Fan control system

Abstract

There is described a method for controlling an exhaust system having at least two fans, a plenum chamber interconnecting the at least two fans, and a bypass air damper in the plenum chamber to allow bypass air to flow therethrough, the method comprising: monitoring pressure in the plenum chamber of the system; detecting a variation of the pressure beyond a predetermined range; and regulating operation of the exhaust system in response to the pressure variation in order to return the pressure to within the predetermined range.

1 . A method for controlling an exhaust system having at least two fans, a plenum chamber interconnecting said at least two fans, and a bypass air damper in said plenum chamber to allow bypass air to flow therethrough, the method comprising: 
 monitoring pressure in said plenum chamber of said system;    detecting a variation of said pressure beyond a predetermined range; and    regulating operation of said exhaust system in response to said pressure variation in order to return said pressure to within said predetermined range.    
   
   
       2 . A method as claimed in  claim 1 , wherein said regulating comprises energizing one of said at least two fans.  
   
   
       3 . A method as claimed in  claim 1 , wherein said regulating comprises de-energizing one of said at least two fans.  
   
   
       4 . A method as claimed in  claim 3 , wherein said de-energizing comprises timing closing of an isolation air damper associated with said fan with said de-energizing of said fan to minimize an overall pressure drop in said plenum chamber.  
   
   
       5 . A method as claimed in  claim 1 , wherein said regulating comprises modulating said bypass air damper to aid in returning said pressure to within said predetermined range.  
   
   
       6 . A method as claimed in  claim 1 , wherein said regulating comprises monitoring a standby fan for time of inactivity, and replacing an active fan with said standby fan after a predetermined time of inactivity.  
   
   
       7 . A method as claimed in  claim 6 , wherein said replacing a fan comprises timing opening and closing of an isolation damper associated with said fan with energizing and de-energizing said fan to minimize an overall pressure drop in said plenum chamber.  
   
   
       8 . An exhaust system assembly comprising: 
 at least two fans;    a plenum chamber having a bypass air damper therein for bypassing air, said plenum chamber interconnecting said at least two fans and having a pressure sensor therein for sensing and detecting a pressure; and    a control module receiving said pressure detected in said plenum chamber and adapted to regulate operation of said at least two fans when said pressure has varied beyond a predetermined range in order to restore said pressure to within said range.    
   
   
       9 . An exhaust system as claimed in  claim 8 , wherein said control module is adapted to energize and de-energize individual fans in response to said pressure variation.  
   
   
       10 . An exhaust system as claimed in  claim 9 , wherein said control module times opening and closing of an isolation damper associated with said fan with energizing and de-energizing of said fan to minimize an overall pressure drop in said plenum chamber.  
   
   
       11 . An exhaust system as claimed in  claim 8 , wherein said control module modulates said bypass air damper to aid in returning said pressure to within said predetermined range.  
   
   
       12 . An exhaust system as claimed in  claim 8 , wherein said control module monitors a standby fan for hours of inactivity, and replaces an active fan with said standby fan after a predetermined time of inactivity.  
   
   
       13 . An exhaust system as claimed in  claim 12 , wherein said control module times opening and closing of an isolation damper associated with said fan with energizing and de-energizing of said fan to minimize an overall pressure drop in said plenum chamber.  
   
   
       14 . In a computer network enabling communication between a plurality of computers, a method comprising: 
 providing at least one sensing device in a fan exhaust system;    monitoring at least one parameter of said system using said at least one sensing device;    comparing said at least one parameter to a predetermined tolerance level; and    sending an alarm signal through said network to a remote computer when said at least one parameter does not meet said predetermined tolerance level.    
   
   
       15 . A method as claimed in  claim 14 , wherein said alarm signal is an email message.  
   
   
       16 . A method as claimed in  claim 14 , wherein said at least one sensing device is a vibration transducer, and said at least one parameter is vibration of a fan.  
   
   
       17 . A method as claimed in  claim 14 , wherein said at least one sensing device is a pressure sensor, and said at least one parameter is pressure.