The present invention relates generally to ion generating devices that produce an electro-kinetic flow of air from which particulate matter is substantially removed.
The use of an electric motor to rotate a fan blade to create an airflow has long been known in the art. Unfortunately, such fans produce substantial noise, and can present a hazard to children who may be tempted to poke a finger or a pencil into the moving fan blade. Although such fans can produce substantial airflow (e.g., 1,000 ft3/minute or more), substantial electrical power is required to operate the motor, and essentially no conditioning of the flowing air occurs.
It is known to provide such fans with a HEPA-compliant filter element to remove particulate matter larger than perhaps 0.3 μm. Unfortunately, the resistance to airflow presented by the filter element may require doubling the electric motor size to maintain a desired level of airflow. Further, HEPA-compliant filter elements are expensive, and can represent a substantial portion of the sale price of a HEPA-compliant filter-fan unit. While such filter-fan units can condition the air by removing large particles, particulate matter small enough to pass through the filter element is not removed, including bacteria, for example.
It is also known in the art to produce an airflow using electro-kinetic techniques, by which electrical power is converted into a flow of air without mechanically moving components. One such system is described in U.S. Pat. No. 4,789,801 to Lee (1988), depicted herein in simplified form as
The high voltage pulses ionize the air between the arrays, and create an airflow 50 from the emitter array toward the collector array, without requiring any moving parts. Particulate matter 60 in the air is entrained within the airflow 50 and also moves towards the collector electrodes 30. Much of the particulate matter is electrostatically attracted to the surfaces of the collector electrodes, where it remains, thus conditioning the flow of air exiting system 10. Further, the high voltage field present between the electrode arrays can release ozone into the ambient environment, which can eliminate odors that are entrained in the airflow.
In the particular embodiment of
In another prior art embodiment shown herein as
Particulate matter collects on the array of collector electrodes, which can be wiped cleaned by a user. After extended use, particulate matter in the form of a deposited layer or coating of fine ash-like material also collects on the wire or wire-like emitter electrodes in the first array, which are much less robust and more fragile than the collector electrodes. (The terms “wire” and “wire like” shall be used interchangeably herein to mean an electrode either made from wire or, if thicker and stiffer than wire, having an appearance of wire.) Thus, care is required during cleaning of the first array of electrodes to prevent excessive force from simply snapping the wire like electrodes. Further, even with care there is always the potential that the wire electrodes will snap. Thus, it would be advantageous produce an array of emitter electrodes that is less delicate and thus easier to clean, that has equivalent or increased ion and/or air transport efficiency.
Other prior electro-kinetic precipitator type devices (not shown) have used electrodes other than wires as the emitting or discharge type electrodes. For example, one or more pin or needle shaped electrodes have been used as the emitter electrodes. For another example, plates having a razor-like edge, a sawtooth type edge, or a plurality of pins extending from an edge, have been used as emitting electrodes. Barbed wire like emitters have also been used.
All of the just described emitter electrodes include sharp edges or points because it has been believed that sharp points or edges were necessary to create a discharge current that sufficiently charges particles in the vicinity of the emitter electrode(s) to electrostatically move the charge particles toward the generally plate like collector electrodes. As with the wire like emitter electrodes discussed above, a fine ash-like material collects on these sharp emitter electrodes, reducing their effectiveness. As with the wire like emitter electrodes, some of the sharp emitter electrodes, such as ones including needles, may be fragile, and thus, difficult to clean. Thus, it would be advantageous to produce an emitter array of electrodes that in addition to being less fragile, is easy to clean.
In accordance with an embodiment of the present invention, an electro-kinetic air conditioner includes a first array of at least one emitter electrode, a second array of at least one collector electrode, and a high voltage generator, wherein the array of emitter electrodes includes an electrically conductive foam.
The inclusion of an electrically conductive foam in the emitter electrodes promotes higher ionization. This is because the electrically conductive foam has more ion emitting surfaces than other designs. The electrically conductive foam is preferably sufficiently robust to withstand cleaning, has a high melting point to retard breakdown due to ionization, and has a rough exterior surface to promote efficient ionization.
The use of a conductive foam as the emitter electrode(s) allows for easier and safer cleaning. Such a foam can be supported by a support structure, e.g., a metal support structure, that will add strength to the foam emitter electrode.
