JP2015108578A - Classification part failure diagnosis device and method in particle classifier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To determine whether a predetermined classification voltage is applied or not without directly measuring a classification voltage of a classifier.SOLUTION: A supply voltage to a classification electrode is lowered to a constant voltage for diagnosis lower than voltage at normal measurement, ON/OFF of power supply to the classification electrode is switched, and on the basis of magnitude of change in an output signal of a current detecting circuit connected to a measuring electrode at that time, it is determined whether the classification electrode is normal or not.

Description

  The present invention is a fine particle measuring device suitable for use in monitoring the concentration of nano particles in automobile exhaust gas, building hygiene management, occupational safety and health, etc., in particular, a fine particle classification measuring device for classifying and measuring fine particles according to the particle size, etc. More particularly, the present invention relates to an apparatus and method for diagnosing whether or not a classification electrode for applying a voltage for a classification electric field is normal.

  As a measuring device having a classification mechanism for classifying fine particles with respect to fine particles having a nanometer order fine particle size, a differential type electric mobility analyzer (DMA) or an integral type electric mobility analyzer is known. As the classification mechanism, a gas that introduces a sample gas from the side wall surface of the classification part and sucks out gas containing fine particles separated into a desired particle size from the side wall surface of the classification part is used (Patent Documents 1 to 5, (See Non-Patent Documents 1 and 2.)

  In the classification by DMA, a classification electric field is applied perpendicularly to the sheath gas flow, and the charged fine particles cross the sheath gas flow by the electrostatic attraction force caused thereby, and the resistance depending on the particle size is moved in the process of moving to the counter electrode. Fine particles are classified by receiving from the sheath gas flow.

  2. Description of the Related Art A classification device using a principle of applying a classification voltage between a pair of electrodes and classifying charged fine particles based on the particle size by a classification electric field generated thereby is widely used, not limited to DMA.

US Patent Application Publication No. 2005/0162173 US Pat. No. 6,230,572 US Pat. No. 6,828,794 US Pat. No. 6,230,572 US Pat. No. 6,787,763

Chen, DR, DYH Pui, D. Hummes, H. Fissan, FR Quant, and GJ Sem, [1998], "Design and Evaluation of a Nanometer Aerosol Differential Mobility Analyzer (Nano-DMA), Journal of Aerosol Science 29/5 : 497-509. Fissan, H.J., C. Helsper, and H.J. Thielen [1983], "Determination of Particle Size Distribution by Means of an Electrostatic Classifier." Journal of Aerosol Science, 14: 354. Journal of Powder Engineering, Vol.22, No.4, pp.231-244 (1985)

  In order to classify charged fine particles based on the particle size by a classification electric field generated by a classification electrode and a classification electric field generated thereby, a predetermined classification voltage must be stably applied. The classification electrode is insulated from the body constituting the classification device in order to apply a voltage. The body is usually made of metal and grounded.

  However, if dirt in the sample gas adheres between the classification electrode and the body during use or condensation occurs, and the insulation between the classification electrode and the body decreases, a predetermined voltage cannot be applied to the classification electrode. The desired classification function cannot be exhibited. Although the output voltage of the power supply device that applies a voltage to the classification electrode is monitored, the polarization voltage decreases if the insulation state between the classification electrode and the body decreases even if the output voltage of the power supply device is constant Therefore, the insulation state between the classification electrode and the body cannot be correctly determined by the output voltage of the power supply device.

  Whether or not a predetermined voltage is applied to the classification electrode can be determined by directly measuring the voltage applied to the classification electrode. However, since the classification voltage is a high voltage, for example, several kV, if the measurement is to be performed accurately, the voltage is measured using a correctly calibrated voltage dividing resistor, which increases the apparatus cost.

  The present invention provides an apparatus and method that can determine whether a predetermined classification voltage is applied without measuring the classification voltage of the classification apparatus.

  The fine particle classifying device as an object of the present invention is arranged on one of a charging part for charging a gas sucked from a sample suction port and an inner surface constituting a flow path through which the gas charged by the charging part flows. The at least one suction electrode formed on the other surface of the inner surface is opposed to the suction electrode, and charged particles in the gas flowing in the flow path between the suction electrode and the suction electrode And a classification electrode for generating an electric field attracted to the side.

  The present invention is a classification unit failure diagnosis apparatus for determining whether or not a classification electrode in such a particle classification apparatus is normal. In order to detect the charge amount of the charged particles sucked by the suction electrode, a galvanometer circuit is connected to the suction electrode. A classification power supply control unit is provided to apply a voltage for failure diagnosis. The classification power supply control unit lowers the supply voltage to the classification electrode to a constant voltage for diagnosis lower than the voltage at the time of normal measurement, and then switches on / off the power supply to the classification electrode. The constant voltage is a classification voltage having such a magnitude that the charged fine particles can be attracted to the measurement electrode to an extent necessary for classifying part failure diagnosis.

