion concentration in the gas to be measured 24 can be measured more accurately.

Embodiment 6 FIG. This embodiment shows an example in which an induction electrode is arranged in a wind tunnel before ion exchange. The induction electrode 91 is for supplying only ions of the polarity to be measured to the rear ion conversion electrode, and the ion induction electrode 91 is provided on an insulating support base 92 for insulatingly attaching to the wind tunnel 32. It is fixed and connected to the DC power supply 38 so that a voltage of a desired polarity can be applied to the induction electrode 92.

The ion induction electrode 91 has a structure in which the aperture ratio is increased and does not collide with the ions in the gas to be measured 24 as much as possible, that is, because the mesh woven with a metal wire having a small diameter has a shape like a coarse metal net. The ions enter the space between the ion induction electrode 91 and the ion exchange electrode 31 without colliding with the ion induction electrode. The cross section of the wind tunnel 32 and the shape of the wire mesh electrode are circular so that the gas to be measured 24 taken in from the space can be uniformly supplied to the ion exchange electrode 31.
It is desirable that the wind tunnel 32 and the ion exchange electrode 31 exist coaxially and linearly. A voltage having the same polarity as that of ions to be measured is applied from a DC power supply 38 to an ion induction electrode 91 attached to the wind tunnel 32 insulated by a support base 92. That is, a positive voltage is applied to the ion induction electrode 91 during positive ion measurement, and a negative voltage is applied to the ion induction electrode 91 during negative ion measurement. Thereby, the electric field from the ion induction electrode 91 toward the ion exchange electrode 31 during the positive ion measurement, and the electric field from the ion exchange electrode 31 toward the ion induction electrode 91 during the negative ion measurement,
It occurs between the ion exchange electrode 31 and the ion induction electrode 91.

Therefore, the gas to be measured 2 from the atmosphere to be measured is
Reference numeral 4 denotes an ion passing through the induction electrode 91 through the wind tunnel 32 at a constant airflow, and the ions passing through the ion induction electrode 91 enter between the ion induction electrode 91 and the ion exchange electrode 31, where the force of the electric field is applied. As a result, positive ions and negative ions are separated by the difference in polarity, and only ions of the polarity to be measured move toward the ion-exchange electrode 31, and eventually collide with the ion-exchange electrode 31 to charge the ions. Transfer to the exchange electrode 31.

Since the ion-exchange electrode 31 is insulated by the support plate 34, the electric charge supplied to the ion-exchange electrode 31 flows as a current only toward the electric quantity processing section 35, and is measured by the electric quantity processing section 35. Converted at possible voltage levels.

As described above, since the induction electrode for supplying only the ion of the polarity to be measured to the ion exchange electrode 31 is provided, the amount of the positive ion and the amount of the negative ion in the gas 24 to be measured can be reduced. Since measurement can be performed separately and only ions of the polarity to be measured can be collected, there is an effect that the concentration of ions of the polarity to be measured in the gas to be measured 24 can be accurately measured.

As shown in FIG. 7, the structure of the ion induction electrode 91 is such that if the opening ratio of the wire mesh is 80% or more,
Almost 100% of ions in the gas to be measured 24 taken into the wind tunnel 32 can be passed. Therefore, it is preferable to design the ion induction electrode 31 by setting the opening ratio of the ion induction electrode 91 to at least 80% or more at a practical wind speed in the wind tunnel 32 when measuring the ion concentration. As described above, by increasing the aperture ratio of the ion induction electrode 91, ions of the gas to be measured 24 can be selectively and efficiently collected, and the ion concentration in the gas to be measured 24 can be measured more accurately. The effect is obtained.

In the above embodiment, the potential of the ion-exchange electrode 31 is set to zero, and a predetermined amount of positive or negative charge is applied to the ion-induction electrode 91. Although the case where an electric field is generated between 91 is shown, as shown in FIG. 17, the DC voltage adjusting device 51 is connected to the operational amplifier D having a high input impedance constituting the current-voltage converter in the electric quantity processing unit 35. The ion exchange electrode 31 may be positively or negatively charged by connecting to the inverted input terminal P and setting the reference potential of the operational amplifier D to a positive or negative potential. This allows
Since the voltage value applied to the repulsion electrode 61 can be reduced and the capacity of the DC power supply 38 can be reduced, there is an effect that the cost can be reduced without deteriorating the performance of the ion amount measurement device.

