This application claims priority to co-pending application Ser. No. 61,695/588 filed on Aug. 31, 2012 and entitled “Advanced Filtration System for Airborne Particles.” The contents of this application are fully incorporated herein for all purposes.
This disclosure relates to a system for the filtration of airborne particles from an occupied space. More particularly, this disclosure relates to the filtration of small airborne particles from an occupied space by manipulating the charge and size of airborne particles and capturing them in a series of filters.
Airborne particles exist in a wide variety of shapes and sizes. Aerosols are composed of either solid or liquid particles. Conversely, gases are molecules that are neither liquid nor solid and expand indefinitely to fill the surrounding space. Both types of contaminates exist at the micron and sub-micron level in air. Most dust particles, for example, are between 5-10 microns in size (a micron is approximately 1/25,400th of an inch). Other airborne contaminates can be much smaller. Bacteria commonly range anywhere between 0.3 to 2 microns in size, and viruses can be as small as 0.02 microns in size or smaller. The importance of removing these contaminates varies based upon the application. Semiconductor clean rooms and hospital operating rooms are two examples of spaces where the ability to remove contaminates is critical.
One factor complicating the removal of contaminates is that particle number density increases with smaller particle size. For example, in the typical cubic foot of outside air there are approximately 1000 10-30 micron sized particles. The same volume of air, however, contains well over one million 0.5 to 1.0 micron particles. As particle measuring instrumentation evolve they are capable of measuring deeper into the submicron range. Thus, advances in particle detection technology has confirmed that a great majority of all airborne particles are less than a micron in size. The prevalence of small particles is problematic from an air quality standpoint because small particles are hard to control and therefore hard to capture. Yet most contamination problems are caused by small particles.
Most small particles have a charge associated with them, while larger particles tend to be more neutral in charge. Thus, the movement of small airborne particles is primarily governed by electromagnetic forces, whereas the movement of large airborne particles is primarily governed by airflow. Further, small particles are also more influenced by Brownian Motion, both thermal and kinetic. However, larger particles have more mass associated with them. This is the basis of why larger particles are controlled more by the airflow generated by an HVAC system.
Particles acquire charge by three basic mechanisms. Diffusion charging occurs when particles are charged by random collisions between ions and other particles. The motion and collisions result from a process known as Brownian motion. The particle can take on multiple charges by this mechanism. Field charging occurs when rapid ion movement in an electric field causes frequent collisions between ions and particles. Finally, static electrification occurs when particles are separated from surfaces, thereby charging the particles. The factors that affect how a particle behaves in an electric field include particle size, the charge associated with the particle, and the strength of the electromagnetic field. The smaller the particle, the more it is influenced by an electromagnetic field. The more charge there is on a particle, the stronger the influence of the electromagnetic field. The stronger the electric field, of course, the more influence it has on the particle.
As discussed above, a great majority of the airborne particles found in nature are less than a micron in size. Thus, conventional air filtration systems that utilize airflow to capture airborne particles by trapping them in a filter device inevitably fail to trap smaller particles, leaving them free to circulate within an occupied space. Furthermore, the more efficient the filter in a system governed by airflow, the greater the pressure drop across the system. This pressure drop consequently decreases the efficiency of air filtration systems dependent on airflow as the primary force on airborne particles.
To overcome the difficulties associated with the capture of small particles, different particle conditioning techniques can be orchestrated together to control the transport, capture, and deactivation of particles. These conditioning tools include but are not limited to, particle ionization, particle polarization, and controlled particle colliding.
Particle Ionization—
Particle ionization occurs when a particle passes through an ion field. One type of ion field is a corona field. A corona field is created when a voltage is passed through a very thin wire or a thin metal blade with a serrated edge. Upon application of the voltage, electric fields concentrate on a sharp point and on a thin edge. When the electric field is strong enough, charges are emitted to the surrounding space, thereby developing a space charge. For example, if a negative high voltage is applied to a thin wire or metal edge, electrons are emitted to the air surrounding the wire or blade. When a particle passes through this created electron field, the particle picks up, or acquires, some of the electrons and becomes a negative ion (this also applies to a positive field which produces a positive ion). In the case of a particle passing through the negative ion field (electrons) the particle becomes negatively charged, thereby allowing it's movement to be controlled by the subsequent application of another electric field. If a grid that has the same voltage applied to it as the corona grid is placed in the path of the particle, the particle will be repelled by the grid (like charges repel each other). Furthermore, if a positive wire is placed downstream from the negative wire the conditioned particle will be propelled towards this positive grid (unlike charges attract each other). This is how the trajectory of particles can be controlled using precisely controlled electromagnetic, electrostatic, and/or electrodynamic fields.