  The first embodiment is configured to automatically perform classification part failure diagnosis, and a determination unit is provided to determine whether or not the classification electrode is normal. The determination unit takes in the output signal of the galvanometer circuit and determines whether the classification electrode is normal depending on whether the magnitude of the change in the output signal in the on / off switching of the power supply to the classification electrode is greater than or equal to a threshold value. Determine. The threshold used by the determination unit is held in the threshold holding unit, and the determination unit takes in the threshold held in the threshold holding unit and determines whether the classification electrode is normal. To do.

  In the classification unit failure diagnosis apparatus of the first embodiment, the determination unit determines whether or not the determination result of whether the classification electrode is normal can be easily understood by an operator who uses the fine particle classification apparatus. It is preferable to further include a display unit for displaying the determination result.

  In the second embodiment, the classifier failure diagnosis is performed by an operator. The second embodiment does not require the determination unit in the first embodiment. Although it is the same as that of the first embodiment in that it includes a current detection circuit and a classification power supply control unit, the second embodiment is a display device that is connected to the current detection circuit and displays an output signal of the current detection circuit. It has. The operator determines whether or not the classification electrode is normal depending on whether or not the magnitude of the change in the output signal of the galvanic circuit displayed on the display device is equal to or greater than a threshold value.

  The third embodiment can realize both the first and second embodiments, and includes both a determination unit and a display device.

  In a preferred embodiment, the apparatus further includes a gas filter that is disposed in the sample suction port and removes particulate components in the gas to be sucked. Although the particle concentration in the gas sucked from the sample suction port changes with time, even if the sample gas is sucked by sucking the gas through the gas filter that removes the particle components in the sucked gas, The particle concentration in the gas becomes 0, and temporal changes can be suppressed. Judgment is made when a plurality of gas electrodes as measurement electrodes are arranged along the flow of gas in order to measure very small gas ions that are charged as gas ions after passing through the gas filter. It is preferable to use a galvanometer circuit connected to the measurement electrode on the most upstream side of the flow of gas flowing through the flow path as the galvanometer circuit that takes in the output signal.

  The classification unit fault diagnosis device displays the judgment result by the judgment unit so that the judgment result of whether the classification electrode is normal or not can be easily understood by the operator using this fine particle classifier. It is preferable to further include a portion.

In the classification part failure diagnosis method of the present invention, the following steps (S1) to (S3) are performed in a state where a galvanometer for detecting the amount of charge is connected to the measurement electrode of the fine particle classifier.
(S1) A step of lowering the supply voltage to the classification electrode to a constant voltage for diagnosis lower than the voltage at the time of normal measurement,
(S2) Thereafter, the step of switching on / off the power supply to the classification electrode, and (S3) the magnitude of the change of the output signal in the on / off switching of the power supply to the classification electrode based on the output signal of the galvanic circuit Determining whether the classification electrode is normal based on the determination.

  The process of the classifying unit failure diagnosis method can be automatically performed by a CPU of a computer such as a dedicated computer of the classifying device or a general-purpose personal computer. At that time, a program may be set up so that the classifying unit failure diagnosis method is automatically started periodically, or the operator may start it as needed before starting the measurement. Further, the classifying unit failure diagnosis method can be manually performed by an operator.

  When carrying out this classification part failure diagnosis method, it is preferable to provide a gas filter for removing particulate components in the gas to be sucked in the sample suction port of the fine particle classifier. When the process of the classifying unit failure diagnosis method is automatically performed, the gas filter may be attached / detached automatically by a command from the CPU, or the gas filter is manually attached / detached. You may make it input into a computer. In the form in which a gas filter is provided at the sample suction port of the fine particle classifier, when a plurality of measurement electrodes are arranged along the flow of gas flowing through the flow path, the most upstream side of the flow of gas flowing through the flow path is used. It is preferable to implement the classifying unit failure diagnosis method based on the output signal of the galvanometer circuit connected to a certain measurement electrode. This is because the gas that has passed through the gas filter is in a state in which almost all of the particle components have been removed, so that the charged fine gas ions are attracted to the measurement electrode located on the most upstream side of the gas flow. It is.

  In the present invention, the supply voltage to the classification electrode is lowered to a constant voltage for diagnosis lower than the voltage at the time of normal measurement, the power supply to the classification electrode is switched on / off, and the galvanometer circuit connected to the measurement electrode at that time Since it is determined whether or not the classification electrode is normal based on the magnitude of the change in the output signal, it is possible to diagnose whether or not the classification electrode has failed without directly measuring the classification voltage.

It is a schematic perspective view which shows an example of the classification measurement apparatus with which the classification part failure diagnostic apparatus of this invention is applied. It is a schematic block diagram which shows one Example with another classification | category measuring apparatus. It is a schematic plane sectional view in the classification measuring device. It is sectional drawing along the flow path of the classification measuring device. It is a schematic perspective view which shows the further another classification measurement apparatus with which the classification part failure diagnostic apparatus of this invention is applied. It is a flowchart which shows operation | movement of one Example.

