In the light of bending of radiation tube in cracking furnace, analysis is done in detail to present related prevention, adjustment and correction measures.

The paper discovers the causes for the bending of water cooled grate of a double grate furnace based on the experimental results and solutions to this problem are also given.

The invention provides a bent-tube heating furnace for heating and softening when a straight tube is processed into a spiral tube by bending in energy-saving lamp manufacture.