Control of pump outlet pressure
Thread Content
The unit is equipped with a water pump for supplying water; it has a head of 60 meters and features a frequency conversion system as well as a pressure control circuit. During automatic operation, 80% frequency conversion can maintain the pressure at 0.4 MPa. But there is concern that someone might close the pump’s self-circulation manual valve, or that the personnel in the control room might suddenly increase the frequency of operation to a high level, resulting in the pump outlet pressure exceeding 0.4 MPa. In such cases, the flow rate of water entering the equipment will exceed the range of the flow meter, leading to inaccurate feeding. Should the pump’s outlet pressure be set directly to 0.6 MPa, and then should the manual valve for adding water to the equipment be adjusted accordingly?
It’s purely a matter of how to manage it.
The pump outlet valve is fully open; the equipment inlet valve is adjusted to a smaller setting. What’s the use of installing an inverter?
“Someone closed the pump’s self-circulation manual valve, or the personnel in the control room suddenly set the frequency conversion value very high – this kind of issue should be resolved through proper management; it’s a simple problem. It is not advisable to change the normal operating characteristics of the equipment. Pump motors cannot have their flow rate controlled by inlet valves, which makes them prone to cavitation and results in unstable operation.
“Someone closed the pump’s self-circulation manual valve by accident, or the personnel in the control room suddenly set the frequency conversion value very high. ” ------------------------------------------------------------------------------------ The pump’s self-circulation manual valve should be sealed to prevent unauthorized operation by staff! The personnel in the control room suddenly increased the frequency conversion setting to a high value–frequency conversion is subject to indicator management, with records taken every two hours to check whether it is operating normally ； Alarm for set pressure at pump outlet pressure; when pressure fluctuates, timely feedback is provided to the operator to make adjustments and identify the cause.
That’s true too; changing the operating characteristics of the pump is indeed unreasonable
Indeed, it is necessary to have a high-pressure alarm and a high-level interlock in place to prevent overpressure
The frequency conversion effect isn’t significant; it’s sufficient to control the outlet pressure well. If there’s a risk of pump overload, add a feedback loop for automatic adjustment