JP6567828B2 - Multi-pulse linear ionizer - Google Patents

Description

  The present invention relates to an AC coronizer for neutralizing both positive and negative electrostatic charges. More specifically, the present invention relates to an AC coronizer that reduces the emission rate of ion emitters with relatively low emission of byproducts such as ozone and nitric oxide.

[Cross-reference of related applications]
This application is a continuation-in-part of US patent application Ser. No. 13 / 210,267, filed Aug. 15, 2011. US patent application Ser. No. 13 / 210,267 is a continuation of US patent application Ser. No. 12 / 049,350, filed Mar. 16, 2008, issued as US Pat. No. 8,009,405. US Patent Application No. 12 / 049,350 claims priority to US Provisional Patent Application No. 60 / 918,512, filed on March 17, 2007.

This application also claims the priority of US Provisional Patent Application No. 61 / 584,173, filed Jan. 6, 2012.
This application is a continuation-in-part of US Patent Application No. 13 / 023,397 filed on February 8, 2011.

  U.S. Patent Application Nos. 13 / 210,267, 12 / 049,350, U.S. Provisional Patent Applications No. 60 / 918,512, 61 / 584,173 and U.S. Patent Application No. 13 / 023,397 are incorporated herein by reference. Part of it.

  AC coronizers are commonly used to neutralize the electrostatic charge of charged objects. It is known in the art that AC colonizers include, for example, features of relatively simple design, high reliability, and low cost. These features are particularly true for AC ionizers that use a single ion emitter configured as a line of thin wire (s) or a line of pointed electrodes. However, these ionizers have a relatively high ozone release and tend to have a higher rate of electrode contamination due to the accumulation of debris from the ambient air. Electrode contamination can reduce ionization efficiency and affect ion balance.

  Therefore, there is a need for a solution to neutralize electrostatic charges that has a slow emitter contamination rate, a relatively low ozone release, and / or a combination thereof.

  Embodiments of the present invention provide an air / gas ionization apparatus and method that generates both positive and negative ions to reduce electrostatic charge on various objects. Embodiments of the present invention can achieve one or more of the following possible advantages.

(1) provide sufficient levels of positive and negative ion flow while limiting ozone and other corona by-product emissions (s);
(2) reduce particle accumulation on the emitter tip or wire electrode and minimize contamination associated with corona discharge particle emission from the ionization bar;
(3) To automatically maintain the ion flow balance in the vicinity of zero and / or (4) To provide a low-cost power supply and ion generation system design that is easy to maintain.

  In one particular embodiment of the invention, the high voltage applied to the tip or wire electrode is designed so that the power is very low and the ionization efficiency is high. This is accomplished by using very strong microsecond wide pulses at very low repetition rates. A flyback type generator naturally generates such a wave in the resonant circuit. Each wave has at least three voltage peaks: an initial low amplitude peak, a second high amplitude peak of opposite polarity and a last low amplitude peak (wave). Normally, only high level waves are used for ionization. As will be described later, the amplitudes of the first wave and the third wave can be greatly reduced by appropriate attenuation. Using such low power reduces ozone generation, corona by-product formation, particle accumulation and shedding, and emitter wear.

  In yet another embodiment of the present invention, the ionization method produces ozone and nitric oxide, although the applied power is sufficient (or satisfactory) to produce positive and negative ions by corona discharge. Providing a relatively short pulse duration so as to erode the emitter and / or be insufficient (or unsatisfactory) to attract particles from the surrounding space.

  In yet another embodiment of the present invention, the ionization method reduces the effects of normal ion density fluctuations between tips and allows the ion balance to be evenly distributed along the length of the ion emitter structure. In order to do so, it can optionally include applying a voltage simultaneously to the linear wire or group of linear emitters. In another embodiment of the present invention, this optional method can be omitted.

  In another embodiment, a method for generating ions in a space separating an emitter and a reference electrode, wherein the number of small sharp pulses and variable repetitions that can vary depending on the distance of the object from the emitter. Generating a number of pulses.

  In yet another embodiment of the present invention, an apparatus and method for generating ions in a space separating an emitter and a reference electrode includes providing the emitter with at least one pulse train, the pulse train comprising: The positive pulse train includes a first plurality of ionized positive voltage pulses in the positive phase and a second plurality of ionized positive voltage pulses in the ionization frequency phase that occurs after the positive phase. And the negative pulse train includes a first plurality of ionization negative voltage pulses in the ionization frequency phase and a second plurality of ionization negative voltage pulses in the negative phase that occur after the ionization frequency phase, Each of the ionized positive voltage pulses is greater than the magnitude of each of the second plurality of ionized positive voltage pulses, and each of the first plurality of ionized negative voltage waveforms is Greater than the respective dimensions of the second plurality of ions, negative, voltage pulse.

