US3711743A - Method and apparatus for generating ions and controlling electrostatic potentials - Google Patents

Abstract

Method and apparatus for producing ions in a highly efficient manner and with a minimum of ozone for utilization in electrostatic control units and the like. A generator produces character-controlled periodic oscillatory pulses of electric energy having positive and negative components of different amplitudes. The energy generated is dispersed into a surrounding gas by being applied to one or more ionizing points spaced a preselected distance from one another and from a ground plate to generate ions. In those forms of energy dispersing apparatus having the gas moved at a preselected velocity the amount of ionization is substantially increased by reducing turbulence between the ionizing point and ground plate.

Description

United States Patent 11 1 Bolasny 1 Jan. 16, 1973 [54] METHOD AND APPARATUS FOR 3,417,302 12/1968 Lueder ..3l7/262 AE GENERATING IONS AND 3,624,448 ll/l97l Suurenmun et ul ..3l7/262 AE CONTROLLING ELECTROSTATIC Primary Examiner-L. T. Hix Attorney--Reilly and Lewis [57] ABSTRACT Method and apparatus for producing ions in a highly efficient manner and with a minimum of ozone for utilization in electrostatic control units and the like. A generator produces character-controlled periodic oscillatory pulses of electric energy having positive and negative components of different amplitudes. The energy generated is dispersed into a surrounding gas by being applied to one or more ionizing points spaced a preselected distance from one another and from a ground plate to generate ions. In those forms of energy dispersing apparatus having the gas moved at a preselected velocity the amount of ionization is substantially increased by reducing turbulence between the ionizing point and ground plate.

33 Claims, 23 Drawing Figures POTENTIALS [75] Inventor: Robert E. Bolasny, Boulder, Colo.

[73] Assignee: Research Corporation, New York,

[22] Filed: April 14, 1971 [21] Appl.No.: 133,943

[52] US. Cl. ..3I7/3, 3 l7l4, 317/262 AE [51] Int. Cl. ..II0lt 19/00, HOlt 19/04 [58] Field of Search ..3l7/3, 4, 262 AB [56] References Cited UNITED STATES PATENTS 2,264,495 l2/l94l Wilner ..3l7/4 3,39l,3l4 7/l968 Carter ..3l7/262 A 3,678,337 7/l972 Grauvogel ..3l7/262 AE 3,308,344 3/1967 Smith et al. ..3 l7/4 r52 54 56 HP-LTJ 53 3! T ss PATENTED-JM 16 I975 iSHEET 1 0F 6 INVENTOR ROBERT BOLASNY BY Q j lu Ok u ATTORNEYS PATENTEU JAN 16 I975 SHEEI 2BF 6 PAIENIEDJAH 16 1975 3,711,743

SHEET 5 OF 6PATENTEDJAH 16 1975 SHEET 8 [IF 6 IONS AND CONTROLLING ELECTROSTATIC POTENTIALS BACKGROUND OF THE INVENTION l.Field This invention in general relates to the generation of ions in a body of gas and more particularly to a method and apparatus for producing ions which is particularly effective in neutralizing undesirable electrostatic potentials and the like.

2. Description of the Prior Art Industries such as aerospace, electronics, graphic arts, plastics and paper frequently require the control of electrostatic potentials to maintain cleanliness, prevent physical damage to components, or difficulty in handling and to alleviate the danger of fire or explosion. Heretofore, the apparatus and methods for generating ions useful in the field of electrostatic control have principally relied on the application of conventional SO-cycle and 60-cycle sinusoidal electric line power to an ionizing point or points. The principal disadvantages of SO-cycle and 60-cycle sinusoidal electric power is that the negative voltage levels have previously been in excess of K volts to effect satisfactory generation of ions. Negative voltages in excess of 5K volts tend to produce ozone. Ozone has been found to be hazardous to health and may degrade plastics, rubber, photographic films, drugs, etc. The 50-cycle and 60-cycle electric energy necessary to generate the required voltage requires relatively large, bulky and expensive power supplies. Past efforts to solve these problems in the production of ions have not proved entirely satisfactory and none are believed to offer the advantages of the present invention.

In prior attempts to increase the frequency of the ionizing energy, resort has been made to the use of a mechanical vibrator-type oscillator and a center tap on a transformer to displace the phase of the 60-cycle power to provide l-cycle sinusoidal power, but no prior art appears to recognize the advantages of controlling the character of the electric energy, such as the amplitude, duration and frequency, for producing ions, nor does the prior art recognize that ionization in a stream of gas being moved under pressure may be increased by reducing the turbulence of the gas flow.

Some of the ionizing equipment presently available utilizes a plurality of ring-shaped ground plates each having an ionizing point centered therein and to. which about 5,000 to 15,000 volts AC of 50 or 60-cycle sinusoidal electric energy is applied. This equipment has the effect of throwing ions out in a spotlight-type pattern and has a severely limited capacity since there is only about inch to 1% inch spacing between the ionizing point and the circular ground plate. This type of equipment does not lend itself to a widening or separation of the ion dispersing or distributing structure to the extent possible in the practices of the present invention.

Accordingly, it is a general object of this invention to provide a highly efficient method and apparatus for generating ions.

Another object of this invention is to provide ionizing apparatus which is as efficient at voltages below a negative 5K volts as the prior art is able to do substantially above a negative 5K volts and with substantially smaller power supplies.

Yet another object of this invention is to reduce the bulk of the unit, eliminate shock hazard and to reduce the possibility of production of ozone.

A further object of this invention is to provide for increased ionization by means of a reduction in the turbulence in the ionized gas flow.

SUMMARY OF THE INVENTION In accordance with the present invention in the preferred embodiments herein there is provided a relatively compact electric generator for producing periodic oscillatory pulses of electric energy having positive and negative repetitive, character-controlled components of different amplitudes at substantially lower negative voltages together with a variety of energy dispersing structures coupled to the output of the generator for producing ions in a body of gas in a highly efficient, relatively safe manner and with a minimum of ozone. A velocity is imparted to the gas in some applications and in those applications ionization is increased by reducing turbulence in the gas flow. The energy dispersing structure for electrostatic control takes the form of an improved ion gun, improved portable units, improved modular units and an improved static bar to which the generator is preferably affixed as an integral part.

