Patent Application
20070261555
The present invention relates generally to modular frames suitable for use in air purification devices.
There are currently a wide range of technologies that are used to purify and/or filter air. One such technology is the electrostatic filter. Generally electrostatic filters include a porous dielectric material that is positioned between a pair of electrodes. A fluid stream (e.g., air) is arranged to pass through the dielectric material. In an active electrostatic filter, a significant potential difference is applied across the electrodes in order to induce an electrostatic field in the dielectric material that is sufficient to cause particulates within the air stream passing through the filter to adhere to the dielectric.
More recently, ion enhanced electrostatic filters have been developed. An ion enhanced electrostatic filter contemplates placing an ion source in front of the electrostatic filter to impart an electric charge to some of the particulates carried by air passing through the filter. The charges imparted to the particulates by the ionizer tend to help their collection within the dielectric.
U.S. Pat. No. 5,474,600, which is owned by the assignee of the present application, discloses an apparatus for the biological purification and filtration of air. Generally, the '600 patent discloses a system which utilizes a course electrostatic filter 1, a cylindrical or polygonal ionizer 5 and a fine electrostatic filter 10 that are all arranged in series. In some of the described embodiments, a pair of ionizers that impart opposite charges are arranged in series between the course and fine electrostatic filters. The system is arranged to inactivate (i.e. kill) biological objects (e.g., microorganisms and viruses) that are carried in the air stream and to filter particulates from the stream.
Commercial embodiments of this type of air purification and filtration system have been successfully used in the MIR space station and in hospitals to purify, filter and decontaminate air. A representative commercial embodiment of such a system is diagrammatically illustrated in
To achieve the foregoing and other objects of the invention, modular frames for use in air purification devices are described. A plurality of frame members are arranged in a linked stack to form a housing for components of an air purification device. The frame members are arranged to define a flow channel through which a fluid stream passes and to support components of the air purification device that receive the fluid stream.
In one aspect of the invention, a plurality of rods are arranged to pass through the frame member stack. A first one of the rods serves as an electrical power source (e.g. bus bar) at a first potential and a second one of the rods serves as an electrical power source at a second potential. Electrical connectors are provided to electrically couple electrodes on selected components of the air purification device to their associated rods. In devices that utilize electrostatic filters, the electrodes that are connected to the rods may include the electrodes of the electrostatic filters. In devices that include ionizers or plasma chambers, the electrodes connected to the rods may include the discharge and/or receptor electrodes.
When desired more than two rods may be used as electrical power sources at different potentials. This is particularly useful in embodiments where it is desirable to operate an ionizer or a plasma generator or other components at a different potential difference than the electrostatic filters.
In another aspect of the invention, the frame members are formed from a plurality of rails. Each rail includes an inner wall, a shelf that extends inward from the inner wall and a retention member that extends from the shelf. The height of the retention member is less than the height of the inner wall. With this arrangement, a component seated on the shelf of a first frame member may be held in place by the retention member of an adjacent frame member.
In some embodiments, the frame member includes one or more seal structures arranged to engage mating structures on an adjacent frame member to provide a fluid seal between the fluid flow channel and a surrounding environment. The frame members may also each include at least one latch mechanism suitable for securing the frame member to an adjacent frame member.
In some embodiments, at least some of the rails include inner and outer walls and a cross beam member that couples the inner and outer walls. In such embodiments, alignment rods may optionally be arranged to pass through corresponding openings in the cross member.
In some embodiments, the frame members are standardized such that they have substantially the same dimensions and shape. In other embodiments, the frame members may be characterized into a few standardized configurations that fit well together.
The invention, together with further objects and advantages thereof, may best be understood by reference to the following description taken in conjunction with the accompanying drawings in which:
FIGS. 6(a) and 6(b) are perspective views illustrating the rods/electrical buses used in the embodiments illustrated in FIGS. 1(a) and 1(b);
In the drawings, like reference numerals are utilized to designate like structural elements. Also, it should be appreciated that the depictions in the figures are diagrammatic and not to scale.
The present invention relates generally to modular frames suitable for use in air (or other gaseous fluid) purification devices.