FIG. 6 shows voltage waveforms of positive and negative ionization pulses and pulse trains according to one embodiment of the present invention. FIG. 6 shows a scope screenshot of the voltage waveform of positive and negative ionization pulses in a column in the real-time domain, according to one embodiment of the invention. FIG. 4 is a circuit diagram of one analog / logic based embodiment of the present invention in the case of an ionization bar with a one wire type emitter electrode. FIG. 3B is a waveform diagram for various inputs of various components of FIG. 3A. FIG. 2 is a block diagram of an embodiment based on a microprocessor of the present invention. FIG. 2 is a block diagram of an embodiment based on a microprocessor of the present invention. FIG. 6 shows one multi-pulse of three different modes for optimizing a high voltage waveform (pulse train) in case of different charge neutralization conditions according to an embodiment of the present invention. FIG. 6 shows one multi-pulse of three different modes for optimizing a high voltage waveform (pulse train) in case of different charge neutralization conditions according to an embodiment of the present invention. FIG. 6 shows one multi-pulse of three different modes for optimizing a high voltage waveform (pulse train) in case of different charge neutralization conditions according to an embodiment of the present invention. 4B is a flowchart of a method performed by software executed by the controller of FIGS. 4A and 4B, according to one embodiment of the invention. 4 is a table showing multi-pulse configurable parameters and corresponding definitions and exemplary parameter range values according to one embodiment of the invention. FIG. 6 shows one multi-pulse of three different modes based on different settings than FIGS. 5A, 5B, 5C, according to one embodiment of the present invention. FIG. 6 shows one multi-pulse of three different modes based on different settings than FIGS. 5A, 5B, 5C, according to one embodiment of the present invention. FIG. 6 shows one multi-pulse of three different modes based on different settings than FIGS. 5A, 5B, 5C, according to one embodiment of the present invention. FIG. 6 is a circuit diagram of another embodiment of the present invention as a two-phase ionization bar with two (wire-type or tip-type) emitter electrodes. Fig. 6 shows a variation of a self-balancing ionization structure in the case of a linear bar according to an embodiment of the invention. 1 is a schematic diagram of a linear bar with a wire emitter and an air assisted ion delivery system, according to one embodiment of the present invention. FIG.

  In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of various embodiments of the invention. Those skilled in the art will appreciate that these various embodiments of the present invention are illustrative only and are not intended to be limiting in any way. Other embodiments of the invention will readily occur to those skilled in the art having the benefit of the disclosure herein.

  One embodiment of the present invention can be applied to many types of air-gas ionizers configured as an ionization bar, blower or in-line ionization device.

  Pulse mode ionizers are known in the art. For example, JP 2008-124035, US Patent Application Publication Nos. 20060151465 and 20090116828 describe AC ionization bars. U.S. Patent No. 8,009,405 discloses an ionization blower design with a high voltage power supply that periodically generates positive and negative pulse bursts.

  These power supplies include positive and negative DC high voltage sources and a summing block connected to the ion emission structure. Low frequency pulses (ranging from about 0.1 Hz to 100 Hz) are generated by turning on and off each high voltage source independently. However, these AC pulse ionization systems are complex, inefficient and tend to accumulate particles on the ion emissive structure.

  One of the main features of one embodiment of the present invention is the use of a very short duration bipolar ionization pulse that is very asymmetric (with respect to positive or negative voltage magnitude). A train of positive and negative pulses (ie, a group of pulses) is applied to a linear emitter or a group of emitters.

  Short duration pulses (with an asymmetric waveform) produce a high voltage gradient, which reduces ion recombination at the emitter, thereby increasing emitter ionization efficiency, so high concentrations of positive and negative ions A relatively or very low power consumption method can be used to generate

  In one embodiment of the invention, positive and negative ion clouds are generated periodically by a train of pulses having a variable number of pulses, pulse train duration, and voltage amplitude for each pulse duration. The number of voltage waveforms is generated by a small high voltage transformer with a primary winding controlled by a low voltage pulse generator and a secondary winding that forms a resonant circuit including the ion emitter and reference electrode of the bar. Can do.

  FIG. 1 is a diagram illustrating voltage waveforms of positive and negative ionization pulses and pulse trains according to one embodiment of the present invention. Low voltage pulses 105a, 105b (controlling the input of the high voltage transformer) are shown at the top of FIG. Each ionization pulse, eg, a positive pulse, can include a series of three different voltage wave components. The output pulse begins with a negative voltage wave having an amplitude below the corona discharge threshold (see waveform 110 at the bottom of FIG. 1). The duration of this period is in the range of a few microseconds or a few nanoseconds.

  As shown in FIG. 1, the pulse train 105 is arranged to include a positive pulse train 105a and a negative pulse train 105b, and the trains 105a and 105b are sequentially switched. A pulse train 105 is provided to the emitter. FIG. 1 also shows the effective emitter signal 110 resulting from the pulse train 105.

  The positive pulse train 105a includes the following pulse: a plurality of ionized positive voltage pulses 106 having a period of Tupulse_rep in a period 115 (positive phase 115) and a pulse width of Tp, and a period 120 (ionization frequency phase generated after the positive phase 115). 120) and a plurality of ionized positive voltage pulses 107 having a pulse width of To (where To <Tp), and a zero value during a period 125 (negative phase 125) occurring after the ionization frequency phase 120 including.

