Micro precise quantifying device with constant flow velocity

The invention relates to the technical field of hydraulic systems, and provides a constant-flow-rate micro-precise quantifying device which comprises a rotary cutting valve, the rotary cutting valve comprises a valve body and a valve element, the valve body is provided with a main flow channel and a plurality of branch flow channels, the valve element is rotatably arranged in the valve body, and the valve element is used for communicating the main flow channel with the different branch flow channels; a pressure sensor communicating with the main flow channel is arranged in the valve body and used for detecting the pressure in the main flow channel. The pressure sensor is arranged in the valve body to detect the pressure in the main flow channel, whether a liquid path is switched correctly or not can be judged according to the pressure of the main flow channel, the needed cost is reduced, the installation space of the sensor is saved, and a closed-loop control loop is formed in cooperation with the controller