US3654534A

US3654534A - Air neutralization

Info

Publication number: US3654534A
Application number: US113929A
Authority: US
Inventors: Ronald S Fischer
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-02-09
Filing date: 1971-02-09
Publication date: 1972-04-04
Anticipated expiration: 1989-04-04
Also published as: GB1321395A; FR2124601A1; IT960801B; DE2205885A1

Abstract

A gas such as common air may be treated so as to be electrically ''''neutralized'''' by passing the gas through the space between charged electrodes. These electrodes are changed by an AC current having a sinusiodal wave form which creates a field having an intensity in the space of at least 8 microamps per square inch. The gas being treated is passed through this space at a rate such that the gas is between the electrodes during a complete cycle of the AC current or during an even multiple of such a complete cycle. As the gas passes through the electrodes, various charges carried by or within the gas are removed from it.

Description

United States Patent Fischer [54] AIR NEUTRALIZATION [72] Inventor: Ronald S. Fischer, 4636 N. Pick Road, El

Monte, Calif. 91735 22 Filed: Feb .9, 1971 [21] Appl. No.: 1 13,929

[52] U.S.Cl ..3l7/262 AE,21/53,21/54 R, 2l/74R,21/l02R,l19/l5 [51] Int. Cl ..A61l 1/00, A611 9/00 [58] Field ofSearch; ..317/262 AE; 128/404, 421; 204/164, 312; 119/15; 21/54 R, 102 R, 53

[56] References Cited UNITED STATES PATENTS 1,388,112 8/1921 Hoofnagle ,.204/3l2 [151 3,654,534 [451 Apr. 4, 1972 1,934,704 1 H1933 Golden ..317/262 AE Primary Examiner-L. T. Hix AttorneyEdward D. O'Brien 57] ABSTRACT A gas such as common air may be treated so as to be electrically neutralized by passing the gas through the space between charged electrodes. These electrodes are changed by an AC current having a sinusiodal wave form which creates a field having an intensity In the space of at least 8 microamps 6 Claims, 5 Drawing F igurcs Patented April 4, 1972 3,654,534

FIG. 5, INVENTOR 52 50 46 RONALD 5. F/SCHER 0-4o 5y TRANSFORMER 50 EDWARD D. OER/AM BACKGROUND OF THE INVENTION The present invention relates to the treatment of a gas such as common air so as to neutralize" the gas being treated.

Such neutralization involves a number of comparatively com- -cal charges as the result of a number of natural and artificial phenomena. Such charges may be in the form of ions and/or free electrons in the air. They may also be present in the form of charged particulate matter such as dust particles, bacteria, fungus spores, and the like. Frequently such particulate matter will be held in the air so that it does not readily settle out because of mechanisms such as Brownian movement, convection currents and the like. It is believed that the charges on such particles frequently prevent these particles settling out.

The positive and negative electrical charges in a gas may be equal so that the gas as a whole will be electrically neutral or uncharged, but still the gas will tend to behave as positively or negatively charged. This may happen under, a number of different circumstances. It may be the result of the way charges are held on gas molecules, particularly large molecules, or the way charges are disposed on a particulate item of particulate matter or the like. Many different particles which may be electrically neutral in an absolute sense behave as and are referred to as charged particles because of the unbalanced way electrical charges are located in or on such particles.

A recognition of these factors has led to the development of a number of different treatment procedures for electrically treating gases such as air so as to purify such gases. Probably most frequently such prior procedures have involved merely passing a gas such as air between oppositely charged electrodes. Such electrodes are normally used with a sufficient current to set up fields which attract electrical charges or charged particles to the individual electrodes where there may be some tendency towards neutralization. Apparatus of this general type frequently involves the use of an electrical discharge for use in removing particulate material.

Procedures as are briefly indicated in the preceding paragraph are widely considered to be reasonably effective in purifying" gases such as air by removing certain types of charges and charged particles from such gases. Procedures such as are indicated are also effective in purifying air by virtue of the fact that such procedures cause or promote certain chemical reactions having what can be a beneficial effect. Thus, procedures such as are indicated can be and frequently have been carried out under such conditions as to promote the production of ozone from oxygen within the space between the electrodes.