  The negative pulse train 105b has the following pulses: a plurality of ionization negative voltages having a zero value in the period 115 (positive phase 115), a period of Tupulse_rep in the ionization frequency phase 120, and a pulse width of To (where To <Tp). A plurality of ionized negative voltage pulses 108, pulses 107, 108 that are offset from each other and not generated at the same time, a period of Tupulse_rep in a period 125 (negative phase 125), and a pulse width of Tn. Of ionization negative voltage pulses 109, wherein Tp and Tn include a plurality of ionization negative voltage pulses 109, which may be the same in length or different in time.

  These ionized positive and negative voltage pulses generate a voltage gradient across the emitter and reference electrode of the ionizer and a corona discharge generates an ion cloud that contains positive and negative ions. As discussed further below, as a result of the positive ionization voltage pulse 107 and the negative ionization voltage pulse 108 in the ionization frequency phase 120, the effective emitter signal 110 has a small magnitude AC pulse 130.

  As shown for period 115, waveform 110 includes a high positive voltage wave having an amplitude that is higher than the positive corona threshold for a given ion emission structure. During that time, the ion emitter produces positive ions in the gap between the ion emitter and the non-ionized (or reference) electrode. This gap between the ion emitter and the non-ionized electrode is shown, for example, in FIG. 6 of US patent application Ser. No. 13 / 210,267, cited above. The positive ion cloud repels electrostatically from the ion emitter and moves to the reference electrode (which is often blown away).

  During period 125, a negative voltage with an amplitude significantly lower than that required for corona discharge occurs. This voltage creates an electrostatic field that slows the movement of positive ions and reduces ion loss to the reference electrode. The amplitude of the negative voltage can be adjusted by an attenuation mechanism in the HVPS (High Voltage Power Supply) circuit.

  The positive ionization pulse is followed by a high-amplitude negative pulse (also shown in FIG. 1) that causes the negative ion cloud to pass over a short period of time in the same manner as discussed above. Generate. The number of repetitions of the ionization pulse can be in the range of 1000 pulses to thousands of pulses per second.

  The effective emitter signal 110 includes ionization pulses 142, 144 that may be followed by smaller negative and positive oscillations 146. The negative and positive vibrations 146 are due to circuit resonances of the power supply used to generate the signal 110 and are in no way intended to limit the present invention. The vibration 146 can be substantially reduced or eliminated completely, for example by using a damping circuit as disclosed in US patent application Ser. No. 13 / 023,387.

  The non-ionization pulses 148 and 150 have a polarity (negative) opposite to that of the ionization pulses 142 and 144 (positive).

  FIG. 1 shows a group of positive and negative ionization pulses 130 simultaneously (central period 120 between periods 115 and 125). The upper dashed line 135 indicates a positive corona threshold voltage that is typically in the range of about 4.0 kV to 5.0 kV, for example, and the lower dashed line 140 is in the range of, for example, about 3.75 kV to 4.50 kV. Indicates a negative corona threshold voltage. Pulses that exceed the negative corona threshold voltage generate negative ions, and pulses that exceed the positive corona threshold voltage generate positive ions.

  The solution for electrostatic charge neutralization using several short high voltage pulses 151, 152, 153, 154, 155 in the microsecond range reduces the generation of ozone and accumulates contamination on the emitter surface. Found to provide sufficient ionization while reducing material.

  The pulse train is arranged to provide alternating positive and negative voltage waveforms, each pulse having a small amount due to the first non-ionized voltage level, the second ionized voltage level, the third non-ionized voltage level and circuit resonance. Has further vibrations. An analog or logic type switching circuit (see FIG. 3) provides a series of alternating positive and negative ionization pulses.

  The use of high voltage flyback generation (generated by flyback type generators) in ferrite core transformers has a moderate turns ratio and does not require voltage multiplier circuitry for positive and negative ionization pulses Provides a simple, efficient, and inexpensive ionizer high voltage power supply that can use very small transformers (eg, about 1 ″ × 1 ″ × 1 ″). Using a ferrite core with a gap and adequately dampening voltage oscillations reduces the magnetic memory effect of the core, thereby allowing the use of multiple ionized pulse sequences consisting of pulses of one or the other polarity. To.

  As a result, a train (sequence or group) of positive and negative ionization pulses provides ample bipolar ionization for at least one emitter electrode having a length in the range of about 100 mm to 2000 mm or more.

  The number of pulses of one polarity can be adjusted to obtain the best object neutralization discharge time, which depends on the air flow and the distance to the charged object. The concentration of alternating polarity ions is sufficient for the ionization bar to neutralize moving objects at distances up to about 1000 mm or more.

