Variable exhaust fan for oven

Abstract

Various embodiments disclosed herein provide for a variable exhaust oven that can modify an exhaust rate of an exhaust fan of the oven based on the firing rate or burn rate of a burner of the oven while still complying with safety regulations. By reducing the exhaust rate of the variable exhaust oven when the burn rate decreases, the variable exhaust oven can save costs by reducing the thermal energy lost due to unnecessary removal of air from the oven, and can lower electrical costs by operating the exhaust fan at a lower speed. The burn rate of the burner is controlled based on a temperature within the variable exhaust oven. A flame safety controller, or other controller, of the variable exhaust oven can control the exhaust rate of the exhaust fan (fan speed and/or damper adjustment) based on the burn rate of the burner.

What is claimed is: 
     
         1 . A variable exhaust oven, comprising:
 a flame safety controller configured to
 receive an input signal from a temperature controller, the input signal specifies a temperature within the variable exhaust oven, a burn rate of a burner of the variable exhaust oven is controlled based on the temperature within the variable exhaust oven, the burn rate of the burner being controlled by a first control signal; and 
 control an exhaust rate of an exhaust fan of the variable exhaust oven based on the burn rate of the burner, the exhaust rate of the exhaust fan being controlled by a second control signal transmitted by the flame safety controller. 
   
     
     
         2 . The variable exhaust oven of  claim 1 , wherein the exhaust rate of the exhaust fan is further based on a second input signal from a gas flow meter that specifies a gas flow rate to the burner. 
     
     
         3 . The variable exhaust oven of  claim 1 , wherein the first control signal is transmitted to a fuel supply valve, and wherein the first control signal controls a fuel supply valve setting of the fuel supply valve. 
     
     
         4 . The variable exhaust oven of  claim 1 , wherein the exhaust fan comprises a variable frequency drive. 
     
     
         5 . The variable exhaust oven of  claim 4 , wherein the second control signal is transmitted to the variable frequency drive, and wherein the variable frequency drive is controlled based on the second control signal to control the exhaust rate of the exhaust fan. 
     
     
         6 . The variable exhaust oven of  claim 1 , wherein the second control signal controls an adjustment of a damper of the exhaust fan to control the exhaust rate of the exhaust fan. 
     
     
         7 . The variable exhaust oven of  claim 1 , wherein the exhaust rate is proportional to the burn rate. 
     
     
         8 . A method to control a variable exhaust oven, comprising:
 receiving, at a flame safety controller, an input signal from a temperature controller, the input signal specifies a temperature within the variable exhaust oven a burn rate of a burner of the variable exhaust oven being controlled based on the temperature within the variable exhaust oven, the burn rate of the burner being controlled by a first control signal; and   controlling an exhaust rate of an exhaust fan of the variable exhaust oven based on the burn rate of the burner, the exhaust rate of the exhaust fan being controlled by a second control signal transmitted by the flame safety controller.   
     
     
         9 . The method of  claim 8 , wherein the exhaust rate of the exhaust fan is further based on a second input signal from a gas flow meter that specifies a gas flow rate to the burner. 
     
     
         10 . The method of  claim 8 , wherein the first control signal is transmitted to a fuel supply valve, and wherein the first control signal controls a fuel supply valve setting of the fuel supply valve. 
     
     
         11 . The method of  claim 8 , wherein the exhaust fan comprises a variable frequency drive. 
     
     
         12 . The method of  claim 11 , wherein the second control signal is transmitted to the variable frequency drive, and wherein the variable frequency drive is controlled based on the second control signal to control the exhaust rate of the exhaust fan. 
     
     
         13 . The method of  claim 8 , wherein the second control signal controls an adjustment of a damper of the exhaust fan to control the exhaust rate of the exhaust fan. 
     
     
         14 . The method of  claim 8 , wherein the exhaust rate is proportional to the burn rate. 
     
     
         15 . A variable exhaust oven, comprising:
 a burner;   a fuel supply valve configured to control a flow of fuel supplied to the burner;   an exhaust fan configured to remove exhaust air from the variable exhaust oven, wherein the exhaust fan has a plurality of exhaust fan settings corresponding to different exhaust rates;   a temperature controller configured to transmit an input signal that specifies a temperature within the variable exhaust oven; and   a flame safety controller configured to:
 receive the input signal from the temperature controller; 
 transmit a first control signal to the fuel supply valve to control a burn rate of the burner, the burn rate being controlled based on the temperature within the variable exhaust oven; and 
 transmit a second control signal to the exhaust fan to control an exhaust rate of the exhaust fan, the exhaust rate being controlled based on the burn rate of the burner. 
   
     
     
         16 . The variable exhaust oven of  claim 15 , wherein the exhaust fan comprises a variable frequency drive, and wherein the variable frequency drive is controlled based on the second control signal to control the exhaust rate of the exhaust fan. 
     
     
         17 . The variable exhaust oven of  claim 16 , wherein the exhaust fan further comprises a damper, and wherein an adjustment of the damper and the variable frequency drive are both controlled based on the second control signal to control the exhaust rate of the exhaust fan. 
     
     
         18 . The variable exhaust oven of  claim 15 , wherein the temperature controller detects the temperature within the variable exhaust oven based on a temperature signal received from a thermocouple within the variable exhaust oven. 
     
     
         19 . The variable exhaust oven of  claim 15 , wherein the exhaust fan comprises a damper, and wherein an adjustment of the damper is controlled based on the second control signal to control the exhaust rate of the exhaust fan. 
     
     
         20 . The variable exhaust oven of  claim 15 , wherein the exhaust rate is proportional to the burn rate.