Patent Publication Number: US-2023143870-A1

Title: Air filtration system and method

Description:
INTRODUCTION 
     The present disclosure relates to a system and method of filtering air for human breathing. Current filtration systems only provide filtration of particles larger than 300 nanometers. Viruses are smaller than this, and are not filtered by current breathing filters. 
     High efficiency particulate air (HEPA) filters and KN95 masks only capture particles that are 300 nanometers or larger in size, and, KN95 masks are only 95% effective. Ultralow particulate air filters (ULFA) filters only capture particles that are 120 nanometers or larger in size. Pollutants and viruses are much smaller than this, as consequently, pass through HEPA and ULFA filters. 
     Thus, while current filtration systems and methods of filtering air achieve their intended purpose, there is a need for a new and improved system and method for filtering air that captures particulates that are as small as 1 nanometer. 
     SUMMARY 
     According to several aspects of the present disclosure, a system for providing filtered air to an enclosed space includes a first air feed pump adapted to pull air from an exterior environment and push pressurized air through the system to the enclosed space, a power source adapted to provide electrical power to the first air feed pump, a first filter media positioned between the first air feed pump and the enclosed space, downstream of the first air feed pump, the first filter media adapted to provide coarse filtration of the pressurized air pumped from the first air feed pump through the first filter media, and a second filter media positioned between the first filter media and the enclosed space, downstream of the first filter media, the second filter media adapted to provide fine filtration of the pressurized air pumped from the first filter media through the second filter media. 
     According to another aspect, the system further includes a first control valve positioned between the first air feed pump and the first filter media, downstream of the first air feed pump, the first control valve being adapted to control the flow of pressurized air from the first air feed pump. 
     According to another aspect, the first filter media is adapted to remove particles that are larger than approximately 5 microns from the pressurized air flowing through the first filter media. 
     According to another aspect, the second filter media is adapted to remove particles that are between approximately 1 nanometer and approximately 20 nanometers in size from the pressurized air flowing through the second filter media. 
     According to another aspect, the enclosed space is a facemask adapted to deliver air that has passed through the first filter media and the second filter media to an individual user. Such facemasks exist and are used, for example, in the healthcare industry. 
     According to another aspect, the power source is adapted to provide between approximately 20 and approximately 32 watts of power to the first air feed pump and the first air feed pump is adapted to provide air that is pressured to between approximately 1 psi and approximately 3 psi to the facemask at a flow rate of between approximately 30 liters per minute and approximately 60 liters per minute. 
     According to another aspect, the enclosed space is a vehicle compartment. 
     According to another aspect, the system further includes a first reversing control valve positioned between the second filter media and the enclosed space, a reverse air flow path extending between and interconnecting the first control valve to the first reversing control valve, and a second reverse control valve positioned between the first control valve and the first filter media, wherein, the first control valve is selectively actuatable to divert pressurized air flow from the first air feed pump to the reverse air flow path, the first reversing control valve is selectively actuatable to stop air flow to the enclosed space and divert air flow from the reverse air flow path through the second filter media and the first filter media, and the second reverse control valve is selectively actuatable to divert pressurized air flow passing through the first filter media to the environment, wherein, when pressurized air flows through the first and second filter media from the reverse air flow path, the pressurized air dislodges particles captured by the first and second filter media and expels the particles dislodged from the first and second filter media out of the system to the exterior environment through the second reverse control valve. 
     According to another aspect, the system further includes a second air feed pump adapted to pull air from the enclosed space and push pressurized air through the system to the exterior environment, and a third filter media positioned between the second air feed pump and the exterior environment, downstream of the second air feed pump, the third filter media adapted to provide fine filtration of the pressurized air pumped from the second air feed pump through the third filter media. 
     According to another aspect, the system further includes a second control valve positioned between the second air feed pump and the third filter media, downstream of the second air feed pump, the second control valve being adapted to control the flow of pressurized air from the second air feed pump. 
     According to another aspect, the third filter media is adapted to remove particles that are between approximately 1 nanometer and approximately 20 nanometers in size from the pressurized air flowing through the third filter media. 
     According to another aspect, the system further includes a fourth filter media positioned between the second air feed pump and the third filter media, downstream of the second air feed pump, the fourth filter media adapted to provide coarse filtration of the pressurized air pumped from the second air feed pump through the fourth filter media before the pressurized air passes through the third filter media. 
