An expander that transfers energy in response to changes in velocity energy as the gas expands. Such expanders are available in single and double, vertical and horizontal, impulsive and reactionary. Single-stage centripetal runoff reaction
   Expander
The external work that is transmitted is absorbed by the generator, blower or oil brake. It is similar to a single-stage centrifugal compressor, but has a (tunable vane) deflector for adjusting the intake air volume. Low-speed bearings are forcibly lubricated with oil, and high-speed gas bearings are used. Turbine expander due to nozzle loss, impeller loss, residual speed loss, wheel friction loss, leakage loss, turbulent loss and external heat intrusion loss, the general adiabatic efficiency is: medium pressure expander 65 ~ 75%, low pressure expander 75 to 85%. In the 1960s, liquid-filled expanders were made, mostly used in natural gas separation equipment.