Particle Polarization—
When a particle passes through a strong electrostatic field it can form a dipole, wherein one end of the particle is positively charged and the other end is negatively charged. This polarization is due to the fact that opposite charges attract and like charges repel. When a particle approaches a strong electrostatic field, such as a −15 kV field, a dipole is formed. Some of the positive charges in the particle will move toward the strong field (front of the particle) and some of the negative charges will move towards the opposite end (rear) of the particle, away from the static field (
Controlled Particle Colliding—
Controlled Particle Colliding performs at least two functions. First, it causes collisions between sub-micron sized particles to form larger particles, thus changing them from being dominantly controlled by electromagnetic fields to being controlled by airflow. Second, it makes particles neutral in charge. Particles will not only stay entrained in the airflow without being influenced by the electromagnetic fields in the room environment, but will not be as likely to form strong bonds with surfaces and objects in the room, even if they should come in contact with them.
Media Filter Systems—
This major class of filter system typically uses no electromagnetics in its operation. Basically this type of air cleaning device is a particle block. The particles that get to the device are filtered in the media material. In other words filtration occurs at the filter. These devices are placed in the airstream perpendicular to airflow. Airflow brings the incoming particles to the filter and the incoming particles get trapped as the air passes through the filter. This type of device depends on airflow.
Collector Systems—
When proper dielectric media material is utilized and an electrostatic field is applied across the media material, an opposite polarizing electric field is generated across the media material causing the material itself to polarize (see
Transport Mechanisms are what control the movement of particles. In every building environment there are forces present that determine these transport mechanisms. The Dominant Transport Mechanisms in a building environment are Airflow and/or Electromagnetic Fields, as described herein. Only relatively large particles, greater than a micron in size, are controlled by airflow. Smaller particles are dominantly controlled by electromagnetic fields. The smaller the particle, the more this statement becomes true.
Two equations dictate particle behavior. 1. Force equals the change in momentum of the particle (F=ma), due to airflow. 2. Charge times the electric field E (F=qE) due to electric forces in the room environment. Note 1: F is the force, m is the mass, a is acceleration, and E is the electric field. The first equation (F=ma) describes how airflow controls particle behavior and the second equation (F=qE) describes how the electric field controls particle behavior.
As is known in the art, the difficulty associated with capturing small airborne particles can be overcome by utilizing Particle Accelerated Collision Technology™ (PACT) (U.S. Pat. No. 7,175,695). PACT makes airflow the dominant transport mechanism and controls the behavior of fine particulates by creating inelastic collisions on a sub-micron level. This causes smaller particles to collide inelastically, thus becoming larger, thereby enabling any associated filtration system to easily remove these larger particles from the air. This collision process significantly improves the ability of a standard filtration system to remove and reduce indoor and outdoor generated contaminate levels.
Controlled Particle Colliding is similar to PACT, but much more compact. By combining it with the other components described herein it is made as effective as PACT. Alone, it would not be as effective due to its depth of influence being much smaller than an actual PACT system.
Also known in the art is Particle Guide Technology (PGT) (Pub. No. 2012/0085234). PGT forces particles to travel in a desired manner to a desired location, and/or a Particle Collector. The Particle Collector then traps the particles, removing them from the occupied space. PACT and PGT both utilize controlled electromagnetic fields to guide particles to a desired location. They are employed as a particle control device.
The majority of present filtration devices depend on airflow to guide particles to the filtration system. In general they are particle traps. Further, the space available in a typical HVAC system is limited. When the space that the filter is placed in is limited (in the direction of depth) the efficiency and/or pressure drop of the system can be compromised. Although great strides have been made in the efficiency of the traps, little has been done to control the particle itself. It should be mentioned that different particle conditioning techniques have been utilized individually to enhance particle filtration. However, to combine these effects in an optimized manner to control particle behavior is the goal of the present invention. By conditioning and controlling particles, the present invention takes advantage of the dominant transport mechanisms in air.