  An example of a fine particle classification measuring apparatus as an example of a fine particle classification apparatus is schematically shown in FIG. The channel 10 has openings at the inlet 12 and the outlet 14, and has a flat shape with a rectangular cross section in both the flow direction and the channel width direction. The dimensions and shape of the flow path are not particularly limited, but are, for example, flat rectangular parallelepipeds having a length (height) of 4 mm, a width (flow path width) of 250 mm, and a depth (flow path length) of 450 mm.

  On the outlet 14 side of the flow path 10, a fan 15 is disposed as a blower mechanism for sample suction. A motor 16 that rotates the fan 15 is driven by a drive circuit 17. A manual butterfly valve is provided as a flow rate adjustment valve 18 on the sample gas suction side of the fan 15, and the sample gas flow rate can be changed by adjusting the flow rate adjustment valve 18. The fan 15 sucks uniformly over the entire width of the flow path 10 and sucks the sample gas from the inlet 12 of the flow path 10. The fan 15 is driven under the condition that the sucked sample gas flows in the flow path 10 as a laminar flow. The conditions for the laminar flow are those for which Reynolds is approximately 2000 or less.

  A flow meter 19 for measuring the flow rate of the sample gas flowing in the flow path is provided downstream of the fan 15 on the outlet side of the flow path 10. The flow meter 19 may be arranged on either the inlet side or the outlet side of the flow channel 10, but it is preferable to arrange the flow meter 19 on the outlet side because particles in the sample gas adhere to the flow meter 19.

  A charger for charging fine particles in the sample gas is disposed near the inlet of the flow path 10. In this embodiment, the charger is configured to take a monopolar charging mode. The charger includes a wire-like discharge electrode 20 attached to one side of the flow channel 10 and a counter electrode 22 disposed on the other side of the flow channel 10 so as to face the discharge electrode 20. . A charging power source 21 is connected to the discharge electrode 20 so as to cause a discharge between the discharge electrode 20 and the counter electrode 22. The shape of the discharge electrode 20 is not limited to a wire shape, and may be one or a plurality of needles attached vertically to the counter electrode 22. As shown in the embodiment of FIG. 2 to be described later, a counter electrode provided perpendicular to the gas flow in the flow path 10 and having an opening at the center, and the tip of the needle is opposed to the center of the opening of the counter electrode It may consist of a discharge electrode arranged in this way. The structure of the charger is not particularly limited as long as it can discharge between the discharge electrode and the counter electrode.

  A pair of wide opposing bottom surfaces (in the embodiment, a ceiling surface and a lower bottom surface) of the channel 10 are parallel to each other and have the same width. A plurality of suction electrodes 24 and 26 are disposed on the lower bottom surface, which is one of the bottom surfaces, at different distances from the inlet 12 along the flow path direction. The suction electrodes 24 and 26 each have a predetermined electrode width along the flow path direction and are electrically separated from each other. Measuring electrodes 24-1 to 24-n (the symbols of the measuring electrodes 24-1 to 24-n may be generally indicated simply as “24” on the suction electrodes 24 and 26. About the galvanometer circuit 28) The trap electrode 26 is included. The current detection circuits 28-1 to 28-n are connected to the measurement electrodes 24-1 to 24-n in order to detect the charge amount of the fine particles reaching the measurement electrodes. The measurement electrodes 24-1 to 24-n can be arranged close to each other, and can be arranged with a gap between the measurement electrodes as in the illustrated embodiment. Although no galvanometer circuit is connected to the trap electrode 26, a galvanometer circuit may be connected here if it is desired to measure a very small particle diameter. An insulating member is sandwiched between adjacent suction electrodes, or the electrodes are electrically separated from each other via an air layer. These insulating members only need to be able to electrically separate the electrodes, and need not be thick. For example, the thickness may be about 0.5 mm, but this thickness naturally depends on the volume resistivity of the insulating member.

  A classification electrode 30 is disposed opposite to the suction electrodes 24 and 26 on the ceiling surface, which is the other bottom surface of the pair of bottom surfaces facing each other with a wide width. The classification electrode 30 generates an electric field that attracts charged fine particles in the sample gas flowing in the flow channel 10 to the suction electrode side between the suction electrodes 24 and 26. The area of the classification electrode 30 and the total area of the suction electrodes 24 and 26 are substantially equal so that this electric field is perpendicular or almost perpendicular to the direction of the flow of the sample gas flowing through the flow path 10. It is preferable that they face each other. Therefore, although the suction electrodes 24 and 26 are electrically separated from each other, it is preferable that the gap between the adjacent suction electrodes 24 and 26 is small. The suction electrodes 24 and 26 may be configured only by the measurement electrode 24 that measures the amount of charge of the charged fine particles that have reached. However, as in this embodiment, the trap electrode that reaches the charged fine particles but is not used as a measurement electrode. 26 may be included. When the trap electrode 26 is included, the trap electrode 26 is also the same as the measurement electrode 24 in order to apply an electric field in a direction perpendicular to or substantially perpendicular to the flow direction of the sample gas flowing through the flow path 10. A potential is applied. The potentials of the trap electrode 26 and the measurement electrode 24 include a ground potential.

