# US 7,607,974 B2 · Rooftop vent for reducing pressure under a membrane roof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,607,974 B2 - Document ID: US7607974B2 - Status: Granted - Kind: B2 - Application number: 11/177,492 - Filed: 2005-07-11 - Published: 2006-01-12 - Granted: 2009-10-27 - Earliest claimed: 2003-04-30 - Assignees: Virginia Tech Intellectual Properties, Inc. - Inventors: James R. Jones; Demetri Telionis; Pavlos Vlachos; Elizabeth Grant; Jose Rullan; Charles S. Johnson - Web page: https://patentgrep.com/patent/US7607974B2 ## CPC - E04D 5/14: Fastening means therefor - E04D 13/17: Ventilation of roof coverings not otherwise provided for (ventilation of rooms or spaces F24F) - E04D: ROOF COVERINGS; SKY-LIGHTS; GUTTERS; ROOF-WORKING TOOLS (coverings of outer walls by plaster or other porous material E04F13/00) ## Abstract Membrane roofs are susceptible to damage in high winds. Wind can lift a membrane roof from a building and cause it to tear or become damaged. The present roof vent prevents liftoff and damage by reducing the air pressure under the membrane during high winds. The present roof vent has two opposed convex domes separated by a gap. Wind blowing across the roof flows between the domes where it accelerates and creates a region of low pressure according to the Venturi effect. The lower dome has an opening at the gap so that the low pressure is applied to the space under the membrane roof. Therefore, when wind blows across the roof, the vent draws air from under the membrane and the membrane is pressed against the roof, preventing liftoff. ## Claims ### Claim 1 A roof vent for use with membrane roofs, comprising: a) a lower dome with a top surface; b) an upper dome supported above the lower dome, wherein the upper dome has a bottom surface and a port in the bottom surface; wherein the top surface and bottom surface face each other and are spaced apart; wherein a distance between the top and bottom surfaces decreases from a periphery to a center of the vent; and c) a hollow leg supporting the upper dome, wherein the hollow leg provides fluid communication between an interior of the upper dome and an interior of the lower dome. ### Claim 2 (depends on 1) The roof vent of claim 1, further comprising a horizontal flange circumscribing a bottom of the lower dome. ### Claim 3 (depends on 1) The roof vent of claim 1, wherein the port is located where the distance between top and bottom surfaces is smallest. ### Claim 4 (depends on 1) The roof vent of claim 1, wherein one of the top surface and the bottom surface is substantially flat. ### Claim 5 (depends on 1) The roof vent of claim 1, wherein the top surface and the bottom surface are both convex. ### Claim 6 A membrane roof, comprising: a roof membrane with a hole; a roof vent, comprising: a) a lower dome with a top surface; b) an upper dome supported above the lower dome, wherein the upper dome has a bottom surface and a port in the bottom surface; c) a hollow leg supporting the upper dome, wherein the hollow leg provides fluid communication between an interior of the upper dome and an interior of the lower dome; wherein the top surface and bottom surface face each other and are spaced apart; and wherein a distance between the top and bottom surfaces decreases from a periphery to a center of the vent. ### Claim 7 (depends on 6) The membrane roof of claim 6, further comprising a subroof disposed under the membrane, wherein the subroof includes grooves conductive to airflow. ### Claim 8 (depends on 6) The membrane roof of claim 6, further comprising a porous layer conductive to airflow under the membrane. ### Claim 9 (depends on 6) The membrane roof of claim 6, further comprising a horizontal flange circumscribing a bottom of the lower dome, wherein the flange is secured to the roof membrane in an area circumscribing the hole. ### Claim 10 (depends on 6) The membrane roof of claim 6, wherein the port is located where the distance between top and bottom surfaces is smallest. ### Claim 11 (depends on 6) The membrane roof of claim 6, wherein one of the top surface or the bottom surface is substantially flat. ### Claim 12 (depends on 6) The membrane roof of claim 6, wherein the top surface and the bottom surface are both convex. ### Claim 13 A roof vent for use with membrane roofs, comprising of: an upper dome having a bottom surface; a lower dome aligned with said upper dome and having a top surface opposite said bottom surface of said upper dome, at least one of said upper and lower surfaces having a convex shape so that a portion of said at least one of said upper and lower surfaces curves toward the other of said upper and lower surfaces defining a wind gap therebetween; and an opening disposed in at least one of said upper and lower surfaces, wherein said wind gap is configured to allow wind to pass between said upper and lower surfaces, thereby reducing air pressure in said lower dome. ### Claim 14 (depends on 13) A roof vent according to claim 13, wherein at least one of said upper and lower domes is substantially enclosed. ### Claim 15 (depends on 13) A roof vent according to claim 13, wherein a plurality of supporting legs extend between said upper and lower surfaces. ### Claim 16 (depends on 13) A roof vent according to claim 13, wherein at least one of said upper and lower surfaces is substantially flat. ### Claim 17 (depends on 13) A roof vent according to claim 13, wherein both of said upper and lower surfaces are substantially convex.