| 摘要 |
<p>A metering pump (18) incorporates a method of relating inner loop current to a pump output pressure. Pump/motor speed, which correlates to current, is measured and controlled by a system controller (12). System temperature is also measured by the system controller (12). The controller (12) monitors the measured system temperature and provides for compensation for system losses, including inductive-resistive (IR) losses, and for density and viscosity shifts, within a pre-determined allowable system temperature operating range. An initial system calibration is conducted using a "shut-off" test, where the metering pump is run at a very slow known speed while the system is shut-off. After initial start-up, a health-monitoring feature continues to monitor the current as an indicator of pump performance and continuously adjusts a motor speed to maintain a desired level of pump performance. This provides the system with the ability to compensate for performance losses, including performance losses due to variations in operating conditions, and to compensate for pump wear.</p> |