DESCRIPTION OF THE DRAWINGS Other objects, advantages and capabilities of the present invention will become more apparent as the description proceeds taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic circuit diagram of a generator for use in producing ions in accordance with the present invention;

FIG. 2 is an illustration of the output waveform produced by the generator of FIG. 1;

FIG. 3 is an alternative form of conversion circuit for the generator shown in FIG. 1;

FIG. 4 is a side elevation view of an ion gun embodying features of the present invention;

FIG. 5 is an enlarged fragmentary side elevation view of the nozzle section of the ion gun shown in FIG. 4;

FIG. 6 is a perspective exploded view of a portable unit;

FIG. 7 is a vertical sectional view taken along lines 7-7 through the center of the ionizing cell portion of FIG. 6;

FIG. 8 is a modified form of portable unit with an external blower;

FIG. 9 is yet another form of portable unit which connects into a flow duct;

FIG. 10 is a perspective view of a modular unit with portions of the end casing broken away to show interior parts and only a portion of the screen and filter shown for clarity;

FIG. 11 is a sectional view taken along lines 1l--ll of FIG. 10;

FIG. 12 is an enlarged fragmentary perspective view showing the releasable attachment of the grounding plates and support rods to the upright end casing;

FIG. 13 is an enlarged perspective view of a fastener for joining the ends of ground plates and support rods;

FIG. 14 is a horizontal sectional view taken through the fastener of FIG. 13;

FIG. is an enlarged perspective view of a fastener in a reversed position from that shown in FIG. 14 using a screw to secure it to the screen;

FIG. 16 is a perspective view of a releasable end coupling between upper and lower sections of the modular units;

FIG. 17 is a perspective view of an alternative form of ionizing cell for the modular unit shown in FIGS. 10-16; I

FIG. 18 is a schematic diagram of a modular unit shown in FIGS. 10-16 in the end of the duct-like body which may be a room;

FIG. 19 is a schematic diagram of a modular unit shown in FIGS. 10-16 in a laminar air flow workbench;

FIG. is a perspective view of a static bar unit viewing the underside thereof;

FIG. 21 is a perspective view of a static bar unit shown in FIG. 20 in an inverted position;

FIG. 22 is an end elevation view of the static bar unit of FIGS. 20 and 21 positioned over a moving web; and

FIG. 23 is an end elevation view of a modified form of static bar unit with a pressurized gas flow input.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring now to FIG. 1 there is shown a generator circuit to which is applied commercial AC power, usually 105-129 or 220-240 volts at 50 or 60 cycles, represented as a signal generator 11 connected toinput terminals 12 and 13. A ground terminal 14 is also shown at the input side. Apower switch 15, shown in its open position, when closed connects the power from the signal generator to the generator circuit described hereinafter. i

A full wave rectifier-type circuit is provided for converting the AC line voltage to a desired level of DC voltage. This converter circuit includes a bridge with two legs in parallel. One leg has a pair ofzener diodes 16 and 17 connected back to back and the other leg has a pair ofrectifiers 18 and 19 connected back to back. The DC output terminals designated 21 and 22 for the rectifier circuit are at a common connecting point forrectifiers 18 and 19 and a common connecting point for thezener diodes 16 and 17, respectively. Acapacitor 23 is connected in the line ahead of the rectifier circuit which serves as an impedance to initially reduce the line voltage. Acapacitor 24 is connected across theDC output terminals 21 and 22 of the full wave rectifier circuit to reduce ripple in the DC. In sequence one half cycle will cause one rectifier and one zener diode to conduct while the others block and on the other half cycle the other rectifier and zener diode conduct while the first ones block. Each zener diode absorbs the excess current not used by the oscillator circuit hereinafter described. A resistor 25 is connected acrosscapacitor 23 to prevent shock when the circuit is disconnected from the power source signal generator 11 by means ofswitch 15.

The DC voltage atoutput terminals 21 and 22 is supplied to a blocking oscillator circuit. The blocking oscillator circuit includes anNPN transistor 28 and a resistor 29 andinductor 31 connected between the base electrode andDC terminal 21 and aresistor 32 connected between the emitter electrode andDC terminal 22. The primary winding 33 of apulse transformer 34 is connected between the collector electrode toDC terminal 21. A series connectedrectifier 35 and resistor 36 are connected across the primary winding 33. Further, a series connectedcapacitor 37 and feedback winding 38 of the transformer connect between the emitter electrode and at a common connecting point betweeninductor 31 and resistor 29.

Reference is now made to the waveforms of FIG. 2 to explain the operation of the above described electronic oscillator circuit which is essentially a blocking-type oscillator. The waveforms of current, voltage and instantaneous power or energy generated by the circuit are essentially the same and are each represented by waveform C shown in FIG. 2. A comparison of the voltage and current waveforms showed that the positive component of the current had a sharper initial increase than the voltage but essentially the same decreasing slope and the negative component of the current had a sharper initial decrease than the voltage, essentially the same decreasing slope and then dropped to zero more rapidly beyond the corona component. The corona components described hereinafter appeared on the current waveform. In the operation of the oscillator over one cycle, resistor 29charges capacitor 37 and provides a bias current for the base electrode turning the transistor ON. This connects the DC voltage across the primary winding 33 of the transformer. This voltage in winding 33 is induced into feedback winding 38 causing current to flow incapacitor 37, throughinductor 31 and into the base electrode of the transistor. This is a regenerative action which also serves to turn the transistor ON and forms the rise for the positive component designated a of the waveform. Component a may also be referred to as the positive driven pulse.

The duration or time interval of the positive component is designated 1 and is basically controlled by the resistance of the DC voltage supply, the inductance, resistance, and capacitance of thepulse transformer 34, the ON resistance and current gain of thetransistor 28, the value ofcapacitor 37 and inductance of theinductor 31. The main function of theinductor 31 is to control the rate at which thecapacitor 37 charges from the regeneration current.

At the time when the regeneration current can no longer be sufficiently amplified by thetransistor 28 to maintain the increasing .primary current required by the pulse transformer, the pulse transformer reverses its polarity and forms the negative component designated b as its magnetic field collapses in an attempt to maintain its current flow. At this time the transistor is biased to the OFF condition by the charge on thecapacitor 37 and the voltage of the negative component appearing across the feedback winding 38.Rectifier 35 and resistor 36 provide a path for current flow during the interval of the negative component designated m. The resistor 36 serves to control the amplitude of the negative component. The duration and shape of the negative component b is controlled by the inductance and stray capacitance of thepulse transformer 34. Component b may also be referred to as the.

negative flyback pulse. The time for the negative cycle of the waveform is controlled by the time it takes resistor 29 to discharge the bias voltage oncapacitor 37 and reverse its charge to the voltage wheretransistor 28 is again turned ON- by bias current flowing into the base electrode.Resistor 32 serves as a part of the source resistance for the DC supply voltage and as a device to protect thetransistor 28 from damage due to excess current. Electric energy in the waveform produced in the primary winding 33 is stepped up in magnitude in the secondary winding 41 of the pulse transformer and appears atoutput terminals 43 and 44, output terminal 44 being connected to ground terminal 14. Acoupling capacitor 42 is connected in the line ahead ofoutput terminal 43 to limit the energy being coupled to the dispersing structure described hereinafter.

