In this thesis a new type of Mass Flow Controller (MFC) is designed, constructed and used. Whilst existing MFCs rely on either pressure loss or temperature rise measurements to estimate and control flows, this new device is based on measuring time, which is more easily and accurately monitored. The device adopts the 'bucket and stopwatch' method to deliver specific and constant masses at pre-set time intervals. By alerting the time intervals, the mass flow is precisely controlled.