DBF series electronic expansion valves are especially designed for commercial air conditioning and heat pump. The balanced flow port design is adopted to realize the accurate bidirectional adjustment of refrigerant flow and the reverse opening pressure difference can reach to 3.5MPa. The wide adjustment range can be accurately matched with the actual load of the system, so that the system can operate in the best working condition, so as to achieve accurate temperature control, rapid cooling and heating or defrosting and reduce energy consumption.