This disclosure provides a system for filtering airborne particles in an occupied space, the system comprising a particle conditioning unit; a first stage collector; and a particle collider. Another embodiment of the present disclosure includes a second stage collector positioned downstream the particle collider. Yet another embodiment of the invention includes a particle deflector system for overcoming the limitations associated with typical air filtration systems based solely on the physical capture of particles guided by airflow.
The disclosed system has several important advantages. For example, the disclosed system functions to make airflow the dominant transport mechanism of airborne particles.
A further possible advantage is that the collector system is more effective and efficient at capturing both small and large airborne particles.
Still yet another possible advantage of the present system is the capture and deactivation of health degrading organisms that interact with the filter system.
Various embodiments of the invention may have none, some, or all of these advantages. Other technical advantages of the present invention will be readily apparent to one skilled in the art.
For a more complete understanding of the present disclosure and its advantages, reference is now made to the following descriptions, taken in conjunction with the accompanying drawings, in which:
Similar reference numerals refer to similar parts throughout the several views of the drawings.
The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown by way of illustration and example. This invention may, however, be embodied in many forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numerals refer to like elements.
The present invention relates to systems and related methods for the filtration of airborne particles in an occupied space. The various components of the present invention, and the manner in which they interrelate, are described in greater detail hereinafter.
By way of example and with reference initially to
With reference to
The second grid 36 of the first stage collector 28 can be grounded 38 or set at the opposite potential of the first grid 18 of the particle conditioning unit 16. The object is to control the trajectory of the conditioned particles 30, 31 as they exit the particle conditioning unit 16 and optimize the collection of these particles. It should be noted that the type of particle least affected by the first stage collector 28 is a neutral (no charge associated with it) particle. In summary, the one objective is to optimize the stranding of the particle conditioning unit 16 so that particles are optimally charged, by creating dipoles 31 and/or ions 30, and then capturing the conditioned particles 30, 31 in the first stage collector 28.
The first grid 18 of the particle conditioning unit 16 also sets up an electrostatic field, Ep, between itself and the second grid 36 of the first stage collector 28. The second grid 36 of the first stage collector 28 may be grounded 38 or set at the opposite potential of the first grid 18 of the particle conditioning unit 16. This becomes important for proper operation of the first particle diffuser 32 in the first stage collector 28, which will be explained below.
The first stage collector 28 may be divided into five parts, including a first particle diffuser 32, a second grid 36, a first collector pad assembly 40 including first and second filter pads 42, 44, and a third grid 50.
The First Particle Diffuser 32—
Conditioned particles 30, 31 penetrate the first particle diffuser 32 pad first. This first particle diffuser 32 pad is placed in front of the second grid 36 of the first stage collector 28. The first particle diffuser 32 distributes the incoming conditioned particles 30, 31 so they do not coat the second grid 36 of the first stage collector 28. The first particle diffuser 32 forces particles to be diffused away from the second grid 36 of the first stage collector 28, thus protecting the grid from coating with particles, which would diminish the operation of the system. This significantly extends the period between maintenance of the system. The first particle diffuser 32 pad has a thickness d, which is much thinner than the first collector pad assembly 40 of thickness L. In this way the majority of particles penetrate to the first and second filter pads 42, 44.
Second Grid 36 of the First Stage Collector 28—
The second grid 36 is grounded 38 or at the opposite potential of the particle conditioning unit 16 as explained above and completes the potential difference between them (Ep). Again, Ep causes the dielectric fibers 34 in the first particle diffuser 32 to polarize creating Edp throughout the first particle diffuser 32 material. The second grid 36 also sets up an E field to the third grid 50 of the first stage collector 28, which is at the opposite potential to the second grid 36. The generated field Ec penetrates the first collector pad assembly 40.