  FIG. 2 is a diagram illustrating a scope screenshot of an exemplary column positive and negative ionization pulse voltage waveform in the real-time domain, in accordance with one embodiment of the present invention. As seen in FIG. 2, the pulse train pair 18 includes a positive pulse train 30 and a negative pulse train 32 that are sequentially switched. The upper dashed line 44 represents a positive corona threshold voltage (eg, 4.5 kV) and the lower dashed line 46 represents a negative corona threshold voltage (eg, −4.25 kV). A positive corona threshold voltage level 44 and a negative corona threshold voltage level 46 are shown in the real time domain. Each positive pulse train 30 is arranged to include an ionized positive voltage waveform having a maximum positive voltage amplitude that exceeds a voltage threshold for generating positive ions by corona discharge. Similarly, the negative pulse train 32 is arranged to include an ionized negative voltage waveform having a maximum negative voltage amplitude that exceeds a voltage threshold for generating negative ions by corona discharge. In this way, each of these positive and negative ionization voltage waveforms alternately creates a voltage gradient across the space between the emitter and reference electrode, and corona discharge causes ions containing positive and negative ions. Generate clouds.

  The number of pulse repetitions can be adjusted according to the required ionization power level and the speed of the moving object. This screenshot illustrates that the effective ratio of high voltage power “on” to power “off” can be about 0.0015 or less. Therefore, according to the ionization method disclosed in one embodiment of the present invention, the corona discharge is usually present for only a small portion (less than about 0.1%) of the time required for ion generation, Less than the time it takes to release and the time it takes to attract the particles to the ion emitter.

  Experiments with one-wire type ionization systems (or ionization cells) have shown that voltage waveforms using micro ionization pulses reduce ozone emissions by about 1/3 to 1/5 at approximately equal charge neutralization efficiency. Indicated. For example, an ionizer similar to that described in US Patent Application Publication No. 2008/0232021, powered by an AC high frequency power supply, is approximately 10 ppb (parts) for the same ionizer according to one embodiment of the present invention. -per-billion) Generates ozone concentration of about 50ppb or more compared to ~ 15ppb.

  FIG. 3a is a circuit diagram of an embodiment of the analog / logic base 300 of the present invention in the case of an ionization bar with a one wire type emitter electrode 305. FIG. In addition, FIG. 3b shows a waveform diagram for the various inputs of the various components in FIG. 3a. A gas source 310 is arranged to provide a gas flow and is electrically coupled to a voltage source V +. Pulse train 105 (formed by positive pulse train 105a and negative pulse train 105b as shown in FIG. 1) is received by emitter 305.

  The power supply 306 can be part of the analog / logic base 300 or can be another component that provides power to components within the base 300. For clarity in the drawing, the reference node (ground etc.) is omitted in FIG. 3a. The values of the components in FIG. 3a (eg, passive elements such as resistors, inductors and capacitors) are in no way intended to limit embodiments of the present invention.

  In the circuit operation of the analog / logic base 300, the timer chip (U3) 315 includes a dual delay logic chip (U1) 320, an adder logic chip (U2) 325, transistors (Q1) 330 and (Q2) 335, and a switching circuit. A short pulse is given to the pulse driving circuit 317 (or the power source 317) formed by 340. The transistors 330 and 335 may be MOSFETs, for example. However, the use of MOSFETs (eg, n-channel MOSFETs or other MOSFET type transistors) is in no way intended to limit embodiments of the present invention.

  The timing of the high voltage pulse from the high voltage output transformer 345 is initially determined by the clock signal generated by the trapezoidal oscillator (U1) 320. The oscillation frequency determines the alternating switching from positive pulse generation to negative pulse generation, called the operating frequency. Its frequency is determined by a fixed capacitor (C1) 346 and an adjustable resistor (R1) 347. A frequency range of about 0.2 Hertz to 60 Hertz is commonly used, with lower frequencies being used for objects at a distance and higher frequencies being used for objects that are closer.

  The output signal from the oscillator (U1) 320 is supplied to a delay device (U2) 325, which generates an antiphase signal at half its frequency. The output from device (U2) 325 is then provided to AND gate (U4) 340, which activates possible activations in transistors 330, 335 (eg, MOSFET drive transistors (Q1) 330 and (Q2) 335). Used to invert.

  The main activation pulse is generated by the timer device (U3) 315. Feedback (signal 351) from the output pin (of timer device 315) is fed back to its trigger pin 2 and threshold pin 6. This allows a very short positive pulse to be generated at the output pin 3. The pulse width is controlled by a fixed capacitor (C2) 350 and an adjustable resistor (R3) 352. The pulse width is typically adjusted to about 2 to 24 microseconds, depending on the design of the flyback output driver 317. The number of repetitions of the pulse is determined by the fixed capacitor (C2) 350 and the variable resistor (R4) 354. The number of repetitions is equal to the inverse of the pulse period. This pulse repetition rate can range from about 20 Hertz to 1000 Hertz, which determines the power output of the high voltage generator and is usually about 250 Hertz.

  The AND gate (U4) 340 mixes the flip-flop signal and the microsecond pulse from the chip (U3) 315, thereby alternating the activation pulses to the gates of the driver transistors (Q1) 330 and (Q2) 335. Apply.

  One output phase from pin 7 (of comparator 356 of chip (U1) 320) is used to stop oscillation in chip (U3) 315, thereby outputting from pin 3 of chip (U3) 315 Interrupt the pulse. This interruption can be used to provide an off-time between positive and negative ionization. This interruption is sometimes used to reduce ion cloud recombination at long object distances or simply to reduce power output. The off time or dead time is adjusted by the bias applied to pins 10 and 13 (comparators 358 and 359 in chip (U1) 320, respectively).