  In this embodiment, one trap electrode 26 is arranged on the inlet side of the first measurement electrode 24-1 closest to the inlet of the flow path in the measurement electrode 24, and the tip position on the inlet side of the trap electrode 26 is The tip position on the inlet side of the classification electrode 30 is positioned so as to be the same position in the flow path direction, and that position is the base point of the classification region. In the following description, the position and width of the measurement electrode 24 are specified as a distance from the base point of this classification area. Between the classification electrode 30 and the suction electrodes 24 and 26 is a classification region. The distance from the entrance of the flow path to the base point of the classification area is called the run-up distance. Since the charged fine particles do not reach the classification region at the run-up distance, they move on the flow of the sample gas without being affected by the classification electric field.

  In this embodiment, the measuring electrodes 24-1 to 24-n and the trap electrode 26 are set to the same potential, and an electric field in a direction perpendicular to or substantially perpendicular to the flow of the sample gas flowing through the flow path between the measuring electrode 24-1 and 24-n. It is formed. A classification power source 32 for applying a classification voltage is connected to the classification electrode 30, and charged fine particles in the sample gas are sucked between the classification electrode 30 and the suction electrodes 24 and 26 by applying a voltage from the classification power source 32. An electric field is formed in the direction attracted to the electrode side. For example, when checking the operation with gas ions after removing particulate components by providing a filter, if you want to check the operation with gas ions having a positive charge, the voltage of the classification electrode 30 becomes a positive voltage and sucked The electrodes 24 and 26 are set to the ground potential. Conversely, when it is desired to confirm the operation with gas ions having a negative charge, a voltage is applied from the classification power source 32 to the classification electrode 30 so that the voltage of the classification electrode 30 becomes a negative voltage.

  The classification power source 32 can change the output voltage so that the applied voltage value is different between the measurement and the classification unit failure diagnosis. Although depending on the dimensions of the flow path 10, the voltage applied to the classification power source 32 during normal measurement is several kV, for example, 1 to 4 kV in this embodiment, and in general, a voltage in a range where dielectric breakdown does not occur can be applied. . The applied voltage value to the classification power source 32 at the time of classifying unit failure diagnosis is switched to several V, for example, 3 to 10V.

  During normal measurement, a constant voltage is continuously supplied from the classification power source 32 to the classification electrode 30. On the other hand, at the time of classifier failure diagnosis, supply of a constant voltage lower than that at the time of measurement is switched from ON / OFF to the classification electrode 30 from the classification power supply 32.

  For example, when monopolar discharge is performed with the counter electrode 22 as the ground potential and the discharge electrode 20 on the positive side, the fine particles in the sample gas have positive monopolar charge, so that the measurement electrodes 24-1 to 24-n of the suction electrode are used. The trap electrode 26 is set to the ground potential, and the classification electrode 30 is set to the positive side.

  In this embodiment, when the charger 16 is operated and the fan 16 is operated in a state where the classification electric field is applied, the sample gas is introduced from the inlet of the flow path 10 and the sample gas is charged by the discharge of the charger. Since a classification electric field is applied between the classification electrode 30 and the suction electrodes 24 and 26, the charged sample gas is sent along the flow into the classification electric field. The sample gas charged by the charger moves in the direction of the sample gas flow until the classification electric field exists. When the sample gas reaches the classification electric field, it moves in the direction of the sample gas while moving in the direction of the sample gas. Start moving in the direction.

  The charged ions move toward the suction electrode while flowing toward the exhaust side along the flow of the sample gas in the electric field of the classification unit. Many small particles are trapped by the suction electrode near the inlet. However, large fine particles sucked at a position close to the suction electrode, that is, a position on the lower bottom surface side of the flow path are also captured by the suction electrode near the entrance. Among the suction electrodes, the charges of the fine particles that have reached the measurement electrodes 24-1 to 24-n are detected by the galvanic circuits 28-1 to 28-n connected to the measurement electrodes 24-1 to 24-n. .

  FIG. 2 to FIG. 5 show a specific structure of an embodiment in which the classification unit failure diagnosis device of one embodiment is applied to another example of the particle classification device. FIG. 4 shows a cross-sectional view along the flow path.

  The flow path 10 is a flat rectangular parallelepiped, and rectifying resistors 11a and 11b are arranged at the inlet 12 and the outlet 14 in order to make the flow of the sample gas parallel. The rectifying resistors 11a and 11b are set so as to have channel resistances such that the sample is uniformly dispersed in the channel width direction. The sample introduction port 13a and the discharge port 13b connected to the flow path have a flow cross-sectional area smaller than that of the flow path 10, but the flow of the sample gas in the flow path 10 is uniform over the width of the flow path by the rectifying resistors 11a and 11b. Parallel flow.