Accordingly by selecting the circuit values above described the amplitude, duration and frequency of the positive and negative components of energy may be directly controlled to effect maximum ionization. The energy thus generated by the circuit may be characterized as being repetitive, character-controlled positive and negative components. The waveform shown in FIG. 2 representing electric energy provided by the circuit may further be characterized as periodic in that it repeats itself regularly in time and form, oscillatory in that it goes both positive and negative with respect to a zero potential and pulses because it has momentary sharp changes. The ratio of the duration of the positive component and the negative component is balanced against the ratio of the amplitude of the positive component of energy and the amplitude of the negative component of energy to effect an optimum balance of positive and negative ionization while controlling positive and negative corona and ozone generation. The amplitude of the positive component is also controlled directly by the turns ratio of thepulse transformer 34.

In the above described circuit the component values are selected so that the waveform repeats preferably at a frequency in excess of line frequency and usually in excess of twice the line frequency, and may be as high as KHz, which may be considered in the high audio frequency range.

Test results using the above circuit show that a positive corona appears on the current waveform at a value corresponding with a positive peak output voltage of about 5 ,000 volts DC and that for best results in positive peak output voltages are between 7,000 volts DC and 8,600 volts DC for component a. The peak current value at 8,600 volts is about 600 microamps. In this range of positive voltages the positive corona may be observed on the current waveform by a component represented in FIG. 2 at d. This positive corona component is diffuse, faint and highly irregular in amplitude and intensity. The amplitude of this positive corona component is comparable to positive component a which is more in the form of a pulse or envelope. In the test results a negative corona was found to appear on the current waveform at a value corresponding with about 3,000 volts DC for component b. The waveform corona component is represented as riding on the waveform component b and is designated e. The negative corona component e was observed as being of a somewhat saw-toothed shape, orderly and of constant amplitude. The negative corona component e follows the declining crest of the negative component b and appears for a shorter time interval than interval m which is designated n. It was found that the negative corona component e began to appear at 3,000 volts DC and the number of the spikes per cycle increases as the negative volts increased to 4,300 volts DC. The peak value of the current waveform at 4,300 volts DC is about 300 microamps. At 4,300 volts DC as shown in FIG. 2 the maximum number of spikes occurred in negative corona component e and the maximum negative ionization of the gas occurred. Above 4,300 volts ozone was found to occur.

Both positive and negative, relatively high DC voltages, on the order of 5,000 volts, are derived from the output across the secondary winding 41 of the above described circuit which may be used with an electrostatic filter or applied to a static generator. The propagation of a relatively high positive or negative voltage on the order of 5 ,000 volts is believed to benefit general health or mental attitude. To this end the secondary winding 41 is provided with atap line 45 so that the electric energy or power from the secondary winding is connected into a positive cascade voltage doubler circuit comprised ofcapacitor 46 connected ahead of a delta network ofhigh voltage rectifiers 47 and 48 and capacitor 49, the output terminal for the positive cascade voltage doubler circuit being designated 51. Thetap line 45 also connects to a negative cascade voltage doubler circuit comprised of acapacitor 52 connected ahead of a delta network ofhigh voltage rectifiers 53 and 54 andcapacitor 55, the output terminal for the negative voltage doubler circuit being designated 56.

In a full sequence of operation for the generator circuit, the AC input power from the line is converted to DC power which is then applied to the blocking oscillator circuit. In the blocking oscillator circuit there is formed a waveform C having repetitive, character-controlled positive and negative components of energy a and b, respectively, which preferably differ from each other both in amplitude and duration together with the superposed corona components d and e for maximum ionization of a body of gas. This energy is applied to active electrodes terminating in one or more ionizing points spaced from ground plates for simultaneously producing both positive and negative ions in the surrounding body of gas as described fully hereinafter.

An alternative converter circuit to that shown in FIG. I is illustrated in FIG. 3. Whereas the converter circuit of FIG. I is specifically adapted to mount on the same circuit board as the other circuit components, the AC to DC converter arrangement of FIG. 3 may be built into a wall box type plug. Commercial 220-240 volt AC power at 50 or 60 cycles is represented by asignal generator 58 and connects across input terminals designated 59 and 61. Commercial -129 volt AC power at 50 or 60 cycles is represented by a signal generator 62 connected acrossinput terminals 63 and 61. Apower switch 64, shown in the open position, when closed connects the AC power to the converter circuit described hereinafter.

The converter circuit comprises a step-downtransformer 65 having a primary winding 66 connected acrossinput terminals 59 and 61 and a center tap of the primary winding is connected to input terminal 63. The voltage from the signal generators is stepped down in the secondary winding 67 and applied across a full wave rectifier bridge designated 68 comprised of four suitably connected rectifiers and the rectified DC then appears atterminals 21 and 22 with a smoothing ION GUN One form of high velocity, low volume, energy dispersing structure to which the above circuit is connected is an ion gun shown in FIGS. 4 and 5. This ion gun, in general, comprises a barrel ortubular body 71 in which there is mounted adjacent its discharge end anelectrode pin 72 terminating in an ionizing point surrounded by a washer-like orannular ground plate 73. The barrel terminates in removable nozzle orhead 74 having acentral discharge orifice 75 and side intake venturis 76 which converge from inlet to outlet ends thereof. Thehead 74 is shown as being provided with external threads which thread .into internal threads formed in the end of the barrel. Theground ring 73 is placed in the end of the barrel and the head is threaded thereinto so that the head holds the ground plate in place in the discharge end of the barrel.

The electric line power is coupled to the generator circuit in ahousing 77 vialine 78 and from which there extends anactive line 79 releasably connected to the electrode by aconnector sleeve 80 and aground line 81 connected to theground ring 73. The electrode pin is centered and releasably supported in the barrel on a cradle-like support 88. Thehousing 77 and barrel are shown as being made integral with one another and abracket 84 connects one end of the housing to ahandle section 82.

A gas, usually air, under pressure is introduced into the inlet end of the barrel via a passage in thehandle section 82 which contains an air flow control valve actuated by atrigger 83. Amale fitting 85 with external threads is shown as releasably coupling the handle section into the barrel and amale fitting 86 with external threads is shown as releasably coupling apressure line 87 into the handle section via a hole inbracket 84 so that thehousing 77 is releasably supported on thehandle section 82. Upon actuation of the trigger 83 a gas under pressure will be forced past the ionizing point and through thenozzle discharge orifice 75 to produce ions which may be directed onto a variety of surfaces requiring electrostatic neutralization.