  The formation of the micropulse is achieved by the following operation. As an example, a short positive pulse (microsecond range) to the gate of MOSFET (Q2) 335 causes a current to flow in the primary winding coil (2, 3) 360 of high voltage transformer 345, thereby initially A small negative voltage pulse is generated across the primary winding coil 360. At the end of the negative voltage pulse, a large positive voltage flyback pulse is generated with small negative and positive oscillations due to circuit resonance.

  Alternatively, a short pulse to the gate of MOSFET (Q1) 330 produces a large negative pulse. These pulse voltages are magnified and phase inverted by the secondary winding 362 of transformer 345 by using a large turns ratio that can be on the order of about 50-500 to 1. In this way, MOSFET (Q2) 335 initiates a negative high voltage pulse and MOSFET (Q1) 330 initiates a positive high voltage pulse. These pulses generate positive and negative ions by the same wire or tip emitter.

The pulse voltage amplitude for both positive and negative polarities is determined by the following parameters.
1. 1. Turn ratio of transformer (T1) 345 2. Inductance of transformer primary coil 360. 3. Duration of MOSFET gate pulse introduced to the gates of transistors 330, 335 4. Input DC voltage as seen in capacitor 364, which is an electrolytic filter. A primary attenuation circuit 363 formed by an attenuation circuit resistor 365 (eg, a 2 ohm resistor), an inductor 367 (eg, an inductance of 22 μH) and a shunt resistor (Rp) 368 across the primary coil 360.
6). 6. Resistance of transistors 330 and 335 connected in series (for example, MOSFETs (Q1) 330 and (Q2) 335) Capacitive load of the ionization assembly (measured at the output of the transformer secondary 362)

  The high voltage output pulse from transformer (T1) 345 has a waveform set by the inductance of primary winding 360 and the capacitive load on the secondary and primary attenuation components of attenuation circuit 363. A shunt resistor (Rs) 365 and an inductor (Ls) 367 placed between the transformer center tap 2 and the power input (Vin) prevent a sudden rise time of the current in the transformer 345, thereby The peak value of the first portion (portion 115 of FIG. 1) of the waveform 110 (FIG. 1) is decreased. The third portion of waveform 110 (FIG. 1) is reduced by shunt resistor (Rs) 365. As a result of selectively or carefully adjusting these components, a maximum ionization efficiency exceeding the high peak level requirement of the second portion 120 (FIG. 1) of the waveform 110 is obtained.

  Referring again to FIG. 2, a high slew rate of the generated pulses can be seen. In the case of the primary coil 360, the voltage rising speed is about 270 V / μs and the falling speed is about 1800 V / μs. In the case of the secondary coil 362, the slew rate may increase to about 35 (± 8) kV / μs. Without using any multipliers, rectifiers and summing blocks, only one small output high voltage transformer 345 can be used to constantly generate asymmetrical positive and negative pulses by the drive circuit 317.

  It should also be noted that the pulse repetition rate can be adjusted depending on the charge density and speed of the neutralization object. Other details regarding signal transmissions (eg, current signals or voltage signals) known to those skilled in the art (s) are further discussed to focus on embodiments of the present invention. Absent. The various standard signal transmissions that occur in an AC coronizer are further detailed in the references cited above. The waveform is defined by the resistance, capacitance, and inductance values (R, C, L, respectively) of all components. The pulse height can be adjusted by changing the pulse duration set in FIG. 3 by resistor (R3) 352 and capacitor (C2) 350 associated with device (U3) 315.

  4a and 4b are block diagrams of an embodiment based on the microprocessor of the present invention. As shown in FIG. 4 a, the pulse drive circuit includes a microcontroller 400 (or other processor or controller 400) for controlling the switching of transistor 330. Microcontroller 400, under software control, generates a narrow pulse, typically about 19 microseconds wide, adjusted by software, where one pulse train 402a is assigned to a positive ionization pulse and one pulse train 402b is negative. Assigned to the ionization pulses. From microcontroller 400, the pulses are a set of pulse drivers 405 (FIG. 4b) that amplify the pulses to a size suitable for driving switching transistors 330, 335 (FIG. 3a), which can be, for example, high power MOSFETs. ). As discussed above, these MOSFETs then drive a high voltage pulse transformer 345.

  As an option that may be excluded in other embodiments of the present invention, the microcontroller 400 may also receive signals 410, 415 from the spark detector 410 and the break detector 425, respectively. In any of the embodiments shown in FIGS. 3a, 4a and / or other figures / drawings herein, the applied power is sufficient to generate positive and negative ions by corona discharge. The pulse duration can be shortened so that it is insufficient to produce ozone and nitric oxide, corrode the emitter, and attract particles from ambient air. In any of the embodiments shown in FIGS. 3a, 4a and / or other figures / drawings herein, the ionizer is, for example, about 250 Hertz (or more) instead of the usual about 50000 Hertz to 70000 Hertz. At very slow repetition rates, such as (less than), provide a strong (or relatively strong) ionization pulse that is at least about 1000 volts above the ionization threshold, thereby producing ions with less ozone.

