Help! Problems with the static ring of mechanical seals
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Dear experts, may I ask whether the gap between the static ring and the shaft in a mechanical seal must be 1-2 mm? Can it be set at 5 mm or more? Can the static ring be rectangular, rather than stepped?
The gap between the static ring on the mechanical seal and the shaft does not necessarily have to be 1-2 mm; if the person in question is unconcerned about leakage or the service life of the mechanical seal, a gap of 5 mm or more can also be chosen. However, this makes sealing more difficult, leads to greater leakage, and reduces the service life of the mechanical seal significantly! As for whether the static ring can be rectangular instead of stepped, without any research, there’s no basis for giving an opinion. . . . . .
Reply to 2# hxlhb: Could you please explain in detail why the leakage increases and why the mechanical lifespan shortens?
Reply to 3# sjp881010: The original poster can search for relevant posts on the forum!
There are no strict requirements for the radial clearance between the static ring and the shaft; different seal types have different designed clearances. “Can the static ring be rectangular, rather than stepped? Is the poster referring to the cross-sectional shape of the static ring? It is usually stepped in shape; in my opinion, this is a design choice aimed at ensuring strength while reducing the friction area.
The distance between the static ring and the shaft depends on factors such as the medium and leakage requirements. There’s no requirement that it have to be 1-2MM, right?
Reply to 5# Yihu Xiangming: It’s like this – when I design the static ring normally, I make it stepped so that the gap between the cross-section of the static ring and the shaft is around 1 mm. But for convenience’s sake, I now want to design the static ring as rectangular; in that case, there is no stepped portion, and the gap between it and the shaft becomes around 5-6 mm. I’m not sure if this is feasible
Sure, we have a type of mechanical seal that is rectangular in shape.
There are no specific requirements regarding the gap between the static ring section and the shaft; the gaps in mechanical seals produced by different manufacturers vary, but they are not very large. Because he took into account the forces acting on the carbon ring and the elastic deformation of the spring; if the wear is too severe, the force exerted by the spring may not be sufficient, which in turn leads to an increase in leakage ； Do square and trapezoidal refer to the cross-section? A trapezoidal shape is used to reduce the friction area and prevent excessive frictional heat. But it also can’t be too narrow; the width must take into account the pressure level required for sealing. If it is made square and very narrow, the strength of the static ring may be too low, making it prone to breaking.