JPH0647006B2 - Self-regulating air ionizer - Google Patents

Description

The present invention relates to devices for increasing the ionic content of air, and in particular to adjusting the ion output of air ionizers.

The air ionizer has one or more pointed electrodes and a high voltage is applied to the electrodes. The resulting strong electric field near the tips of the electrodes ionizes nearby air molecules into positive and negative ions. Ions having a polarity opposite to the high voltage polarity are attracted to and neutralized by the electrodes. Ions of the same polarity as the high voltage are repelled by the electrodes and also repelled each other and diffuse outward from the ionizer into the surrounding atmosphere.

Air ionizers of the type described above were primarily configured primarily to provide beneficial effects to people breathing air and / or to remove contaminant particles such as dust, smoke, etc. from the air. Both positive and negative polar ions are effective in removing the pollutant particles by applying an electric charge to the pollutant particles as described above, but in particular, the negative air ions are physically advantageous. Charged particles settle on nearby walls or other articles as a result of electrostatic attraction.

The ion output ratio of such an air ionizer is basically determined by the size of the high voltage and the area and shape of the electrodes. Ion output regulation in early ionizers was usually limited to using voltage regulators in the high voltage generator power supply. The regulator effectively maintained the high voltage of the electrodes at a fixed level or, in some cases, a selectable level. This does not guarantee that the ion output remains constant over time. The electrode deteriorates and changes shape as a result of the corona discharge that occurs at the tip of the electrode. As a result, the ion generation rate is gradually reduced. Degradation of other components can also change the ion output.

It may be desirable to more accurately adjust the ion output. In particular, the air ionization device has been recognized as an extremely effective means for suppressing the electrostatic charge on the articles in the room. Articles and people are prone to electrostatic charges in the range of up to thousands of volts due to movement and friction associated with movement, dielectric effects and discharges from other articles. If such static electricity is discharged rapidly, it may make people uncomfortable and damage various devices and articles. In particular, for example, computers and recording devices may be disturbed by electrostatic discharge.

In a so-called clean room where semiconductor electronic components are manufactured, it is necessary to pay close attention. Electrostatic discharge can destroy minute conductive components of microcircuits. There is also a problem that a semiconductor wafer or the like is electrostatically charged and adsorbs dust and other contaminating particles and becomes a defective product. Maintaining a high level of air ions around such products helps to minimize the occurrence of defective products because the electrostatic charge of the expected polarity is neutralized by charge exchange with air ions of the opposite polarity. This is an extremely effective method.

Air ionizers for suppressing electrostatic build-up are usually configured to generate both positive and negative ions. Charge storage on the article is possible with ions of either polarity. This requires precise adjustment of the output of each polarity ion.

The desired abundance of positive and negative ions can be made equal or other ratios depending on the static charge accumulation tendency of a particular clean room. In either case, changes in the ratio of positive and negative ion output caused by electrode degradation or other reasons can be detrimental. Ionizers tend to charge an article with an electrostatic charge rather than suppress it. For this reason, changing the combined output ratio of positive and negative ions also has a negative effect.

The generation rate of air ions at a specific electrode can be controlled by adjusting the magnitude of the high voltage applied to the electrode, and increasing the voltage applied to the electrode increases the ion output and lowers the voltage. If so, the ion output is reduced. In order to control the voltage in this way and maintain the desired amount of generated ions, it is necessary to monitor the ion output and detect the amount of generated ions.

Conventional monitoring systems for this purpose use ion detectors that are usually located in the area of the article that is intended to suppress electrostatic charge away from the ionization electrodes. The ion sensor outputs a signal indicating a change in the amount of ions in the air near it.
This signal can be input to the instrument to read the ion content and manually adjust the electrode voltage, or it can be fed back to the servo controller of the high voltage generator for automatic voltage adjustment.

Systems controlled by ion sensors suffer from various limitations and have various drawbacks. The ion sensor has a problem that it picks up ambient noise and limits the spatial range. Further, the ion sensor is expensive. This is extremely disadvantageous in a system in which a large number of ionizing electrodes are arranged apart from each other and controlled over a wide area. Numerous ion sensors are required to detect positive and negative ion imbalances or changes in total ion content throughout the chamber. Ideally, in an ion sensor control system, one air ion sensor should be provided for each ionization electrode, but in many cases it is impossible to actually perform it because the device is expensive. is there.

INDUSTRIAL APPLICABILITY The present invention is capable of maintaining a desired high ion concentration in an adjacent atmosphere and a desired ratio of negative ions to positive ions, and is accurate and reliable, and is expensive. It is intended to make the use of the air ionizer extremely easy by configuring it to be controllable without any need.

Therefore, the air ionizer according to the present invention includes at least one electrode exposed to the air to be ionized, a high voltage generator for applying a high voltage having a predetermined polarity to the electrode, and a ground return electric resistance. The electric charges having the opposite polarities are discharged from the high voltage generator through the electric resistance at a rate corresponding to the rate of air ion generation by the electrodes. The detection means generates an electrical feedback signal whose magnitude changes in response to fluctuations in the voltage drop across the electrical resistance.
The air ionizer according to the present invention further receives a feedback signal and applies a higher voltage to the electrodes in response to the reduction of the feedback signal and a lower voltage to the electrodes in response to the increase of the feedback signal. And a voltage adjusting means for adjusting the high voltage generator so that the high voltage generator is operated.

Also, the device according to the invention further comprises control means for generating a voltage control signal indicative of the desired ion output rate. The voltage adjusting means changes the high voltage generated by the high voltage generator according to the change of the voltage control signal and in the opposite relation to the change of the feedback signal.

