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. 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. “S” curve type products optional, which optimized flow curve can make the heat pump unit stable heating operation in low temperature environment with small opening, while meeting the needs of high temperature refrigeration and low temperature defrosting.