Pliable air duct with pressure responsive discharge outlets

Abstract

An air-handling system (preferably a variable air volume system) includes an inflatable air duct with a discharge member whose discharge opening varies with the static pressure or flow rate within the duct. To prevent the duct from deflating at low airflow rates, the discharge opening, in some embodiments, tends to close in response to reduced air pressure associated with the lower airflow. The closing of the discharge opening prevents the static pressure from decreasing as much as the pressure would otherwise if the discharge opening were fixed. In some embodiments, the discharge opening responds to static pressure or airflow within the duct such that the discharge member redirects the discharge air as a function of the static pressure of flow volume. Warmer air at relatively low volume, for instance, can be directed downward, and cooler air at greater airflow rates can be directed upward.

1 . An air-handling system for conveying air at a pressure, comprising: 
 an air duct having a pliable wall; and    a discharge member disposed on the pliable wall, wherein the discharge member defines a variable discharge opening having a degree of opening that varies with the pressure of the air within the air duct.    
   
   
       2 . The air-handling system of  claim 1 , wherein the degree of opening decreases with a decrease in the pressure of the air within the air duct.  
   
   
       3 . The air-handling system of  claim 1 , wherein the discharge member has at least a larger degree of opening and a smaller degree of opening and is biased toward the smaller degree of opening.  
   
   
       4 . The air-handling system of  claim 1 , wherein the discharge member includes a resiliently flexible flap that moves in response to a change in the pressure of the air within the air duct.  
   
   
       5 . The air-handling system of  claim 1 , wherein a portion of the discharge member is an integral extension of the pliable wall.  
   
   
       6 . The air-handling system of  claim 1 , wherein the discharge member releases the air in a direction that varies in response to a change in the pressure of the air within the air duct.  
   
   
       7 . The air-handling system of  claim 1 , wherein the discharge member releases the air in a more upward direction when the pressure of the air in the air duct increases.  
   
   
       8 . The air-handling system of  claim 1 , further comprising a variable speed blower in fluid communication with the air duct, whereby the variable speed blower can vary the pressure of the air in the air duct.  
   
   
       9 . An air-handling system for conveying air at a pressure, comprising: 
 an air duct having a pliable wall;    a variable speed blower in fluid communication with the air duct, wherein the variable speed blower can vary the pressure of the air in the air duct; and    a discharge member disposed on the pliable wall, wherein the discharge member defines a variable discharge opening having a degree of opening that varies in response to the pressure of the air within the air duct.    
   
   
       10 . The air-handling system of  claim 9 , wherein the degree of opening decreases with a decrease in the pressure of the air within the air duct.  
   
   
       11 . The air-handling system of  claim 9 , wherein the discharge member has at least a larger degree of opening and a smaller degree of opening and is biased toward the smaller degree of opening.  
   
   
       12 . The air-handling system of  claim 9 , wherein the discharge member includes a resiliently flexible flap that moves in response to a change in the pressure of the air within the air duct.  
   
   
       13 . The air-handling system of  claim 9 , wherein a portion of the discharge member is an integral extension of the pliable wall.  
   
   
       14 . The air-handling system of  claim 9 , wherein the discharge member releases the air in a direction that varies in response to a change in the pressure of the air within the air duct.  
   
   
       15 . The air-handling system of  claim 9 , wherein the discharge member releases the air in a more upward direction when the pressure of the air in the air duct increases.  
   
   
       16 . A method for conveying air through an air duct, wherein the air is conveyed at a static pressure that can vary, the method comprising: 
 forcing the air through the air duct;    releasing the air from within the air duct through a discharge opening of the air duct;    decreasing the static pressure of the air within the air duct; and    altering the discharge opening in response to decreasing the static pressure of the air.    
   
   
       17 . The method of  claim 16 , wherein the step of altering the discharge opening involves restricting the discharge opening.  
   
   
       18 . The method of  claim 16 , wherein the step of altering the discharge opening involves redirecting the air through the discharge opening.  
   
   
       19 . The method of  claim 16 , wherein the step of altering the discharge opening involves deflecting a resiliently flexible flap.  
   
   
       20 . The method of  claim 16 , wherein the step of altering the discharge opening involves biasing the opening toward a smaller degree of opening.  
   
   
       21 . An air-handling system for conveying air at an airflow rate that varies, comprising: 
 an air duct having a pliable wall; and    a discharge member disposed on the pliable wall, wherein the discharge member defines a variable discharge opening having a degree of opening that varies with the airflow rate within the air duct.    
   
   
       22 . The air-handling system of  claim 21 , wherein the degree of opening decreases with a decrease in the airflow rate.  
   
   
       23 . The air-handling system of  claim 21 , wherein the discharge member has at least a larger degree of opening and a smaller degree of opening and is biased toward the smaller degree of opening.  
   
   
       24 . The air-handling system of  claim 21 , wherein the discharge member includes a resiliently flexible flap that moves in response to a change in the airflow rate.  
   
   
       25 . The air-handling system of  claim 21 , wherein the discharge member releases the air in a direction that varies in response to a change in the airflow rate.  
   
   
       26 . The air-handling system of  claim 21 , wherein the discharge member releases the air in a more upward direction when the airflow rate increases.  
   
   
       27 . The air-handling system of  claim 21 , further comprising a variable speed blower in fluid communication with the air duct, whereby the variable speed blower can vary the airflow rate.  
   
   
       28 . A method for maintaining the static pressure of air within an inflatable air duct, wherein the inflatable air duct conveys the air at an airflow rate that varies and releases the air through a discharge opening in the inflatable air duct, wherein the discharge opening is of a size that can vary, the method comprising: 
 reducing the airflow rate through the inflatable air duct; and    reducing the size of the discharge opening to maintain the static pressure above a certain threshold, thereby maintaining the inflatable air duct in an inflated state.    
   
   
       29 . The method of  claim 28 , wherein the step of reducing the size of the discharge opening is done automatically in response to the airflow rate being reduced.