The highly reactive characteristics of ozone makes this gas highly desirable in oxidizing many common impurities such as may be present in air. However, the production of ozone can also be extremely disadvantageous inasmuch as such ozone emanating from an air treatment apparatus as described may cause many undesired reactions such as dye fading and the like. Also to many the smell of oxone is somewhat objectionable. It is understood that the effects of significant quantities of oxone on the human body are not completely understood.

The various different procedures indicated in the preceding discussion for electrically treating gases such as air so as to purify such gases have been sufiiciently successful to indicate that electrical treatment of gases such as air so as to neutralize various charges in such gases is beneficial. It is also recognized that any such procedure to be acceptable in inhabited areas must be of such a character as to minimize ozone production. Although these things have been recognized it is considered that no one has adequately developed satisfactory procedures for electrically neutralizing a gas by passing such a gas in a field between charged electrodes.

SUMMARY OF THE INVENTION An objective of the present invention is to provide a new and improved method and a new and improved apparatus for air neutralization. From this it will be apparent that a broad objective of the present invention is to provide for air neutralization of a type which overcomes defects and limitations of the prior art in this field. More specifically objectives of the invention are to provide for effective air neutralization, efficient air neutralization and economic air neutralization.

These objectives standing by themselves in a sense do and in a sense do not indicate the purposes of the present invention. Simply stated one of the major purposes or objectives of the present invention is to economically clean-up gases such as air so as to make such air much more desirable and so as to tend to remove from such air particulate matter which is either charged or which behaves substantially as if it is charged. In accomplishing this the invention does not only operate upon the inanimate content of air, but also operates upon living particles such as bacteria, fungus spores and the like found within air and other gases.

These objectives of the present invention are achieved by treating a gas such as air by passing the gas through the space between spaced electrodes to which an AC current is applied so as to create a field intensity in the space of at least 8 microamps per square inch. In accordance with this invention the gas is passed through this space at a rate such that the gas is between the electrodes an amount of time corresponding to a complete cycle of the AC current or during an even multiple of such a cycle. In other words, when the gas being treated is within the space between the electrodes it is not subjected to a partial AC cycle. It is considered necessary to use a structure as hereinafter indicated in order to accomplish this mode of operation over a prolonged period on an economic basis.

BRIEF DESCRIPTION OF THE DRAWING The nature of the present invention is best explained in detail with reference to the accompanying drawing in which:

FIG. 1 is an isometric view of a presently preferred embodiment or form of an air neutralizer of the present invention;

FIG. 2 is a cross-sectional view taken at line 2-2 of FIG. 1;

FIG. 3 is a partial cross-sectional view taken at line 3-3 of FIG. 2;

FIG. 4 is a partial cross-sectional view taken at line 4-4 of FIG. 2; and

FIG. 5 is a schematic view indicating the connection of various components or parts within the air neutralizer shown.

It will be recognized that the accompanying drawing is primarily intended for explanatory purposes in order to show the construction of an air neutralizer in accordance with this invention. Those skilled in the art of the construction and use of apparatuses for electrically treating air and other gases will realize that various changes may be made in the precise structure shown through the use or exercise of routine skill in this field without departing from the essential principles of the invention as defined or summarized in the claims forming a part of this specification.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT In the drawing there is shown an air neutralizer 10 of the present invention. This neutralizer 10 includes a generally rectilinear housing 12 having a hinged lid 14 adapted to be opened in order to provide access to the interior of the housing 12. At one end 16 of the housing 12 there is located a three sided frame 18 adapted to be closed by means of a small hinged lid 20 so as to retain in the end 16 a conventional air inlet filter pad 22 in such a manner that this pad 22 may conveniently be replaced from time to time without opening the lid 14.

The interior of the frame 18 in back of the filter pad 22 is separated from the interior of the housing 12 by means of another frame 24 which holds across its center a conventional protective screen 26. A duct 38 leads from the frame 24 to one end of an electrode assembly 30. The construction of this electrode assembly 30 is best seen in FIGS. 2 and 4 of the drawing. This assembly 30 includes a frame 32 of a conventional dielectric material such as an acrylic polymer, a polyvinyl chloride or the like. This frame 32 is directly connected to the duct 28.