The present invention also provides an air ionization apparatus including a plurality of ion emitters that are spaced apart from each other, a power supply, and a plurality of high voltage generators. Each high voltage generator is connected to a power source and also to each of the ion emitters, each high voltage generator having an electrical resistance path and having a polarity opposite to the high voltage generated by the high voltage generator. And a return current having a magnitude corresponding to the proportion of the ion output from the ion emitter connected to the high voltage generator flows in a direction away from the high voltage generator via the electrical resistance path. A first portion of the high voltage generator produces a positive high voltage and a second portion produces a negative high voltage. The return current detection means generates a plurality of feedback signal voltages, each of which changes according to the variation of the return current from each of the high voltage generators. The ionizer according to the present invention further comprises means for varying the high voltage generated by each generator in an inverse relationship to variations in the feedback signal voltage from the particular generator. The air ionizer according to the present invention maintains a predetermined total ion output and produces positive and negative ions in a substantially constant ratio.

In addition, the air ionization apparatus according to the present invention includes a plurality of air ionization units, each of which has at least one ion emission electrode exposed to the atmosphere, and which are installed apart from each other. The high voltage outputs of the plurality of high voltage generators provided in the air ionization unit are respectively connected to the respective electrodes and each have means for changing the output voltage in response to the voltage control signal. The first part of the high voltage generator is the negative high voltage generator and the other part generates the positive high voltage. The control box is the first for the power supply and the negative high voltage generator.
Means for alternately and repeatedly generating a separate second voltage control signal for the voltage control signal and the positive high voltage generator. A multi-conductor cable extends from the control box to each ionization unit, the cable including an input conductor connected to each high voltage generator, first and second voltage control signal conductors, and a high voltage generated by the generator. Has a ground return conductor that receives a ground return current of opposite polarity from each high voltage generator, the ground return current having a magnitude equal to the ion output at an electrode connected to the generator. The device according to the invention further comprises a plurality of feedback circuits, each feedback circuit being respectively connected between the high voltage generator, the ground return conductor and one of the first and second voltage control signal conductors. Each feedback circuit is responsive to a received voltage control signal to operate a generator connected to the feedback circuit to change the voltage output of the generator in an inverse relationship to variations in the return current from the generator. Have and.

The air ionizer according to the present invention has the unique property of being able to maintain a substantially constant expected total ion output in the event of electrode deterioration or input voltage fluctuations. In addition, in the air ionizer according to the present invention having a plurality of ion emitters having different polarities, the ion output of each ion emitter is self-regulated independently of the ion outputs of other ion emitters, so that it is negative or positive. The expected power ratio of the ions remains substantially constant. Negative and positive air ion content imbalances in local areas do not occur even when a particular electrode degrades more rapidly than the opposite polarity electrodes located nearby. In one embodiment of the invention, means are provided for varying the voltage applied to each electrode to compensate for the neutralization of air ions occurring at the other adjacent electrode. According to the present invention, the air ion content is accurately and reliably adjusted without the need to use an expensive air ion sensor that continuously monitors the ion content of the air.

Next, an embodiment of the present invention will be described with reference to the drawings.

First, the air ionization apparatus 11 according to the embodiment of the present invention shown in FIG. 1 is configured to be installed in the chamber 12 so as to suppress the electrostatic charge generated on the articles and human beings in the room. In this example, a plurality of bipolar ionization units 13 are mounted spaced apart from each other on a ceiling 14 and are connected to each other by multiple conductor portions 16 of a multi-conductor electrical cable, one of which is easily accessible on a wall 18. Control box mounted in the desired position
It has been extended to 17.

In FIG. 1, two ionization units 13 are shown as an example. However, one ionization unit may be sufficient, and in a room with a large area, more static electricity is suppressed to further increase the number of ionization units. It may be necessary to arrange the ionization units.

Each ionization unit 13 has an outer case 19, and a pair of insulating hollow rods 21 spaced apart from the outer case 19 are extended downward by a predetermined distance to provide positive and negative ion emitters 22, above an area where electrostatic charge should be suppressed. Supports 23 each. Emitter 2
The electrodes 2 and 23 are provided with electrodes 24 and 26 each having a downward tip, and these electrodes are exposed to the atmosphere, and preferably a large-diameter annular insulating protection ring 27 is provided on the outer circumference. Although thoriated tungsten needles are used for the electrodes 24 and 26 shown in this example, other electrode materials having various shapes including a multi-pointed shape can also be used.

For this reason, the physical structure of the ionization unit 13 including the emitters 22 and 23 is Scott J. S. Geharuke et al., US Pat. No. 4,542,434, issued September 17, 1985, "Sequence Controlled Bipolar Air Ionization Method and Apparatus". It can be similar to the corresponding components of the device described in. As in this U.S. patent, each ionization unit 13 has a positive high voltage generator 28 connected to electrode 24 and a negative high voltage generator 29 connected to electrode 26. The present invention differs from the above-mentioned U.S. patent in that, among many other differences, each ionization unit 13 also includes a positive voltage control and feedback circuit 31, a negative voltage control and feedback circuit 32, and a feedback signal summation. Circuit 33
And an individual DC power supply 40 for other circuits of the ionization unit.

As will be described in more detail below, voltage control and feedback circuits 31 and 32 are provided in each of the individual emitters 22, 23 in the system, regardless of individual electrode degradation, supply voltage variations or other changes. Ion output is maintained. This automatically maintains the ideal predetermined ratio of positive and negative air ions over the area where electrostatic charge generation is to be suppressed without the need for external air ion monitoring sensors for control purposes. If the ion output of each electrode in the system is kept constant, then
No local imbalance of ionic bipolar names due to 26 deterioration.

As shown in FIG. 2, a low-voltage AC power source 34 is provided in the control box 17.
And a timing pulse generator 36 is provided which, as will be described in more detail below, is an ion emitter.
It is possible to activate and deactivate 22, 23 and also to select the expected levels of positive and negative ion output.

