Internally Grooved Tube Heat Exchanger is mainly used under the condition that boiling heat transfer happens inside the tube. The material of internally grooved tubes can be carbon steel, chromium-molybdenum steel, stainless steel, copper and falcial alloy, etc. The inner surface of the pipe wall has linear or helical grooves, and the outer surface of the tube wall is smooth, corrugated or grooved, which increases the number of boiling evaporation cores, enhances the boiling heat transfer coefficient. The heat transfer coefficient of Internally Grooved Tubes is 1.5 to 3.5 times of that of normal tubes, while the coefficient of resistance is the same as that of normal pipe, and thus the tubes are specially advantageous for application on vertical heat exchangers.