It supports an aligned stack of a plurality of separate, parallel, identical glass plates 34 so that the adjacent side edges of these plates 34 are spaced from one another by

small spacers

36 and 37. The spacers 36 are preferably of a conventional dielectric material such as a phenolic polymer; the spacers 37 are of a conductive metal such as brass for a purpose as hereinafter indicated. The

spacers

36 and 37, the plates 34 and the frame 32 are preferably secured together with a known resilient dielectric material adhesive (not shown separately) such as known silicone rubber polymer used on all of the abutting faces or surfaces of these parts. Such an adhesive is considered preferable since it accommodates limited movement and shifting of the parts joined by it so as to increase the effective life of the neutralizer 10.

The construction and spacing of the plates 34 is considered to be quite important in obtaining effective results with the invention and in providing for long, effective utilization of the neutralizer 10. These factors will be more fully explained hereinafter. The plates 34 carry on their surfaces inert, thin metal electrodes 38 which are in electrical contact with the spacers 37. At the sides of the assembly 30 these spacers 37 are connected together by conventional buss bars 40 so that alternate electrodes at the sides of the assembly 30 are connected.

The electrodes 38 should preferably be closely adhered to the plates 34 so that no air is trapped between these electrodes 38 and the plates 34 in order to increase the length of time the neutralizer 10 may be used without breakdown. Preferably the electrodes 38 are secured or adhered to the plates 34 by the use of a very thin layer of a bonding or cementing agent having a dielectric coefficient which is the same or within 10 percent of the dielectric coefficient of the plates 34. This is also considered so as to increase the length of time the neutralizer 10 may be used without breakdown. It is considered that a suitable bonding and cementing agent is an equal part by weight mixture of bees wax and refined rosin.

During the operation of the neutralizer 10 a gas such as air being treated within this neutralizer 10 will be drawn into the housing 12 through the filter pad 22, the duct 28 and the electrode assembly 30 through the operation of a conventional blower 42. This blower 42 is mounted within the housing 12 so that it will pull gas through the parts indicated and then force or convey such gas outwardly through a small outlet 44. The performance of the blower 42 is considered quite important to the invention as hereinafter indicated.

The power necessary to operate the neutralizer 10 is obtained through a conventional lead-in cord 46. It will be seen from an examination of FIG. of the drawing that the power is supplied through a conventional fuse 48, a conventional onoff switch 50 and a conventional interlock switch 52 operated by the lid 14 so as to automatically shut off the neutralizer in the event that this lid 14 is opened. This power is supplied across the primary terminals of a transformer 54 mounted within the housing 12. The secondaries from this transformer 54 are connected to the buss bars 40 through wires 52 so as to supply power to the electrodes 38. Preferably, the motor 56 of the blower 42 is connected in parallel across the primary of the transformer 54. Also a conventional neon lamp assembly consisting of a resistor 58 and a lamp envelope 60 are also preferably connected in parallel across the primaries of the transformer 54 in order to indicate when the complete neutralizer 10 is being operated.

During such operation of the neutralizer 10 the individual electrodes 38 are supplied with AC power through the transformer 54. As these electrodes 38 are charged through the applied AC current, air or any other gas being treated in the neutralizer 10 is drawn past the electrodes 38 through the operation of the blower 42. As the air or other gas is moved in this manner it will, of course, be subjected to the AC field between the electrodes 38 resulting from the applied power. With the present invention effective results coupled with prolonged, reliable performance of the neutralizer 10 require rather precise, careful control of the operation of the neutralizer l0 and rather precise control of the construction of this device. This can be illustrated by referring to any of a plurality of closely related factors which are critical in one sense or another as far as the invention is concerned.

Effective air neutralization in accordance with the invention requires that the gas being treated is moved between parallel leading and trailing edges 62 and 64, respectively, of the electrodes 38 a period of time such that any increment of such gas is subjected to a complete cycle of an AC field or an even multiple of such a cycle, but not more or less than such a cycle or multiple thereof. Any significant deviation from such a complete cycle is considered to be undesirably ineffective inasmuch as any such deviation does not subject a gas to equal positive and negative fields. An unbalance between the positive and negative fields as applied to the gas passing between the electrodes 38 is considered to cause some residual charge to remain on or in the gas being treated.