  FIGS. 5a, 5b, 5c show three different modes of multi-pulses that optimize the high voltage waveform (pulse train) for different charge neutralization conditions, and FIG. 5d shows a microcontroller according to one embodiment of the present invention. 4 illustrates a method performed by software executed by 400. Modes A, B, and A + B depend on charge neutralization requirements such as discharge time for positive and negative charges, acceptable voltage swing (field effect), distance to the object, etc. The microcontroller 400 executes software that can provide three modes of ionization pulses as required by the application implementing embodiments of the present invention: Mode A, Mode B, and Mode A + B.

  Mode A: As shown in FIG. 5a, Mode A is defined by a repeating sequence of combinations of positive and negative pulses. Each positive pulse 505 (beyond the positive corona threshold 506a) is followed by a negative pulse 510 (beyond the negative corona threshold 506b), after which each negative pulse 510 is followed by a positive pulse 505. Continue. A positive pulse train 515a and a negative pulse train 515b are shown, with positive and negative voltage pulses alternating. This mode is typically used at very close object distances (eg, about 200 mm or less) where the ionization field voltage needs to be reduced.

  In mode A, the pulse amplitude 529, the micropulse period 525, and the pulse widths 530 and 535 of the positive micropulse 505 and the negative micropulse 510 can be adjusted by software executed by the microcontroller 400, respectively. The positive micropulse amplitude and positive micropulse duration are adjusted by the load pulse MP_P value by a timer / counter at block 563 (FIG. 5d). The negative micropulse amplitude and negative micropulse duration are adjusted by the load pulse MP_N at block 566 (FIG. 5d). The period for positive and negative micropulses is adjusted by the repetition frequency value by a load repetition frequency (Reprate) timer / counter at block 551 (FIG. 5d).

  Mode B: As shown in FIG. 5b, mode B includes a repetition sequence 540 of positive pulses 541 followed by a repetition sequence 542 of negative pulses 543, followed by a repetition of positive pulses 541 as shown. A series 540 follows and is defined by repeating it. A small delay 544, or off-time, can be added between the positive pulse sequence 540 and the negative pulse sequence 542 to reduce ion recombination. The off time is a time during which no ionization pulse is generated. This mode is typically used at object distances that are very far (over 500 mm). The number of MP_N values in block 568 (FIG. 5d) loaded into block 554 (FIG. 5d) is used to set an off-time delay value 544 (FIG. 5b) at which no pulse is generated. The positive ionization pulse width is adjusted by the Tpmax value by the load pulse timer / counter at block 556 (FIG. 5d). The positive ionization pulse period is adjusted by the repetition frequency value by the load repetition frequency timer / counter at block 551 (FIG. 5d). The negative ionization pulse width is adjusted by the Tnmax value by the load pulse timer / counter at block 560 (FIG. 5d). The negative ionization pulse period is adjusted by the repetition frequency value by the load repetition frequency timer / counter at block 551 (FIG. 5d).

  Mode A + B: As shown in FIG. 5c, mode A + B is a combination of mode A and mode B, mode A occurs in off-time region (time) 550, mode B is on-time region (time) 551, Occurs at 552. This mode is typically used for objects at intermediate distances (200 mm to 500 mm) where the ionization field voltage needs to be kept low, but the object distance varies with the process. On-time areas 551, 553 are adjusted at block 554. The off-time region 550 is adjusted by the number of pulses MP_P and pulses MP_N that determine the width of this region (ie, set in block 554). The positive micropulse width is adjusted by block 563. The negative micropulse width is adjusted by block 566. The negative ionization pulse width is determined by block 560. The number of negative pulse repetitions is determined by block 551. FIG. 5 d shows various blocks 550-573 that describe other functions of the method 574 performed by software executed by the microcontroller 400. FIG. 5e is a table 575 showing multi-pulse configurable parameters and corresponding definitions, and exemplary parameter range values, according to one embodiment of the invention. FIGS. 5f, 5g, 5h also illustrate multipulses in three different modes based on different settings from FIGS. 5a, 5b, 5c, according to one embodiment of the present invention.

  In all three modes, the user can (1) change the positive or negative pulse width or both to control the ionization amount in the on-time region (Tpmax and Tnmax) independently of the off-time region (MP_P, MP_N) And (2) the ion balance can be changed by changing the time ratio between the positive on-time region and the negative on-time region. The time between pulses (Treprate) is the same in all regions and can be adjusted to control the ionization power. High power is a place where the Treprate is small and produces more frequent ionization pulses, resulting in more ionization. On the other hand, the greater the Treprate, the less frequently the ionization pulses are generated, resulting in less ionization.

  Therefore, one embodiment of the present invention provides a method of ionization and an associated circuit diagram (apparatus). This embodiment produces very short bipolar micropulses and provides efficient bipolar air (or other gas) ionization with a normal emitter at normal atmospheric pressure.