In accordance with an embodiment of the present invention, the electrically conductive foam electrode(s) can be removed from the housing by a user, and is less likely to be broken than other potential emitter electrodes that may be used in an ion generating electro-kinetic system. The electrically conductive foam electrode(s) should also be safer to clean than emitter electrodes that rely on sharp points or edges for ionization.
In accordance with an embodiment of the present invention, the electrically conductive foam is or includes a carbon foam. The carbon foam, can be, for example, an open cell glass carbon foam. The electrically conductive foam can be or include, for example, a silicon carbide, a cross-linked polyethylene, a carbon-loaded polyolefin plastic, and/or a metal plated open-cell foam.
In accordance with another embodiment of the present invention, an electrically conductive carbon foam is located downstream or near the downstream ends of the collector electrodes to neutralize any excess positive ions.
Other objects, aspects, features and advantages of the invention will appear from the following description in which the preferred embodiments have been set forth in detail, in conjunction with the accompanying drawings and also from the following claim.
Overall Air Transporter-Conditioner System Configuration:
Accessible through the upper or top surface 103 of the housing 102 is a user-liftable handle member 112, which is used to remove an electrode assembly 220 from the housing 102, for the purpose of cleaning the assembly. In this embodiment, the electrode assembly 220 includes a first array 230 of emitter electrodes 232 and a second array 240 of collector electrodes 242. In the embodiment shown, the lifting member 112 lifts both the first array electrodes 230 and the second array electrodes 240 upward, causing the electrodes to telescope out of the top 103 of the housing 102 and, if desired, out of unit 100 for cleaning. As is evident from
In another embodiment, shown in
In each of the embodiments where an array of electrodes is removable, there is likely one or more contact terminals within the housing that will provide a conductive path from a terminal of the high voltage generator 170 to an appropriate array, when that array is in its resting position within the housing. When the array is lifted (e.g., using a user-liftable handle), the array and the contact terminal will disengage from one another. This will ensure that an array lifted from the housing is no longer providing a high voltage potential. If the liftable array is intended to be grounded in accordance with an embodiment of the present invention, the corresponding contact terminal within the housing for that array should be grounded.
In the exemplary embodiments shown in
The general shape of the embodiments shown in
As will be described, when unit 100 is energized using S1, high voltage or high potential output by ion generator 160 produces ions at the first electrode(s), which ions are attracted to the second electrodes. The movement of the ions in an “IN” to “OUT” direction carries with the ions air molecules, thus electro-kinetically producing an outflow of ionized air. The “IN” notation in
The housing may have a substantially oval-shaped or-elliptically shaped cross-section with dimpled side grooves. Thus, as indicated above, the cross-section looks somewhat like a figure eight. It is within the scope of the present invention for the housing to have a different shaped cross-section such as, but not limited to, a rectangular shape, an egg shape, a tear-drop shape, or circular shape. The housing preferably has a tall, thin configuration. As will become apparent later, the housing is preferably functionally shaped to contain the electrode assembly.
As mentioned above, the housing has an inlet and an outlet. Both the inlet and the outlet may be covered by fins or louvers. Each fin is a thin ridge spaced-apart from the next fin, so that each fin creates minimal resistance as air flows through the housing. The fins are, for example, horizontal and are directed across the elongated vertical upstanding housing of the unit. Thus, the fins are substantially perpendicular in this preferred embodiment to the electrodes. The inlet and outlet fins are aligned to give the unit a “see through” appearance. Thus, a user can “see through” the unit from the inlet to the outlet. The user will see no moving parts within the housing, but just a quiet unit that cleans the air passing therethrough. Alternatively the fins can be parallel with the electrodes in another preferred embodiment. Other orientations of fins and electrodes are possible in other embodiments.
As best seen in
The high voltage generator unit 170 preferably comprises a low voltage oscillator circuit 190 of perhaps 20 KHz frequency, that outputs low voltage pulses to an electronic switch 200, e.g., a thyristor or the like. Switch 200 switchably couples the low voltage pulses to the input winding of a step-up transformer T1. The secondary winding of T1 is coupled to a high voltage multiplier circuit 210 that outputs high voltage pulses. Preferably the circuitry and components comprising high voltage pulse generator 170 and circuit 180 are fabricated on a printed circuit board that is mounted within housing 102.
