... 2.long service life 3.nice appearance air heat exchanger technical requirements1,heat exchanger is made of carbon steel tune of φ18×2.0 ... :300°C.4,making standard:GB/T14296-93.5,the heat exchanger is made of mult flow path,6,connector: φ48X3.07 ... ,sheet above and below is carbon steel of 2mmTHX air heat exchanger for aquatic feed drying