The low voltage power supply 34 in this embodiment includes a voltage step-down transformer 37 whose primary winding 28 receives a standard utility line alternating current of, for example, 115 volts via an on / off switch 39 and a protective fuse 41. Varistor 42 is connected in parallel with primary winding 38 to protect the circuit from power surges that occur on the power line. An indicator lamp is also connected in parallel with the primary winding 38 to provide a visible signal indicating that the ionizer 11 is active.

The secondary winding 44 of the transformer 37 is connected across the pair of low voltage AC conductors 46, 47 of the cable 16 connected to the ionization unit 13. A high resistance 45 is connected across the windings 38, 44 of the transformer 37 and is configured to specifically serve as a common or chassis ground conductor for the electrical components of the ionization unit 13. If conductor 46 is directly earthed to ground, then earthing resistor 45 is not required. In all cases it is not necessary to operate the ionization unit 13 with a stepped down low voltage input, but by doing so it is possible to use a light and inexpensive cable 16 to interconnect the units in the system. There are advantages.

Cable 16 includes two additional conductors 48, 49 which connect to separate the output channels of timing pulse generator 36. As will be described in more detail below, conductor 48 receives a first voltage control signal that determines the ion output of positive ion emitter 22, and conductor 49 receives a second voltage control signal that determines the ion output of negative ion emitter 23. receive.

The voltage control signals 51 and 52 can be continuous voltages of selectable magnitude if the positive and negative ion emitters 22 and 23 are to operate continuously, but preferably,
The pulse generator 36 is preferably of a known type which produces pulse signals 51, 52 of selectable waveforms. In this example,
Signals 51 and 52 alternate from a predetermined maximum voltage to a selectable lower voltage for a selectable period. In addition to the controller 53 for selecting the lower voltage level of each signal 51 and 52, the pulse generator 36 has an additional controller 54 to select the duration of the voltage drop of each signal 51 and 52 separately, The signal 51 is also selected to have an off time between each voltage drop and the sequential voltage drop of the signal 52 and an off time between the voltage drop of the signal 52 and the sequential voltage drop of the signal 51. An example of an adjustable pulse timing circuit applicable for this purpose is disclosed in U.S. Pat. No. 4,542,434, column 9, line 64 to column 12, line 11. Positive and negative ion emitter 2
The alternating operation between the off times of 2 and 23 is extended to the range of the ionizer 11 for the reason described later.

The operating power of the pulse generator 36 is provided by a DC power supply 56 of known construction which receives AC input power from conductor 47. The cable 16 includes an additional conductor 57, which is a component of the alarm circuit 58 described below.

In the illustrated example, the transformer 37 supplies 60 volts alternating current of 48 volts to the ionization unit 13 via the power conductor 47. The pulse generator 36 outputs +15 volt DC through conductors 48 and 49 except during a periodic voltage drop, and during the periodic voltage drop, the DC voltage depends on the set value of the ion output controller 53.
Drop to a selected value in the range of +2 volts to +10 volts. The controller 54 in this example allows independent adjustment of the off period after the voltage drop of the voltage control signal 51 and the off period after the voltage drop of the signal 52, and can also adjust the time of the voltage drop, Each voltage drop time is 0 to 9.9 in this example.
It can be selected within the range of seconds. These specific values for voltage and duration are given as examples only, and other values and ranges of values can be selected and used in other embodiments.

As shown in FIG. 3, the positive high voltage generator 28, the negative high voltage generator 29 and the DC power source 40 of each ionization unit 13 are connected between the AC conductor 47 and the chassis ground conductor 46 of the cable 16, respectively. .

The positive and negative high voltage generators 28 and 29 can be of the same construction except that some components are grounded in opposite orientations, as will be described below. Each such generator includes a voltage step-up transformer 64 whose primary winding 66 is connected in series with a charge storage capacitor 68 between a circuit junction 67 and a ground conductor 46. Circuit junction
67 is a positive half cycle of alternating current from conductor 47 to capacitor
It is received via 69, diode 71 and charging resistor 72. Diode 71 blocks the negative half cycle from circuit junction 67. Thus, a positive charge is stored on capacitor 68 during each positive half cycle of alternating current. Capacitor
68 is discharged through the primary winding 66 of the voltage step-up transformer 64 during each positive half cycle of alternating current, as described in detail below.

Another diode 73 is connected between ground conductor 46 and circuit junction 74 between capacitor 69 and diode 71 to allow positive charging of capacitor 60 during the negative half cycle of the alternating current. The capacitor during this positive half cycle of alternating current
When combined with the additional positive charging of 69, capacitor 69 and diode 73 act as a voltage multiplier. As a result,
In this embodiment, a maximum voltage of about 135 volts charges capacitor 68 during each positive half cycle.

SCR (Silicon Controlled Rectifier) 76 is circuit junction 67 and ground conductor
Connected to 46 to discharge the capacitor 68 through the primary winding at specific times during each positive half cycle of the alternating current. This induces a high voltage pulse in the secondary winding 74. The magnitude of the voltage generated across the secondary winding is that the voltage of the capacitor itself gradually increases in the initial part of the half cycle.
It depends on the timing of the discharge of the capacitor involved in the positive half cycle. The output voltage of transformer 64 is relatively low when capacitor 68 is discharged prematurely in the positive AC half cycle, and highest when capacitor 68 is discharged at the peak or after the positive AC half cycle. Becomes

The gate terminal 77 of the SCR76 is connected to the ground conductor via the gate resistor 78.
Connected to 46 to receive the trigger signal voltage pulse from the associated voltage control and feedback circuit 31 or 32,
Circuit 31 or 32 determines the timing of the SCR76 short circuit,
This controls the output voltage of the transformer 64. An additional diode 79 is connected across SCR76 in the opposite positive orientation,
It allows for repeated cycles of damped oscillations in the resonant circuit formed by winding 66 and capacitor 68. The voltage developed across the secondary winding 74 depends on the positive and negative peak voltage of this oscillation.