Referring initially to
Representative frame members 102 are illustrated in
In the embodiment shown, the frame member 102 is composed of four rails including two end rails 103 and two side rails 104. The various rails may have the same or different constructions. In the embodiments shown, the side rails have similar constructions and the end rails have similar constructions although the side and end rails have different constructions. Additional rails can be provided as needed such that the frame may have any desired footprint geometry (e.g., triangular, hexagonal, etc.). In the embodiments shown, the rails are substantially straight. However, this is not a requirement and the rails may have any lengthwise geometry that is appropriate to meet the needs of a particular application (e.g., curved so that the reactor may fit within a circular cross section duct, etc.).
In the embodiment illustrated in
As best seen in
With this arrangement, selected internal reactor components can effectively be held in place by the shelves cooperating with the flanges of the overlying frame member. In some circumstances the components that are held in place can be sized to have a thickness that is slightly larger than the gap so that the flanges 209, 309 affirmatively clamp the component in place. However in other arrangements, the components can be slightly thinner than (or nominally the same thickness as) the gap so that the flange serves to generally retain (or prevent substantial movement of) the component without applying an affirmative clamping force. The arrangement of the frame members will be described in more detail below.
Each frame member 102 includes a latch mechanism suitable for securing the frame to an adjacent frame. The latch mechanism can take any suitable form. By way of example, in the embodiment illustrated in
In the embodiment shown in
The frame member 102 also has sealing structures 290 that are arranged to provide a good fluid seal between adjacent stacked frame members.
The end rails 103 have a sealing structure as well. As best seen in
A wide variety of materials may be used to form the frame members. Preferably, the frame members are formed from a non-conductive material that is easily moldable. Thus, the frame member can help electrically isolate various electrically charged components within the reactor. By way of example, plastic materials such as Acrylonitrile Butadiene Styrene, polycarbonate or polypropylene work well although a number of other materials including various ceramic and other dielectric materials may be used as well.
As best illustrated in
Any number of rods may be provided. In the illustrated embodiments, a total of four rods are provided. However, it should be appreciated that the actual number of rods may be varied to meet the needs of a particular design. In some embodiments, (and particularly embodiments that utilize other electrical connection schemes) the rods may be eliminated altogether.
As previously discussed, the reactor 100 has a number of components including a plurality of electrostatic filters. Each electrostatic filter 116 includes porous positive and negative electrodes 162, 165 that are separated by a suitable porous dielectric material 168. The electrodes 162, 165 are porous so that air passing through the reactor can pass through the electrodes. A relatively high potential difference is applied across the dielectric material. By way of example, potential differences of 4-40,000 volts or greater are preferred. Generally it is desired (but not required) to generate a field having a strength of at least 1000 V/cm. In some designs, the potential difference between the electrostatic filters electrodes is the same as the potential difference between the discharge and receptor electrodes in the plasma generators. However, this is not a requirement, and often it may be desirable to utilize higher potential differences for the filter electrodes. By way of example, such an arrangement is illustrated in the embodiment of FIGS. 1(a) and 1(b).
The electrodes may be formed from a variety of different materials. By way of example, metals, conductive polymers or other conductive materials can be used to form the electrodes. In one specific embodiment, metallized open cell foams as described in U.S. Pat. No. 6,805,732 are used to form the electrodes. Other suitable electrodes, including a variety of insulated electrodes, are described U.S. Provisional Application No. 60/751,497. The dielectric 168 can also be formed from a variety of different materials. A variety of suitable dielectric materials are described in the same two patent applications. In the embodiments shown, the electrodes 162, 165 take the form of electrode plates that are sized to fill the opening within an associated frame member 102 and rest on the shelf of the member 102 s can be readily seen in FIGS. 1(a) and 1(b). The relative thickness of the plates (at least in a peripheral region) is selected in conjunction with the standoff distance (gap 214, 314) between the shelves 207, 307 of the associated frame member and the flanges 209, 309 of the adjacent frame member. With this arrangement the shelf and flange effectively work to hold the electrode in place. In some embodiments, the height of the gap 214, 314 may be slightly less than the thickness of the electrode so that the flanges 209, 309 affirmatively clamp the electrode in place. In other embodiments, the height of the gap may be slightly greater than (or nominally the same as) the thickness of the electrode so that the flanges 209, 309 prevent substantial movement of the plate without applying a clamping pressure.