  A blower 40 is connected as a blower mechanism to the discharge port 13 b connected to the outlet 14 of the flow path 10, and an air volume sensor 42 is disposed upstream of the blower 40. A flow rate adjusting valve 18 for adjusting the flow rate of the sample gas flowing through the flow path 10 to be constant is disposed between the air volume sensor 42 and the blower 40. The flow rate adjusting valve 18 adjusts the air volume detected by the air volume sensor 42 so as to be a predetermined constant amount so that the sample gas becomes a laminar flow. The flow rate adjusting valve 18 can be manually adjusted, and can be configured to perform feedback control based on the signal of the air volume sensor 42.

  There is a sample inlet 12 for introducing a sample gas into the sample inlet 13a. When carrying out the classifying part failure diagnosis method, a filter mounting portion (not shown) is provided in the sample suction port 12 so that the sample suction port 12 can be provided with a gas filter 50 for removing particulate components in the sucked gas. ) Is provided. As the gas filter 50, a HEPA filter, a ULPA filter, or the like is appropriate. An example of such a gas filter 50 is the CCG series manufactured by Advantech Toyo. A sensor such as a micro switch that detects that the gas filter 50 is attached may be provided in the filter attaching portion, and an output signal of the sensor may be taken into the computer 100. When such a sensor is not provided, it may be input to the computer 100 that the gas filter 50 is attached. The gas filter 50 can be automatically attached and detached according to a command from the CPU of the computer 100. Further, the gas filter 50 can be manually attached and detached.

  An impactor 13 and a charging unit are disposed between the sample suction port 12 and the sample introduction port 13a. The impactor 13 has a structure in which a nozzle is opened at the center of a plate that blocks the flow path, and a collecting plate is disposed downstream of the nozzle so as to face the nozzle. This is an apparatus that collects and removes fine particles on the large side of the aerosol on a collecting plate using inertial collision of the aerosol ejected from the nozzle, and passes the fine particles on the small side.

  The charging unit includes a discharge electrode 20a and a counter electrode 22a, and is disposed between the impactor 13 and the sample introduction port 13a. The discharge electrode 20a has a needle shape, and the counter electrode 22a is made of an electrode plate that blocks the flow path, and has an opening at the center thereof. The tip of the discharge electrode 20a is disposed toward the center of the opening of the counter electrode 22a. The counter electrode 22a is grounded. A charging voltage is applied from the charging power source 21 to the discharge electrode 20a. When a positive voltage is applied to the discharge electrode 20a, the charged portion charges the fine particles in the sample gas positively. When a negative voltage is applied to the discharge electrode 20a, the charged portion charges the fine particles in the sample gas negatively. Let me. The structure of the discharge electrode 20a and the counter electrode 22a is not limited to this.

  In order to adjust the voltage applied to the discharge electrode 20a in accordance with the desired ion concentration, charge polarity, etc., a charge voltage regulator 23a is connected to the charge power source 21, and the output voltage and current of the charge power source 21 are adjusted. A charging current / voltage monitoring device 23 b for displaying is connected to the charging power source 21.

  On the lower bottom surface of the flow path 10, a trap electrode 26 and six measurement electrodes 24-1 to 24-6 are arranged in order from the upstream side at different distances from the inlet 12 along the flow path direction. . The measurement electrodes 24-1 to 24-6 are arranged close to each other, and are arranged with a gap between adjacent measurement electrodes. A stud 46 is welded to the trap electrode 26 and each of the measurement electrodes 24-1 to 24-6 at a central position with respect to the flow path direction. Three studs 46 are provided along the flow path width direction for the trap electrode 26 and the measurement electrodes 24-1 to 24-6. Each stud 25 is fitted in a hole formed in the base substrate 48 of this measuring device, whereby the trap electrode 26 and the measuring electrodes 24-1 to 24-6 are positioned in the flow path direction.

  Of the studs 46 of the measurement electrodes 24-1 to 24-6, the one arranged at the center in the flow path width direction also serves as a terminal for taking out the detected current, and these studs 46 are respectively galvanic detection circuits. 28-1 to 28-6. The galvanometer circuits 28-1 to 28-6 include an amplifier circuit (amplifier). Although the galvanometers 28-1 to 28-6 are provided for all the measurement electrodes here, they may be connected only to the measurement electrodes for which the current value is to be detected. A current detection circuit is not connected to the stud 46 of the trap electrode 26 and is grounded. One classification electrode 30 is disposed on the ceiling surface of the flow path 10 so as to face the trap electrode 26 and the measurement electrodes 24-1 to 24-6. The position on the inlet 12 side of the trap electrode 26 and the position on the inlet 12 side of the classification electrode 30 coincide with each other, and the positions on the measurement electrode 24-6 and the classification electrode 30 outlet 14 side coincide with each other.