PORTABLE UNITS A portable unit shown in FIGS. 6 and 7 comprises an open-ended elongatedhollow casing 89 which converges or tapers inwardly from its inlet end toward the outlet end. This convergence serves to attain the maximum air flow velocity from the internally mounted motor-fan unit 105 described hereinafter. Thecasing 89 has aU-shaped flange 91 mounted on the bottom thereof and an internally threadedwasher 92 on the flange facilitates its support on abase 93 by a suitable fastener such as a headedbolt 94. The base may take various forms such as a handle so that it may be handheld or a jointed arm adapted to mount on a flat topped surface such as a bench top. The ionizing cell for this unit includes a singleionizing electrode pin 95 mounted in the center of the discharge end of the'casing and thepin 95 extends longitudinally thereof. A ground ring orannulus 96 formed preferably of a metal foil is mounted along the inner peripheral edge of anannular end cap 97. Theend cap 97 supports a latticelike grid orduct assembly 98 which in turn provides support for the ionizing electrode pin. Thisduct assembly 98 is made up of a plurality of relatively wide intersecting strips with one group of spaced parallel strips 98a arranged parallel to one another and another group ofstrips 98b parallel to one another and at right angles to the first group and in this way acenter duct 980 is formed. The ionizing electrode pin is slidably mounted in a cup-shapedsupport 99 located in thecenter duct 980. A light shield 101 has a base portion which fits over the center duct and has an imperforate head portion normal to the gas flow. Anactive line 102 extends through the center ofbase 99 and connects to electrodepin 95. Aground line 103 connects to theground ring 96. Theduct assembly 98 serves to direct the gas flow between the ionizing electrode pin andground ring 96 with a minimum of turbulence, which has been found to increase ionization.

A motor-fan unit 105 is mounted in aremovable end frame 106 slidably received in the intake end of the casing. A pair ofcorrugated filters 107 and 108 turned at right angles to one another slidably fit into a recess in the intake end of theframe 106 to cover the fan unit and remove particulates from the ionizing gas. The generator circuitry is mounted in a relativelycompact housing 109 which inserts into theU-shaped support flange 91 and is held in place by theend frame 106. Line power is connected into the housing vialine 110.

In the operation of the portable unit shown in FIGS. 6 and 7 the ionizing energy applied to pin 95 produces an electric field between the point of the pin andground ring 96. The gas flow in the direction indicated by arrows causes the electric field produced to bow outwardly in the direction of the gas flow as shown in dashed lines causing ionization of the body of gas between thepin 95 andring 96.

In FIG. 8 there is shown a portable unit which is similar to that shown in FIGS. 6 and 7 but has a tubular cylindrical casing 111 of uniform cross section throughout its length having ahousing 112 mounted thereon for the generator circuitry with a power con trol switch 112a on the housing. A circular ionizing cell andduct assembly 113 are mounted at the discharge end of the casing with a single ionizing pin 113a at the center of the cell surrounded by a lattice-like duct assembly. A conventionalcentrifugal blower assembly 114 is mounted at the intake end of the casing to illustrate an external fan arrangement for forcing air through theionizing cell 113. In FIG. 9 there is shown the same tubular cylindrical casing 111 supporting ahousing 112 having an on-off power control switch 112a. The casing is mounted in a gas flow duct represented at 115 which typically could be placed in any air flow line delivering air to a room in a building.

MODULAR UNITS A modular unit generally designated A, shown in FIGS. 10-16, in general includes anupright end casing 1 16 providing support for one end of a matrix-type pattern of ionizing cells, each cell being generally designated 1 17 and arranged in the same plane in vertically spaced rows rising one above the other and in spaced aligned columns adjacent ascreen 119 and afilter 120. A gas, usually air, is moved therethrough in the direction shown by the arrows in FIG. 11, first through the filter 121), then thescreen 119 and then past each cell. Thescreen 119 is of aluminum sheet material with multiple perforations and the filter is a high efficiency particulate air-type filter commonly known in the trade as a l-IEPA filter. Only a portion of the screen and filter are shown in FIG. 10 for clarity but it is understood that they are coextensive with the rear face of all of theionizing cells 1 17.

Theend casing 116 is hollow and houses a generator circuitry such as that above described in FIGS. 1-3. A printedcircuit board 121 inside the casing extends the full length thereof and supports the generator circuit. Aconductive strip 122 in the board provides a common connector for the output of the generator to each active electrode. Aconductive strip 123 in theboard 121 provides a connector for each ground plate. An on-offcontrol switch 124 is mounted on the casing as well as ameter 125 for measuring and indicating current flow of the generator. Input electric line power is connected to the generator through a cord represented at 126. The upper end of thecasing 116 is provided with a femaleelectric socket 127 and the next above casing designated 116 hasmale prongs 128 on its lower end as best seen in FIG. 16 arranged to releasably insert into thefemale socket 127 of the lower casing so as to provide for a vertical alignment of the two end casings and an electrical connection between two stacked modular units. This electric connection may be to transfer either the line power or electric ionizing energy from the generator to the next above modular unit and also provides a ground connection.

Each row of theionizing cells 117 is formed by a set of vertically spaced upper and lowerinterchangeable ground plates 131 and 132, respectively, with an interchangeable horizontal support rod oractive electrode 133 preferably located midway between the ground plates and parallel thereto and having a plurality of ionizing electrode pins 134 at spaced intervals along the support rod. Each ionizing pin terminates at its distal end in asharp ionizing point 135.

As best seen in FIG. 11, the ground plates and the support rod are shaped in cross-section as an airfoil section presenting upper and lower concave surfaces to the gas flow to provide minimum flow resistance and minimize turbulence. The electrode pins 134 are mounted on one edge of the airfoil section with the distal end pointing away from the incoming gas flow. The sets of upper and lower ground plates for the modular unit shown are arranged in three tiers with three ionizing pins being in a vertical alignment.

As an alternative the ionizing cells 117a may be shaped so that the upper ground plate has a series of alternatingstraight sections 131a and upwardly extendingarcuate sections 131b and in turn the lower ground plate may be shaped with a series of alternatingstraight sections 132a and downwardly extending arcuate sections l32b with a pin mounted on thesupport rod 133 centrally located in the arcuate sections. Each upper arcuate section is in a vertical alignment with a lower arcuate section and these sections are in a concentric arrangement about theionizing pin 134 so that the gas flows through a generally circular ground plate structure.