One output terminal 81 of the transformer 64 is connected to the air ionization electrode 24 or 26 by a capacitor 97, a circuit junction 83, and another capacitor 9
3. Connected via a circuit junction 86 and a current limiting resistor 87, which prevents a strong discharge from occurring when an external conductive object contacts the electrode. The other terminal 88 of the secondary winding 74 is connected to ground via an electrical resistance in the associated voltage control and feedback circuit 31 or 32, as described in detail below.

Ground terminal 88 is also connected to circuit junction 86 via capacitor 94, another circuit junction 92 and diode 84. Another diode 91 is connected between junction points 83 and 92, and another diode 82 is connected between junction points 83 and 88.

Diodes 91, 82 and 84 have opposite orientations in the two high voltage generators 28 and 29. The diodes 91, 82 and 84 of the negative high voltage generator 29 can negatively charge the capacitors 93, 94 and 97 by the output current from the secondary winding 74, but when the winding voltages are reversed the capacitors are passed through the windings. Is oriented so as to prevent discharge of. During the first negative half cycle of the output of winding 74, capacitor 97 negatively charges through diode 82 to the peak output voltage. Capacitor 94
Is charged to twice the peak voltage through capacitor 97 and diode 91 during the next positive half cycle. In the next negative half cycle, capacitor 97 recharges to the peak voltage, and as capacitor 93 transfers the charge on capacitor 94, capacitor 93 charges through capacitor 94 and diode 84 to twice the peak voltage. Because capacitors 93 and 97 are in series between electrode 26 and the ground terminal, a negative voltage that is substantially three times greater than the peak voltage from winding 74 is applied to ionizing electrode 26.

The diodes 91, 82 and 84 of the positive high voltage generator 28 are oriented opposite the diodes 91, 82 and 84 of the negative high voltage generator. Therefore, the capacitors 93, 94 and 97 of the positive high voltage generator 28 obtain a positive charge from the winding 74 and apply a positive voltage to the air ionization electrode 24 to which the high voltage generator is connected.

Referring now specifically to the negative high voltage generator 29, a strong electric field adjacent the tip of the electrode 26 breaks down the molecules of the constituent gas of the air into ions, which ions show a charge. The decomposition produces negative and positive charges in equal amounts. The negative ions are repelled by the electrode 26 and diffuse outward into the surrounding atmosphere. The positive charge is attracted to the electrode 26 and neutralized by charge exchange with the electrode. Since such charge exchange tends to reduce the voltage on capacitors 93, 94 and 97,
Compensation positive current from high voltage generator 29 to terminal 88, return current conductor
It flows out to the chassis ground through 96 and the feedback signal addition circuit 33. This return current has a magnitude proportional to the generation rate of the electrodes 26 and air ions.

Obviously, the outward diffusion of the negative charge from electrode 26 should be matched to an equal flow of positive charge to ground when viewed in other ways. Otherwise, the accumulated positive charge is rapidly neutralizing the negative high voltage.

The positive high voltage generator 28, for the same reason, is a negative current, but via the return current conductor 96 a feedback signal summing circuit.
Return to 33 and generate current. The return currents from the two generators 28,29 are not necessarily of the same magnitude because the air ion outputs from the electrodes 24,26 are not the same.

The voltage control and feedback circuits 31 and 32 each detect the return current and regulate the voltage produced by the high voltage generators 28, 29 required to maintain the return current substantially constant. It functions to maintain a predetermined rate of ion generation at electrodes 24 and 26.

DC power supply 40 for components of the ionization unit 13
Can be of known configuration and can be
Connected to 47. The power supply 40 in this example has outputs B + and B-, which provide +15 volts and -15 volts, respectively. Supply bypass capacitors 50 are connected between each output and ground to suppress vibrations in the power supply circuit.

As shown in FIG. 4, the return currents from the high voltage generators 28 and 29 are sent to the summing junction 98 via the resistors 99 and 101, respectively, and this junction is connected to the chassis via the high resistance 103 to the ground. The high resistance 103 also functions as a return current detection resistance. The voltage drop across resistor 103 at a particular time is proportional to the return current from one of the high voltage generators 28 or 29 being activated at this particular time. The summing circuit 33 includes, as another component, an amplifier 104, which feeds the feedback signal output from this amplifier via a resistor 106 to the voltage control and feedback circuits 31 and 32. The positive or non-inverting input of amplifier 104 is connected to summing junction 98, and the inverting input terminal is grounded to the chassis via resistor 107. A feedback resistor 108 connected between the output and the inverting input of the amplifier 104 fixes the gain of the amplifier, and a capacitor 109 in parallel with the resistor 108 suppresses the influence of circuit noise by slightly delaying the response of the amplifier. .

In practicing the present invention, a summing circuit is provided by providing a separate return current resistor 103 for each high voltage generator 28 and 29 which separately inputs the feedback signal to the two voltage control and feedback circuits 31 and 32. It can also be configured without 33. The advantage of the summing circuit 33 is that it compensates for air ion losses, which significantly reduces the effective ion output of a system having a pair of ionizing electrodes 24, 26 placed close to each other. In particular, a significant portion of the ions generated by each electrode 24, 26 are attracted to and neutralized by the other electrode. As a result, charge will flow out of the high voltage generator 28 or 29 connected to the other electrode via the return current conductor of this generator, which outflow is proportional to the rate of occurrence of such air ion neutralization. A summing circuit 33 routes this charge outflow to the return current from the active generator 28 or 29 and the total junction.
Combine at 98. The voltage input from inactive generator 28 or 29 to junction 98 is of opposite polarity to the voltage input from the active generator, so that the feedback signal voltage transmitted by amplifier 104 is inactive. Is reduced by an amount proportional to the rate of ionic neutralization at the electrode. The active voltage control and feedback signal 31 or 32 cannot distinguish between the reduction of the feedback signal due to reduced ion generation and the reduction of the feedback signal proportional to the rate of ion neutralization described above, and at the inactive electrode. It counteracts by raising the voltage generated by the active high voltage generator in an amount that compensates for ion neutralization.

