uf-20000 series is the linear-cam and dual plunger type pump with the AC servo motor to be used for column packing and high pressure preparative works.
For column packing, the constant pressure flow mode is generally used. When the pump starts to work, it runs at a constant flow rate.
When the pressure reaches its maximum setting, the maximum pressure is maintained with the flow rate down. After the column packing is finished, the flow rate increases to the set point so that the washing liquid flows at a constant flow rate.