The outer end of the upper andlower ground plates 131 and 132 andsupport rods 133 for each modular unit releasably inserts through openings in theend casing 116 and are held by aflexible fastener 138.Fastener 138 engagesstrip 123 to make an electric contact. The inner adjacent ends of the ground plates are arranged to be releasably coupled together so that a selected widthof assembly of modular units may be made up as required. To this end, as best seen in FIGS. 13 and 14, the adjacent ends of two ground plates overlap with one end having a steppedportion 136 with aslot 136a and the other a raisedportion 137 extending into theslot 136a. Areleasable fastener 138 in the form of a clip fits over the overlapping ends to secure them end to end and in alignment with one another. Theclip fastener 138 has alower loop portion 139 encompassing the overlapping ends of the adjacent ground plates, an upstandingvertical portion 141 with anaperture 142 and an upperdownturned hook portion 143. Thehook portion 143 is positioned to hook into thescreen 119 to support the plate or rod therefrom or in the alternative the clip may be turned around and ascrew 144 may extend through theaperture 142 and fasten into thescreen 119, as best seen in FIG. 15. The active electrodes orsupport rods 133 releasably connect together in the same way withfasteners 138.

Two examples of typical commercial applications for the modular units are shown in FIGS. 18 and 19. In FIG. 18 a plurality of modular units designated A, B, C and D are stacked one on another to form a composite modular assembly at one end of a hollow duct-like member generally designated 146. The duct-like member 146 is closed on all sides and may be a duct in an air conditioning system, a room in a building and the like.Member 146 includes atop wall 147, abottom wall 148 andopposed side walls 149 and 151 and is shown as having arecirculation duct 152 along the ends and top together with ablower 152 to provide means for circulating a gas through the duct-like member 146.

In FIG. 19 a single modular unit A is mounted in an upright position at the rear end of a clean room or laminar air flow-type workbench 154. This modular unit has essentially a duct-like member located forwardly of the modular unit including anupper cover 155, lower work table 156 andside walls 157 and 158 arranged together to confine and direct the gas flow through the ionizing cells of the modular unit A. Acirculation duct 159 behind the modular unit directs air flow from ablower 161 through the modular unit and out the duct-like member in which work is being carried out.

In the operation of the above-described modular units the gas flow through the electric field between the ionizing points and ground plates moves ionized gas in the direction of gas flow. This ionization of the gas tends to dissipate in effectiveness as the space between the ionizing point and ground plates increases. In both the above described portable and modular units the control static energy is almost entirely by the ionized gas particles giving up their energy to reduce the electrostatic potential on an object. The relatively large open area provided between the ionizing point and ground plate provided by the dispersing structure of the present invention generates a relatively large and uniform electric field. Gas passing through this field is broken apart creating charged molecules commonly called ions. It was found that if control grid or latticelike duct assembly is placed in the gas flow the amount of turbulencev has been considerably reduced permitting the ions to be carried by the force of the gas a much longer distance with a minimal recombination and results in increased ionization.

A comparison of the velocity and volume ranges of the above described ion gun, portable units and modular units helps to differentiate in the possible application in which they are used. The ion gun may be characterized as a high velocity, low volume unit. The portable unit of FIGS. 6 and 7 may be characterized as a medium velocity and medium volume unit, and the portable units of FIGS. 8 and 9 may range from medium to high velocity and medium to high volume. With regard to the modular units of FIGS. 10-16, in an air conditioning system it may operate at a high volume and high velocity whereas in a bench-type unit as shown in FIG. 19 it would be a medium volume and medium velocity unit. For a comparison of volumes and velocities the following approximate values are used:

High Velocity 4000 fpm and above Medium Velocity 1000 fpm Low Velocity 500 fpm and below High Volume 2000 Cfm and above Medium Volume I Cfm Low Volume Cfm and below STATIC BARS Referring now to FIGS. 20 and 23, a static bar-type device is shown which includes an outer elongated U- shaped orchannel support member 163 normally inverted in the operable position having a pair of spacedparallel sides 164 and 165 and an intermediatetop section 166 connecting the sides. I-Ioles 166a are provided in member. 163 for mounting the device above a moving web represented at 169. A pair ofconductive strips 167 and 168 are mounted along the lower extremities of theinner surfaces of the sides of the support member and extend. the full length thereof to form the ground plates for the energy dispersing structure.Side 165, which is the leading side relative to the moving web represented at 169, is provided with a lateral extension orextended section 171 terminating in a serratededge defining points 172 which forms an induction device positioned ahead of the active ionizing portion to initially reduce the static charge on the movingweb 169.

An elongatedactive electrode rod 173 extends along the inside of the support member and has a plurality of spaced ionizing electrode pins 174 at regularly spaced intervals along the rod, therod 173 being shown as offset to one side of the center of thesupport member 164 and thepins 174 inclined downwardly toward the web and each terminating in an ionizing point located at the center of the support member and passing beyondslot 177 only a short distance.

A channel-shapedcover member 176 has a pair of spaced parallel sides extending in opposite directions from that of the support member and are spaced to slidably fit into the open side of the support member.

Member 176 has elongatedslots 177 centered in the 178 to direct air past the ionizing pins and confine air under pressure therein if the unit is pressurized. A downwardly bowed .light shield 179 slidably fits between the sides of the support member and extends across the open end thereof. The light shield has a series of inwardly bowed longitudinally extendingside edges 179a formed therein. The leading side of the support member is provided withelongated slots 181 which facilitate the circulation of a gas flow from the moving web through the channel and out of thecenter slots 177 surrounding the ionizing pins. This additional gas flow about the ionizing pins has been found to increase the ionization and efficiency of the device.

The energy generator circuit is mounted in ahousing 183 positioned on the top and at one end of thesupport member 163. Power is connected into the generator by a cord represented at 184. This arrangement with the energy generator integral with the support member makes an assembly which is much more compact and easier to operate.

A modified form of static bar is shown in FIG. 23 having theside slots 181 closed and a gas under pressure shown schematically as being produced by ablower 186 is introduced through a flow line 187 into the side of the support member and causes the electric field between the ionizing points to extend further from the apparatus and produce increased ionization. For relatively short static bars a single inlet flow line opening into the support member may be used but for relatively long static bars the gas under pressure may be introduced at several points along the bar such as by means of a manifold structure or the like.

In the static bar units above described theinduction device 171 is usually placed approximately one-fourth inch to one inch from the moving web and serves to reduce the electrostatic energy on a moving web before it passes through the electric field produced by the ionizing cells or powered portion of the static bar.