  The galvanometers 28-1 to 28-6 are connected to a computer (not shown) in order to perform calculation for classification. In the normal measurement, the detection signals of the galvanometers 28-1 to 28-6 are obtained by classifying the charged particles in the sample gas flowing through the flow path 10 and sucking them into the measurement electrodes 24-1 to 24-6. Since it is reflected, classification measurement can be performed based on those detection signals.

  Since the present invention is not intended for normal measurement and is intended to diagnose whether the classification electrode is normal or not, the galvanometers 28-1 to 28-6 are provided so that the diagnosis can be performed manually. The current monitor devices 29-1 to 29-6 are connected as display devices, and the detected current values of the galvanometer circuits 28-1 to 28-6 are displayed. The current monitoring device 29-1 of the galvanometer circuit 28-1 connected to at least one of the current monitoring devices 29-1 to 29-6, preferably the measurement electrode 24-1 disposed on the most upstream side is an operator. Can be used when performing a failure diagnosis of the classification unit.

  In this fine particle classification device, the classification unit failure diagnosis device that automatically determines whether or not the classification electrode is normal is any one of the galvanic circuits 28-1 to 28-6, the classification power supply control unit 102, and the determination. Part 104 and a threshold value holding part 106. The classification power supply control unit 102 and the determination unit 104 are realized by a CPU and a program of a general-purpose computer such as a dedicated computer of a classification device or a personal computer, and the threshold value holding unit 106 is realized by a memory device of the computer. Is done.

  As the galvanic circuit that constitutes the classifying unit failure diagnosis apparatus, the detection current of the galvanometer circuit 28-1 that can detect the charge amount of the smallest particles among the galvanometer circuits 28-1 to 28-6 is used. The galvanometer 28-1 is a galvanometer connected to the measurement electrode 24-1 disposed on the most upstream side of the gas flow in the flow path among the galvanometers 28-1 to 28-6. .

  The classification power supply control unit 102 is configured to lower the supply voltage to the classification electrode 30 to a constant voltage for diagnosis lower than the voltage at the time of normal measurement, and to switch on / off the power supply to the classification electrode 30. ing. The classification power supply control unit 102 is connected to the classification power source 32 so that the supply voltage to the classification electrode 30 can be changed. The classification power supply control unit 102 supplies the classification power supply from the classification power source 32 to the classification electrode 30. Change the voltage. After the supply voltage to the classification electrode 30 is lowered to a constant voltage for diagnosis, the classification power supply control unit 102 issues a command to the classification power supply 32 to switch on / off the power supply to the classification electrode 30.

  The determination unit 104 captures the output signal of the galvanometer circuit 28-1, captures the threshold value from the threshold value holding unit 106, and the rectifier circuit 28-1 switches on / off the power supply to the classification electrode 30. If the magnitude of the change in the output signal is equal to or greater than the threshold value, it is determined that the insulation between the classification electrode 30 and the body 11 is normally maintained. Otherwise, the separation between the classification electrode 30 and the body 11 is determined. It is determined that the insulation between them has decreased.

  The classification power supply control unit 102 is configured to be able to change the supply voltage from the classification power supply 32 to the classification electrode 30 manually so that the classification unit failure diagnosis can be performed manually. The power supply to the classification electrode 30 can be switched on / off manually.

  As a preferred embodiment, the gas filter 50 can be disposed in the sample suction port 12. The gas filter 50 removes particle components whose concentration changes in the sucked gas. Therefore, the classifier failure diagnosis can be performed using the charged gas ions using the gas from which the concentration-changing particle component has been removed while sucking the sample gas from the sample inlet 12. In that case, when a plurality of 26-1 to 26-6 are arranged along the flow of gas flowing through the flow path as measurement electrodes, the determination section 104 serves as a galvanometer circuit that captures an output signal. It is preferable to use a galvanometer circuit 28-1 connected to the measurement electrode 26-1 located on the most upstream side of the flowing gas flow. Finely charged particles are taken into the galvanometer circuit 28-1.

  In order to make it easy for an operator who uses the fine particle classification device to easily determine whether or not the classification electrode is normal, a display unit 108 for displaying the determination result by the determination unit 104 is provided. Yes. The display unit 108 is preferably, for example, a liquid crystal display device or a lamp that can identify the determination result by the color to be displayed.

  The flow of gas flowing through the flow path 10 and the current detection circuit are also affected by temperature and relative humidity. Therefore, in order to keep the flow path 10 at a constant temperature and prevent relative humidity from increasing, the body 11 of the flow path 10 is provided with a heater 60 and a temperature detection end 62 of the temperature sensor. The body 11 is made of a metal having good thermal conductivity, and the heater 60 is provided in such a form that the entire body 11 has a uniform temperature. The energization of the heater 60 is feedback-controlled through the temperature regulator 64 so that the temperature detected by the temperature detection end 62 becomes a predetermined temperature. A temperature monitor device 66 is connected to the temperature controller 64 and displays the temperature of the body 11.