     According to another aspect, the fourth filter media is adapted to remove particles that are larger than 5 microns from the pressurized air flowing through the fourth filter media. 
     According to several aspects of the present disclosure, a method of providing filtered air to an enclosed space includes providing, with a power source, electrical power to a first air feed pump, pulling, with the first air feed pump, air from an exterior environment and pushing, with the first air feed pump, pressurized air to the enclosed space, providing, with a first filter media positioned between the first air feed pump and the enclosed space, downstream of the first air feed pump, coarse filtration of the pressurized air pumped from the first air feed pump through the first filter media and removing, with the first filter media, particles that are larger than approximately 5 microns from the pressurized air, and providing, with a second filter media positioned between the first filter media and the enclosed space, downstream of the first filter media, fine filtration of the pressurized air pumped from the first filter media through the second filter media and removing, with the second filter media, particles that are between approximately 1 nanometer and approximately 20 nanometers in size from the pressurized air. 
     According to another aspect, the providing, with the power source, electrical power to the first air feed pump further includes providing, with the power source, between approximately 20 and approximately 32 watts of power to the first air feed pump, and the pushing, with the first air feed pump, pressurized air to the enclosed space further includes pushing, with the first air feed pump, air that is pressured to between approximately 1 psi and approximately 3 psi to the enclosed space at a flow rate of between approximately 30 liters per minute and approximately 60 liters per minute. 
     According to another aspect, the method further includes pulling, with a second air feed pump, air from the enclosed space and pushing, with the second air feed pump, pressurized air to the exterior environment, and providing, with a third filter media positioned between the second air feed pump and the exterior environment, downstream of the second air feed pump, fine filtration of the pressurized air pumped from the second air feed pump through the third filter media and removing, with the third filter media, particles that are between approximately 1 nanometer and approximately 20 nanometers in size from the pressurized air. 
     According to another aspect, the method further includes providing, with a fourth filter media positioned between the second air feed pump and the third filter media, downstream of the second air feed pump, coarse filtration of the pressurized air pumped from the second air feed pump through the fourth filter media and removing, with the fourth filter media, particles that are larger than 5 microns from the pressurized air before the pressurized air passes through the third filter media. 
     According to another aspect, the system further includes a first reversing control valve positioned between the second filter media and the enclosed space, a reverse air flow path extending between and interconnecting the first control valve to the first reversing control valve, and a second reverse control valve positioned between the first control valve and the first filter media, the method further includes diverting, with the first control valve, pressurized air flow from the first air feed pump to the reverse air flow path, stopping, with the first reversing control valve, air flow to the enclosed space and diverting air flow from the reverse air flow path through the second filter media and the first filter media and dislodging particles captured by the first and second filter media, and diverting, with the second reverse control valve, pressurized air flow passing through the first filter media to the environment and expelling particles dislodged from the first and second filter media out of the system to the exterior environment. 
     Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
         FIG.  1    is a schematic view of a system for providing filtered air to an enclosed space, wherein the enclosed space is a face mask, according to an exemplary embodiment; 
         FIG.  2    is a schematic view of a system for providing filtered air to an enclosed space, wherein the enclosed space is a vehicle compartment, according to an exemplary embodiment; 
         FIG.  3    is a schematic view of the system of  FIG.  1   , wherein the pressurized air flow through the first and second filter media is reversed; 
         FIG.  4    is a schematic view of the system shown in  FIG.  1    wherein air is filtered before being expelled to the environment from the enclosed space; and 
         FIG.  5    is a flowchart illustrating a method of providing filtered air to an enclosed space according to an exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. 
     Referring to  FIG.  1   , a system  10  for providing filtered air to an enclosed space  12  includes, a first air feed pump  14  that is adapted to pull air from an exterior environment  16 , as indicate by arrow  18 , and push pressurized air through the system  10  to the enclosed space  12 , as indicated by arrow  20 . A power source  22  is adapted to provide electrical power to the first air feed pump  14 . A first filter media  24  is positioned between the first air feed pump  14  and the enclosed space  12 , downstream of the first air feed pump  14 . The first filter media  24  is adapted to provide coarse filtration of the pressurized air pumped from the first air feed pump  14  through the first filter media  24 , as indicated by arrow  26 . A second filter media  28  is positioned between the first filter media  24  and the enclosed space  12 , downstream of the first filter media  24 . The second filter media  28  is adapted to provide fine filtration of the pressurized air pumped from the first filter media  24  through the second filter media  28 , as indicated by arrow  30 . From the second filter media  28 , the filtered air is pushed to the enclosed space  12 , as indicated by arrow  32 . 