In the static bar units there is provided a relatively wide spacing between the ionizing points and the conductive strips forming ground plates on the channel and the objective here is to provide maximum quantity of ions per unit of time. In the form shown a satisfactory spacing between the ionization point and ground plate is 0.75 inches. Three factors reduce static charges on the movingweb 169. First, as the web reaches the induction points, charge flows from the web to points which are at a ground potential. This effect is helped by a weak ion field carried forward from the induction points 171. The induction device serves to reduce the charge to about 4 Kv to 5 Kv at optimum conditions. The distance from the induction points and the web is preferably between one-quarter inch to one inch depending on the charge. The web passes under an intense field of ionization and the ions serve to make the gas more conductive, permitting the charge to move from the web to the. grounded edges of the channel. A secondary effect in reducing charge is gained by the ions giving up their energy to reduce the charge. The third effect is due to air flow through the channel in the direction of travel of the ion spread adding time for the ions to reduce charge. The ionization points of the bar preferably are spaced 1 to 3 inches from the web. The relatively wider bar provides more time for the web to be under its influence and therefore a more complete removal of the charge on the web.

Although the present invention has been described with a certain degree of particularity, it is understood that the present disclosure has been made by way of example and that changes in details of structure may be made without departing from the spirit thereof.

What is claimed is:

1. In a method of producing ions with greater efficiency and a minimum of ozone, the steps of:

generating character-controlled periodic oscillatory pulses of electric energy having positive and negative components of different amplitudes, and applying the generated electric energy to an ionizing point surrounded by a body of gas to generate ions.

2. In a method of producing ions as set forth inclaim 1 further including the step of moving the gas at a preselected velocity.

3. In a method of producing ions as set forth inclaim 2 further including the step of minimizing the turbulence of the flow of the gas to increase the ionization thereof.

4. In a method of producing ions with greater efficiency and a minimum of ozone comprising the steps of:

converting low. frequency electric line power to a,

character-controlled periodic oscillatory pulses of electric energy having positive and negative components of different amplitudes,

separately controlling the amplitude of each of said positive and negative going components of electric energy to maximize the production of positive and negative ions and minimize the production of ozone; and

applying the generated energy to an ionizing point surrounded by a body of gas so as to simultaneously produce positive and negative ions.

5. In apparatus for generating ions generator means for producing character-controlled periodic oscillatory pulses of electric energy having positive and negative components of different amplitudes,

dispersing means for said energy including an ionizing point to which the generated energy is applied and a ground plate a preselected distance from the ionizing point for producing ions in a body of gas between said ionizing point and ground plate.

6. In apparatus as set forth inclaim 5 wherein said generator means is operable to generate a waveform having positive and negative repetitive components of electric energy having a repetition rate for a full cycle in excess of twice the line power frequency.

7. In apparatus as set forth inclaim 5 wherein the amplitude of each positive component of energy is substantially in excess of the amplitude of each of said negative components of energy.

8. ln apparatus as set forth inclaim 5 wherein said positive and negative components of electric energy are pulses.

9. In apparatus as set forth inclaim 5 wherein the peak value of each said positive component of energy is in the range of 7,000 to 8,600 volts.

10. In apparatus as set forth inclaim 5 wherein the peak value of each said negative component of energy is in the range of 3,500 to 4,300 volts.

1 1. In apparatus as set forth inclaim 5 further includ- 6 ing means for moving the gas between the ionizing point and ground plate at a preselected velocity.

12. In apparatus as set forth in claim 11 further including means for reducing the turbulence of the moving gas. 7

13. In apparatus as set forth inclaim 5 wherein said generator means includes:

a converter circuit for changing an input low frequency line voltage to a DC voltage,

an electronic oscillator for changing said DC voltage to a waveform having repetitive, character-controlled positive and negative components of electric energy, said waveform having a frequency above Hz, and

a transformer for stepping up the voltage of the waveform produced by said electronic oscillator.

14. In apparatus as set forth inclaim 13 wherein said electronic oscillator is a blocking type oscillator circuit which produces a positive driven pulse and a negative flyback-type pulse.

15. In apparatus as set forth inclaim 13 further including AC to DC converter means to convert components of electric energy to separate positive and negative DC voltages.

16. In apparatus as set forth inclaim 13 further including input means for applying a low frequency alternating current electric power to said converter circuit.

17. In apparatus for producing ions and controlling electrostatic potentials,

energy dispersing structure including a ground plate and an ionizing electrode terminating in an ionizing point electrically insulated from the ground plate and spaced a preselected distance from the ground plate, and

electric generator means secured to the dispersing structure for converting input electric line power to character-controlled periodic oscillatory pulses of electric energy having positive and negative components of different amplitudes coupled to said ionizing electrode to produce ions in a body of gas between the ionizing point and said ground plate.

18. In apparatus as set forth inclaim 17 wherein said energy dispersing structure includes an upright end casing containing the electric generator means, conductive means extending through the casing, and a support rod releasably connected at one end to the conductive means supporting a plurality of spaced electrode pins with the ends of the pins defining ionizing points, said ground plate being defined by spaced upper and lower conductive plates above and below said support rod, respectively.

19. In apparatus as set forth inclaim 18 wherein said conductive means is in the form of a first conductive strip on a printed circuit board to which said support rod connects and a second conductive strip on said board to which said conductive plates connect.

20. In apparatus as set forth inclaim 17 wherein said energy dispersing structure includes an elongated hollow casing, said ground plate being defined by a conductive ring mounted in a removable head at the discharge end of the casing and an electrode pin mounted at the center of said conductive ring with a sharp point on the end of the pin defining said ionizing point, and further including a lattice-like grid assembly across the gas discharge end of the casing between said ring and pin formed of a plurality of flat intersecting non-conductive strips for directing a gas flow of relatively high velocity through the adjoining body of gas in a nonturbulent flow.

21. In apparatus as set forth inclaim 17 wherein said energy dispersing structure is a generally channelshaped member with conductive portions on the ends thereof forming the ground plates, said ionizing point being defined by an electrode pin mounted in the channel-shaped member between said end portions, one side wall of said channel-shaped member having elongated slots to direct a gas flow along the ionizing points.

22. In apparatus as set forth inclaim 17 wherein said energy dispersing structure is a barrel terminating in a high velocity nozzle head with a ring inside the head forming the ground plate, said ionizing point being defined by an electrode pin mounted in the center of the barrel upstream of the nozzle head, said head having venturi-like intake sections upstream of the ionizing point.

