Tube heating furnace is one of the important devices in oil refining and chemical production. Its task is to heat the raw material oil to a certain temperature to ensure the smooth progress of the next process.5-AXIS CNC TOOL GRINDING MACHINE – TG560 & TG580 Therefore, the outlet temperature of feedstock oil is often selected as the controlled parameter, and the fuel flow rate is the control variable. In the temperature control system, the disturbances that affect the outlet temperature of feedstock oil include feedstock oil flow rate, feedstock inlet temperature, fuel pressure, and fuel pressure.6-AXIS FIVE-LINKAGE CNC TOOL GRINDER -TG680 The system controls the opening of the fuel valve according to the temperature change of the raw oil outlet, and controls the crude oil outlet temperature at a specified value by changing the fuel flow rate. It is a simple control system. Martensitic stainless steel quenching vacuum heat treatment process After the fuel flow changes through three volumes, the outlet temperature of the raw material oil changes. The time constant of this channel is very large, about 15 minutes, and the reaction is slow. The temperature regulator is controlled according to the deviation between the outlet temperature of the raw material oil and the set value.