Air preheaters, Air Preheater tubes are essentially a type of Heat exchanger tubes use for the purpose of heating air which is further used in other applications like Boilers, Dryers etc. An air preheater (APH) is a general term used to describe any device designed to heat air before another process (for example, combustion in a boiler ) with the primary objective of increasing the thermal efficiency of the process . The air passing through the Air Pre Heater is heated by allowing the air to flow on the Outer Surface of the tubes which have a highly heated fluid flowing inside through them. The heat is exchanged over the surface of these tubes and which in turn raises the temperature of the Air flowing over it. The heat transfer can further be improved by use of finned tubes(increasing the contact surface area) .

Air preheaters, Air Preheater tubes are essentially a type of Heat exchanger tubes use for the purpose of heating air which is further used in other applications like Boilers, Dryers etc. An air preheater (APH) is a general term used to describe any device designed to heat air before another process (for example, combustion in a boiler ) with the primary objective of increasing the thermal efficiency of the process . The air passing through the Air Pre Heater is heated by allowing the air to flow on the Outer Surface of the tubes which have a highly heated fluid flowing inside through them. The heat is exchanged over the surface of these tubes and which in turn raises the temperature of the Air flowing over it. The heat transfer can further be improved by use of finned tubes(increasing the contact surface area) .