The First Collector Pad Assembly 40—
The first collector pad assembly 40 may include two pad components, a first filter pad 42 (open weave pad) and a second filter pad 44 (closed weave pad). The two pads are composed of dielectric impregnated fibers 46, or dielectric material 48, that are polarized by the Ec field. The open weave structure in the first filter pad 42 attracts some of the incoming particles 30, 31 and allows other particles to penetrate deeper into the second filter pad 44 for proper distribution and a larger surface area, and as a result, longer filter life. The velocity and charge associated with the conditioned incoming particles 30, 31 determine the penetration depth of these particles. In a manner similar to that described for the first particle diffuser 32, the field Ec polarizes the media in the first collector pad assembly 40 and creates an opposite field in the media Ecp1 and Ecp2.
Third Grid 50 of the First Stage Collector 28—
The third grid 50 of the first stage collector 28 is necessary to complete the potential difference across the first and second filter pads 42, 44. The second and third grids 36, 50 create the electric field Ec across the dielectric material 48 in the first and second filter pads 42, 44, as explained above, thus polarizing the dielectric material 48 in the first and second filter pads 42, 44, creating field Ecp1 and Ecp2 shown in
It should be apparent to one skilled in the art that the system 10 described kills, disables, an/or deactivates pathogens or organisms, including viruses and bacteria. This anti-pathogenic activity of the system 10 results from the ionization and/or polarization fields established by the system 10. In one embodiment of the invention, the anti-pathogenic activity of the system results from the ionization and/or polarization fields established by at least one of the particle conditioning unit 16, the particle collider 56, and the first and second stage collectors 28, 70. Thus, one possible advantage of the present system is the capture and deactivation of health degrading organisms that interact with the filter system.
With reference to
The particle collider 56 conditions and forces particles to inelastically collide with each other, thereby creating larger particles 68. In one embodiment of the invention, the particle collider 56 consists of emitter plates spaced equally apart 58, 61 or a wire array 59 system. Each plate or wire array has an alternating electric voltage 66 applied to it. The plates alternate at switching time T. If emitters are utilized, they preferably have sharp points 62 that emit ions (in the form of protons and electrons, depending on polarity) into the space in front of each emitter creating a space charge. Since each emitter has the opposite charge associated with it, incoming particles pick up the charge in the region it passes through. This section of the particle collider 56 is the particle conditioning section. Therefore, as particles moves into the particle collider 56, they pass through the appropriate ion field set up by the emitter. The emitters emit equal amounts of positive and negative charges at a high voltage and low enough current not to generate ozone. After the particles pick up their appropriate charge(s) they enter the collision accelerator section of the particle collider 56. The conditioned particles are now conditioned to be influenced by the electric fields set up between the plates of the emitters. As the particles continue to the plate area, after the sharp blades 58, 61, they go back and forth between the plates (as the plates alternate between voltages) and the particles collide with other opposite-charged particles, created by the conditioning section of the particle collider 56, also going back and forth between the plates. Since the emitters voltage alternates particles move back and forth between plates colliding into each other forming larger particles 68. When particles of opposite charge collide they form ionic bonds (inelastic collisions) and do not come apart. The exiting particles are larger than the incoming particles and are more neutral in charge. It should be noted that a wire array system, or combination of wires and plates as well as sharp point emitters, can also be employed. Also, by utilizing thin wires on the third grid 50 of the first stage collector 28 and taking advantage of the ionized particles created by the particle conditioning unit 16 and first stage collector 28, plates or blades 61 alone can be used in the particle collider 56 to collide particles independent of conditioning serrated blades and/or wires.
To summarize, the particle collider 56 performs two operations, particle conditioning and particle colliding. Once the particle enters the electric field, this field becomes the dominant force on the particle. Since each particle has a net charge associated with it, generated by the particle conditioning section of the particle collider 56, it is immediately attracted to the opposite charged plate (emitter). When the field switches the particle is now attracted to the other plate where it is constantly on a collision course with other, oppositely charged particle. Two particles collide and stick together (inelastic collision) making them a larger particle. Then, the larger particle moves towards the opposite charged plate. Again, the electric field of the emitters switch and the larger particle 68 is attracted to the opposite plate. This process continues hundreds of times until the resulting larger particles leave the particle collider 56 with a more neutral charge than the original particles entering the particle collider (see
In another embodiment of the invention, controlled particle colliding is accomplished in two steps, particle conditioning and particle colliding. In the particle conditioning step, particles are conditioned with a small amount of space charge. By putting a charge on particles, they become susceptible to electrodynamic fields. Using thin serrated blades or thin wire arrays the particles entering the particle collider acquire a charge. The particle collider 56 emits equal amounts of positive and negative charges at an extremely low current level to avoid generating ozone. As particles pass through this section of the particle collider they pick up these charges. This makes the particles more influenced by the electrodynamic fields in the particle colliding section of the particle collider that increases their attractive force to each other, thus enhancing inelastic collisions.