Output pulses from high voltage generator 170 preferably are at least 10 KV peak-to-peak with an effective DC offset of, for example, half the peak-to-peak voltage, and have a frequency of, for example, 20 KHz. Frequency of oscillation can include other values, but frequency of at least about 20 KHz is preferred as being inaudible to humans. If pets will be in the same room as the unit 100, it may be desired to utilize and even higher operating frequency, to prevent pet discomfort and/or howling by the pet. The pulse train output preferably has a duty cycle of for example 10%, which will promote battery lifetime if live current is not used. Of course, different peak-peak amplitudes, DC offsets, pulse train waveshapes, duty cycle, and/or repetition frequencies can be used instead. Indeed, a 100% pulse train (e.g., an essentially DC high voltage) may be used, albeit with shorter battery lifetime. Thus, generator unit 170 for this embodiment can be referred to as a high voltage pulse generator. Unit 170 functions as a DC:DC high voltage generator, and could be implemented using other circuitry and/or techniques to output high voltage pulses that are input to electrode assembly 220.
As noted, outflow (OUT) may include appropriate amounts of ozone that can remove odors and preferably destroy or at least substantially alter bacteria, germs, and other living (or quasi-living) matter subjected to the outflow. Thus, when switch S1 is closed and the generator 170 has sufficient operating potential, pulses from high voltage pulse generator unit 170 create an outflow (OUT) of ionized air and ozone. When S1 is closed, the LED will visually signal when ionization is occurring.
In practice, unit 100 is placed in a room and connected to an appropriate source of operating potential, typically 117 VAC. With S1 energizing ionization unit 160, systems 100 emits ionized air and preferably some ozone via outlet vents 106. The airflow, coupled with the ions and ozone freshens the air in the room, and the ozone can beneficially destroy or at least diminish the undesired effects of certain odors, bacteria, germs, and the like. The airflow is indeed electro-kinetically produced, in that there are no intentionally moving parts within unit 100. (Some mechanical vibration may occur within the electrodes.)
Foam Emitter Electrodes
Having described various aspects of the invention in general, preferred embodiments of electrode assembly 220 are now described. In the various embodiments, electrode assembly 220 includes a first array 230 of at least one emitter electrode or conductive surface 232, and further includes a second array 240 of preferably at least one collector electrode or conductive surface 242. Understandably material(s) for electrodes 232 and 242 should conduct electricity, be resistant to corrosive effects from the application of high voltage, yet be strong enough to be cleaned.
In the various electrode assemblies to be described herein, electrode(s) 232 in the first electrode array 230 preferably include an electrically conductive foam (labeled 404 in
In the prior art, emitter or discharge electrodes have generally be made from one or more thin wires, one or more tapered needles, or one or more plates having a sharp or razor like edge, or an edge from which extend pins or a sawtooth like edge. As mentioned above, the thin wires are generally delicate, causing them to be subject to snapping when being cleaned. The alternative types of emitters, such as needless, sawtooth edges or sharp edges, on the other hand, may also be difficult to clean. The use of a conductive foam as the emitter electrode allows for easier cleaning. As will be described below, such a foam can be supported by a support structure, e.g., a metal support structure, that will add strength to the foam emitter electrode. Accordingly, the electrically conductive foam electrode(s) 232 are easier to clean (because they can be removed from the housing by a user) and less likely to be broken than other possible emitter electrodes that may be used in an ion generating electro-kinetic system. The electrically conductive foam electrode(s) 232 should also be safer to clean than emitter electrodes that rely on points or edges for ionization. Various types of foams can be used as the electrically conductive foam 404. In accordance with embodiments of the present invention, the foam is or includes a carbon material and/or is heavily doped with carbon. For example, the electrically conductive foam can be or include a carbon filter material. The electrically conductive foam can be or include an open cell glass carbon foam. In another embodiment, the electrically conductive foam is or includes silicon carbide. In still another embodiment, the electrically conductive foam is or includes a cross-linked polyethylene. According to an embodiment, the electrically conductive foam is or includes a carbon-loaded polyolefin plastic. In a further embodiment, the conductive foam is or includes a metal plated open-cell foam. These are just some types of electrically conductive foams that can be used with embodiments of the present invention. One or ordinary skill in the art will appreciate that other types of electrically conductive foams are also within the spirit and scope of the present invention.
In accordance with an embodiment of the present invention, the electrically conductive foam is or includes an intrinsically conducting polymer (ICP). An ICP has a distinct advantage when used as or in an emitter electrode because the polymer can be doped with varying concentrations of conductive material to act as an internal series resistance component to the emitter array. Such resistivity, and conversely controlled conductivity, act as a current limiting element that helps control corona break-over, and assists with short circuit protection.