The necessity with the invention of passing the gas being treated through the space between the electrodes 38 at a rate such that the gas is between the electrodes 38 during a complete cycle of the applied AC current or during an even multiple of such a cycle in effect dictates or governs several design parameters within the neutralizer 10. The capacity of the blower 42 used must be such as to move the gas being treated at the rate indicated under normal conditions of operation. Inasmuch as little if any significant advantage is considered to be achieved by using multiples of complete AC cycles in treatment in accordance with this invention preferably the blower capacity is such that the gas treated is present between the electrodes 38 during only a complete cycle of the applied AC current.

The time of such presence is related to the frequency of the applied current which should be used. If the frequency of the applied current is relatively high for gas to be between the electrodes 38 for a period as indicated either (1) the gas velocity created by the blower 42 has to be so high as to cause mechanical problems in the operation of the neutralizer 10 such as problems of noise production or (2) the path length between the electrodes 38 has to be comparatively short. It is relatively difficult to accurately make such a short length in a device such as the neutralizer 10 correspond to a complete AC treatment cycle with a conventional blower. In short, at high frequencies either the air neutralizer 10 becomes something of a wind tunnel or the electrodes 38 become relatively short.

The undesirable consequences of using high frequencies are avoided in accordance with the invention by utilizing frequencies of about cycles per second or less. However, the frequency used should preferably be no less than about 30 cycles per second. In general if a lower frequency than this is employed either (I) the length of the path taken by a gas in passing between the electrodes 38 has to be undesirably long or (2) the blower 42 used has to operate extremely slowly so that the gas will traverse the electrodes at a very slow rate. If the electrodes are comparatively long the neutralizer 10 is considered to take up more space than reasonably necessary. If the blower 42 employed only moves the gas very slowly, such a blower will tend to be inefficient in its operating characteristics and will normally not cause adequate circulation of the gas being treated on the outside of the neutralizer l0. Particularly suitable results can be achieved using a frequency of 60 cps.

The wave form of the AC voltage applied to the electrodes 38 is considered to be important in achieving desired results in accordance with this invention. It is considered that the applied AC used in connection with the electrodes 38 should have as reasonably close to a pure sinusiodal wave form as it is possible to obtain. Although a pure sinusiodal wave form is desired, it is considered that a close approximation of such a pure wave form will produce the desired results with this in-' vention. It is considered that an acceptable wave form will not depart by more than 5 percent of the total harmonic shape of an AC sinusiodal wave. Such a wave shape is considered preferable since it enables a gas being treated with the neutralizer to be subjected to an electrostatic field that changes at a uniform linear or constant rate. This is considered to minimize any tendency towards the creation of electrically unbalanced conditions in any gas treated in the neutralizer 10.

These factors are also related to the intensity of the electrostatic field created in the spaces in the assembly 30 traversed by a gas being treated. It is considered that if this electrostatic field is below about 8 microamps per square inch in intensity that the neutralizer will not adequately neutralize charges in or charged particles in any gas being treated within it. The precise reasons for this are not known, but it is believed that such reasons pertain to the amount of energy necessary to radiate the gas treated so that charges may be readily removed from such gas. in other words, unless the field intensity is at least 8 microamps per square inch the degree of neutralization achieved with the invention is undesirably low.

On the other hand, if the field intensity is above about 12 microamps per square inch, a different type of problem is encountered with the invention. In general, materials such are used in the construction of the assembly 30 and various parts of it will not withstand the comparatively great dielectric stresses caused by field intensities of this level and above for prolonged periods. Since commercial and related economic reasons make it necessary that the neutralizer 10 operate for prolonged periods without breakdown, it is apparent that a field intensity above about 12 should not be used with the invention. Although, field intensities of from 8 to 12 microamps per square inch may be used, it is presently considered preferable to utilize a field intensity of 10 microamps per square inch since this intensity works effectively without significantly or noticeably causing deterioration within the assembly 30.

It will be recognized that such field intensities are related to other factors by known mathematical relationships. One item which is related to the field intensities which can be used in the neutralizer l0 concerns the dielectric materials between the electrodes 38 in the assembly 30. It will be recognized that there are two types of dielectric materials between the electrodes 38: (l) the material within the plates 34 and (2) the material within the gas being treated. Normally the latter will be air.