  FIG. 5 schematically shows still another example of the fine particle classifier to which the classification unit failure diagnosis apparatus of the present invention is applied. The difference from the fine particle classifier shown in FIG. 1 is that the suction electrode facing the classification electrode 30 is only the measurement electrode 24a and the trap electrode 26a, and the other configurations are the same. The same parts as those of the embodiment of FIG.

  The suction electrode facing the classification electrode 30 is a trap arranged on one measurement electrode 24a and on the upstream side of the measurement electrode 24a with respect to the flow direction of the sample gas in the flow path, that is, on the inlet side of the flow path 10. It consists of an electrode 26a. As in the embodiment of FIG. 1, the tip position of the classification electrode 30 on the channel inlet side and the tip position of the trap electrode 26a on the channel inlet side are positioned at the same distance from the channel inlet. Becomes the base point of the classification region, and the distance from the flow path inlet to the base point of the classification region is the run-up distance.

  The measurement electrode 24a and the trap electrode 26a are set to the same potential, and the current detection circuit 28a is connected to the measurement electrode 24a, and the current detection circuit is not connected to the trap electrode 26a. .

  Fine particles contained in the sample gas introduced from the channel inlet are charged by the discharge of the discharge electrode 20a. A classification electric field is applied between the classification electrode 30, the trap electrode 26a, and the measurement electrode 24a, and the charged fine particles are sent into the classification electric field along the flow of the sample gas.

  The charged fine particles move toward the trap electrode 26a and the measurement electrode 24a while flowing toward the exhaust side along the flow of the sample gas in the electric field of the classification unit. A very small particle and a very large particle are captured by the trap electrode 26a on the inlet side, and only a particle having a specific particle size range reaches the measurement electrode 24a, and the charge is connected to the measurement electrode 24a. Detected by.

  The classifying unit failure diagnosis apparatus takes in the output current of the galvanometer circuit 28a and diagnoses the presence or absence of a failure of the classification electrode 30 based on the current value. The configuration of the classifying unit failure diagnosis apparatus is the same as that shown in FIG.

  FIG. 6 shows a process for performing classifier failure diagnosis. This process includes a case where the process is automatically performed by the computer 100 and a case where the operator makes a judgment by looking at the display on the current monitor device 19-1.

  First, a case will be described in which the classifying unit failure diagnosis apparatus automatically executes a diagnosis operation. When the classification power supply control unit 102 recognizes that the filter 50 is attached to the sample suction port 12 by sensor output or input by the operator to the computer 100, the classification power supply control unit 102 sends the classification electron microscope 32. Then, the supply voltage to the classification electrode 30 is lowered to a constant voltage for diagnosis (for example, 5 V) lower than the voltage (several kV) during normal measurement. The constant voltage for diagnosis is a classification voltage that can generate an electric field large enough to allow fine charged particles to be taken into the measurement electrode 26-1 at the most upstream side of the gas flow through the flow path. Such a constant voltage for diagnosis is set in the classified power supply control unit 102 in advance.

  After the supply voltage to the classification electrode 30 decreases, the classification power supply control unit 102 switches on / off the power supply to the classification electrode 30. If the insulation between the classification electrode 30 and the body 11 is normally maintained, when the power supply to the classification electrode 30 is switched from on to off, the current flows to the galvanometer circuit 28-1 when the power supply is turned on. If the insulation between the classification electrode 30 and the body 11 is not maintained normally, the current is lost because the current disappears. However, if the power supply to the classification electrode 30 is on, the current detection circuit 28- Since a predetermined current does not flow through 1, the change in the current value is small even when the power supply to the classification electrode 30 is switched from on to off. The magnitude of the change in the current value associated with the switching of the power supply to the classification electrode 30 from on to off is compared with a threshold value. If the threshold value is greater than the threshold value, it is determined that the classification electrode 30 is normal. Otherwise, it is determined as a failure, and each is displayed on the display unit 108.

  When this operation is performed manually, it is confirmed visually that the filter 50 is attached to the sample suction port 12, the supply voltage to the classification electrode 30 is manually lowered, and then the power supply to the classification electrode 30 is performed. Switch on / off manually. Whether the change in the current value of the galvanometer circuit 28-1 based on the result is larger than a predetermined value is visually determined by the current monitor device 29-1.

  The particle classifier to which the classifying unit failure diagnosis apparatus and method of the present invention is applied is not limited to the one shown in the examples. For example, in the embodiment, the cross-sectional shape in the direction perpendicular to the flow direction of the flow channel is flat in the lateral direction in the embodiment, but the cross-sectional shape of the flow channel is 90 degrees rotated from that of the embodiment by 90 degrees. The shape may be flat in the direction. Further, the flow path is not limited to a rectangular cross section as shown in the embodiment, but a circular one, or a suction side electrode (measurement electrode and trap electrode) and a classification electrode are opposed to each other in a double cylindrical shape. The structure arranged in The present invention can be applied to any classification device that uses the principle of applying a classification voltage between a pair of electrodes and classifying charged fine particles based on the particle size by a classification electric field generated thereby.