In one embodiment of the invention, the particle conditioning step is followed by the particle colliding step. After the particles are conditioned they then enter the switching electrodynamic fields. Particles are accelerated and deflected, thereby enhancing Brownian motion. In this section of the particle collider 56 the collision process is rapidly accelerated and particles interact more rapidly than they would naturally. Both positively charged and negatively charged particles, created by the particle conditioning section of the particle collider 56, go through the switching electrodynamic fields and as a result collide with each other. When they collide they collide inelastically, the applied charges on the particles form ionic bonds with other particles, and larger particles 68 are created. This process of colliding continues throughout the particle colliding section of the particle collider, thereby forming larger and larger particles 68. These particles go into the occupied space 14 and continue the process of colliding with other particles, TVOCs, and gases. Smaller particles, TVOCs and gasses absorb and adsorb onto these larger particles 68, that are now controlled by airflow, and get eliminated from the occupied space 14 because the filtration/collector system is more effective in capturing these particles.
With continued reference to
Like the first stage collector 28 described above, the second stage collector 70 may include five parts. Further, the first stage collector 28 and the second stage collector 70 may share an identical construction. The second stage collector 70 would be configured to have an opposite field associated with it than the first stage collector 28. The second stage collector 70 attracts remaining charged particles that escaped the other components of the system. Larger neutral particles 68, formed by the particle collider 56 will escape the second stage collector 70 and go out into the occupied space 14 to collect other particles, including but not limited to TVOCs, gases, odors, bacteria, and viruses.
In another embodiment of the present invention and with reference to
In yet another embodiment of the present disclosure and with reference to 9A, 9B, 10A and 10B, the particle conditioning unit 16 is at a potential of −15 kV. However, the electrically conductive elements 20, or wires, have a larger diameter (large gauge) and do not create an ion field. The particle conditioning unit 16 creates a negative plane field at the grid assembly (see
Yet another embodiment of the present disclosure employs a No Pressure Drop Collector System. The particle conditioning unit 16 is set to −15 kV and a Particle Deflector 88 is set to 15 kV. The wires in the particle conditioning unit 16 have a small diameter and creates an ion field. The particle conditioning unit 16 creates negative ions out of incoming particles (see
Yet another embodiment of the present disclosure, the particle conditioning unit 16 is at a potential of −14 kV. The second grid 36 of the first stage collector 28 is +14 kV and the third grid 50 is at −14 kV. If a second stage collector 70 is utilized it has the opposite polarities in the second grid 36 and the third grid 50, which sets up opposite fields of the first stage collector 28 (
In yet another embodiment of the present disclosure the particle conditioning unit 16 is at a potential of −14 kV. However, the electrically conductive elements 20, or wires, have a larger diameter (large gauge) and does not create an ion field. The particle conditioning unit 16 creates a negative plane field at the first grid 18 assembly (see
In yet another embodiment of the present disclosure, a No Pressure Drop Collector System is employed. The particle conditioning unit 16 is set to −14 kV and the particle deflector 88 is set to −14 kV. The electrically conductive elements 20, or wires, in the particle conditioning unit 16 have a small diameter and create an ion field or corona field 26. The particle conditioning unit 16 creates negative ions out of incoming particles 12 (see
In yet another embodiment of the invention, the system 10 for filtering airborne particles 12 in an occupied space 14 further comprises a particle deflector 88 and a fifth voltage source 90, the particle deflector 88 positioned downstream the particle conditioning unit 16, wherein a fifth voltage 92 is applied to the particle deflector 88 by the fifth voltage source 90 sufficient for redirecting particles received from the particle conditioning unit 16 to at least one of the first stage collector 28 and second stage collector 70.
In yet another embodiment of the present invention, the system 10 for filtering airborne particles 12 in an occupied space 14, the first stage collector 28 and the second stage collector 70 are positioned perpendicular to the particle conditioning unit 16.
