FlowTrac-II is an intelligent, versatile system composed of a flow pump and a computer with monitor. The flow pump, which regulates pressure and volume in a test cell, houses a high speed, precision micro stepper motor that moves a piston in a water-filled cylinder. An embedded control board with a dedicated CPU uses readings from the pressure transducer mounted at the end of the cylinder to determine what signals should be sent to the stepper motor. The number of motor steps is used to compute volume change. Two-way solenoid valves are used to control the direction of flow to the cell or sample (output valve), and the manual fill/drain operation (supply valve). FlowTrac-II is capable of maintaining a desired pressure within 0.35 kPa (0.05 psi) while monitoring volume changes within 0.001 cc. Pressure increments may increase and decrease in any pattern by any amount (without exceeding the system’s limits) as specified by the user, even while a test is in progress.

The FlowTrac-II system requires no special skills to operate, other than those used in conventional testing. A person familiar with soil testing can learn to use the system confidently within a few days. Familiarity with using Windows can significantly reduce the learning time.