Compression amount of mechanical seal spring
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For a mechanical seal of this type, with a spring section that is 45 mm long, how many millimeters should the spring generally be compressed after tightening the impeller nut to be appropriate?
You should measure the total pressure and set it at around 60 to 70 percent
Ask the sealing manufacturer for the sealing assembly diagram.
First, there must be installation drawings for the mechanical seal (designed by the mechanical seal manufacturer), as mechanical seals come in various forms. Relatively speaking, the containerized type is simpler; otherwise it’s more complicated. Considering the sealing type, the calculations for balanced, semi-balanced, and unbalanced types are all different. Moreover, the impact of the shaft penetration amount must also be taken into account. Take a look at what the mechanical seal design team has to say (see figure).
There is a calculation formula for this; I just installed it, and the volume was reduced by 1/3. A hydrostatic test was conducted, and there was no leakage.
This post was last edited by Mechanical seal_CFVR on 2021-4-13 at 10:02. This so-called calculation formula is just some installation experience. The working height will not pose any major problems within a certain range, especially regarding the large spring seal. It is recommended to consult the sealing manufacturer. For this type of large-spring mechanical seal shown in the image, it is generally required that both ends of the spring be polished to a depth of at least 3/4; it seems that this requirement isn’t met in the image.
Contact the manufacturer to get the appropriate amount; this also depends on the size and thickness of the shaft sleeve shoulder. An experienced installer should try turning the shaft by hand after installation – it shouldn’t be too tight nor too loose.
It generally has nothing to do with the spring length; instead, the total compression amount of the moving ring and the stationary ring should be measured. Adjust the bolts shown in the diagram until the compression reaches more than 1/2 of the total compression amount – excessive compression leads to wear, while too little compression can result in leaks
This post was last edited by Guifuoudei on 2021-5-31 at 16:54. This is a single-end large-spring mechanical seal; here, after measuring the sealing force, applying half of that force is usually sufficient.