DESCRIPTION OF SYMBOLS 10 Flow path 12 Sample inlet 20, 20a Discharge electrode 22, 22a Counter electrode 24-1-24-n Measuring electrode 28-1 to 28-n, 28a Current detection circuit 29-1 to 29-6 Current monitor apparatus 30 Classification Electrode 32 Classification power supply 50 Gas filter 100 Computer 102 Classification power supply control unit 104 Determination unit 106 Threshold value holding unit 108 Display unit

Claims (6)

A charging part for charging the gas sucked from the sample suction port, at least one suction electrode arranged on one of the inner surfaces constituting the flow path through which the gas charged by the charging part flows, and the inner surface A classifying electrode that is disposed on the other surface of the gas electrode so as to face the suction electrode, and generates an electric field that attracts charged particles in the gas flowing in the flow path to the suction electrode side between the suction electrode and the suction electrode; A classification unit failure diagnosis apparatus for determining whether or not the classification electrode is normal in a fine particle classification apparatus comprising:
A galvanic circuit connected to the suction electrode to detect the amount of charge;
A classification power supply control unit that switches on / off power supply to the classification electrode while lowering the supply voltage to the classification electrode to a constant voltage for diagnosis lower than the voltage at the time of normal measurement;
Whether or not the classification electrode is normal depending on whether or not the magnitude of the change of the output signal in the on / off switching of the power supply to the classification electrode is greater than or equal to a threshold value is taken in the output signal of the galvanometer circuit A determination unit for determining;
A threshold value holding unit that holds the threshold value used by the determination unit and supplies the held threshold value to the determination unit;
Classification unit fault diagnosis device equipped with.   The classification unit failure diagnosis apparatus according to claim 1, further comprising a display unit configured to display a determination result by the determination unit. A charging part for charging the gas sucked from the sample suction port, at least one suction electrode arranged on one of the inner surfaces constituting the flow path through which the gas charged by the charging part flows, and the inner surface A classifying electrode that is disposed on the other surface of the gas electrode so as to face the suction electrode, and generates an electric field that attracts charged particles in the gas flowing in the flow path to the suction electrode side between the suction electrode and the suction electrode; A classification unit failure diagnosis apparatus for determining whether or not the classification electrode is normal in a fine particle classification apparatus comprising:
A galvanic circuit connected to the suction electrode to detect the amount of charge;
A classification power supply control unit that switches on / off power supply to the classification electrode while lowering the supply voltage to the classification electrode to a constant voltage for diagnosis lower than the voltage at the time of normal measurement;
A classifier failure diagnosis apparatus comprising: a display device connected to the galvanometer circuit and displaying an output signal of the galvanometer circuit. A gas filter that is disposed in the sample suction port and that removes particulate components in the gas to be sucked;
A plurality of the measurement electrodes are arranged along the flow of the gas flowing through the flow path, and the galvanometer circuit in which the determination unit captures an output signal is located on the most upstream side of the flow of gas flowing through the flow path. The classification part fault diagnosis apparatus according to any one of claims 1 to 3, which is a galvanometer circuit connected to a certain measurement electrode. A charging part for charging the gas sucked from the sample suction port; at least one suction electrode arranged on one of the inner surfaces constituting the flow path through which the gas charged by the charging part flows; and the inner surface A classifying electrode that is disposed on the other surface of the gas electrode so as to face the suction electrode, and generates an electric field that attracts charged particles in the gas flowing in the flow path to the suction electrode side between the suction electrode and the suction electrode; A classification unit failure diagnosis method for determining whether or not the classification electrode is normal in a fine particle classification apparatus comprising:
Connect a galvanometer circuit that detects the amount of charge to the suction electrode,
(S1) lowering the supply voltage to the classification electrode to a constant voltage for diagnosis lower than the voltage at the time of normal measurement;
(S2) Thereafter, a step of switching on / off the power supply to the classification electrode; and (S3) an output signal in switching on / off of the power supply to the classification electrode based on the output signal of the galvanic circuit Determining whether the classification electrode is normal based on the magnitude of the change;
Classification part fault diagnosis method including When carrying out this classification part failure diagnosis method, the sample suction port is provided with a gas filter for removing particulate components in the gas to be sucked,
When a plurality of the measurement electrodes are arranged along the flow of gas flowing through the flow path, the output signal of the galvanometer circuit connected to the measurement electrode at the most upstream side of the flow of gas flowing through the flow path The classification part failure diagnosis method according to claim 5, wherein the determination in step S <b> 3 is performed based on the determination.

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