When dielectric impregnated media material 48 is placed in an electrostatic field the media material 48 is polarized setting up an opposite electric field from the original field. The material becomes a deflector to incoming particles. The objective is to protect a grid system attached to it from coating with incoming particles.
Although this disclosure has been described in terms of certain embodiments and generally associated methods, alterations and permutations of these embodiments and methods will be apparent to those skilled in the art. Accordingly, the above description of example embodiments does not define or constrain this disclosure. Other changes, substitutions, and alterations are also possible without departing from the spirit and scope of this disclosure.
Number | Name | Date | Kind |
---|---|---|---|
1357466 | Moller | Nov 1920 | A |
2906369 | Lagarias | Sep 1959 | A |
3984215 | Zucker | Oct 1976 | A |
3985524 | Masuda | Oct 1976 | A |
4056372 | Hayashi | Nov 1977 | A |
4094653 | Masuda | Jun 1978 | A |
4170447 | Goldstein et al. | Oct 1979 | A |
4209306 | Feldman et al. | Jun 1980 | A |
4265641 | Natarajan | May 1981 | A |
4357150 | Masuda et al. | Nov 1982 | A |
4496375 | Le Vantine | Jan 1985 | A |
4690694 | Alig et al. | Sep 1987 | A |
4734105 | Eliasson et al. | Mar 1988 | A |
4781736 | Cheney et al. | Nov 1988 | A |
4822381 | Mosley et al. | Apr 1989 | A |
4979364 | Fleck | Dec 1990 | A |
5061296 | Sengpiel et al. | Oct 1991 | A |
5199257 | Colletta et al. | Apr 1993 | A |
5255178 | Liberati | Oct 1993 | A |
5282891 | Durham | Feb 1994 | A |
5401299 | Kroeger et al. | Mar 1995 | A |
5403383 | Jaisinghani | Apr 1995 | A |
5542964 | Kroeger et al. | Aug 1996 | A |
5547493 | Krigmont | Aug 1996 | A |
5547496 | Hara | Aug 1996 | A |
5647890 | Yamamoto | Jul 1997 | A |
5695549 | Feldman et al. | Dec 1997 | A |
5707422 | Jacobsson et al. | Jan 1998 | A |
5707428 | Feldman et al. | Jan 1998 | A |
5711788 | Kim et al. | Jan 1998 | A |
5733360 | Feldman et al. | Mar 1998 | A |
5787704 | Cravero | Aug 1998 | A |
6004376 | Frank | Dec 1999 | A |
6162285 | Fong et al. | Dec 2000 | A |
6245299 | Shiloh et al. | Jun 2001 | B1 |
6375714 | Rump et al. | Apr 2002 | B1 |
6611440 | Johnston et al. | Aug 2003 | B1 |
6713026 | Taylor et al. | Mar 2004 | B2 |
6773489 | Dunn | Aug 2004 | B2 |
6790259 | Rittri et al. | Sep 2004 | B2 |
6872238 | Truce | Mar 2005 | B1 |
6878192 | Pasic | Apr 2005 | B2 |
6989049 | Belson et al. | Jan 2006 | B2 |
7175695 | Hess | Feb 2007 | B1 |
7261765 | Katayama | Aug 2007 | B2 |
7404847 | Hess | Jul 2008 | B2 |
7803213 | Hess | Sep 2010 | B2 |
20010025570 | Fukushima | Oct 2001 | A1 |
20040159232 | Mohamed | Aug 2004 | A1 |
20070022876 | Hess | Feb 2007 | A1 |
20070137479 | Hess | Jun 2007 | A1 |
Number | Date | Country |
---|---|---|
0646416 | Apr 1995 | EP |
S5233173 | Mar 1977 | JP |
S5245781 | Apr 1977 | JP |
H07246347 | Sep 1995 | JP |
H11156237 | Jun 1999 | JP |
2001334172 | Dec 2001 | JP |
2003103196 | Apr 2003 | JP |
Number | Date | Country | |
---|---|---|---|
20140076163 A1 | Mar 2014 | US |
Number | Date | Country | |
---|---|---|---|
61695588 | Aug 2012 | US |