The dielectric material in the plates 34 is preferably a conventional isotropic dielectric material. Particularly, satisfactory results can be achieved using conventional soda glass. Anisotropic materials are not desired for use with the plates 34 since such materials are apt to breakdown after use for extended periods in the neutralizer 10, whereas isotropic materials will withstand prolonged use without significant breakdown. The plates 34 should of course be of uniform physical characteristics and thickness. They should have no surface imperfections and their edges should be polished so as to avoid edge effects. It is considered that the plates 34 should have a dielectric constant or coefficient of at least five since with materials having a lower dielectric constant than within this range, the voltage gradient which will appear across the plates 34 is sufficient to cause electrical stresses which will detrimentally effect the period of use of the dielectric without physical breakdown.

With the invention even the thickness of the plates 34 is considered to be important. If these plates 34 are less than about 0.040 inches thick, it is considered that these plates are too fragile for practical utilization. If on the other hand, these plates are thicker than about 0.125 inches thick it is considered more material is used than is reasonably needed. The plates 34 should contain only enough dielectric material in order to support the electrodes 38 used adequately without there being danger of physical breakdown.

A factor which enters into the intensity of the electrostatic field obtained is of course the spacing between the plates 34 and the electrodes 38-i.e. the air gap through which a gas flows in the neutralizer 10. It is considered that if this dimension is less than about one-thirty-second inch that the friction resulting from gas flow at the velocities necessary to obtain treatment as described is unnecessarily high. This, of course, raises the the performance requirements for the blower 42. When there is such friction it is considered that power will be waisted as the result of physically moving a gas as described to obtain neutralization as herein indicated.

On the other hand, it is considered that if the spacing herein discussed is greater than about three-sixteenths inch, the voltage requirements at the electrodes 38 necessary to achieve electrostatic fields of the intensity indicated become impractically large. As used in this preceding sentence the term impractically relates to economic considerations as well as to factors such as size and weight. It is considered that preferred results are achieved using an electrode spacing of one-sixteenth inch. Gas will flow readily within a space this thick and with such spacing the voltage requirement in the neutralizer 10 does not become impractical.

The voltage gradients across both the plates 34 and the spaces between the plates and the electrodes 38 are considered important in connection with the preceding parameters of the invention and in connection with achieving satisfactory operation. If the voltage gradient in the space traversed by the gas being treated is less than about volts per mil, it is considered that the neutralizer 10 will not operate satisfactorily. This is because with lesser voltage gradients it is considered that the gas being passed through the assembly 30 will not be adequately affected so as to cause a desired degree of charged neutralization at the air flow rates used. On the other hand, it is considered that if a voltage gradient in the space traversed by the gas is greater than 100 volts per mil that there is an unnecessary utilization of power. It is presently preferred to utilize a voltage gradient in the space traversed by the gas being treated of volts per mil since within this range adequate neutralization can be achieved without the unnecessary or uneconomic expenditure of power.

The voltage gradient across the plates 34 used is critical in another regard. If the voltage gradient across these plates 34 is in excess of 20 volts per mil, the electrical stresses set up in the plates 34 will tend to cause them to break down earlier than desired. In other words, a voltage gradient across the dielectric of over 20 volts per mil will tend to effect the duration of time the neutralizer 10 may be used without break down. From this it will be apparent that the lower the voltage gradient across the dielectric paltes 34, the lower the useful like of the neutralizer 10 in service.

However, there is a practical lower limit as to the voltage gradient across the plates 34 which can be employed. This limitation concerns the field intensity in the space traversed by gas treated in the neutralizer 10. There must be adequate power present within this space so as to obtain the desired neutralization. It is considered that normally the voltage gradient across the plates 34 should not be less than 12 volts per mil. Effective results without danger of premature break down cannot be achieved with the voltage gradient across the plates 34 being more than about 15 volts per mil.

From a careful consideration of the preceding it will be apparent that all of the factors or parameters discussed relate to the total power consumption in a neutralizer as described.