Further, in the above embodiment, the case where the ion induction electrode 91 for supplying only ions of the polarity to be measured to the ion exchange electrode 31 as an ion conversion electrode has a wire mesh structure has been described. As shown in FIG. 18, the electrode for separating ions is a point-like electrode 93,
The point-like electrode 93 may be supported by an insulating support plate 94 attached to the wind tunnel 32 in an insulating manner. Thus, it is possible to prevent ions having a polarity different from the polarity to be measured from colliding with the ion induction electrode, and it is possible to more accurately measure the ion concentration in the gas to be measured 24.

[0100]

According to the present invention, there is provided an ion amount measuring apparatus for removing an electric charge from ions present in a gas;
A measured gas supply unit for supplying a gas containing ions to the ion conversion electrode, an electric quantity processing unit for processing an amount of electricity generated in the ion conversion electrode, and an electricity quantity for measuring the magnitude of the processed amount of electricity Since it consists of a measuring unit, it is possible to accurately measure only the amount of electricity obtained by conversion of ions without being affected by ambient noise, etc., to accurately measure ion concentration and to use several types of ions with different mobilities. Even if it is included, the ion concentration in the gas to be measured can be clarified.

Since the ion conversion electrode is disposed in the wind tunnel and is a metallic porous body through which gas can flow, the flow of gas into the space of the electrode and the transfer of ion charges during the flow process are good. Suitable for continuous measurement of ion concentration.

In the present invention, if the metal porous body is a metal mesh, it can be easily fixed to the wind tunnel, the flow resistance of the gas is small, and the continuous measurement of the ion concentration in the flow process becomes easy.

In addition, at least the current-
Since the voltage conversion circuit and the noise removal filter circuit are provided, only the amount of electricity obtained by ion conversion can be accurately measured without being affected by ambient noise and the like, and the ion concentration can be accurately measured.

If at least the inner surface of the wind tunnel is made of an electric insulator, the consumption of ions in the gas on the wall surface can be reduced, and the measurement accuracy of the ion amount can be improved.

The wind tunnel can be made of a conductor. If the wind tunnel is electrically insulated from the ground, the consumption of ions in the gas on the wall surface can be reduced, and the measurement accuracy of the ion amount can be improved. be able to.

If the ion conversion electrode is insulated from the wind tunnel, a potential of a desired polarity can be applied to the ion conversion electrode. Further, the electric charge generated by the ion conversion electrode can be measured by the electric quantity processing unit without escaping to the parts other than the electric quantity processing unit, and there is an effect that the ion concentration can be accurately measured.

According to the present invention, in particular, by providing a potential adjusting means,
If the reference potential of the ion conversion electrode can be arbitrarily changed, a potential of a desired polarity can be added to the ion conversion electrode, and the amount of ions can be measured by separating positive and negative ions. Also, there is an effect that the concentration of only the ion of the polarity desired to be measured can be accurately measured by eliminating ions of the polarity that is not measured.

If the above-mentioned potential adjusting means is a DC power supply circuit which can be switched between a positive potential and a negative potential connected to the non-inverting input of the operational amplifier of the current-voltage conversion circuit connected to the ion conversion electrode, it is simple. A potential of a desired polarity can be applied to the ion conversion electrode, and the amount of ions can be easily measured by separating positive and negative ions.

If an ion guiding means for guiding ions to the ion conversion electrode in the air flow in the wind tunnel is disposed in the wind tunnel, it is effective to capture ions passing through the ion conversion electrode and to improve the accuracy associated therewith.

If the ion inducing means is a metal conductor arranged in an air current and further includes a DC power supply for applying a DC voltage, it is effective for capturing ions passing through the ion conversion electrode and improving the accuracy associated therewith. .

If the ion inducing means includes an ion repelling electrode provided on the downstream side of the ion converting electrode, and a potential having a polarity opposite to the ion charge to be measured is applied to the ion repelling electrode, The probability of capture at the ion conversion electrode is increased by repelling the ions that pass through, and this is effective for the accompanying improvement in accuracy.

If the ion repulsion electrode is a metal net, the structure is simple, the probability of trapping by the ion conversion electrode increases, and the accompanying improvement in accuracy can be easily realized.

If the ion inducing means includes an ion inducing electrode arranged on the upstream side of the ion converting electrode, and a potential having the same polarity as the ion charge to be measured is applied to the ion inducing electrode, To increase the efficiency of ion capture
This is effective for improving measurement accuracy.

When the ion induction electrode has an opening area ratio of 80% or more, the passage of ions to be measured through the ion induction electrode can be ensured, and the capture efficiency can be increased.

