Barometric relief air zone damper

Abstract

A zone damper having a first 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, a coupling mechanism coupling the first and second portions to limit the relative movements of the two portions with respect to each other, and a biasing mechanism exerting a torque against the system static pressure differential.

1 . A method of operating a zone damper comprising:
 activating an actuator to position a mechanical blade portion of the zone damper in a first position to substantially inhibit a flow of conditioned air through a shell of the zone damper, the position of the mechanical blade portion in the first position responsive to a signal;   enabling movement of the mechanical blade portion in a predetermined range while in the first position, the movement of the mechanical blade portion responsive to a static pressure differential, so that the static pressure differential increasing above a selected level causes movement of the mechanical blade portion to bleed an amount of conditioned air past the mechanical blade portion; and   activating the actuator to drive the mechanical blade portion to a second position, responsive to the signal, to allow a maximum flow of conditioned air through the shell of the zone damper, wherein the mechanical blade portion is not responsive to the static pressure differential while in the second position.   
     
     
         2 . The method of  claim 1 , further comprising:
 activating the actuator to drive the mechanical blade portion to a third position to partially block the flow of conditioned air through the shell of the zone damper responsive to the thermostat signal; and   enabling movement of the mechanical blade portion in a second predetermined range while in the third position, responsive to the static pressure differential increasing above a second selected level to allow a variable amount of conditioned air past the mechanical blade portion, the variable amount of conditioned air while the mechanical blade portion is in the third position being greater in volume than the amount of conditioned air while the mechanical blade portion is in the first position.   
     
     
         3 . The method of  claim 2 , wherein the predetermined range of the mechanical blade portion in the first position is greater than the second predetermined range of the mechanical blade portion in the third position. 
     
     
         4 . The method of  claim 2 , wherein the third position is between the first position and the second position. 
     
     
         5 . The method of  claim 1 , further comprising biasing the movement of the mechanical blade portion to a first end of the predetermined range by a biasing member. 
     
     
         6 . The method of  claim 1 , wherein the movement of the mechanical blade portion is caused by the static pressure differential. 
     
     
         7 . The method of  claim 1 , wherein the mechanical blade portion is coupled to the actuator by a shaft which passes through the shell of the zone damper. 
     
     
         8 . The method of  claim 7 , wherein movement of the mechanical blade portion is limited to the predetermined range by the movement of a projection within a slot, wherein one of the projection or the slot is associated with the mechanical blade portion and the other of the projection or the slot is associated the shaft. 
     
     
         9 . The method of  claim 1 , further comprising providing the amount of conditioned air to a zone. 
     
     
         10 . A method of operating a zone damper comprising:
 activating an actuator to drive a shaft to a first position responsive to a temperature signal, wherein the shaft is coupled to a mechanical blade portion of the zone damper;   enabling movement of the mechanical blade portion toward a first end of a predetermined range about the shaft so that the mechanical blade portion is substantially blocking a flow of conditioned air through a shell of the zone damper,   while the shaft is in the first position, enabling variation in positioning of the mechanical blade portion within the predetermined range by a static pressure differential so that the static pressure differential increasing above a selected level moves the mechanical blade portion to allow an amount of conditioned air to bleed past the mechanical blade portion towards a zone; and   activating the actuator to drive the shaft to a second position responsive to the temperature signal, to allow a substantially unrestricted flow of conditioned air through the shell of the zone damper towards a zone, wherein the mechanical blade portion is not responsive to the static pressure differential while the shaft is in the second position.   
     
     
         11 . The method of  claim 10 , further comprising:
 activating the actuator to drive the shaft to a third position, responsive to a temperature signal;   while the shaft is in the third position, enabling movement of the mechanical blade portion toward the first end of the predetermined range about the shaft, so that the mechanical blade portion partially blocks the flow of conditioned air through the shell of the zone damper; and   enabling variable movement of the mechanical blade portion in the predetermined range while in the third position, by a static pressure differential increasing above a second selected level or decreasing below the second selected level to allow a variable amount of conditioned air past the mechanical blade portion towards a zone, the variable amount of conditioned air while the shaft is in the third position being great in volume than the amount of conditioned air while the shaft is in the first position.   
     
     
         12 . The method of  claim 11 , wherein the predetermined range of the movement of the mechanical blade portion while the shaft is in the first position is greater than the predetermined range of movement of the mechanical blade portion when the shaft is in the third position. 
     
     
         13 . The method of  claim 11 , wherein the third position is between the first position and the second position. 
     
     
         14 . The method of  claim 10 , further comprising biasing the movement of the mechanical blade portion to a first end of the predetermined range by a biasing member. 
     
     
         15 . A method of operating a zone damper comprising:
 activating an actuator, responsive to a thermostat signal, to drive a shaft of the zone damper to a first position, the first position having a first end element, wherein the shaft is coupled to a mechanical blade portion of the zone damper, and wherein the first end element defines a limit as to a range of motion of the mechanical blade portion with respect to the first end element;   while the shaft is in the first position, enabling movement of the mechanical blade portion to substantially block a flow of conditioned air through a shell of the zone damper;   while the shaft is in the first position, enabling variable movement of the mechanical blade portion in the range of motion, the variable movement of the mechanical blade portion responsive to a static pressure differential, so that the static pressure differential increasing above a selected level causes movement of the mechanical blade portion to bleed an amount of conditioned air past the mechanical blade portion; and   activating the actuator, responsive to the thermostat signal, to drive the shaft to a second position to allow the flow of conditioned air through the shell of the zone damper, wherein the while the shaft is in the second position, the mechanical blade portion is not responsive to the static pressure differential.   
     
     
         16 . The method of  claim 15 , wherein the range of motion is defined between the location of the first end element, and a point wherein the mechanical blade portion is not responsive to the static pressure differential. 
     
     
         17 . The method of  claim 16 , further comprising:
 activating the actuator to drive the shaft to a third position, responsive to a thermostat signal, wherein the mechanical blade portion rests against the first end element and is positioned to partially block the flow of conditioned air through the shell of the zone damper; and   while the shaft is in the third position, enabling variable movement of the mechanical blade portion in the range of motion while in the third position, responsive to the static pressure differential increasing above a second selected level to allow a variable amount of conditioned air past the mechanical blade portion, the variable amount of conditioned air while the shaft is in the third position being great in volume than the amount of conditioned air while the shaft is in the first position.   
     
     
         18 . The method of  claim 16 , wherein the first end element is located at a first end of a slot, and wherein variable movement of the mechanical blade portion is limited by the movement of a projection within the slot. 
     
     
         19 . The method of  claim 18 , further comprising enabling variable movement of the mechanical blade portion against a second end of the slot to define a maximum responsiveness of the mechanical blade portion to move in the range of motion in response to the static pressure differential. 
     
     
         20 . The method of  claim 15 , further comprising biasing the movement of the mechanical blade portion to a first end of the range of motion by a biasing member.