A problem encountered when pouring the pump
Thread Content
Today, after I reversed the pump (the pump was a variable frequency pump), I observed the DCS and found that a U-shaped bend appeared. About three minutes later, the volume suddenly dropped vertically to the bottom of the U-shaped bend. It recovered after three minutes (the end of the pump reversed may be due to the adjustment of the frequency converter in the house). The liquid level in the tower basically did not change. Why? There is a problem with the indoor operation: after the other pump is started, the frequency conversion of the pump to be switched drops to a very low level before the outlet valve of the pump to be switched is completely closed! How can we keep the volume basically stable during the switching process of the machine pump?
Which pump starts first or stops first?
The standby pump should be turned on first and then the active pump should be turned off.
2# guanshanyue1987 opened it first! ~
Start the backup pump first, turn on the minimum return flow, adjust the frequency converter to increase the outlet pressure of the pump simultaneously, wait until the outlet pressure of the two pumps is constant, gradually close the outlet valve of the active pump, open the outlet valve of the backup pump, adjust the flow through frequency conversion to stabilize, and at the same time adjust the minimum return flow of the current pump accordingly. When the outlet flow of the backup pump meets the process requirements, close the outlet valve of the current pump, reduce the frequency conversion, and stop the pump.