The dielectric 169 is sized so that it substantially fills the opening between a pair of electrodes. In the embodiment shown, the dielectrics do not extend onto the shelves of the frame member but rather are sized to abut or nearly abut the inner side of the flanges 209, 309. The thickness of the dielectric can vary somewhat, but typically its thickness will be sized to fill the gap between its associated electrodes with no or little compression. This is because compression of the dielectric generally tends to reduce the efficiency of the dielectric in part by reducing its void fraction. However, in some implementations it may be desirable to apply a compressive force to the dielectric and the described arrangement is well suited for applying such a compressive force by simply selecting the free thickness of the dielectric appropriately.
In the embodiment shown in
The pre-filter 110 is generally intended to trap large particles. The pre-filter can be any type of filter including electrostatic filters and simple replaceable mechanical filters. In the embodiment illustrated in
Other components within the reactor 100 may be held in place using the same or similar approaches. Sometimes the structure (e.g. base plate, rim, tabs, etc.) of a component that is intended to engage the shelf may be thinner than the gap 214. If this difference is too great, it may be desirable to eliminate some of the resulting slop. This can be addressed in a variety of ways. For example, gaskets, spacers, tabs or rim structures may be applied to peripheral portions of the base structures in order to provide the thickness desired to engage the flanges 209, 309 on the adjacent frame member. These structures may be integrally formed with the base structure, attached to the base structure or provided as separate parts. By way of example, the plasma generator 113 illustrated in
The plasma generator may take a variety of different forms. By way of example, suitable plasma generators are described in U.S. Pat. No. 5,474,600 and co-pending U.S. provisional application No. 60/751,497. The plasma generators described in these applications utilize a plurality of plasma chambers that are generally elongated in the direction of the airflow with the discharge electrodes extending substantially parallel to the airflow and generally co-axially with the chamber walls. These types of plasma chambers are generally referred to herein as co-axial plasma chambers.
In the diagrammatic illustration of FIGS. 1(a) and 1(b), a single chamber is shown to represent each plasma generator. However, in most implementations that use co-axial plasma chambers, it is desirable to provide a plurality of plasma chambers arranged in parallel for each plasma generator. The number of plasma chambers used for each plasma generator will depend on a number of factors including the size of the generators and the amount of airflow that the plasma reactor is designed to accommodate. By way of example, a representative plasma generator may be composed of 12 adjacent plasma chambers arranged in parallel, with each plasma chamber having a hexagonal cross section with co-axial needle type discharge electrode. However, the cross sectional shape of the chambers may be any of a variety of other appropriate shapes (e.g., circular, oval, octagonal, or other polygonal shapes). In one particular implementation, the chamber walls are cylindrical and have an internal diameter in the range of 0.5 to 10 cm (as for example 5 cm). The discharge electrodes 172 are positioned co-axially with the chambers. In another particular implementation, the chamber walls are hexagonal and have minimum chamber widths in the range of 0.5 to 10 cm (as for example 5 cm).
In the embodiment shown in
As can be seen in FIGS. 1(a) and 1(b), the length of the plasma generators is significantly longer than the height of a single frame member 102. In the illustrated embodiment, the receptor electrode 174 (which also acts at an electrode for an adjacent electrostatic prefilter) is clamped in place as described above with respect to the electrostatic filter electrodes. The height of the remaining portion of the plasma generators is arranged extends a length equal to the height of three stacked frame members 102. The base plate 171 is held in place on the shelf of the frame member located three above the frame member that the receptor electrode 174 rests on. An intermediate support member 176 is also provided to help support the plasma chambers 177. The support member is sized to rest on the shelf of an associated frame member 102 and includes a peripheral rim 178 that may be engaged by the flanges 209, 309 of the adjacent frame member. The support member may be formed from a conductive material (such as metal) or have conductors placed thereon to provide the desired electrical conductivity to the walls of the plasma chamber which are preferably used as additional receptor electrodes. If the size of the plasma chamber merits it, multiple spaced apart support members may be provided, with each support member resting on the shelf of an associated frame member. Of course, the relative length of the plasma generator may be widely varied and the appropriate number of frame members may be used to define the channel in the region of the plasma generator.