23. In apparatus for producing ions and controlling electrostatic potentials in a duct-like body having a filter and screen across an intake end thereof and having means for circulating the gas through the duct-like body at a preselected velocity, v

a modular assembly mounted at the intake end of the duc t Iike body adjacent the filter and screen made up of a plurality of modular units releasably connected and stacked one on another, each said modular unit including an upright end casing having an internal printed circuit board,

a matrix-typepattern of ionizing cells supported at one end of the casing and arranged in vertically spaced rows and in spaced aligned columns includmg a first group of generally horizontal support rods arranged at vertically spaced intervals and arranged parallel to one another, each support rod having one end releasably secured to the end casing at one end,

a second group of generally horizontal support rods releasably connected end to end to another one in the first group, each said support rod having a plurality of electrode pins arranged at equally spaced intervals therealong having end points located in the same plane defining a plurality of ionizing points,

an upper ground plate positioned above each support rod and a lower grounding plate below each support rod, and

a generator mounted in the end casing having an output terminal connected to said ionizing points for converting electric line power to character-controlled periodic oscillatory pulses of electric ionizing energy having positive and negative components of different amplitudes, said end casing having releasable coupling means for electrically and mechanically connecting to each casing of each successive unit.

24. In apparatus for producing ions and controlling electrostatic potentials in a body of gas, a hollow casing, an ionizing cell at the discharge end including a conductive ring forming a ground plate and an electrode mounted at the center of said ringhaving a terminal end defining an ionizing point,

a lattice-like flow control duct assembly across the discharge end of the casing including a plurality of intersecting non-conductive strips defining a plurality of ducts in the one end of the casing for directing gas between the ionizing point and ground plate in a non-turbulent flow,

gas-flow generating means operatively associated with the casing for directing a relatively high velocity body of gas through the casing from the intake to the discharge end thereof, and

a generator mounted on the casing having an output terminal connected to said electrode for applying character-controlled periodic oscillatory pulses of electric ionizing energy having positive and negative components of different amplitudes to said electrode for producing ions in said body of gas. 25. In apparatus as set forth inclaim 24 wherein said casing converges in cross section from the intake to the discharge end.

26. In apparatus for controlling electrostatic potentials as set forth inclaim 24 wherein said gas-flow generating means is an axial fan mounted at the gas intake end of the casing.

27. In apparatus as set forth inclaim 24 wherein said gas-flow generating means is a centrifugal blower mounted on the gas intake end of the casing.

28. In apparatus as set forth inclaim 24 wherein said casing is open at each end and adapted to couple into a duct to utilize the gas flow passed through that duct to move the gas.

29. In apparatus for producing ions and controlling electrostatic potentials, the combination comprising:

a barrel having a gas inlet and terminating in a nozzle head having an inlet and a restricted outlet,

a ring-shaped ground plate mounted in the barrel and coaxially aligned therein,

an electrode pin centered in the barrel terminating in an ionizing point located in coaxial alignment with the ground plate,

means for introducing a gas under pressure into the inlet of the barrel to flow between said ground plate and electrode pin, and

generator means mounted on the barrel for producing periodic oscillatory pulses of electric ionizing energy having positive and negative components of different amplitudes for producing ions in a body of gas between said ionizing point and ground plate.

30. In apparatus as set forth in claim 29 further including a handle section containing a valve for controlling the gas flow into the barrel, said generator means being mounted in a housing integral with said barrel and releasably attached to said handle section.

31. In apparatus for producing ions and controlling electrostatic potentials,

an elongated generally U-shaped support member having a plurality of elongated slots in one side thereof to induce a gas flow thereinto, said support member having an induction member forming an extension of one side thereof,

a plurality of ionizing points in thesupport member 6 defined by an elongated support rod extending longitudinally of the support member having electrode pins projecting therefrom at regularly spaced intervals, and

of said support member, said cover member having restricted openings through which said electrode pins extend.

33. In apparatus as set forth inclaim 32 further including means to direct a gas under pressure into the inside of said support member to be directed through said restricted openings and past said electrode pins.

Claims (32)

