I would like to ask about the reasons for leakage at the pump shaft seal
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This post was last edited by I believe LEE on 2018-4-25 at 15:12. The existing pump has a flow rate of 150 cubic meters per hour and a head of 40 meters; it is used to transport dilute phosphoric acid. When a double-end face seal (PLAN54) is used, the seal flushing water flows in but not out (the same issue occurs with new seals as well). The pumps nearby use the same flushing system and water flows out normally there, with normal flushing pressure. When no water flows out, a sucking sound can be heard from the outlet pipe, and a negative pressure can be felt when touching it； It was later changed to a packing seal, but it leaks frequently; the packing installation is fine. What could be causing this? Unstable medium feed?
Why does the flushing water for double-end face mechanical seals only flow in and not out? Was the excuse given wrong? And why change it to a filler? The packing will definitely leak; without any lubricating medium, it will rub against each other and generate heat. Finally, what kind of pump is this?
The last edit to this post was made by I believe LEE on 2018-4-25 at 15:13. The inlet and outlet of the mechanical seal are connected correctly; the issue is that currently, the sealing water only enters but does not exit, thus it ends up inside the medium, diluting it. The process does not allow the use of a mechanical seal in this condition； The filler allows for some dripping, but now there is a leakage – in other words, the leakage is quite severe. No lubricating medium is required; cooling water with filler is used instead ； This pump is used to transport dilute phosphoric acid
It’s a failure in the sealing at the medium side of the mechanical seal; you need to have the manufacturer deal with it. The packing will definitely cause significant leakage, and taking appropriate actions regarding the packing shaft sleeve can help reduce this leakage, but since it’s the manufacturer who needs to handle it, it’s not convenient to discuss details here
It’s not a problem with the friction pair at the medium side; the new seal presents the same issue. Actually, we are also pump manufacturers: lol. It definitely isn’t a problem with the shaft sleeve, nor is it an issue related to the packing installation. I mainly want to know if it’s caused by factors such as the process medium or other aspects
It’s scary – it’s already at negative pressure; both the medium side and the seal chamber have been connected…… What I mean is that it’s possible to make changes to the shaft sleeve, and such changes can help reduce the amount of leakage
Yes, when you touch the area where the metal hose exits, there is an immediate inward pulling force.:
Is the pump empty? It seems that in this situation, the pressure on the mechanical pump’s working surface is already negative
Use a secondary impeller + packing seal, or a secondary impeller with dual seals
It is a structure consisting of a secondary impeller and a packing seal