A furnace system of a heating, ventilation, and/or air conditioning (HVAC) system includes a burner assembly having a burner enclosure configured to receive a fuel for ignition to generate heated combustion byproducts. The furnace system also includes a controller configured to detect a value associated with a wave signal transmitted through the burner enclosure and operate the furnace system based on a comparison between the value and a threshold value.

A method and an apparatus for protection of a combustion unit of a chemical process against over firing, the burner(s) of the combustion unit are limited by a fuel and duty limiter which limits the duty based on process feeds, combustion gas and fuel flows.

Example furnaces and methods related thereto are disclosed herein. In an embodiment, the furnace includes a burner box including at least one burner configured to combust a fuel/air mixture. In addition, the furnace includes a first blower including an inlet nozzle having an air inlet and fuel inlet. The inlet nozzle is configured such that operation of the first blower is to pull air and fuel into the inlet nozzle to produce the fuel/air mixture at a fuel/air ratio that is configured to produce flue products having less than 14 Nano-grams per Joule of nitrogen oxides when combusted. Operation of the first blower is configured to push the fuel/air mixture into the burner box. Further, the furnace includes a heat exchanger assembly fluidly coupled to the burner box through a vestibule, and a second blower configured to pull the flue products through the heat exchanger assembly.

A flame sensor assembly includes a flame sense rod and a flame sensor body. The flame sense rod includes a flame sensor end and a coupling end opposite the flame sensor. The flame sensor body defines a receptacle for receiving the coupling end of the flame sense rod, and includes an adjustable positioning bracket. The assembly also includes a wiring adapter for connecting the flame sensor body with a flame sense signal connector, and a mounting bracket adapted to mount the flame sensor body to a heating device with the flame sensor end of the flame sense rod positioned adjacent a flame of the heating device. Methods of replacing a flame sensor assembly for a heating device are also disclosed.

Example furnaces and methods related thereto include a burner box including at least one burner configured to combust a fuel/air mixture. In addition, the furnace includes a first blower including an inlet nozzle having an air inlet and fuel inlet. The inlet nozzle is configured such that operation of the first blower is to pull air and fuel into the inlet nozzle to produce the fuel/air mixture at a fuel/air ratio that is configured to produce flue products having less than 14 Nano-grams per Joule of nitrogen oxides when combusted. Operation of the first blower is configured to push the fuel/air mixture into the burner box. Further, the furnace includes a heat exchanger assembly fluidly coupled to the burner box through a vestibule, and a second blower configured to pull the flue products through the heat exchanger assembly.

An ultra wideband (UWB) combustion sensor detects presence or absence of combustion corresponding to an effect on a transmitted, time-gated pulse and detection by a presence or absence of charged particles associated with combustion. A combustion system includes a UWB combustion sensor. A method for operating a combustion system includes operation of a UWB combustion sensor.

A cooking appliance and method may generate one or more audible and/or visual indications to a user of various gas burner states during the operation of a gas burner, including, for example, states that are associated with different types of ignition operations, such as initial ignition operations, programmed re-ignition operations and/or flame loss re-ignition operations and/or states that are associated with ignition operations, normal operating conditions, and/or failure conditions.

Apparatus and methods for a gas furnace are disclosed. The gas furnace includes a variable combustion control which monitors the temperature of the burner and modifies one of the amount of combustion air supplied and the amount of gas fuel supplied to the mixing chamber. The described systems can dynamically accommodate differences in air quality and gas fuel supply to provide an optimum BTU output irrespective of differences in geographic location of usage. The gas furnace can include a dynamic response unit which predicts an optimum rate of heating to maintain a target room temperature, thereby preventing unnecessary shut down and costly re-ignition sequences, and maintaining the gas furnace at an optimum BTU output level.

A method of operating a multi-ring gas burner includes sending a spark to a first ring of the multi-ring burner. After sending the spark to the first ring, the method determines a flame status of the first ring and adjusts a position of an electronic gas valve connected to a second ring of the multi-ring gas burner based on the determined flame status of the first ring.

A direct reduction plant is disclosed. The direct reduction plant includes an oxygen injection system, a reformer, and a shaft furnace. The oxygen injection system includes an oxygen injection reactor and a main oxygen burner. The oxygen injection reactor is adapted to receive a gas mixture. The main oxygen burner is adapted to increase a temperature of the gas mixture by burning a mixture of fuel and oxygen fed to the main oxygen burner. The reformer is adapted to reform the gas mixture with the increased temperature. The shaft furnace is adapted to reduce iron ore using the reformed gas mixture.