Please~~ does a centrifugal pump actually have a suction lift? ?
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Several of my company’s senior engineers told me that there is no such thing as a suction lift, but after searching online, I learned that the suction lift of a centrifugal pump equals 10 meters of atmospheric pressure minus the cavitation head plus a safety margin. I called our centrifugal pump supplier and he said they do exist, but in practice it seems unable to draw in even 0.5 meters of fluid. . . . . Please tell me whether there is actually a suction lift, and also whether this calculation formula is correct and what the differences are from reality.
In reality, that operation was carried out with a bottom valve in place; the liquid level was only 0.5 meters above the centerline of the pump’s inlet. It started working by building up pressure, but after 30 minutes it stopped functioning.
Please, I’m going crazy. Tell me the truth! ! ! !
In reality, just treat the centrifugal pump as having no suction lift. A centrifugal pump should be equipped with a foot valve (it is important that the foot valve has good sealing properties), but this is not a long-term solution; it is better to purchase a self-priming pump instead. If a self-priming pump cannot meet the operational requirements, a centrifugal pump combined with a siphon tank can also be used.
There is no suction lift; self-priming pumps have suction lift.
I finally found out; I just looked at the Grundfos catalog! There is a problem with this formula; one element is missing, namely the head pressure of vaporization! ! One less has been deducted: at 100 degrees Celsius, H=10 meters; at 80 degrees Celsius, H=5 meters! ! It also reduces the head loss at the inlet. I would like to ask what temperature the impeller area of a centrifugal pump can reach while it is in operation?
It’s not that there’s definitely no suction lift – it needs to be calculated; suction lift and self-priming capability are two different concepts! !
How high can the temperature of the impeller area of a centrifugal pump reach while it is in operation? This also depends on the operating temperature of the conveying medium. Also, don’t keep bringing up these calculation formulas; they are theoretical and not in line with reality.
It used to have a foot valve installed~~ The correct formula should be H=atmospheric pressure-cavitation head loss-inlet pipe losses-vaporization pressure (related to liquid temperature)-safety margin. I know that in practice there seems to be no suction lift, but I just want to know why! ! !
I posted this to ask someone to explain to me why it’s possible in theory but not in practice – what’s the reason? If we need to remember that centrifugal pumps don’t have a suction lift in reality, that’s easy to remember. I just want to know why it doesn’t exist in reality
Thank you, expert who replied to me. I don’t want to think about this problem anymore; I’ll just treat it as if it doesn’t exist. I’m feeling dizzy. . .