Questions about a rotary jet pump
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In the workshop I’m in charge of, there is an alkali pump (a rotary jet pump). When the outlet valve is opened too wide, the pump trips; when it’s opened too narrow, the flow rate isn’t sufficient and pressure builds up. The electrician who checked it couldn’t explain why this happens, and it’s really confusing. Moreover, the backup pump keeps breaking down as well. I hope some experts can help me resolve these issues. Thank you
This is why it is required to close the outlet valve before starting the centrifugal pump
Is there any way to solve this? How can it be made to work properly?
There is an issue with the selection, or the pump does not meet the requirements
a. The flow rate range of the jet grouting pump is quite narrow; opening the outlet valve causes it to operate at high flow rates, leading to overpower overload protection； b. At low flow rates, the outlet pressure is very high; over time, the internal energy of the medium continues to increase, causing the temperature of the medium to rise and thus damaging components such as the collector tube and impeller ； c. The backup pumps are always broken; this could be attributed to quality issues on the part of the manufacturer. So far, no similar problems have been encountered with the rotary shell pumps produced by our company ； Solution: 1. In accordance with **standards**, there should be a 25% surplus in power under normal operating conditions. It’s possible that during discussions with the manufacturer, it wasn’t made clear that the power level should not exceed the rated value at high flow rates; the equipment should operate at the rated capacity. If the power level still exceeds the rated value, since the rotary jet pump motor is usually an inverter-driven motor, adjusting the motor frequency can help reduce its speed of operation ； 2. Try to avoid using the valve when it is closed or at a very low opening degree ； 3. It is intuitively clear that there are significant issues with the equipment selection; the parameter settings deviate from the rated operating conditions. While this may not cause major problems in the short term, it will be detrimental to production over time. It is recommended to contact the manufacturer to resolve the issue or select a different pump model.
The volute pump has high outlet pressure, so it was operated at a lower capacity to prevent pressure buildup. How long has this situation been going on? Has it been available since production started, or is it something that appeared only recently?