  In the embodiment shown in FIG. 8, the high voltage pulse generator includes various ion emitters: single or group of wires, saw blade type emitters, various ionization cells with tip electrode (s). Power). The ionization bar can also have an internal source of air flow (air channel) connected to a nozzle, small diameter orifice or slot located in close proximity to the ion emitter. Therefore, FIG. 8 shows a schematic diagram of a linear bar comprising a wire emitter and an air assisted ion delivery system, according to one embodiment of the present invention.

  Another embodiment of the invention relates primarily to ionization bar design. FIG. 6 (FIGS. 6a, 6b) shows a schematic diagram of another embodiment of the present invention as a two-phase ionization bar comprising two (wire and tip type) emitter electrodes E1 and E2. In this two-phase ionizer with two emitters, any emitter can be configured as a sharp tip electrode, a row of wires or blades, or as a row of nozzles with a tip emitter. Further details of the elements within the linear bar are disclosed in the above-cited US Provisional Patent Application No. 61 / 584,173.

  The high voltage section design uses the same driver circuit (discussed above) as the MOSFET, but the MOSFET transistor drains (M1 and M2) are reversed to the primary side of a pair of high voltage transformers T1, T2. It is connected to the.

  Control resistor R1 and attenuation capacitor C2 (FIG. 6) are selected to produce the same alternating polarity pulses as in the circuit design shown in FIG. Therefore, each pulse has a predominantly positive or negative peak amplitude and the polarity is reversed.

  In FIG. 7, the capacitor C2 is connected in series with the bottom system portion of the transformers T1, T2, allowing the ionization system to operate in a self-balancing mode. Both ion emitters are floating relative to the ground, and according to the law of charge conservation, the output ion cloud will be fairly well balanced. Otherwise, any normal imbalance will produce an opposite DC voltage across capacitor C2. Further details on how to achieve the above balance can be found in US Pat. No. 5,055,963 by Leslie W. Partridge, co-owned and assigned to the same assignee, which is cited To form part of this specification.

  The ion emitters connected to the transformers T1, T2 have voltage ionization pulses with opposite polarities. The voltage waveform 602 for this two-phase ionization system is shown in (FIG. 6a) and a simplified bar cross-section 605 with emitter (1) E1 and emitter (2) E2 is shown in (FIG. 6b). It is.

  This embodiment of FIG. 6 has at least two advantages over the single phase ionization system. In many cases, charge neutralizing objects are sensitive to electric fields and need to have an ionizer that has the effect of canceling out the electric field. A two-phase ionization system simultaneously generates voltages of opposite polarity, thereby significantly reducing the radiated electric field.

  This feature is also important when the ionization bar is to be placed in close proximity to a charged object. For example, with respect to the distance between the ionization bar and the object in the case of a positive pulse train duration (pulse duration, amplitude or pulse frequency, etc.), the distance is the negative pulse train in one cycle for one emitter. The reverse polarity may become saturated in the next one cycle. It brings about the “push” effect of the ion cloud and accelerates the movement of ions to the object.

  Two-phase ionization systems do not have any bulky reference electrodes and have the additional advantage of avoiding ion loss at these electrodes.

  In addition, the out-of-phase voltage source can significantly (approximately half) reduce the voltage amplitude required at each emitter to generate a corona discharge. Therefore, these transformers can be of the same design or have a low primary to secondary turns ratio. When in close proximity to each other, emitters tend to increase the electric field between the emitter pair, so a low turns ratio can be used.

  FIG. 6 also shows an embodiment of a (C3, C4) two-phase linear ionizer in which each emitter is capacitively coupled to the outputs of transformers T1, T2. The secondary coils of both transformers T1, T2 are grounded. This is another variation of a self-balancing ionization system with capacitive coupling.

  The difference between the embodiment shown in FIG. 3 and the embodiment shown in FIG. 6 is mainly the reaction time to the ion balance offset. Capacitors (C3, C4) can provide a short transition time to balance. A small capacitor connected in series with each emitter can fine tune the phase shift between the emitters and help limit the current when the emitters are in contact.

Ion balance control:
In one embodiment, the ionizer can have a number of different variations (shown in FIG. 7) self-balancing system, where a wire emitter (indicated by dashed line 705) is capacitively coupled to the HVPS output, The floating transformer secondary emitter and reference can both be grounded to the reference electrode and capacitively coupled to the HVPS.

  The linear ionizer can also have an active ion balance system that uses an external ion balance sensor (s) that is placed in close proximity to the charged object. In this case, the microprocessor-based control system and the bar HVPS can mainly generate ionized micropulses and generate ions of opposite polarity to the charge of the object.

  A schematic diagram of a linear ionization bar with a wire-type emitter is shown in FIG. A wire electrode 801 is attached to the bar chassis (or cartridge) by a spring 802. Spring 802 provides wire tension and is connected to the output of the high voltage power supply (not shown in FIG. 8) discussed above. The reference electrode 803 is configured as two stainless steel strips attached to both sides of the chassis. A high intensity electric field creates a corona discharge in the form of an ion plasma sheath over the wire emitter.

  Air port 804 provides an air flow that helps ions generated by the emitter to travel to the object. Therefore, ions travel to the charged object by a combination of electric field and aerodynamic force. As a result, the discharge time for neutralizing the charge of the object is shortened (within a few seconds).

