The issue of the pump’s minimum return line
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Why is the inlet of the pump’s minimum return line connected to the inlet pipe of the container in some cases? Are some connected directly to the container? Are some of them meant to prevent fluctuations in liquid level from affecting the chain lock? I would like to ask the experienced masters. . . . . . . . Thank you
What is a minimum return path and what is it used for?
Before starting the high-pressure pump, in order to prevent excessive starting current, the minimum flow line is opened to return the fluid to the inlet tank. As the name implies, this results in a low flow rate; therefore it’s not suitable to connect it to the inlet pipeline – it should be connected to the inlet container instead. In the event that a small amount of gas is present in the pump, causing it to run under vacuum, one should not try to...
In my opinion, considering the pressure relief capacity and the main emission medium, if the medium is in gaseous form, then pipeline surge must be taken into account; returning it to the container is a safer option. That’s about it!
Here, we connect them directly to the containers; I’ve never seen them connected to pipelines: handshake
It is generally installed at the pump inlet, as it serves to prevent a too low flow rate at the pump inlet from causing vacuum conditions; typically, the opening degree of the minimum flow valve is automatically controlled by the flow rate at the pump inlet
An important function of the return line is to maintain a minimum flow rate. When the pipeline has no flow output due to adjustments or process requirements, the small return line can help maintain this minimum flow rate, thereby preventing cavitation in the pump
We used a multi-stage centrifugal pump before; the minimum return line (as I understand it) led back to the pump inlet, and it seemed to be part of the pump itself. . . It might not be in compliance with regulations, but it took at least 20 years; I saw similar photos taken in other workshops that day
The one you’re referring to is probably the wire used to maintain the temperature of the backup pump, right? ! There should be a flow control orifice plate above. . . . . .
When the pump operates below a certain low flow rate, it experiences vibration and heating. The use of a return pipe helps to prevent operation at such low flow rates, as well as avoiding pump damage caused by accidental overpressure.
The purpose of the minimum flow rate is to ensure that the pump operates above its minimum flow point, thereby preventing damage to the pump caused by too low a flow rate. Additionally, the minimum flow rate can be either a permanent minimum value or one controlled by a control valve; not all cases involve the use of flow restriction orifice plates.
The process I’ve seen also involves returning to the container inlet; I’ve never seen it return to the pump inlet. Is it a design error? Hehe
Please explain the function of the minimum flow line
If the rated flow rate of the pump is lower than its minimum flow rate, it will cause the fluid inside the pump to heat up, leading to cavitation and vibration in the pump. At this point, it is necessary to set a minimum return line in order to increase the inlet flow rate of the pump; generally, the inlet flow rate should be 10% higher than the pump’s minimum flow rate. This pipeline is generally connected to the inlet pipeline of the pump. The pipeline connected to the container mentioned upstairs is probably one installed to maintain the liquid level in the container.
Is the pump’s minimum return line connected to the container or to the pump’s inlet? I’m a newcomer; please give me some advice!
It is generally connected to the container, but it can also be connected to the inlet pipeline of the container near the container itself
All of our magnetic pumps are equipped with a minimum return line, on which there are flow control orifice plates. These serve to prevent a sudden closure of the valve at the pump outlet from causing a decrease in the pump’s flow rate, as well as to avoid damage to the pump due to lack of internal circulation. In some cases, the minimum return line is connected to the inlet container, while in other cases it is connected to the inlet pipeline
Just go back into the container, just like the return line to the tank