The positive voltage control and feedback circuit 31 is an input amplifier.
112, whose non-inverting input receives the feedback signal from summing circuit 33. The inverting input of amplifier 112 is resistor 11
Grounded to chassis via 3. Variable feedback resistor 114 is connected in series with fixed resistor 116 between the non-inverting input and output of amplifier 112 to allow selective adjustment of amplifier gain. This results in the selection of a positive ion output rate at electrode 24, which is different from the negative ion output rate at electrode 26 in the desired environment.

A trigger pulse having a timing that determines the magnitude of the voltage generated by the positive high voltage generator 28 is generated by a comparator 117 which determines whether the voltage at one input is equal to the reference voltage applied to the other input. Or it shall be the type that outputs the output voltage when it exceeds. The inverting input of the comparator 117 is the cable conductor 48
To the chassis via a resistor 148A and grounded via a resistor 148A, which receives the positive voltage control signal described above, which voltage control signal is from a fixed maximum to a selected low value indicating the desired ion output ratio. Cyclically descends to
In this particular embodiment, the maximum value is +15 volts and the minimum value is in the range of +2 volts to +10 volts.

As shown in FIGS. 3 and 4, the positive input of comparator 117 is connected to circuit junction 67 of positive high voltage generator 28 through circuit junction 118 and resistor 119, thereby providing the generator. It receives an alternating voltage that rises and falls according to the alternating current. The voltage drop resistor 119 lowers the maximum AC voltage at junction 118 to +10 volts, which occurs when there is a positive AC half cycle at generator junction 67 at each peak. It is also the voltage applied from the cable conductor 48 to the inverting input of the comparator 117 when the positive voltage control signal is selected for maximum ion output.

An amplifier 112 that inverts the return current feedback signal from the summing circuit 33 has an output 121 connected via a resistor 122 to a circuit junction 118. The capacitor 120 is connected in parallel with the resistor 122 to suppress circuit noise. Because of this
The AC voltage signal input to the comparator 117 is combined with the inverted return current feedback signal from the positive high voltage generator 28 and modulated. This causes the voltage rise at the positive input of the comparator 117 to be inversely dependent on the magnitude of the feedback signal from the positive high voltage generator 28 indicative of the ion output at the electrode 24 during each positive half cycle of the alternating current. Definitely delay. The reduced feedback signal, which indicates a reduction in ion output, causes the comparator 117 to send a trigger signal after each positive half cycle of the alternating current, and the increased feedback signal advances the timing of the trigger signal.

A positive feedback resistor 123 is connected between the output of the comparator 117 and the positive input and the comparator output is connected to the aforementioned SCR gate terminal 77 of the positive high voltage generator 28 via resistor 124 and diode 126.

As mentioned above, the timing of the trigger signal at SCR gate terminal 77 for the positive half cycle of the AC is
Determines the magnitude of the high voltage generated by. As such, the voltage control and feedback circuit 31 functions to maintain a substantially constant positive ion output by varying the timing of the trigger signal as desired for the desired purpose.

During the period between each operation of the high voltage generator 28, the cable conductor 48
Since the voltage control signal from 1 rises to +15 volts, for example, the generation of the trigger signal by the comparator 117 is stopped. Therefore, during the above period, the AC voltage signal is continuously received through the resistor 119, and
It is preferable to connect 118 to ground to terminate the trigger signal rapidly, and a period of time is required to dissipate the high voltage on electrode 24, during which the return current feedback signal is continuously received. Be done.

To this end, in this example, the collector-emitter circuit of NPN transistor 129 is connected between junction 118 and chassis ground. Resistor 13 base of transistor 129
Ground to chassis via 1 and via Zener diode 132 and resistor 133 positive voltage control signal conductor 48
Connect to. Zener diode 132 becomes conductive in response to the full supply voltage appearing on conductor 48 during the off period, applying a bias voltage to the base of transistor 129. This makes the transistor conductive and the comparator 117
Immediately the voltage at the positive input of P is reduced to substantially zero.
A diode 134 is connected between junction 118 and ground to protect comparator 117 from negative voltage transients.

The negative voltage control and feedback circuit 32 can be similar in most respects to the positive circuit 31 described above, but since the return current has the opposite polarity during operation of the negative high voltage generator 29, An input amplifier 136 is connected so that the adder circuit 33 outputs the feedback signal without inversion. In particular, the positive or non-inverting input of input amplifier 136 is connected to output resistor 106 of summing circuit 33, while the inverting input is connected to chassis ground via resistor 137.

A variable feedback resistor 138 is connected between the output of the amplifier 136 and the inverting input to allow independent adjustment of the negative ion output ratio and the output of the amplifier to the circuit junction 14
0, the resistor 141, and another circuit connection point 142, and connected to the positive input of the comparator 139, and the capacitor 143 is connected in parallel with the resistor 141. Resistor 144 to negative high voltage generator 29
Connect the AC voltage signal from terminal 67 of the to send to junction 142 and connect diode 146 between the junction and chassis ground. The other input of comparator 139 is connected via resistor 147 to negative voltage control signal conductor 49 and via another resistor 148 to chassis ground. Connect the feedback resistor 149 between the positive input and output of the comparator 139, and use the comparator 139 to resist the trigger signal.
Negative high voltage generator 29 via 145 and diode 150
Connected to send to SCR gate terminal 77.