  Although the invention has been described in certain embodiments, it should be understood that the invention is not to be construed as limited by such embodiments. Rather, the present invention should be construed according to the claims that follow.

300 logic base 300 base 305 emitter electrode 305 emitter 306 power source 310 gas source 315 timer chip (U3)
315 Timer device (U3)
315 Timer device 315 Chip (U3)
315 devices (U3)
317 Pulse Drive Circuit 317 Power Supply 317 Flyback Output Driver 317 Drive Circuit 320 Dual Delay Logic Chip (U1)
320 Trapezoidal oscillator (U1)
325 delay device (U2)
330 MOSFET (Q1)
335 MOSFET (Q2)
340 Gate (U4)
345 High Voltage Output Transformer 346 Fixed Capacitor (C1)
347 Adjustable Resistor (R1)
350 Fixed Capacitor (C2)
352 Adjustable resistor (R3)
354 Variable resistor (R4)
356 Comparator 358 Comparator 359 Comparator 360 Transformer primary coil 362 Transformer secondary coil 363 Primary attenuation circuit 364 Capacitor 365 Shunt resistor (Rs)
367 Inductor (Ls)
368 Shunt resistor (Rp)
400 Microcontroller 405 Pulse driver 410 Spark detector 425 Disconnection detector

Claims (13)

In a method for charge neutralization by generating bipolar ions during corona discharge between an emitter and a reference electrode,
Produces sharp micropulses with short duration,
Each micropulse includes a positive voltage portion and a negative voltage portion,
The micropulse is asymmetric with respect to the magnitude and amplitude of the positive and negative voltages;
The voltage magnitude of at least one pole exceeds the corona threshold,
The pulse train includes a plurality of waves, each wave including an initial low amplitude peak, a second high amplitude peak of opposite polarity, and a last low amplitude peak;
The pulse is a bipolar pulse train in which the number of pulses, the duration, the number of repetitions, and the amplitude are variable depending on the moving speed of the charge neutralization object and the distance between the charge neutralization object and the emitter .   The method of claim 1, wherein the duration of the micropulse is in the range of a few nanoseconds, and the applied power is sufficient to generate positive and negative ions by corona discharge. The micropulse reduces particle accumulation on the emitter tip or wire electrode, minimizes contamination associated with corona discharge particle emission from the ionizer, and minimizes production of ozone and nitric oxide, 0 ... So that sufficient power is applied to the emitter to generate positive and negative ions by corona discharge. The method according to claim 2, wherein the pulse train is formed with a low duty ratio of less than 1%.   In order to reduce the effect of ion density variation between tips and to be able to distribute the ion balance evenly along the length of the emitter, a voltage is applied simultaneously to a linear wire or group of linear emitters. The method of claim 1 further comprising:   The method of claim 1, further comprising controlling and adjusting a pulse parameter or a pulse train parameter.   The method of claim 1, further comprising using a dual ion emitter that generates a reverse polarity voltage, thereby reducing the emitted electric field. In an apparatus that generates bipolar ions during corona discharge between an emitter and a reference electrode,
Comprising a pulse driving circuit for generating sharp micropulses having a short duration;
Each micropulse includes a positive voltage portion and a negative voltage portion,
The micropulse is asymmetric with respect to the magnitude and amplitude of the positive and negative voltages;
Ensure that the voltage magnitude of at least one pole exceeds the corona threshold;
The pulse train includes a plurality of waves, each wave including an initial low amplitude peak, a second high amplitude peak of opposite polarity, and a last low amplitude peak;
An apparatus in which the pulse driving circuit generates bipolar pulses with variable number of pulses, duration, number of repetitions and amplitude depending on the moving speed of the charge neutralization target and the distance between the charge neutralization target and the emitter. . 8. The apparatus of claim 7 , wherein the duration of the micropulse is in the range of a few nanoseconds and the applied power is sufficient to generate positive and negative ions by corona discharge. The micropulse reduces particle accumulation on the emitter tip or wire electrode, minimizes contamination associated with corona discharge particle emission from the ionizer, and minimizes production of ozone and nitric oxide, 0 ... So that sufficient power is applied to the emitter to generate positive and negative ions by corona discharge. 9. The apparatus of claim 8 , wherein the apparatus is a pulse train with a low duty ratio of less than 1%. The pulses include strong ionization pulses that are at least about 1000 V higher than the ionization threshold at very slow repetition rates, such as about 250 Hertz, instead of the usual about 50000-70000 Hertz, thereby reducing ozone. The apparatus according to claim 7 , wherein ions are generated. The pulse drive circuit reduces the effect of ion density fluctuations between tips and allows a uniform distribution of ion balance along the length of the emitter to provide a linear wire or a group of linear emitters. The apparatus according to claim 7 , wherein a voltage is simultaneously applied to the two electrodes. 8. The apparatus of claim 7 , further comprising a microcontroller for controlling and adjusting pulse parameters or pulse train parameters. 8. The apparatus of claim 7 , wherein the emitter further comprises a dual ion emitter that generates a reverse polarity voltage, thereby reducing the emitted electric field.

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