Digital high turndown burner

Abstract

A gas burner system for a heating device includes a burner, a valve assembly for controlling a flow of fuel to the burner, a blower assembly for directing air to the burner, and a control system. The burner includes one or more burner plates for facilitating the mixture of air and fuel to be combusted in a combustion chamber. The control system is configured to independently control the valve assembly and the blower assembly according to a control profile, for generating a plurality of air/fuel mixtures each configured for operation of the burner at a different firing rate. By mapping the characteristics of both the gas valve and the combustion blower independently, the burner system is assured of operating at the proper air/fuel mixture over a very wide range of firing rates, with a turndown ratio of 30:1 or greater, and within ANSI safety and performance standards.

1 . A gas burner system for a heating device, said system comprising:
 a burner having at least one burner plate for facilitating the mixture of air and fuel to be combusted in a combustion chamber;   a valve assembly for controlling a flow of fuel to the burner;   a blower assembly for directing air to the burner; and   a control system that independently controls the valve assembly and the blower assembly according to a control profile, said control profile mapping an operational range of the valve assembly to an operational range of the blower assembly for generating a plurality of air/fuel mixtures each for operation of the burner at a different firing rate.   
   
   
       2 . The system of  claim 1 , wherein:
 the valve assembly is controlled according to a valve assembly control value, and the blower assembly is controlled according to a blower assembly control value; and   the control profile maps a range of possible valve assembly control values to a range of corresponding blower assembly control values, each corresponding blower assembly control value and valve assembly control value establishing one of said plurality of air/fuel mixtures.   
   
   
       3 . The system of  claim 2 , wherein the control system determines a corresponding valve assembly control value and blower assembly control value from the control profile by applying a control signal to the control profile, said control signal relating to a desired heat output rate of the gas burner system. 
   
   
       4 . The system of  claim 3 , wherein:
 the valve assembly comprises a ball valve for controlling the flow of fuel into the burner, and a valve actuator for controlling the ball valve based on a first operational signal received from the control system, said first operational signal corresponding to the valve assembly control value determined by the control system; and   the blower assembly comprises a motor, a fan driven by the motor, and a blower control circuit configured to run the motor based on a second operational signal received from the control system, said second operational signal corresponding to the blower assembly control value determined by the control system.   
   
   
       5 . The system of  claim 1 , wherein each of the plurality of air/fuel mixtures generated according to the control profile is configured for combustion, in conjunction with the burner and combustion chamber, within ANSI regulatory safety and performance parameters for indirect-fired gas burners. 
   
   
       6 . The system of  claim 1 , wherein the burner is a single burner unit, and the control system is configured for operation of the single burner unit at a turndown ratio of at least 30:1. 
   
   
       7 . The system of  claim 6 , wherein each of the plurality of air/fuel mixtures generated according to the control profile is configured for combustion, in conjunction with the single burner unit and combustion chamber, within ANSI regulatory safety and performance parameters for indirect-fired gas burners. 
   
   
       8 . The system of  claim 1 , wherein:
 the valve assembly comprises a ball valve for controlling the flow of fuel into the burner, and a valve actuator for controlling the ball valve based on a first operational signal received from the control system,   the blower assembly comprises a motor, a fan driven by the motor, and a blower control circuit configured to run the motor based on a second operational signal received from the control system; and   wherein said first and second operational signals being determined by the control system by applying a control signal to the control profile, said control signal relating to a desired heat output rate of the gas burner system   
   
   
       9 . The system of  claim 8 , wherein:
 the control system is operably interfaced with an HVAC controller that controls the heating device, said HVAC controller providing the control signal to the control system.   
   
   
       10 . The system of  claim 9 , wherein the control system is imbedded in the HVAC controller. 
   
   
       11 . The system of  claim 1 , wherein the burner comprises at least two burner plates, said burner plates being arranged in a generally V-shaped configuration. 
   
   
       12 . A heating device comprising:
 a combustion chamber;   a housing in fluid communication with the combustion chamber;   a burner disposed in the housing, said burner comprising at least one burner plate for facilitating the mixture of air and fuel to be combusted in the combustion chamber;   a blower assembly connected to the housing for directing air into the interior of the housing;   a valve assembly connected to the housing for controlling a flow of fuel into the burner; and   a control system that independently controls the valve assembly and the blower assembly according to a control profile, said control profile mapping an operational range of the valve assembly to an operational range of the blower assembly for generating a plurality of air/fuel mixtures each for operation of the burner at a different firing rate.   
   
   
       13 . The system of  claim 12 , wherein each of the plurality of air/fuel mixtures generated according to the control profile is configured for combustion, in conjunction with the burner and combustion chamber, within ANSI regulatory safety and performance parameters for indirect-fired gas burners. 
   
   
       14 . The system of  claim 12 , wherein the burner is a single burner unit, and the control system is configured for operation of the single burner unit at a turndown ratio of at least 30:1. 
   
   
       15 . The system of  claim 14 , wherein each of the plurality of air/fuel mixtures generated according to the control profile is configured for combustion, in conjunction with the single burner unit and combustion chamber, within ANSI regulatory safety and performance parameters for indirect-fired gas burners. 
   
   
       16 . A heating device comprising:
 a combustion chamber;   a housing in fluid communication with the combustion chamber;   a single-burner unit disposed in the housing, said single-burner unit having at least one burner plate for facilitating the mixture of air and fuel to be combusted in the combustion chamber;   a blower assembly connected to the housing for directing air into the interior of the housing, said blower assembly being controlled according to a first operational signal;   a valve assembly connected to the housing for controlling a flow of fuel to the single-burner unit, said valve assembly being controlled according to a second operational signal; and   a control system that independently controls the valve assembly and the blower assembly by generating the first and second operational signals, respectively, wherein the control system determines the first and second operational signals by applying a control signal, indicative of a desired heat output level of the heating device, to a control profile, said control profile mapping an operational range of the valve assembly to an operational range of the blower assembly for generating a plurality of air/fuel mixtures each for operation of the burner at a different firing rate;   wherein a ratio of the highest of said firing rates to the lowest of said firing rates is at least 30:1; and   wherein each of the plurality of air/fuel mixtures generated according to the control profile is configured for combustion, in conjunction with the single-burner unit and combustion chamber, within ANSI regulatory safety and performance parameters for indirect-fired gas burners.   
   
   
       17 . A method of controlling a gas burner, said method comprising the steps of:
 determining a gas valve control signal and an air blower control signal by cross-referencing information associated with a received control signal to a gas burner control profile, said information relating to a desired heat output of the gas burner, wherein the control profile correlates a range of gas valve control signals to a range of air blower control signals for operation of the gas burner at a turndown ratio of at least 30:1;   outputting the gas valve control signal to a gas valve unit, for controlling the gas output of the gas valve; and   outputting the air blower control signal to an air blower unit, for controlling the air output of the air blower unit, said gas output and air output being combined for combustion in the gas burner.