1. 2. In a method of producing ions as set forth in claim 1 further including the step of moving the gas at a preselected velocity.
2. 3. In a method of producing ions as set forth in claim 2 further including the step of minimizing the turbulence of the flow of the gas to increase the ionization thereof.
3. 4. In a method of producing ions with greater efficiency and a minimum of ozone comprising the steps of: converting low frequency electric line power to a, character-controlled periodic oscillatory pulses of electric energy having positive and negative components of different amplitudes, separately controlling the amplitude of each of said positive and negative going components of electric energy to maximize the production of positive and negative ions and minimize the production of ozone; and applying the generated energy to an ionizing point surrounded by a body of gas so as to simultaneously produce positive and negative ions.
4. 5. In apparatus for generating ions generator means for producing character-controlled periodic oscillatory pulses of electric energy having positive and negative components of different amplitudes, dispersing means for said energy including an ionizing point to which the generated energy is applied and a ground plate a preselected distance from the ionizing point for producing ions in a body of gas between said ionizing point and ground plate.
5. 6. In apparatus as set forth in claim 5 wherein said generator means is operable to generate a waveform having positive and negative repetitive components of electric Energy having a repetition rate for a full cycle in excess of twice the line power frequency.
6. 7. In apparatus as set forth in claim 5 wherein the amplitude of each positive component of energy is substantially in excess of the amplitude of each of said negative components of energy.
7. 8. In apparatus as set forth in claim 5 wherein said positive and negative components of electric energy are pulses.
8. 9. In apparatus as set forth in claim 5 wherein the peak value of each said positive component of energy is in the range of 7, 000 to 8,600 volts.
9. 10. In apparatus as set forth in claim 5 wherein the peak value of each said negative component of energy is in the range of 3, 500 to 4,300 volts.
10. 11. In apparatus as set forth in claim 5 further including means for moving the gas between the ionizing point and ground plate at a preselected velocity.
11. 12. In apparatus as set forth in claim 11 further including means for reducing the turbulence of the moving gas.
12. 13. In apparatus as set forth in claim 5 wherein said generator means includes: a converter circuit for changing an input low frequency line voltage to a DC voltage, an electronic oscillator for changing said DC voltage to a waveform having repetitive, character-controlled positive and negative components of electric energy, said waveform having a frequency above 120 Hz, and a transformer for stepping up the voltage of the waveform produced by said electronic oscillator.
13. 14. In apparatus as set forth in claim 13 wherein said electronic oscillator is a blocking type oscillator circuit which produces a positive driven pulse and a negative flyback-type pulse.
14. 15. In apparatus as set forth in claim 13 further including AC to DC converter means to convert components of electric energy to separate positive and negative DC voltages.
15. 16. In apparatus as set forth in claim 13 further including input means for applying a low frequency alternating current electric power to said converter circuit.
16. 17. In apparatus for producing ions and controlling electrostatic potentials, energy dispersing structure including a ground plate and an ionizing electrode terminating in an ionizing point electrically insulated from the ground plate and spaced a preselected distance from the ground plate, and electric generator means secured to the dispersing structure for converting input electric line power to character-controlled periodic oscillatory pulses of electric energy having positive and negative components of different amplitudes coupled to said ionizing electrode to produce ions in a body of gas between the ionizing point and said ground plate.
17. 18. In apparatus as set forth in claim 17 wherein said energy dispersing structure includes an upright end casing containing the electric generator means, conductive means extending through the casing, and a support rod releasably connected at one end to the conductive means supporting a plurality of spaced electrode pins with the ends of the pins defining ionizing points, said ground plate being defined by spaced upper and lower conductive plates above and below said support rod, respectively.
18. 19. In apparatus as set forth in claim 18 wherein said conductive means is in the form of a first conductive strip on a printed circuit board to which said support rod connects and a second conductive strip on said board to which said conductive plates connect.
19. 20. In apparatus as set forth in claim 17 wherein said energy dispersing structure includes an elongated hollow casing, said ground plate being defined by a conductive ring mounted in a removable head at the discharge end of the casing and an electrode pin mounted at the center of said conductive ring with a sharp point on the end of the pin defining said ionizing point, and further including a lattice-like grid assembly across the gas discharge end of the casing between said ring and pin formed of a plurality of flat intersecting non-conductive strips for dIrecting a gas flow of relatively high velocity through the adjoining body of gas in a nonturbulent flow.
20. 21. In apparatus as set forth in claim 17 wherein said energy dispersing structure is a generally channel-shaped member with conductive portions on the ends thereof forming the ground plates, said ionizing point being defined by an electrode pin mounted in the channel-shaped member between said end portions, one side wall of said channel-shaped member having elongated slots to direct a gas flow along the ionizing points.
21. 22. In apparatus as set forth in claim 17 wherein said energy dispersing structure is a barrel terminating in a high velocity nozzle head with a ring inside the head forming the ground plate, said ionizing point being defined by an electrode pin mounted in the center of the barrel upstream of the nozzle head, said head having venturi-like intake sections upstream of the ionizing point.
22. 23. In apparatus for producing ions and controlling electrostatic potentials in a duct-like body having a filter and screen across an intake end thereof and having means for circulating the gas through the duct-like body at a preselected velocity, a modular assembly mounted at the intake end of the duct-like body adjacent the filter and screen made up of a plurality of modular units releasably connected and stacked one on another, each said modular unit including an upright end casing having an internal printed circuit board, a matrix-type pattern of ionizing cells supported at one end of the casing and arranged in vertically spaced rows and in spaced aligned columns including a first group of generally horizontal support rods arranged at vertically spaced intervals and arranged parallel to one another, each support rod having one end releasably secured to the end casing at one end, a second group of generally horizontal support rods releasably connected end to end to another one in the first group, each said support rod having a plurality of electrode pins arranged at equally spaced intervals therealong having end points located in the same plane defining a plurality of ionizing points, an upper ground plate positioned above each support rod and a lower grounding plate below each support rod, and a generator mounted in the end casing having an output terminal connected to said ionizing points for converting electric line power to character-controlled periodic oscillatory pulses of electric ionizing energy having positive and negative components of different amplitudes, said end casing having releasable coupling means for electrically and mechanically connecting to each casing of each successive unit.
23. 24. In apparatus for producing ions and controlling electrostatic potentials in a body of gas, a hollow casing, an ionizing cell at the discharge end including a conductive ring forming a ground plate and an electrode mounted at the center of said ring having a terminal end defining an ionizing point, a lattice-like flow control duct assembly across the discharge end of the casing including a plurality of intersecting non-conductive strips defining a plurality of ducts in the one end of the casing for directing gas between the ionizing point and ground plate in a non-turbulent flow, gas-flow generating means operatively associated with the casing for directing a relatively high velocity body of gas through the casing from the intake to the discharge end thereof, and a generator mounted on the casing having an output terminal connected to said electrode for applying character-controlled periodic oscillatory pulses of electric ionizing energy having positive and negative components of different amplitudes to said electrode for producing ions in said body of gas.
24. 25. In apparatus as set forth in claim 24 wherein said casing converges in cross section from the intake to the discharge end.
25. 26. In apparatus for controlling electrostatic potentials as set forth in claim 24 wherein said gas-flow generating means is an axial fan mounted at the gas intake end of the casing.
26. 27. In apparatus as set forth in claim 24 wherein said gas-flow generating means is a centrifugal blower mounted on the gas intake end of the casing.
27. 28. In apparatus as set forth in claim 24 wherein said casing is open at each end and adapted to couple into a duct to utilize the gas flow passed through that duct to move the gas.
28. 29. In apparatus for producing ions and controlling electrostatic potentials, the combination comprising: a barrel having a gas inlet and terminating in a nozzle head having an inlet and a restricted outlet, a ring-shaped ground plate mounted in the barrel and coaxially aligned therein, an electrode pin centered in the barrel terminating in an ionizing point located in coaxial alignment with the ground plate, means for introducing a gas under pressure into the inlet of the barrel to flow between said ground plate and electrode pin, and generator means mounted on the barrel for producing periodic oscillatory pulses of electric ionizing energy having positive and negative components of different amplitudes for producing ions in a body of gas between said ionizing point and ground plate.
29. 30. In apparatus as set forth in claim 29 further including a handle section containing a valve for controlling the gas flow into the barrel, said generator means being mounted in a housing integral with said barrel and releasably attached to said handle section.
30. 31. In apparatus for producing ions and controlling electrostatic potentials, an elongated generally U-shaped support member having a plurality of elongated slots in one side thereof to induce a gas flow thereinto, said support member having an induction member forming an extension of one side thereof, a plurality of ionizing points in the support member defined by an elongated support rod extending longitudinally of the support member having electrode pins projecting therefrom at regularly spaced intervals, and a generator mounted on the support member having an output terminal connected to said support electrode for applying character-controlled periodic oscillatory pulses of electric ionizing energy having positive and negative components of different amplitudes to said ionizing points to produce ions.
31. 32. In apparatus as set forth in claim 31 further including a cover member closing the open side and ends of said support member, said cover member having restricted openings through which said electrode pins extend.
32. 33. In apparatus as set forth in claim 32 further including means to direct a gas under pressure into the inside of said support member to be directed through said restricted openings and past said electrode pins.

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