The ion conversion electrode utilizes one or two or more conductors arranged in the airflow direction in a wind tunnel having an opening capable of sucking gas, and a metal conduit having both ends opened around each conductor. Since a gas having a polarity opposite to that of the measured ion charge is applied so as to allow gas flow, the measured ions can be almost completely captured, and the measurement accuracy can be improved.

When the gas supply means is a suction fan disposed downstream of the ion conversion electrode, the ion conversion electrode is supplied to the ion conversion electrode at a stable supply speed without any consumption of ions. Ions can be supplied.

If a DC motor is used as the gas supply means for driving the fan, the rotation of the fan is stable, the noise is small, and the measurement accuracy of the ion amount is effective.

If the diameter of the opening of the wind tunnel is made larger than the diameter of the wind tunnel at the position where the ion conversion electrode is disposed, the intake air volume in a laminar flow state can be increased, and the sensitivity for measuring the ion volume can be increased. .

When the diameter of the opening of the wind tunnel is smaller than the diameter of the wind tunnel at the position of the ion conversion unit, the flow velocity at the position of the ion conversion unit can be reduced, and the efficiency of capturing ions can be increased.
Measurement accuracy can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view (A) of a device for measuring the amount of ions in gas according to an embodiment of the present invention, and a block diagram (B) of an electric quantity processing unit.

FIG. 2 is a schematic cross-sectional view of an apparatus for measuring the amount of ions in gas according to an embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view of an apparatus for measuring the amount of ions in gas according to an embodiment of the present invention.

FIG. 4 is a graph showing a relationship between a gas flow rate and a wind tunnel diameter when a gas flow to be measured becomes a laminar flow.

FIG. 5 is a schematic cross-sectional view of an apparatus for measuring the amount of ions in gas of a cavity whose diameter is enlarged according to an embodiment of the present invention.

FIG. 6 is a schematic cross-sectional view of an apparatus for measuring the amount of ions in gas according to an embodiment of the present invention.

FIG. 7 is a diagram showing a relationship between an opening ratio of a metal mesh of an ion exchange electrode and an ion collection rate in the ion exchange electrode.

FIG. 8 is a schematic cross-sectional view of an apparatus for measuring the amount of ions in gas according to an embodiment of the present invention.

FIG. 9 is a schematic cross-sectional view of an apparatus for measuring the amount of ions in gas according to an embodiment of the present invention.

FIG. 10 is a graph showing the effect of the electric field intensity between the ion exchange electrode 31 and the repulsion electrode 61 on the ion collection rate of the ion exchange electrode 31.

FIG. 11 is a graph showing a relationship between a wind speed and a required minimum electric field strength when 100% of ions are collected.

FIG. 12 is a schematic cross-sectional view of an apparatus for measuring the amount of ions in gas according to an embodiment of the present invention.

FIG. 13 is a schematic cross-sectional view of an apparatus for measuring the amount of ions in gas according to an embodiment of the present invention.

FIG. 14 is a schematic cross-sectional view of an apparatus for measuring the amount of ions in gas according to an embodiment of the present invention.

FIG. 15 is a schematic cross-sectional view of an apparatus for measuring the amount of ions in gas according to an embodiment of the present invention.

FIG. 16 is a schematic sectional view of an apparatus for measuring the amount of ions in gas according to an embodiment of the present invention.

FIG. 17 is a schematic cross-sectional view of an apparatus for measuring the amount of ions in gas according to an embodiment of the present invention.

FIG. 18 is a schematic cross-sectional view of an apparatus for measuring the amount of ions in gas according to an embodiment of the present invention.

FIG. 19 is a block diagram of a conventional apparatus for measuring the amount of ions in gas.

FIG. 20 is a circuit diagram showing a conventional gas ion amount measuring apparatus.

