Air sampling pump system

摘要

A pump is driven by a pump motor drive circuit that produces a series of pulse width modulated signals. A closed loop system is included to provide data indicative of any variation in the fluid flow. This is accomplished by using a Venturi located in the fluid flow path to create a pressure differential indicative of the fluid flow. A pressure transducer electronically measures this pressure differential which is then compared to a reference pressure differential indicative of the desired fluid flow. Any variation between the measured and desired fluid flow causes the pump motor drive circuit to vary the width of the pulses that are transmitted to the pump motor.