Method of operating a safety vacuum release system
View Patent ↗Embodiments of the invention provide a method of operating a safety vacuum release system (SVRS) with a controller for a pump including a motor. The method can include measuring an actual power consumption of the motor necessary to pump water and overcome losses. The method can include triggering the SVRS when a dynamic suction blockage is identified in order to shut down the pump substantially immediately. The SVRS can also be triggered when a dead head condition is identified based on the actual power consumption.
1. A method of operating a safety vacuum release system with a controller for a pump including a variable speed motor, the method comprising:
measuring an actual power consumption of the motor necessary to pump water and overcome losses;
filtering the actual power consumption with a fast low-pass filter to obtain a current power consumption;
incrementing an absolute counter value if at least one of the actual power consumption and the current power consumption is greater than a threshold power curve;
identifying a dead head condition if the absolute counter value exceeds an absolute counter threshold value; and
triggering the safety vacuum release system when the dead head condition is identified in order to shut down the pump substantially immediately.
2. The method of claim 1 and further comprising:
calculating an absolute power variation based on the actual power consumption;
incrementing a dynamic counter value if the absolute power variation is negative;
calculating a relative power variation based on the actual power consumption;
identifying a dynamic suction blockage if at least one of the dynamic counter exceeds a dynamic counter threshold value and the relative power variation is below a negative threshold.
3. The method of claim 2 and further comprising:
filtering the actual power consumption with a slow low-pass filter to obtain a lagged power consumption; and
calculating the absolute power variation by subtracting the lagged power consumption from the current power consumption.
4. The method of claim 3 wherein the fast low-pass filter has a time constant of about 200 milliseconds and the slow low-pass filter has a time constant of about 1400 milliseconds.
5. The method of claim 3 wherein the actual power consumption is filtered for about 2.5 seconds.
6. The method of claim 3 wherein the absolute power variation is updated about every 20 milliseconds to provide dynamic suction blockage detection.
7. The method of claim 3 and further comprising calculating a relative power consumption by dividing the absolute power variation by the current power consumption.
8. The method of claim 1 wherein the absolute counter threshold value is 10.
9. The method of claim 1 and further comprising restarting the pump after a time period has elapsed.
10. The method of claim 1 and further comprising preventing the pump from being restarted if the dead head condition is identified again.
11. The method of claim 2 wherein the dynamic counter threshold value is 15.