By adding electrically conductive fillers in varying concentrations, polymer emitters can be designed with specific properties tailored to each application (e.g., to provide the desired degree of emissivity). For example, electrically conductive fillers can be added to plastics to produce conductive composites. Metal particles (e.g., fibers), including, but not limited to aluminum, steel, iron, copper and nickel coated fiberglass can be used as the conductive fillers. Carbon black and/or carbon fiber may also be used without adverse effect on the thermal conductivity of the material.
In accordance with an embodiment of the present invention, an electrically conductive serrated polymer with a resistivity in the range of about 10 MΩ/cm and a thermal dissipation capability in the range of about 1 watt is used in each of the emitter electrodes. This would provide the desirable current limiting, short circuit protection, and threshold limiting of corona breakover. This may also reduce or eliminate the need for expensive series high voltage resistors that are typically used for short circuit protection and threshold limiting of corona breakover.
The positive output terminal of unit 170 is coupled to first electrode array 230, and the negative output terminal is coupled to second electrode array 240. It is believed that with this arrangement the net polarity of the emitted ions is positive, e.g., more positive ions than negative ions are emitted. This coupling polarity has been found to work well, including minimizing unwanted audible electrode vibration or hum. However, while generation of positive ions is conducive to a relatively silent airflow, from a health standpoint, it is desired that the output airflow be richer in negative ions, not positive ions. It is noted that in some embodiments, one port (preferably the negative port) of the high voltage pulse generator can in fact be the ambient air. Thus, electrodes in the second array need not be connected to the high voltage pulse generator using a wire. Nonetheless, there will be an “effective connection” between the second array electrodes and one output port of the high voltage pulse generator, in this instance, via ambient air. Alternatively the negative output terminal of unit 170 can be connected to the first electrode array 230 and the positive output terminal can be connected to the second electrode array 240. It is also possible that one of the arrays is grounded, while the other array is connected to a terminal of the high voltage pulse generator 170. For example, the first electrode array 230 may be grounded, while the second array 240 can be connected the negative terminal (or less preferably the positive terminal) of the high voltage generator 170.
With this arrangement an electrostatic flow of air is created, going from the first electrode array 230 towards the second electrode array 240. (This flow is denoted “OUT” in the figures.) Electrode assembly 220 is preferably mounted within transporter system 100 such that second electrode array 240 is closer to the OUT vents 106 and first electrode array 230 is closer to the IN vents 104.
When voltage or pulses from high voltage pulse generator 170 are coupled across first and second electrode arrays 230 and 240, a plasma-like field is created surrounding the emitter electrodes 232 in the first array 230. This electric field ionizes the ambient air between the first and second electrode arrays and establishes an “OUT” airflow that moves towards the second array 240. It is understood that the IN flow enters via vent(s) 104, and that the OUT flow exits via vent(s) 106.
Ozone and ions are generated simultaneously by the first array electrodes 232, essentially as a function of the potential from generator 170 coupled to the first array 230 of electrodes or conductive surfaces. Ozone generation can be increased or decreased by increasing or decreasing the potential at the first array 230. Coupling an opposite polarity potential to the second array electrodes 242 essentially accelerates the motion of ions generated at the first array 230, producing the airflow denoted as “OUT” in the figures. As the ions and ionized particulates move toward the second array 240, the ions and ionized particles push or move air molecules toward the second array 240. The relative velocity of this motion may be increased, by way of example, by decreasing the potential at the second array 240 relative to the potential at the first array 230.
For example, if +10 KV were applied to the first array 230, and no potential were applied to the second array 240, a cloud of ions (whose net charge is positive) would form adjacent the first electrode array 230. Further, the relatively high 10 KV potential would generate substantial ozone. By coupling a relatively negative potential to the second array 240, the velocity of the air mass moved by the net emitted ions increases.
On the other hand, if it were desired to maintain the same effective outflow (OUT) velocity, but to generate less ozone, the exemplary 10 KV potential could be divided between the electrode arrays. For example, generator 170 could provide +4 KV (or some other fraction) to the first array 230 and −6 KV (or some other fraction) to the second array 240. In this example, it is understood that the +4 KV and the −6 KV are measured relative to ground. Understandably it is desired that the unit 100 operates to output appropriate amounts of ozone. Accordingly, the high voltage is preferably fractionalized with about +4 KV applied to the first array 230 and about −6 KV applied to the second array 240. According to an embodiment, there is a 16 KV potential difference between first array 230 and second array 240. For example, generator 170 could provide +8 KV to the first array 230 and −8 KV to the second array 240. These examples are not meant to be limiting.
