Barometric relief air zone damper

Abstract

A zone damper having a first portion and second portion controlled by a actuator to move between an open and a closed position in response to a zone thermostat, a second portion responsive to the static pressure in a HVAC system to open and bleed an amount of conditioned air past the damper when the static pressure of the system increases above a selected level, and a weight adjustment for modifying the torque exerted by the second portion against the system static pressure to adjust the selected level.

1 . A zone damper responsive to a zone thermostat, the damper comprising a shell including a mechanical portion responsive to a static pressure differential in a HVAC system to open and bleed an amount of conditioned air past the damper when the static pressure of the system increases above a selected level. 
     
     
         2 . The zone damper of  claim 1 , further comprising a biasing member coupled to the mechanical portion for biasing the mechanical portion toward a closed position. 
     
     
         3 . The zone damper of  claim 2 , wherein the biasing member is either a spring or a weight. 
     
     
         4 . The zone damper of  claim 1 , further comprising another mechanical portion movable only in response to the zone thermostat, and a lock adapted to couple the two mechanical portions to limit the relative movements of the two mechanical portions with respect to each other. 
     
     
         5 . A zone damper comprising a shell containing a first portion and second portion controlled by a actuator to move between an open and a closed position in response to a zone thermostat, the second portion being movable relative to the first portion and responsive to the static pressure in a HVAC system to open and bleed an amount of conditioned air past the damper when the static pressure of the system increases above a selected level. 
     
     
         6 . The zone damper of  claim 5 , further comprising a biasing member coupled to the second portion to bias the second portion into alignment with the first portion. 
     
     
         7 . The zone damper of  claim 6 , wherein the biasing member comprises at least one weight situated on the second portion so that gravity acting on the at least one weight biases the second portion into alignment with the first portion. 
     
     
         8 . The zone damper of  claim 6 , wherein the biasing member comprises at least one spring coupled between the first and second portions. 
     
     
         9 . The zone damper of  claim 5 , further comprising a lock adapted to couple the first and second portions together to limit the relative movement of the second portion with respect to the first portion. 
     
     
         10 . A zone damper comprising a shell, a first portion and second portion mounted within the shell and controlled by an actuator to move between an open and a closed position in response to a zone thermostat, the second portion being movable relative to the first portion and responsive to the static pressure differential in a HVAC system to bleed an amount of conditioned air past the zone damper when the static pressure differential of the system increases, and a basing element coupled to the second portion to resist movement of the second portion until the static pressure differential reaches a selected level. 
     
     
         11 . The zone damper of  claim 10 , further comprising an adjustment feature for adjusting the bias exerted by the biasing element against the system static pressure differential to adjust said selected level. 
     
     
         12 . The zone damper of  claim 11 , wherein the biasing element comprises a weight coupled to the second portion. 
     
     
         13 . The zone damper of  claim 12 , wherein the adjustment feature comprises an opening in the shell permitting access to the weight for changing the size and/or location of the weight. 
     
     
         14 . The zone damper of  claim 10 , wherein the biasing element comprises a spring coupled to the first and second portions. 
     
     
         15 . The zone damper of  claim 10 , further comprising further comprising a lock adapted to couple the first and second portions together to limit the relative movement of the second portion with respect to the first portion. 
     
     
         16 . The zone damper of  claim 15 , wherein the lock is movable between an unlocked position allowing movement of the second portion relative to the first portion, and a locked position preventing any relative movement between the first and second portions. 
     
     
         17 . The zone damper of  claim 10 , further comprising a shaft coupled to the actuator and passing through the shell, the shaft being fixed to the damper first portion for concurrent movement therewith. 
     
     
         18 . The zone damper of  claim 17 , at least one hinge coupling the second portion to the shaft and first portion to permit movement of the second portion relative to the shaft and first portion.