Do flange connection bolts require spring washers?
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I have a project currently, and the client asked me why all the fully threaded studs on the pipe flanges lack flat washers and spring washers. How should I respond? Actually, before installing it, I visited other factories and didn’t see anything like that there, so I followed the instructions as given. But I don’t know why – it certainly isn’t to save money; after all, it’s not worth ruining everything just for a little bit of money. Thank you all for your answers!
Check the pipeline standards for implementation to see if there are any instructions in there. For ASME pipes without gaskets, it is possible to make estimates based on the bolt length, nut thickness, and flange thickness; the space occupied by the gasket is not taken into account ； The pipeline should have elastic pads to prevent the nuts from loosening.
Using spring cushions always has advantages and no disadvantages, right? I’ve seen some users say that using them makes leaks more likely, which is hard to understand. Besides, vibration is relative – as long as one is close to the outlet of the power equipment, there will still be some vibration
I didn’t even receive any reminder. I don’t understand why adding them makes it easier to overlook issues; could it be that the nuts are all tightened with wrenches, without checking the torque applied to each one to ensure even force distribution?
My main concern now is how to give the owner a satisfactory explanation: 1. It’s unnecessary and a waste – such an explanation definitely won’t work; 2. No one in the industry adds it, so I didn’t add it either – this explanation is even worse； 3. If the owner insists on adding spring pads regardless of whether vibration is present or not, and he has no problem with the cost, he believes that it’s better to have them installed than not to have any protection at all ； 4. Which specifications should be referred to? It can’t be that something isn’t required just because the specifications don’t mandate it, right? Thank you!
In the 1997 version of the Ministry of Chemical Industry flanges, Appendix A of HG20613 contains the statement that (gaskets are generally not considered).
For this issue, I think it’s because the gasket between the flanges is compressed to some extent; as a result, the nut comes into contact with and presses against the back side of the flange. This has a similar effect to using a gasket, so there’s no need to use a gasket between the flange bolts and nuts
The hardness of flat washers is usually not high; once the bolt tightening torque reaches the required level, the flat washer may be crushed. Spring pads tend to fail and are not allowed to be used in military products. Therefore, the flange surface does not require a flat gasket. As long as the bolts are tightened to the required torque, they generally will not loosen. For vibrating applications, it is still better to use gaskets and flanging for a secure lock.
When there are large temperature differences or large pore sizes, design considerations are necessary; generally, the use of flanges is not mandatory.
It can be added or left out; some owners request that it be added. If the customer asks for it, then add it anyway – it’s not much money either
The standards do not require the use of shims, so no shims are used nowadays.