Although, the described co-axial plasma chambers work very well and can be constructed at a relatively modest cost, it should be appreciated that a variety of other ion generating technologies may be used to create the desired plasmas or ionization zones. For example, RF, microwave, UV or other D.C. ion generators could be used in place of the co-axial plasma chambers in various embodiments. In other applications it will be desirable to combine different types of ion/plasma generators in the same reactor. For example, it may be desirable to combine a UV ion generator in combination with the described co-axial D.C. ion generators. These devices can all be readily adapted to be held in place by the described modular frame stack.
The reactor 100 illustrated in
It should be apparent that the described frame stack approach is very modular and is particularly well suited for supporting reactors having a wide variety of different configurations and/or designs. That is, components may readily be added, subtracted or changed to the reactor configuration by simply adding the required number of frame members.
As suggested above the rods 248 serve as bus bars that are arranged to supply electrical power to the various electrical components of the reactor 100 such as the electrodes used in the electrostatic filters and plasma generators. If the same potential difference is used between the electrodes in the electrostatic filters and the receptor and discharge electrodes used in the plasma generator, then just two rods may be provided, or only two of a larger number (e.g. 4) rods might be electrically active as bus bars. In embodiment where more distinct power sources potentials are desired, additional rods can be added or made into bus bars.
A variety of mechanisms may be used in order to electrically connect the rods to their associated components. By way of example, one such electrical connector 259 is illustrated in
In some embodiments, the recesses 370 are provided adjacent each alignment hole 245. In other embodiments, frangible punchouts are formed in the inner wall adjacent each alignment hole. The punchouts may be removed during assembly in order to form the recesses. With this arrangement, the recesses only need to be formed adjacent the rods that are being electrically connected to the adjacent component.
With the described arrangement, each component that rests on a shelf may be electrically connected to one of the rod bus bars simply by inserting a connector 259 on the appropriate rod. This can be used to power the electrodes on the electrostatic filters, the receptor and discharge electrodes on the plasma generator/ionizer, catalysts electrodes and/or any other components of the reactor. The connectors that make electrical connections between the rods 248 and the electrode in the various reactor components are shown in FIGS. 1(a) and (b). Rod 248(a) is the positive power source for the corona discharge devices. As such, it is maintained at a positive potential that is suitable for use in the receptor electrodes of the plasma generator. Accordingly, it can be seen that connectors 259 electrically couple rod 248(a) only to the receptor electrode 174 and the support member 176 (which charges the chamber walls). Rod 248(b) is maintained at the negative or lower potential for the corona discharge devices. In the illustrated embodiment it is maintained at a ground potential and is connected to the base plate 171 (and in turn discharge electrode 172) on the plasma generator. Rod 248(c) (which is illustrated in exploded form to the left side of rod 248(a)) serves as the positive bus bar for the electrostatic filters. As such, it is maintained at a higher positive potential than rod 248(a). Rod 248(d) is maintained as the negative bus bar for the electrostatic filters. Thus, it may be maintained at a negative or ground potential.
The rods can also be used to electrically connect other components within the reactor. For example, provisional application No. 60/751,497 describes the use of insulated electrodes that have conductive surfaces that are used to prevent the buildup of opposing charges on the surface of the electrode insulation. In some implementations, it may be desirable to electrically connect the conductive surfaces and one of the alignment bars together with suitable conductors as described above may be used as part of the circuit that connects the conductive surfaces.
Referring next to
Although only a few embodiments of the invention have been described in detail, it should be appreciated that the invention may be implemented in many other forms without departing from the spirit or scope of the invention. The modular frame has been described primarily in the context of a plasma reactor type air purification device. However, the same modular frame can be used in a variety of different air purification/filtering/treatment systems including ion enhanced electrostatic filters, volatile organic compound (VOCs) treatment systems, catalyst based purification systems, etc.
A few specific embodiments of the frame members have been described. However, it should be appreciated that the construction of the rails and the various features of the frame members (e.g., the latch mechanisms, the seal structures, etc.) may all be widely varied. Therefore, the present embodiments are to be considered as illustrative and not restrictive and the invention is not to be limited to the details given herein, but may be modified within the scope and equivalents of the appended claims.
This application claims priority benefit of U.S. Provisional Patent Application No.: 60/800,657, filed May 15, 2006, entitled “MODULAR FRAME FOR AIR PURIFICATION DEVICES,” which is hereby incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60800657 | May 2006 | US |
