Method for Heating an Industrial Furnace and a Heating Apparatus for Carrying Out Said Method
The invention relates to a method for heating an industrial furnace, wherein, apart from heating gas, a combustible process gas is also fed to a burner arrangement ( 9 ) of the industrial furnace for heating an interior space in the course of a heat treatment cycle. In order to optimize the use of the combustible process gas for the heating of the industrial furnace, the heat treatment cycle is split up into a plurality of process phases, wherein the supply of the process gas to the burner arrangement ( 9 ) is regulated depending on the process phase. Furthermore, the invention relates to a heating device ( 8 ) for an industrial furnace, as well as an industrial furnace that includes the heating device.
1 . A method for heating an industrial heat treating furnace comprising the steps of supplying a combustible process gas to a burner arrangement ( 9 ) of the industrial heat treating furnace and burning the combustible process gas to produce heating of an interior space of the industrial heat treating furnace during a heat treatment cycle, wherein the heat treatment cycle is divided into a plurality of process phases and the step of supplying the combustible process gas is regulated according to conditions in the industrial heat treating furnace during each of the process phases.
2 . The method according to claim 1 , wherein during the step of supplying the process gas to the burner arrangement ( 9 ), at least one burner ( 10 , 11 ) of the burner arrangement ( 9 ) is supplied with the process gas.
3 . The method according to claim 2 , wherein during the step of supplying the process gas to the burner arrangement ( 9 ), a plurality of burners ( 10 , 11 ) of the burner arrangement ( 9 ) are supplied with the process gas individually one after the other or in groups during a heat treatment cycle.
4 . The method according to claim 3 , wherein during the step of supplying the process gas to the burner arrangement ( 9 ), the plurality of burners ( 10 , 11 ) of the burner arrangement ( 9 ) are supplied with the process gas in pairs.
5 . The method according to claim 1 , comprising the step of supplying heating gas to at least one burner ( 10 , 11 ) of the burner arrangement ( 9 ) as part of the heat treatment cycle and/or with the process gas.
6 . The method according to claim 1 comprising the steps of:
supplying only heating gas to the burner arrangement ( 9 ) in a first process phase of the heat treatment cycle in which the industrial furnace is charged with a batch ( 6 ) and the interior space is then heated to a target temperature,
performing the step of supplying the process gas to the burner arrangement ( 9 ) in at least one following process phase of the heat treatment cycle in which heating-up is continued from the target temperature to a process holding temperature or in which the furnace temperature is held at the given process temperature, and then
supplying heating gas alone to the burner arrangement in a concluding process phase of the heat treatment cycle in which the batch ( 6 ) is quenched and then removed from the industrial furnace.
7 . The method according to claim 1 , wherein the step of supplying the combustible process gas comprises the step of conveying the combustible process gas via a furnace pressure-dependent frequency-regulated blower ( 16 ).
8 . A heating apparatus ( 8 ) for an industrial furnace comprising:
a gas line ( 14 ) connected to a process waste-gas outlet ( 13 ) of an industrial furnace or to a temporary process gas storage facility and to a burner arrangement ( 9 ) whereby a process gas can be conveyed from the process waste-gas outlet ( 13 ) or the temporary storage facility to the burner arrangement ( 9 ); and
a gas flow control apparatus connected to the gas line ( 14 ) by which flow of the process gas to the burner arrangement ( 9 ) can be regulated depending on a process phase during a heat treatment cycle performed in the industrial furnace.
9 . The heating apparatus according to claim 8 wherein the gas flow control apparatus comprises at least one valve ( 17 ).
10 . The heating apparatus according to claim 9 wherein the valve ( 17 ) is a solenoid valve and the gas flow control apparatus comprises a controller ( 18 ) connected to the solenoid valve for actuating the solenoid valve.
11 . The heating apparatus according to claim 9 further comprising a variable speed blower ( 16 ) provided in the line ( 14 ) downstream of the valve ( 17 ).
12 . The heating apparatus according to claim 11 wherein the valve ( 17 ) is a solenoid valve and the gas flow control apparatus comprises a controller ( 18 ) connected to the solenoid valve for actuating the solenoid valve and connected to the variable speed blower ( 16 ) for adjusting the speed of the blower in response to the gas pressure inside the industrial furnace.
13 . An industrial furnace comprising:
a housing ( 1 ) that defines a main chamber ( 3 ) and a pre-chamber ( 4 );
a process-waste gas outlet ( 13 ) provided in the housing ( 1 ) so as to provide a gas flow channel from the pre-chamber ( 4 ) through the housing; and
a heating apparatus ( 8 ) comprising:
a gas line ( 14 ) connected to the process waste-gas outlet ( 13 ) and to a burner arrangement ( 9 ) whereby a process gas can be conveyed from the process waste-gas outlet ( 13 ) to the burner arrangement ( 9 ); and
a gas flow control apparatus provided in the line ( 14 ) by which flow of the process gas to the burner arrangement ( 9 ) can be automatically regulated depending on a process phase during a heat treatment cycle performed in the industrial furnace.
14 . The industrial furnace according to claim 13 wherein the burner arrangement ( 9 ) comprises at least one radiant tube burner ( 10 , 11 ) that is configured as a duplex burner that can be operated with a heating gas and/or with the process gas.