     As shown in  FIG.  1   , in one exemplary embodiment, the enclosed space  12  is a facemask  34  adapted to deliver air that has passed through the first filter media  24  and the second filter media  28  to an individual user  36 . For providing breathing air to a face mask  34  for an individual user  36 , the power source  22  is adapted to provide between approximately 20 and approximately 32 watts of power to the first air feed pump  14  and the first air feed pump  14  is adapted to provide air that is pressured to between approximately 1 psi and approximately 3 psi to the face mask  34 . Air that is expelled by the individual  36  into the face mask  34  is routed out of the system  10 , as indicated by arrow  38 . To support breathing for an individual  36 , the first air feed pump  14  must deliver air to the face mask  34  at a flow rate of between approximately 30 liters per minute and approximately 60 liters per minute. Because the power consumption of the power source  22  is relatively low, between approximately 20 and 32 watts of power, the power source  22  could be a rechargeable battery pack, thus enabling the system  10  to be portable. 
     Referring to  FIG.  2   , in another exemplary embodiment, the enclosed space  12  is a vehicle compartment  40 . The first feed pump  14  of the system  10  draws air in from outside a vehicle  42  through inlets  44 , as indicated by arrows  46 , and pushes filtered air from the system  10  to the interior vehicle compartment  40  through air vents  48  within the vehicle  42 . The system  10  can incorporate a first feed pump  14  capable of providing increased flow rate so the system  10  can feed filtered air to the entire interior vehicle compartment  40 , thus providing filtered air to all of the passengers in the vehicle  42  with an HVAC system operating in recirculation mode. Likewise the system  10  can be adopted to provide filtered air directly to the face mask  34  of the passenger  36  in the vehicle  42  making it independent of the HVAC system operation and hence reducing it&#39;s capacity requirements. Likewise the system  10  can be adapted to provide personal protection space to seated aircraft passengers and similarly to healthcare workers and patients. Likewise, the system  10  could be adapted to provide filtered air to a larger enclosed space  12 , such as a room, or an entire building. If the system  10  is designed for a relatively large enclosed space, such as a large room or an entire building, such as a home, the system  10  can be designed with larger second filter media  28 , or multiple second filter media  28 , positioned in parallel, to provide adequate air flow with a conservatively sized first air feed pump  14 . 
     Referring again to  FIG.  1   , in another exemplary embodiment, a first control valve  50  is positioned between the first air feed pump  14  and the first filter media  24 , downstream of the first air feed pump  14 . The first control valve  50  is adapted to control the flow of pressurized air from the first air feed pump  14 . 
     The first filter media  24  provides coarse “microfiltration” and is adapted to remove particles that are larger than approximately 5 microns from the pressurized air flowing through the first filter media  24 . The first filter media  24  will capture larger particles of pollution such as dust and dirt. As shown, the first filter media  24  is positioned downstream of the first air feed pump  14 . It should be understood that the first filter media  24  may also be positioned upstream of the first air feed pump  14 , such as at an inlet to the first air feed pump  14  without departing from the spirit of the present disclosure. Such filter materials exist and are used, for example, in air and water purification processes. 
     The second filter media  28  is a membrane that provides fine “ultrafiltration” and is adapted to remove particles that are between approximately 1 nanometer and approximately 20 nanometers in size from the pressurized air flowing through the second filter media  28 . Such membrane materials exist and are used, for example, in water purification processes. Such membrane materials have not been used for air filtration due to the resistance they impart to air flowing through them. A human being would be unable to draw air through a membrane of such a material, thus the first feed pump  14  is necessary to push the air through the second filter media  28  to the enclosed space  12 . 
     The power requirements of the first air feed pump  14  are directly related to the resistance of the air flowing through the second filter media  28 , thus, if filtration requirements are less stringent a smaller or less powerful first air feed pump  14  that uses less power can be used. For example, if the system  10  is only required to filter particles that are 30 nanometers or larger in size, the system can be designed with a second filter media  28  membrane that provides less resistance to air flow than a second filter media  28  membrane that would capture particles that are 1 nanometer or larger in size, thus requiring less air pressure to push the air through the second filter media and a smaller, less power consuming, first air feed pump. This allows the system to be customized for specific filtration needs to optimize power consumption. 