The function and operation of the components of circuit 32 described above are similar to the function and operation of the corresponding components of positive voltage control and feedback circuit 31 described above.

As in circuit 31, transistor 151 is connected between circuit junction 142 and chassis ground to cause the trigger signal to terminate rapidly at the end of each voltage control pulse, with the base of the transistor at the negative voltage control signal conductor. Connect to 49 via Zener diode 152 and resistor 153 and to chassis ground via resistor 154.

If the operation of the air ionizer can be easily monitored to confirm that the air ionizer is operating properly, and if a malfunction occurs, give a signal indicating the occurrence of this malfunction. Then it is advantageous. For this purpose, an indicating and warning circuit 35 can be provided as shown in FIG.

A first light emitting diode 155 (hereinafter referred to as an LED) visually indicates the period of positive ion generation, and a second LED 156 indicates the period of negative ion generation. The third LED 157 visually indicates the loss of ion production should it occur during operation of the device. As shown in FIG. 2, LEDs 155, 156, 15
7 is provided on the surface of the outer case 19 of the air ionization unit 13 at a position easily visible.

In addition, as shown in FIG.
Controlled by 8, the positive input of this comparator is connected via an input resistor 159 to the positive voltage control signal conductor 48 of cable 16. The reference input of the comparator 158 is the voltage dividing resistors 162 and 163.
A voltage of, for example, +10 volts is received from a junction point 161 between them, and these voltage dividing resistors 162, 163 are connected between the DC power supply terminal B + and the chassis ground by another junction point 164 and a pair of diodes which function as another resistor. It is connected in parallel with 166 and 167. Connect a positive feedback resistor 168 between the positive input and output of comparator 158, and
It is connected to DC power supply terminal B + via 169 and LED155.

As mentioned earlier, the positive voltage control signal from conductor 48 is at +15 volts, except when positive ions are generated and fall to a lower value selected within the range of +2 to +10 volts. is there. Therefore, during the period when positive ions are not generated,
The voltage at the positive input of comparator 158 is
At or above +10 volts at the reference input. Therefore, in such a period, the output of the comparator 158 is high, and no current flows through the LED 155. During the positive ion generation period, the output of the comparator 158 becomes low as a result of the drop of the positive voltage control signal. This allows
The LED 155 is energized and emits light, and it is therefore visible that positive ions are being generated.

A similar circuit is used to generate a visible signal by the LED 156 indicating that negative ions are being generated. In particular,
One input of the other comparator 171 receives the negative voltage control signal via the resistor 172, while the reference input receives from the circuit junction 161, for example +10 volts. Connect a positive feedback resistor 173 between the input and output of comparator 171, through the output through resistor 174 and through LED 156.
Connected to DC power terminal B +.

Two alarm LEDs 157 that visually indicate the loss of ion output
It can be operated by any of the four additional comparators 176 and 177. Both comparators 176 and
The 177 reference input is connected to junction 164 to receive a low DC voltage of, for example, 1.2 volts. Comparator 17
The positive input of 6 is connected to the above-mentioned terminal 121 of the positive voltage control and feedback circuit 31 to receive the return current feedback signal during the positive ion generation period, and the diode 17
It receives the output from the comparator 158 via 8. The positive input of comparator 177 is connected to receive the return current feedback signal from terminal 140 of circuit 32, previously described, during the negative ion generation period and the diode is connected.
Connect to output of comparator 171 via 179. Capacitors 181 and 182 are connected between chassis ground and the inputs of comparators 176 and 177, respectively, to slow the comparator's response to changes in input voltage by, for example, about 1/4 second. Both comparators 176 and 177 have a positive feedback resistor 183 and the outputs of both comparators are connected to the DC power supply terminal B + via LED 157 and resistor 184.

During the positive ion generation period, the output of comparator 176 is usually high because the feedback signal voltage received from circuit 31 exceeds the low reference voltage from junction 164. Therefore,
During the positive ion generation period, sufficient current does not flow to the alarm LED 157, and the alarm remains stopped. This condition continues normally after the end of the positive ion generation period, which is high when the positive voltage control signal from conductor 48 rises to +15 volts as described above. 176 will receive it. comparator
If the feedback signal voltage is not received during the period when the output of 158 is low and indicates that positive ions are generated, the output of the comparator 176 becomes low. comparator
When the output of 176 is low, current flows through the alarm LED 157,
The LED flashes to visually indicate the occurrence of malfunction. Positive feedback ensures circuit activation by preventing unwanted vibrations from occurring when an alarm condition occurs.

If the negative feedback signal voltage from the circuit 32 should not be received when the voltage on conductor 49 drops to indicate the generation of negative ions, the comparator 177 will activate to alert the alarm LE.
D 157 operates in a similar manner.

In the example shown, it is advantageous if the alarm LED 157 in a particular one of the ionization units is activated with the activation of the main alarm 186 provided in the control box 17, as shown in FIG. The alarm 186 is a beeper (alarm generator) that produces an acoustic signal in the illustrated example, but may be any of various other forms of electrically or acoustically or visually alerting device. be able to.

Alarm 186 to normally closed relay 187 between AC power conductors 46 and 47.
Connected in series with the relay, the relay is preferably of the type which exhibits a short delay before closing in response to the extinction of drive current. Under normal conditions, relay 186 is held open to prevent drive current from cable conductor 57 connected to DC power source 56 via resistor 185 from activating the alarm.
As shown in FIG. 5, the indicator and alarm circuit 35 of each ionization unit includes an NPN junction transistor 188 having an emitter collector circuit connected between the cable conductor 57 and chassis ground. PNP junction transistor 189 is DC
It has an emitter-collector circuit connected in series with a voltage drop resistor 190 between the power supply terminal B + and the base of the transistor 188. The outputs of both comparators 176 and 177 are connected to the base of transistor 189 via resistor 191.

