Suction short pipe for self-priming pump
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The last edit to this post was made by 3983596_FPPZ on 2018-11-17 at 14:21. It is a diagram of the suction inlet section of a self-priming pump; clearly, the diameter of this pipe is smaller than that of the pump’s own inlet. Why is that?
What about exports? Is there also a short tube like this? I’ve seen some slurry pumps have this as well; is it used to regulate flow?
A search on Baidu does show such pumps; are they useful for gas-liquid separation?
The outer diameter of the pump’s pipe is large; the inner diameter should be roughly the same as that of the pipe segment. Is this done to enhance strength?
Looking forward to the original poster and other experts providing answers and clarifications: lol
I am not the designer of this pump, so in my opinion there could be two reasons: 1. By increasing the diameter of the suction pipe, the flow velocity is reduced, which improves the pump’s cavitation resistance; this allows the pump’s suction capacity to increase (the negative pressure at the inlet rises), thereby raising the suction height. However, I do not approve of this approach of changing the pipe diameter directly without using a reducer. 2. It’s possible that the parameters of this particular pump model are suitable for the given application, but its inlet is large and its diameter does not match the requirements; as a result, there is a situation where the inside is loose while the outside is tight. To address this, connections with a different diameter are used. This is a common practice – making use of the well-established hydraulic principles of ordinary pumps instead of using a self-priming pump. I personally speculate that the second reason is highly likely.
The original pump inlet was probably DN65, but it was not allowed to use a DN65 fitting, so it was changed to DN50
It should be related to the process flow requirements