# US 6,719,820 B2 · Air filter system and method of installation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 6,719,820 B2 - Document ID: US6719820B2 - Status: Granted - Kind: B2 - Application number: 10/365,104 - Filed: 2003-02-12 - Published: 2003-11-13 - Granted: 2004-04-13 - Earliest claimed: 2002-05-13 - Inventors: James Alan Wolf; Jerry William Wolf - Web page: https://patentgrep.com/patent/US6719820B2 ## CPC - F24F 13/28: Arrangement or mounting of filters - Y10S 55/31: Filter frame - F24F: AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING (removing dirt or fumes from areas where they are produced B08B15/00; vertical ducts for carrying away waste gases from buildings E04F17/02; tops for chimneys or ventilating shafts, terminals for flues F23L17/02) - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS ## Abstract A filter retaining apparatus and method for installing a thicker filter in an existing conventional return air duct in a conventional heating and air conditioning system. The filter is commercially available but is thicker than one conventionally used in such systems. A thicker filter provides more efficient air filtration and has a longer life, thus, requires less frequent cleaning or replacement. The retaining apparatus is capable of retaining the thicker filter and is adaptable to the existing return air duct opening without modification of the existing opening or the grill cover. The apparatus has the same length and width dimensions as the existing thin filter and is mounted on the same landing surface. The greater depth of the apparatus extends into the air duct. Thus, from the room interior it is not possible to detect the use of the apparatus. The greater depth of the apparatus retains the thicker commercially available filter. Another embodiment of the retaining apparatus, can be adapted to an existing return air duct that is somewhat shallower in depth while still retaining the commercially available thicker filter. ## Claims ### Claim 1 An apparatus for retaining an air filter adaptor frame mounted inside an existing air return frame, disposed about a return air duct, said return air duct having a termination point in a wall, floor, or ceiling, comprising: an air filter; a first air return frame disposed about said termination point having a first landing area and a second landing area and a first extended sidewall and a second extended sidewall, an air filter adaptor frame having an inside and outside surface, a first end and a second end, a first flange disposed about the outer perimeter of said first end, and a second flange disposed about the inner perimeter of said second end; and said first flange disposed about the outer perimeter is mounted on said second landing area. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein said adaptor frame is sized to fit within said first frame disposed about said return air duct termination point. ### Claim 3 (depends on 1) The apparatus of claim 1, wherein said air filter is sized to fit within said adaptor frame. ### Claim 4 (depends on 1) The apparatus of claim 1, wherein said first flange and said second flange maybe fixedly attached to said first end and said second end respectively. ### Claim 5 (depends on 1) The apparatus of claim 1, wherein said first flange and said second flange maybe integral to said first end and said second end respectively. ### Claim 6 An apparatus for retaining an air filter adaptor frame mounted inside a return air duct, said return air duct having a termination point in a wall, floor, or ceiling, comprising: an air filter; a first frame disposed about said termination point having a first landing area and a second landing area and a first extended sidewall and a second extended sidewall, an air filter adaptor frame having an inside and outside surface, a first end and a second end, a first flange disposed about the outer perimeter of said first end, and a second flange disposed about the inner perimeter of said second end; and said flange disposed about the outer perimeter is mounted on said first landing area. ### Claim 7 (depends on 6) The apparatus of claim 6, wherein said adaptor frame is sized to fit within said first frame disposed about said return air duct termination point. ### Claim 8 (depends on 6) The apparatus of claim 6, wherein said air filter is sized to fit within said adaptor frame. ### Claim 9 (depends on 6) The apparatus of claim 6, wherein said first flange and said second flange maybe fixedly attached to said first end and said second end respectively. ### Claim 10 (depends on 6) The apparatus of claim 6, wherein said first flange and said second flange maybe integral to said first end and said second end respectively. ### Claim 11 A method for installing an apparatus for retaining an air filter into a return air duct frame comprising steps of: providing a return air duct terminating adjacent to a wall, floor, or ceiling; providing a frame disposed about the termination point having a first landing area and a second landing area and a first extended sidewall and a second extended sidewall; providing an air filter; providing an air filter adaptor frame having an inside and outside surface, a first end and a second end, a first flange disposed about the outer perimeter of said first end, and a second flange disposed about the inner perimeter of said second end; and inserting said air filter adaptor frame into said existing frame disposed about said termination point until said first flange contacts said second landing area. ### Claim 12 (depends on 11) The method in claim 11, further including the step of: providing a sealing means between the said first flange and said second landing area. ### Claim 13 (depends on 11) The method in claim 11, further including the steps of: providing an attachment means for securing said air filter adaptor frame to said existing frame. ### Claim 14 A method for installing an apparatus for retaining an air filter into a return air duct frame comprising steps of: providing a return air duct terminating adjacent to a wall, floor, or ceiling; providing a frame disposed about the termination point having a first landing area and a second landing area and a first extended sidewall and a second extended sidewall; providing an air filter; providing an air filter adaptor frame having an inside and outside surface, a first end and a second end, a first flange disposed about the outer perimeter of said first end, and a second flange disposed about the inner perimeter of said second end; and inserting said air filter adaptor frame into said existing frame disposed about said termination point until said first flange contacts said first landing area. ### Claim 15 (depends on 14) The method in claim 14, further including the step of: providing a sealing means between the said first flange and said first landing area. ### Claim 16 (depends on 14) The method in claim 14, further including the steps of: providing an attachment means for securing said air filter adaptor frame to said existing frame.