The structure and working principle of the syringe pump

The syringe pump is composed of a stepping motor and its driver, a screw rod and a bracket, etc., and has a reciprocating screw and a nut, so it is also called a screw pump. The nut is connected to the piston of the syringe, and the syringe contains the liquid medicine.


When working, the single-chip microcomputer system sends out control pulses to make the stepper motor rotate, and the stepper motor drives the screw to turn the rotary motion into a linear motion, pushes the piston of the syringe to inject infusion, and injects the liquid in the syringe into the human body.
By setting the rotation speed of the screw, it can adjust the advancing speed of the syringe needle, thereby adjusting the given drug dose. Generally, the injection delivery speed of the syringe pump is 0.1 ~ 99.9ml/h.

In layman's terms, the injection action of the syringe pump is completed by a DC motor.
The rotation of the DC motor is converted into linear motion through the transmission wheel and the transmission shaft, and the needle bolt is pushed to complete the injection.
The injection speed can be set by the operator through keyboard operation. After the syringe pump is started, the CPU provides the motor drive voltage by means of D/A conversion. The motor rotation detection circuit is a group of photoelectric coupling circuits, which generate a pulse signal through the rotation of the motor, and this pulse signal is fed back to the CPU, and the CPU controls the motor voltage according to this feedback to obtain the set speed.