Blower assembly with closed-loop feedback

Abstract

A closed-loop blower includes a blower assembly having a motorized fan that draws ambient air in through an inlet and exhausts air out an outlet. A control circuit is coupled to the motorized fan and a pressure sensing device near the outlet measures pressure of the exhaust air and generates a pressure signal. The control circuit receives the pressure signal and adjusts the speed of the motorized fan to obtain a desired pressure at the outlet. Temperature and motor speed readings may also be detected and input to the control circuit to adjust the speed of the motor and thus the fan. An input device may be provided to adjust the desired pressure values or the control circuit may be programmed with the desired value.

What is claimed is:  
     
         1 . A closed-loop blower, comprising: 
 a blower assembly having a motorized fan that draws ambient air in through an inlet and exhausts air out an outlet;    a control circuit coupled to said motorized fan;    a pressure sensing device near said outlet to measure pressure of the exhaust air, said pressure sensing device generating a pressure signal; and    said control circuit receiving said pressure signal and adjusting the speed of said motorized fan to obtain a desired pressure at said outlet.    
     
     
         2 . The blower according to  claim 1 , further comprising: 
 a temperature sensing device associated with said blower assembly and generating a temperature signal; and    said control circuit receiving said temperature signal to adjust said pressure signal and adjust the speed of said motorized fan to obtain the desired pressure at said outlet.    
     
     
         3 . The blower according to  claim 2 , further comprising: 
 at least one Hall effect switch coupled to said motorized fan to generate a speed signal; and    said control circuit receiving said speed signal to adjust the speed of said motorized fan.    
     
     
         4 . The blower according to  claim 1 , further comprising: 
 a temperature sensing device associated with said blower assembly and generating a temperature signal;    at least one Hall effect switch coupled to said motorized fan to generate a speed signal; and    said control circuit receiving said temperature, pressure and speed signals to adjust the speed of said motorized fan to obtain the desired pressure output.    
     
     
         5 . The blower according to  claim 4 , further comprising: 
 a second pressure sensing device, not directly associated with the blower to measure an end-use pressure signal;    said control circuit receiving said pressure signal and said end-use pressure signal to determine a differential pressure; and    said control circuit adjusting the speed of said motorized fan to obtain a desired differential pressure.    
     
     
         6 . The blower according to  claim 1 , further comprising: 
 an input device for sending desired pressure value to said control circuit.    
     
     
         7 . A method for generating a desired pressure value from a blower assembly that includes a motorized fan that draws in ambient air through an inlet and exhausts air out an outlet, the method comprising: 
 inputting a set pressure value to a control circuit;    positioning a pressure sensing device near the outlet;    generating a pressure signal by said pressure sensing device;    receiving said pressure signal in said control circuit; and    adjusting the speed of the motorized fan by said control circuit depending upon the value of said pressure signal to match said set pressure value.    
     
     
         8 . The method according to  claim 7 , further comprising: 
 measuring a temperature value near the blower assembly;    generating a temperature signal representative of said temperature value;    receiving said temperature signal in said control circuit; and    adjusting said pressure signal based upon the value of said temperature signal.    
     
     
         9 . The method according to  claim 8 , further comprising: 
 coupling at least one Hall effect switch to the motorized fan to generate a speed signal;    receiving said speed signal in said control circuit; and    adjusting the speed of said motorized fan based upon said pressure, temperature and speed signals.    
     
     
         10 . The method according to  claim 7 , further comprising: 
 positioning a second pressure transducer away from said blower but within the exhaust air flow;    measuring a second pressure value at said second pressure transducer to generating an end-use pressure signal;    receiving said end-use pressure signal and said pressure signal in said control circuit to determine a differential pressure value; and    adjusting the speed of the motorized fan by said control circuit to match said differential pressure value with said set pressure value.