Such power will also be determined or governed by other factors than are specifically discussed in the preceding such as the number of the plates 34 in the assembly 30, the dimensions of this assembly 30 and of the individual parts of it and the like. Through routine calculations the power to be consumed in a neutralizer such as the neutralizer 10 designed in accordance with the preceding discussion can be readily determined. To facilitate an understanding of the invention it can be indicated that a neutralizer corresponding to the neutralizer 10 has been operated satisfactorily utilizing a 60 cps. 5,000 rms. voltage output off of the secondary of a transformer as indicated at a total power level of about 1. 75 watts.

To a large extent the manner in which the neutralizer 10 serves to treat a gas such as air and particles of various types carried by a gas will be obvious from a careful consideration of the preceding portions of this specification. The neutralizer 10 is constructed so that any given increment or quantity of gas being treated is subjected to neither more or less than a complete AC current cycle. Effectively any charges or particles within the gas treated which tend to behave as cahrged will be treated in the neutralizer 10 so that there is an adequate opportunity for charges or unbalanced charges to be discharged in the field created.

The field intensity used is adequate to accomplish this effect without significant or normally noticeable production of ozone. This is considered to be quite significant since ozone is relatively undesirable in many locations. One aspect of the present invention which is considered quite significant relates to the effectiveness of air neutralization as described in reducing the bacteria content of the air within an enclosed or relatively enclosed area without the use of ozone to kill such bacteria.

It is known that after prolonged use of air neutralization as described over a period of days in an area of a hospital, in a chicken house or the like that the bacteria content in the area of such use is significantly decreased. The effectiveness of air neutralization of the present invention in controlling bacteria content within a room is considered to evidence the unique character of the results achieved with the present invention.

From studies of the morphology of typical bacteria it has been learned that in general such bacterias are electrically complex structures which are electrically unbalanced in that positive and negative charges in such bacteria are grouped in certain areas or regions. Because of this it is considered that the air neutralization treatment described involving subjecting bacteria to a complete AC cycle in a field of the intensity described tends to neutralize the unbalanced charges-that is the groupings of segregated positive and negative chargeson bacteria in such a way that after air neutralization as described such bacteria are either inactivated or killed as a result of an electrically disrupted or altered internal structure. However, the operation of the invention in the control of bacteria and related micro-organisms does not appear to recognize that such micro-organsims go through an apparatus as described. Airwithin a closed room which is circulated through an apparatus as indicated is neutralized so that it, the air, appears to remove or discharge charges or ions on bacteria or other related organisms not going through the apparatus, which charges or ions are necessary for their survival.

lCLAlM:

1. An apparatus for treating a gas so as to neutralize electric charges, which apparatus comprises:

treatment means including electrodes separated by a dielectric and an air space,

means for applying an AC current at a power level sufficient to create a field between said electrodes in said air space having an intensity of at least 8 microamps per square inch, and

means for moving a gas through said air space at a rate such that the gas is moved between said electrodes so as to be subjected to said field for a complete cycle of said AC current or an even multiple thereof.

2. An apparatus as claimed in claim 1 wherein:

said air space is from one thirty-second to three-sixteenths inch thick,

said AC current has a sinusiodal wave form of less than 5 percent total harmonic, the frequency of said AC current is from about 30 to 90 cycles per second,

the intensity of said field is from about 8 to about 12 microamps per square inch,

the dielectric constant of said dielectric is at least 5 said dielectric being an isotropic material, and

said current creates a voltage gradient across said air space offrom to 100 volts per mil.

3. An apparatus as claimed in claim 1 wherein:

said air space is about one-sixteenth inch thick,

said AC current has a sinusiodal wave form of less than 5 percent total harmonic content,

said AC current is a 60 cycles per second current,

the intensity of said field is about 10 microamps per square inch,

the dielectric constant of said dielectric is at least 5,

said dielectric is an isotropic material, and

said current creates a voltage gradient across said air space of about 95 volts per mil.

4. A process for treating a gas so as to neutralize electric charges which comprises:

passing a gas to be treated through an air space between two electrodes separated by a dielectric and said air space while applying an AC current to said electrodes so as to create a field within said air space having an intensity of at least 8 microamps per square inch, said gas being passed through said space at a rate such that said gas is between said electrodes within said field during a complete cycle of said current or an even multiple thereof.