If the output of comparator 176 or 177 goes low as described above, it signals the loss of ion output and
189 is biased conductive and applies a base bias voltage to transistor 188 which also causes transistor 188 to become conductive. This grounds the cable conductor 57, causing the voltage on this conductor to drop to substantially zero.
As shown again in FIG. 2, grounding conductor 57 causes relay 187 to close, applying an operating current to alarm 186.

Referring again to FIG. 1, the output rate of the device 11 is first adjusted in the control box 17 to increase the concentration of air ions and the ratio of positive ions to negative ions is produced for the articles in a particular chamber 12. It is effective in suppressing the electrostatic charge. The ideal concentration and ratio can be varied from chamber to chamber, but after detecting charge in a localized area using a charge detector of known structure, the output of ions of opposite polarity is increased to accumulate such ions. The ideal concentration and ratio can be determined during the initial adjustment by eliminating Amplifier feedback resistor 114 or 138
By adjusting the gain of the feedback circuit amplifier (see FIG. 4) coupled to the ion emitter to adjust the relative output of any one ion emitter 22 or 23 to the other ion emitter. It can be raised or lowered as required according to the purpose.

Referring again to FIG. 1, the device 11 provides a chamber 12 for extended periods of time without the need to constantly monitor the ion content in the air by means of ion sensors or similar detection means.
It is possible to very effectively prevent electrostatic charges from being generated in the articles inside. The deterioration of the electrodes and the fluctuation of the line voltage do not adversely affect the ion outputs of the ion emitters 22 and 23. Electrodes 24 or 26 of specific ion emitters 22, 23
Even if is degraded at a greater rate than electrodes near the opposite polarity, a local imbalance of positive and negative ions does not occur. The ion output of each of the ion emitters 22 and 23 maintains a constant value regardless of such variables. It is desirable to readjust the device 11 if there is a large change in the content of ions contained in the air in the chamber 12 or in the activity in the chamber, but it is usually not necessary to make such a readjustment.

The embodiments of the invention described herein alternately generate positive and negative ions in periods separated by inactive periods that do not generate ions. Since the ions of each polarity can diffuse far from the ion emitters 22 and 23 before the positive and negative ions substantially mix and neutralize each other, the ionizer
11 effective ranges have been expanded. The present invention can be applied to a system in which there is no delay between the alternating generation periods of positive and negative ions, or ions of both polarities are simultaneously generated.

Single electrode air ion generators that generate ions of only one polarity tend to apply an electric charge to nearby articles, which is why they are not commonly used for the purposes of the above-described embodiments.
Such unipolar ion generators are widely used for other purposes such as improving the physiological effects of air, and such ion generators are used when it is desired to maintain a constant ion output. May also include a single feedback circuit 31 or 32 according to the present invention.

Although the present invention has been described with reference to one embodiment, the present invention is not limited to the illustrated embodiment and can be implemented with various modifications within the scope of the present invention.

[Brief description of drawings]

FIG. 1 is a perspective view showing a preferred embodiment of the device of the present invention installed in a chamber where the electrostatic charge should be neutralized, and FIG. 2 is a schematic view showing the control components of the device shown in FIG. FIG. 4 is a circuit diagram of individual ionization units of the apparatus shown in FIG. 1, FIG. 4 is a detailed circuit diagram of an adder circuit shown in a block in FIG. 3, positive and negative voltage control and feedback circuits, and FIG. FIG. 6 is a circuit diagram of an instruction and alarm circuit that may be provided in the device shown. 11 …… Air ionizer, 12 …… Room 13 …… Ionization unit, 16 …… Conductor part 17 …… Control box, 22,23 …… Ion generator 24,26 …… Electrodes 31, 32 …… Voltage control and Feedback circuit 33 …… Adding circuit 35 …… Instruction and alarm circuit 40 …… Power supply

Claims (17)

