How to interlock the start and stop of the boiler feed water pump with the drum level
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The boiler feed pump and the drum level are interlocked for start/stop operations. The set upper and lower limits of the liquid level are very close to each other, causing the feed pump to start and stop frequently. Isn’t this detrimental to the pump? Start and run for 10 seconds every 30 seconds?
The boiler feed water pump and the drum level can be started and stopped in interlock through an electrical control system. When the drum liquid level is below the set value, the feed water pump will automatically start to supply water; when the drum liquid level is above the set value, the feed water pump will automatically stop supplying water, thereby maintaining a stable drum liquid level. A small distance between the upper and lower liquid level limits, along with frequent start-stop operations, can affect the lifespan and operational stability of the feed water pump, and may also lead to increased energy consumption. Starting and running for 10 seconds every 30 seconds is not a good approach. It is advisable to adjust the interlock settings so as to broaden the range of level fluctuations, or to set a delayed start/stop function to reduce the number of start-ups and shutdowns of the feed water pump. This can reduce the operating frequency of the pump, extend its lifespan, and improve energy efficiency as well. .
Then just increase the upper and lower limits, or use a smaller pump. The drum liquid level shouldn’t need to be controlled that strictly, right? Either it remains active, with PID control of the upper regulating valve
Generally, there are control valves and recirculation, right? It’s impossible to start and stop high-power motors frequently. . .
Can the frequency control be changed? This should prevent the pump from starting and stopping frequently.
Based on the steam generation capacity of the drum, and using the performance curve of the pump, the corresponding pump frequency is determined and set as the initial frequency. If the liquid level is low, increase the frequency slightly to boost the water supply; if the liquid level is high, reduce the frequency slightly on top of that to decrease the water supply. Maintaining the liquid level within an appropriate range also prevents the water pump from starting frequently, thereby reducing damage to the pump. Save energy consumption.
All are regulated using control valves, or the water supply volume is adjusted via frequency conversion; the water pumps should not be started and stopped frequently.
But it seems like this pump has never broken down
Our boiler feed pump does not have any interlock mechanism linked to the drum level; only a PID controller is used to regulate the frequency of the feed pump. In fact, frequent starting and stopping is not a big issue.