In the embodiments of
If the support structure 402 is electrically conductive, then the support structure 402 can be connected to a terminal of the high voltage generator 170 (to thereby provide the high voltage potential to the electrically conductive foam 404) or to a grounded terminal (in those embodiments where the emitter electrodes 232 are intended to be grounded). If the support structure 402 is not electrically conductive, e.g., because it is made of plastic, then some type of wire or other conductor can provide a conductive path from the electrically conductive foam 404 to a terminal of the high voltage pulse generator 170, or to a grounded terminal.
In embodiment shown, electrodes 242 of the second electrode array 240 are generally “U”-shaped, and formed, for example, from sheet metal, and preferably of stainless steel, although brass or other metals could be used. The sheet metal is readily configured to define side regions 244 and bulbous nose region 246, forming the hollow, elongated “U”-shaped electrodes 242. The electrode(s) 242 in the second electrode array 240 preferably have a highly polished exterior surface to minimize unwanted point-to-point radiation. As such, electrodes 242 are preferably fabricated from stainless steel and/or brass, among other materials. The polished surface of electrodes 242 also promotes ease of electrode cleaning.
For these and the other embodiments, the term “array of electrodes” or “electrode array” may refer to a single electrode or a plurality of electrodes. In the exemplary embodiment shown in
While
Note the inclusion in
Additionally, or alternatively, the collector electrode(s) 242 of the second electrode array include electrically conductive foam that will generate substantial negative ions (since the electrode is coupled to relatively negative high potential) to neutralize excess positive ions otherwise present in the output airflow. In such embodiments, the electrically conductive foam can take the place of the output controlling electrode(s) 243. This is discussed in more detail below.
In the embodiments of
In
An electrode array electrical connection can be made in number of locations. Thus, emitter electrodes 232 are shown electrically connected together at their bottom regions by conductor 234, whereas collector electrodes 242 are shown electrically connected together in their middle regions by the conductor 244. However, arrays may be connected together in more than one region, e.g., at the top and at the bottom. It is preferred that the wire of strips or other inter-connecting mechanisms be at the top, bottom, or periphery of the second array electrodes 242, so as to minimize obstructing stream air movement through the housing 102.
In the above described embodiments output controlling electrodes 243 and 243′ were shown as being pointed. Accordingly, such pointed electrodes may be sharp, requiring care to be taken when cleaning them, especially for the electrodes 243′ shown in
In accordance with embodiments of the present invention, the sharp or pointy output controlling electrodes 243 and 243′ are replaced with electrically conductive foam controlling electrodes, which can be made of the same materials as the electrically conductive emitter electrodes discussed above. For example, referring back to
Referring now to
In
As also shown in
The foregoing description of the preferred embodiments of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations will be apparent to the practitioner skilled in the art. Modifications and variations may be made to the disclosed embodiments without departing from the subject and spirit of the invention as defined by the following claims. For example, many of the embodiments disclosed herein can be combined with the embodiments described in U.S. Pat. No. 6,176,977 or U.S. patent application Ser. No. 10/074,827, which were incorporated herein by reference above. Embodiments were chosen and described in order to best describe the principles of the invention and its practical application, thereby enabling others skilled in the art to understand the invention, the various embodiments and with various modifications that are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents.
This application claims priority to under 35 U.S.C. § 119(e) to U.S. Provisional Patent Application No. 60/504,582, entitled “Electro-Kinetic Air Transporter-Conditioner Devices with Electrically Conductive Foam Emitter Electrode,” filed Sep. 19, 2003. The present invention is related to the following patent and application, which are incorporated herein by reference: U.S. Pat. No. 6,176,977, entitled “Electro-Kinetic Air Transporter-Conditioner; and U.S. patent application Ser. No. 10/074,827 (Attorney Docket No. SHPR-01041USQ), filed Feb. 12, 2002, entitled “Electro-Kinetic Air Transporter-Conditioner with Non-Equidistant Collector Electrodes.”
Number | Date | Country | |
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60504582 | Sep 2003 | US |