[Claims] 1. An electrode exposed to the air to be ionized, a high voltage generator connected to the electrode for applying a high voltage of a predetermined polarity to the electrode, and an earth return electrical resistance. In an air ionization device configured to derive electric charges of opposite polarity via the electric resistance from the high voltage generator at a rate corresponding to the air ion generation rate by the electrode, in accordance with fluctuations in voltage drop across the electric resistance. Detecting means for generating an electric feedback signal of varying magnitude, receiving the feedback signal, applying a higher voltage to the electrode in response to the reduction of the feedback signal, and increasing the feedback signal. Responsive to voltage adjustment means for adjusting the high voltage generator to apply a lower voltage to the electrodes. Air ionizer apparatus. 2. The high voltage generator further comprising control means for generating a voltage control signal indicating a desired ion output ratio, the high voltage generator according to a change in the voltage control signal and in an inverse relationship to a change in the feedback signal. An apparatus according to claim 1, wherein said voltage adjusting means is arranged to change the high voltage generated by said voltage adjusting means. 3. The high voltage generator is configured to receive input power having a periodic voltage that periodically increases and decreases, and a relative variation in timing of a repetitive trigger signal with respect to the increase and decrease of the periodic voltage. Further comprising means for changing the high voltage at the electrodes in response to
The apparatus of claim 1 wherein said high voltage adjusting means is configured to send said trigger signal to said high voltage generator and change the timing of said trigger signal in response to a change in the magnitude of said feedback signal. 4. A comparator having first and second inputs and an output connected to the high voltage generator for applying the trigger signal; and increasing and decreasing in response to the feedback signal and the periodic voltage. 4. The apparatus according to claim 3, wherein said voltage adjusting means comprises means for combining a signal from the above and applying a combined signal to said first input, and means for applying a reference signal of selectable magnitude to said second input. 5. A plurality of the electrodes and a plurality of the high voltage generators, each high voltage generator being connected to each of the electrodes, each high voltage generator being independently adjustable. It has a high voltage output and further comprises control means for sending an input current to each of said high voltage generators, said detection means generating a plurality of said feedback signals, each feedback signal being an ion at each of said electrodes. Shows the output,
The invention further comprises a plurality of said voltage adjusting means, each voltage adjusting means being connected to each of said high voltage generators and adapted to respond to each of said feedback signals generated by each of said generators. The described device. 6. The high voltage generator at least a first generator produces a positive high voltage and the high voltage generator at least a second generator produces a negative high voltage. Equipment. 7. The control means intermittently and alternately operates the first and second high voltage generators, and the detection means controls the flow of charge from both the first and second high voltage generators. A summing circuit connected in combination to deliver a combined charge flow to the electrical resistance, whereby the voltage regulating means regulates the voltage generated by each generator during operation of each generator to the other generator. 7. A device according to claim 6, adapted to compensate for the neutralization of ions at the electrodes connected to the. 8. A circuit junction and a pair of resistors connected between the circuit junction and each high voltage generator for directing the charge flow from each generator to the circuit junction.
8. The method of claim 7 including means for delivering a charge flow from said junction to said electrical resistance, and an amplifier having an input connected to said circuit connection and an output connected to apply a feedback signal to each voltage regulating means. apparatus. 9. The control means generates a positive voltage control signal relating to the magnitude of the selectable amount and a negative voltage control signal independently relating to the magnitude of the selectable amount, and the first and second voltage adjusting means. Changing the voltage produced by the first and second high voltage generators in response to changes in each of the positive and negative voltage control signals and further changing the voltage in response to the feedback signal. Item 5. The apparatus according to item 5. 10. At least a pair of high voltage generators and at least a pair of electrodes connected to each of these high voltage generators, the first generator being a positive high voltage generator and the second generator being a positive high voltage generator. The generator is a negative high voltage generator, and further comprises first and second voltage adjusting means connected to each of said generators, and further, the positive and negative high voltage generators are intermittently alternated. The control means for activating each of the voltage adjusting means, and the means for stopping the operation of each voltage adjusting means during the intermittent period when the generator connected to the voltage adjusting means is stopped by the control means. apparatus. 11. The control means alternately generates a first voltage control signal and a second voltage control signal, and the first voltage adjusting means controls the first voltage control signal.
11. The device configured to respond to the first voltage control signal by operating a generator and the second voltage adjusting means to respond to the second voltage control signal by operating the second generator. Equipment. 12. An alarm circuit further comprising a signal generator for electrically braking the alarm circuit and alarm control means for comparing the feedback signal and the voltage control signal, wherein the control means outputs a voltage. 11. The signal generating device is configured to be activated when the feedback signal drops to a predetermined value during the generation of the control signal.
The described device. 13. The control means further comprising an alarm signal conductor, a power supply connected to deliver a predetermined voltage to the conductor, and means for activating the signal generator in response to a voltage drop on the conductor. 13. The apparatus of claim 12, wherein the alarm control means is configured to drop the voltage on the conductor if the feedback signal drops to the predetermined value during the time when the voltage control signal is being generated by the. 14. A plurality of ion emitters installed separately from each other, a power source, and a plurality of high voltage generators,
Each high voltage generator is connected to the power source and is also connected to each of the ion emitters, each high voltage generator having an electrical resistance path, opposite the high voltage generated by the high voltage generator. The return current has the polarity of and has a magnitude corresponding to the ratio of the ion output from the ion emitter connected to the high voltage generator, in the direction in which the return current goes away from the high voltage generator through the electric resistance path. Flow, an air ionizer in which the first part of the high voltage generator is a positive high voltage generator and the second part is a negative high voltage generator, wherein the return current of each of the high voltage generators is A return current detection means that generates a plurality of feedback signal voltages that respectively change according to fluctuations, and each generator has an inverse relationship to fluctuations in the feedback signal voltage from a specific generator. Means for altering the high voltage generated, whereby the air ionizer maintains a predetermined total ion output and positive and negative ions are generated at a substantially constant ratio. apparatus. 15. The apparatus of claim 14 further comprising means for selectively varying the high voltage generated by each generator independent of the high voltage generated by the other generator. 16. A plurality of air ionization units, each of which has at least one ion emission electrode exposed to the atmosphere, and which are installed separately from each other, and a high-pressure unit provided in the air ionization unit and connected to each of the electrodes. A plurality of voltage outputs, each having means for varying the output voltage in response to a voltage control signal, the first portion being a positive high voltage generator and the second portion being a negative high voltage generator. A control box having a high voltage generator and means for alternately and repeatedly generating a first voltage control signal for the positive high voltage generator and a second voltage control signal for the negative high voltage generator; Extending from this control box to each ionization unit, it has an input conductor connected to each high voltage generator and a ground return conductor connected to each high voltage generator, each of which is of opposite polarity to the generated high voltage. A multi-conductor electrical cable for receiving a ground return current from the generator and having a magnitude equal to the ion output at the connected electrodes and having first and second voltage control signal conductors, each high voltage generator and said ground. Return conductor and first and second
A plurality of feedback circuits each connected to one of the voltage control signal conductors, each feedback circuit being connected to a means for activating a connected generator in response to the voltage control signal received; Means for changing the voltage output of the generator in an inverse relationship to the fluctuation of the return current. 17. Each of said ionization units has a pair of said electrodes and a high voltage generator, one of said pair of generators being a positive high voltage generator and the other being a negative high voltage generator. Yes, each said unit comprises a pair of said feedback circuits, each feedback circuit being connected to a respective pair of high voltage generators, the ions from one of said electrodes being neutralized by charge exchange with the other of said electrodes. 19. The apparatus of claim 18, further comprising means for detecting a condition and means for adjusting the high voltage generated by a generator connected to the one electrode in an amount sufficient to compensate for this neutralization.