The advantage of proportional pinch valves is the need for clean and sterile high-precision flow control to produce more controllable pinching force. Each valve includes a stepper motor that receives PWM square wave pulse from the controller and converts each pulse into a stepper motor that rotates at 1.8-degre. The stepper motor is a high-precision lead screw produced in Japan with a linear motion with a step rotation of 0.0127 mm. Tubing hardness of 50 - 75 Shore A is recommended.
