The flow rate of the multi-stage pump is unstable
Thread Content
Our company has a boiler feed multi-stage pump, and about one month after it was installed and put into operation, flow instability began to occur. The traffic keeps dropping, and it’s necessary to make manual adjustments every half hour; otherwise, the required level won’t be achieved. Another issue is that the temperature of the cooled water exiting the system is extremely high; even after replacing the packing, the problem of overheating occurs again after just a week. I really don’t know what to do.
Ask, where do you adjust manually? A mechanical seal would be better for this type of pump.
The inlet flow can’t keep up; is it by adjusting the inlet bypass?
Cavitation? Or is the axial force balance poor?
What is the situation regarding filler leakage? Take a look at the previous image; it’s possible that as the filler seal leaks, air is drawn into the pump, causing cavitation or vacuum conditions in the pump. Tighten the filler gland, replace the filler, or implement mechanical sealing as part of the 21st sealing and flushing scheme. Also, check whether the pump inlet filter is clogged, and examine the pump inlet pressure; a low inlet pressure can cause cavitation when the pump is pumping hot water
The filler discharge flow is insufficient, or the medium water is severely scaled
The flow rate is gradually decreasing; manually adjust the outlet valve, return valve, etc
The inbound traffic is definitely sufficient, and it’s all open. The outlet valve and return valve that we adjust
1 Specific parameters not available. 2 How to determine that the inlet flow is sufficient; 3 various parameters for pump operation; 4 the condition of the inlet and outlet pipelines. We have encountered similar situations; in the end, tower packing fell off and blocked the inlet filter.
The problem description is unclear; the main cause of the decrease in flow rate could be cavitation, while a high temperature of the cooling water for the seal water may be due to a leak in the boiler water.