5. A process as claimed in claim 4 wherein:

said air space is from one-thirty-second to three-sixteenths inch thick,

said AC,current has the sinusiodal wave form of less than 5 percent total harmonic,

the frequency of said AC current is from about 30 to cycles per second,

the intensity of said field is from about 8 to 12 microamps per square inch,

said dielectric is an isotropic material,

said current creates a voltage gradient across said air space of from 80 to 100 volts per mil.

6. A process as claimed in claim 4 wherein:

said air space is about one-sixteenth inch thick,

said AC current is a 60 cycles per second current,

the intensity of said field is about 10 microamps per square inch,

the dielectric constant of said dielectric is at least 5,

said dielectric is an isotropic material, and

said current creates a voltage gradient across said air space of about volts per mil.

@3 3 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 54 534 Dated April 4 1972 Inventor(s) Rona] d 3 Fischer It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the Abstract:, line 3, "changed" should be --charged--;

Column 3, line 4, "duct 38" should be --duc t 28--;

Column 6, line 57, "paltes should be --plates--;

Column 6, line 57, "lower" should be higher;

Column 6, line 58, "like" should be "life- Signed and sealed this 5th day of September 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents 22 53? UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 654 534 Dated April 4 1972 Inventor(s) Rona] d 5. Fl SChEl" It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In tne Abstract, line 3, "changed" should be --charged--;

Column 3, line 4, "duct 38" should be --duct 28--;

Column 6, line 57, "paltes" should be "plates";

Column 6, line 57, "lower" should be --h1'gher;

Column 6, line 58, "like" should be "life" Signed and sealed this 5th day of September 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents

Claims

1. An apparatus for treating a gas so as to neutralize electric charges, which apparatus comprises: treatment means including electrodes separated by a dielectric and an air space, means for applying an AC current at a power level sufficient to create a field between said electrodes in said air space having an intensity of at least 8 microamps per square inch, and means for moving a gas through said air space at a rate such that the gas is moved between said electrodes so as to be subjected to said field for a complete cycle of said AC current or an even multiple thereof.

2. An apparatus as claimed in claim 1 wherein: said air space is from one thirty-second to three-sixteenths inch thick, said AC current has a sinusiodal wave form of less than 5 percent total harmonic, the frequency of said AC current is from about 30 to 90 cycles per second, the intensity of said field is from about 8 to about 12 microamps per square inch, the dielectric constant of said dielectric is at least 5, said dielectric being an isotropic material, and said current creates a voltage gradient across said air space of from 80 to 100 volts per mil.

3. An apparatus as claimed in claim 1 wherein: said air space is about one-sixteenth inch thick, said AC current has a sinusiodal wave form of less than 5 percent total harmonic content, said AC current is a 60 cycles per second current, the intensity of said field is about 10 microamps per square inch, the dielectric constant of said dielectric is at least 5, said dielectric is an isotropic material, and said current creates a voltage gradient across said air space of about 95 volts per mil.

4. A process for treating a gas so as to neutralize electric charges which comprises: passing a gas to Be treated through an air space between two electrodes separated by a dielectric and said air space while applying an AC current to said electrodes so as to create a field within said air space having an intensity of at least 8 microamps per square inch, said gas being passed through said space at a rate such that said gas is between said electrodes within said field during a complete cycle of said current or an even multiple thereof.

5. A process as claimed in claim 4 wherein: said air space is from one-thirty-second to three-sixteenths inch thick, said AC current has the sinusiodal wave form of less than 5 percent total harmonic, the frequency of said AC current is from about 30 to 90 cycles per second, the intensity of said field is from about 8 to 12 microamps per square inch, said dielectric is an isotropic material, said current creates a voltage gradient across said air space of from 80 to 100 volts per mil.

6. A process as claimed in claim 4 wherein: said air space is about one-sixteenth inch thick, said AC current has a sinusiodal wave form of less than 5 percent total harmonic content, said AC current is a 60 cycles per second current, the intensity of said field is about 10 microamps per square inch, the dielectric constant of said dielectric is at least 5, said dielectric is an isotropic material, and said current creates a voltage gradient across said air space of about 95 volts per mil.