     Referring to  FIG.  3   , in an exemplary embodiment, the system  10  further includes a first reversing control valve  74  positioned between the second filter media  28  and the enclosed space  12 , a reverse air flow path  76  extending between and interconnecting the first control valve  50  to the first reversing control valve  74 , and a second reverse control valve  78  positioned between the first control valve  50  and the first filter media  24 . The first control valve  50  is selectively actuatable to divert pressurized air flow from the first air feed pump  14  to the reverse air flow path  76 , as indicated by arrows  80 . The first reversing control valve  74  is selectively actuatable to stop air flow to the enclosed space  12  and divert air flow from the reverse air flow path  76 , as indicated by arrow  82 , through the second filter media  28 , as indicated by arrow  54 , and through the first filter media  24 , as indicated by arrow  52 . The second reverse control valve  78  is selectively actuatable to divert pressurized air flow passing through the first filter media  24  to the environment, as indicated by arrow  56 . When pressurized air flows through the second and first filter media  28 ,  24  from the reverse air flow path  76 , the pressurized air dislodges particles captured by the first and second filter media  24 ,  28  and expels the dislodged particles out of the system  10  to the exterior environment through the second reverse control valve  78 . Alternatively, when pressurized air flows through the second and first filter media  28 ,  24  from the reverse air flow path  76 , the pressurized air dislodges particles captured by the first and second filter media  24 ,  28  and the system  10  shakes and drops the dislodged particles inside a chamber surrounding the first and second filter media  24 ,  28 . 
     Referring to  FIG.  4   , in another exemplary embodiment, the system  10  further includes a second air feed pump  58  adapted to pull air from the enclosed space  12  and push pressurized air through the system  10  to the exterior environment  16 , as indicated by arrow  60 . A third filter media  62  is positioned between the second air feed pump  58  and the exterior environment  16 , downstream of the second air feed pump  58 . The third filter media  62  is a membrane, similar to the second filter media  28 , that is adapted to provide fine filtration and remove particles that are between approximately 1 nanometer and approximately 20 nanometers in size from the pressurized air flowing through the third filter media  62 , as indicated by arrow  64 . A human being would be unable to push air through a membrane of such a material, thus the second air feed pump  58  is necessary to push the air through the third filter media  62  to the environment  16 . 
     According to another exemplary embodiment, the system  10  may include a second control valve  66  positioned between the second air feed pump  58  and the third filter media  62 , downstream of the second air feed pump  58 . The second control valve  66  being adapted to control the flow of pressurized air from the second air feed pump  58 . 
     In yet another exemplary embodiment, the system  10  includes a fourth filter media  68  positioned between the second air feed pump  58  and the third filter media  62 , downstream of the second air feed pump  58 . The fourth filter media  68 , like the first filter media  24 , is adapted to remove particles that are larger than approximately 5 microns from the pressurized air flowing through the fourth filter media  68 , as indicated by arrow  70 . The fourth filter media  68  will provide coarse filtration of the air and capture larger particles of pollution before the air gets to the third filter media  62 . The third and fourth filter media  62 ,  68  will ensure that small particles, such as viruses, are removed from the air expelled by an individual  36  using the system  10  before such air is released back to the environment  16 , as indicated by arrow  72 , helping to prevent spread of such viruses. 
     Referring to  FIG.  5   , a method  100  of providing filtered air to an enclosed space  12  with a system  10  according to the present disclosure is shown schematically. Beginning at block  102 , the method includes providing, with the power source  22 , electrical power to the first air feed pump  14 . Moving to block  104 , the method  100  includes pulling air, with the first air feed pump  14 , from the exterior environment and pushing, with the first air feed pump  14 , pressurized air to the enclosed space  12 , as shown by arrows  18  and  20  in  FIG.  1   . 
     Moving to block  106 , the method includes providing, with the first filter media  24  that is positioned between the first air feed pump  14  and the enclosed space  12 , downstream of the first air feed pump  14 , coarse filtration of the pressurized air pumped from the first air feed pump  14  through the first filter media  24 , as indicated by arrow  26  in  FIG.  1   , and removing, with the first filter media  24 , particles that are larger than approximately 5 microns from the pressurized air. 