[Explanation of symbols]

31 ion exchange electrode, 32 wind tunnel, 33 blower, 3
4 support stand, 35 electricity quantity processing unit, 36 electricity quantity measurement unit, 41 opening, 51 DC voltage regulator, 61 repulsion electrode, 62 support stand, 71 wire electrode, 72 metal conduit,
81 Different diameter wind tunnel, 91 ion induction electrode, 92 insulating support base, 93 point electrode, 94 insulating support plate.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Yoshio Hanasa, 2-3-2 Marunouchi, Chiyoda-ku, Tokyo In-house Mitsui Electric Co., Ltd. (72) Noriaki Yasuiin 2-3-2, Marunouchi, Chiyoda-ku, Tokyo Inside of Mitsubishi Electric Co., Ltd. (72) Junichi Uno 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Co., Ltd. (72) Mikio Mori 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Inside Electric Machinery Co., Ltd. (72) Inventor Shigeru Takasugi 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsui Electric Co., Ltd. (72) Inventor Yuji Kakegawa 1163 Shimosei Plane, Inari-cho, Nagano City, Nagano Prefecture Inside Nagano Japan Radio Co., Ltd. (72) Inventor Akihiko Taniya 1163 Shimoyo Plane, Inari-cho, Nagano City, Nagano Prefecture F-term in Nagano Japan Radio Co., Ltd. 5C030 AA02 AB06

Claims (20)

[Claims] 1. A wind tunnel for forming an atmosphere gas flow, an ion conversion electrode disposed in the wind tunnel to receive an electric charge of ions present in a gas to be measured, and a gas for supplying the gas to the ion conversion electrode Measurement of the amount of ions in a gas, comprising: a supply unit, an electric amount processing unit that converts an electric amount generated in the ion conversion electrode into an electric signal, and an electric amount measuring unit that calculates the magnitude of the ion electric amount from the electric signal. apparatus. 2. The measuring device according to claim 1, wherein the ion conversion electrode is a metallic porous body arranged in a wind tunnel and through which gas can flow. 3. The metal porous body is a metal net.
The measuring device according to item 1. 4. The measuring apparatus according to claim 1, wherein the electric quantity processing unit includes a current-voltage conversion circuit for converting the electric quantity into a voltage signal, and a noise removal filter circuit for the voltage signal. 5. The measuring device according to claim 1, wherein at least the inner surface of the wind tunnel is an electric insulator. 6. The measuring device according to claim 1, wherein the wind tunnel is formed of a conductor, and the wind tunnel is electrically insulated from ground. 7. The measuring device according to claim 1, wherein the ion conversion electrode is insulated from the wind tunnel. 8. The measuring device according to claim 1, further comprising potential adjusting means for arbitrarily changing a reference potential of the ion conversion electrode. 9. An ion conversion electrode is connected to an inverting input of a differential operation unit of the current-voltage conversion circuit, and the potential adjusting means is connected to a non-inversion input of a working amplifier of the current-voltage conversion circuit. The measuring device according to claim 8, wherein the measuring device is a DC power supply circuit that can be switched between a potential and a negative potential. 10. The measuring apparatus according to claim 1, wherein an ion guiding means for guiding ions to an ion conversion electrode in an air flow in the wind tunnel is disposed in the wind tunnel. 11. The measuring apparatus according to claim 10, wherein the ion guiding means is a metal conductor arranged in an air flow, and the metal conductor includes a DC power supply for applying a DC voltage. 12. The ion repelling electrode according to claim 11, wherein the ion inducing means includes an ion repelling electrode provided on the downstream side of the ion conversion electrode, and applies a potential having a polarity opposite to the ion charge to be measured to the ion repelling electrode. measuring device. 13. The measuring device according to claim 12, wherein the ion repulsion electrode is a metal net. 14. The ion induction device according to claim 10, wherein the ion induction means includes an ion induction electrode arranged on the upstream side of the ion conversion electrode, and a potential having the same polarity as the ion charge to be measured is applied to the ion induction electrode. The measuring device as described. 15. The ion induction electrode has an opening area ratio of 80%.
The measuring device according to claim 14 having the above. 16. One or two ion conversion electrodes arranged in a gas flow direction in a wind tunnel having an opening through which gas can be sucked.
10. A conductive wire according to claim 1, wherein at least one conductive wire is provided, and a metal conduit having openings at both ends is arranged around the conductive wire so that gas can flow therethrough, and a potential having a polarity opposite to the ionic charge to be measured is applied. Measuring device. 17. The measuring device according to claim 1, wherein the gas supply means is a suction fan arranged downstream of the ion conversion electrode. 18. The measuring apparatus according to claim 17, wherein the motor for driving the fan in the gas supply means is a DC motor. 19. The wind tunnel according to claim 1, wherein an opening of the wind tunnel is larger than a diameter of the wind tunnel at a position where the ion conversion electrode is arranged.
8. The measuring device according to any one of 8 above. 20. The measuring apparatus according to claim 1, wherein the diameter of the opening of the wind tunnel is smaller than the diameter of the wind tunnel at the position of the ion conversion unit.