     Moving to block  108 , the method  100  includes providing, with the second filter media  28  that is positioned between the first filter media  24  and the enclosed space  12 , downstream of the first filter media  24 , fine filtration of the pressurized air pumped from the first filter media  24  through the second filter media  28 , as indicated by arrow  30  in  FIG.  1   , and removing, with the second filter media  28 , particles that are between approximately 1 nanometer and approximately 20 nanometers in size from the pressurized air. 
     In an exemplary embodiment, the providing, with the power source  22 , electrical power to the first air feed pump  14  further includes providing, with the power source  22 , between approximately 20 and approximately 32 watts of power to the first air feed pump  14 . Additionally, the pushing, with the first air feed pump  14 , pressurized air to the enclosed space  12  further includes pushing, with the first air feed pump  22 , air that is pressured to between approximately 1 psi and approximately 3 psi to the enclosed space  12  at a flow rate of between approximately 30 liters per minute and approximately 60 liters per minute. 
     Moving to block  110 , in an exemplary embodiment, the method  100  further includes pulling, with the second air feed pump  58 , air from the enclosed space  12  and pushing, with the second air feed pump  58 , pressurized air to the exterior environment  16 , as indicated by arrow  60  in  FIG.  4   . 
     Moving to block  112 , the method  100  includes providing, with the third filter media  62  that is positioned between the second air feed pump  58  and the exterior environment  16 , downstream of the second air feed pump  58 , fine filtration of the pressurized air pumped from the second air feed pump  58  through the third filter media  62 , as indicated by arrow  64  in  FIG.  4   , and removing, with the third filter media  62 , particles that are between approximately 1 nanometer and approximately 20 nanometers in size from the pressurized air. 
     Moving to block  114 , in an exemplary embodiment, the method  100  further includes providing, with the fourth filter media  68  that is positioned between the second air feed pump  58  and the third filter media  62 , downstream of the second air feed pump  58 , coarse filtration of the pressurized air pumped from the second air feed pump  58  through the fourth filter media  68 , as indicated by arrow  70  in  FIG.  4   , and removing, with the fourth filter media  68 , particles that are larger than 5 microns from the pressurized air before the pressurized air passes through the third filter media  62 . 
     Moving from block  102  to block  116 , in another exemplary embodiment, the method  100  includes diverting, with the first control valve  50 , pressurized air flow from the first air feed pump  14  to the reverse air flow path  76 , as shown by arrows  80  in  FIG.  3   . Moving to block  118 , the method  100  includes stopping, with the first reversing control valve  74 , air flow to the enclosed space  12  and diverting air flow from the reverse air flow path  76 , as shown by arrow  82  in  FIG.  3   , through the second filter media  28 , as indicated by arrow  54  in  FIG.  3    and the first filter media  24 , as indicated by arrow  52  in  FIG.  3   , and dislodging particles captured by the first and second filter media  24 ,  28 . Moving to block  120 , the method  100  includes diverting, with the second reverse control valve  78 , pressurized air flow passing through the first filter media  52  to the environment and expelling particles dislodged from the first and second filter media  24 ,  28  out of the system  10  to the exterior environment, as indicated by arrow  56  in  FIG.  3   . Moving to block  122 , in an alternative exemplary embodiment, the method  100  includes diverting, with the second reverse control valve  78 , pressurized air flow passing through the first filter media  52  to the environment and the system  10  shakes and drops the dislodged particles inside a chamber surrounding the first and second filter media  24 ,  28 . 
     A system  10  and method  100  of the present disclosure offers several advantages. These include filtering air to remove particles much smaller than is capable by existing systems, including viruses, to protect an individual  36  that is breathing such air. The system  10  and method  100  includes using a first feed pump  14  to push air through a filter membrane that a human would be unable to draw air through, allowing the use of filter membrane material that is suited to capture particles sized between 1 and 20 nanometers. Reversibility of the airflow through the first and second filter media  24 ,  28  allows the first and second filter media  24 ,  28  to be cleaned of particles previously captured, allowing the system  10  to self-clean. Usage of third and fourth filter media  62 ,  68  and a second air feed pump  58  downstream of the enclosed space  12  allows air expelled from an individual  36  or group of individuals to be filtered prior to being expelled to the environment  16 . A system  10  of the present disclosure stops virus particles sized between 1 and 20 manometers from being breathed in by a user of the system  10  and stops a user of the system from expelling virus particles sized between 1 and 20 nanometers to the environment  16 . 
     The description of the present disclosure is merely exemplary in nature and variations that do not depart from the gist of the present disclosure are intended to be within the scope of the present disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the present disclosure.