Is it Groundhog Day? You may feel like it if your life is a never-ending saga of blown gaskets. At some point, it’s time to say enough is enough and figure out what you need to change in order to prevent this problem from occurring again.
Your first instinct when a gasket is blown should not be to immediately try a different gasket. There are many things that could be the root cause of your issue, and unless you understand why the gaskets are failing, you are probably going to wake up tomorrow and have the same problem.
So What Next?
Ok, so you’re now staring at an application that isn’t running, and you are holding a blown gasket in your hand. How should you be troubleshooting this? There could be any number of issues. Here are some of the more common problems and why they can cause a blowout. Hopefully at least one of these will get you pointed in the right direction.
How hot is your application running? One of the most common culprits of gasket issues is heat and the reality that your application is running hotter than you think. Do some additional testing, consider the peak exposure, and select a material that is designed to survive those conditions.
Are you expecting your gasket to seal a high pressure joint? If so, is your gasket reinforced? Metal reinforced gaskets can provide enough radial strength to hold up to the high pressure.
Ensure that your joint is properly assembled. There are recommended torque values as well as a sequence that should be followed. If you are using a compressible gasket, a final torque once operating temperature has been achieved is helpful to maintain load over long term service.
4. Flange Loading
This is one of the most critical pieces of the bolted joint. Without the proper loading, no gasket will seal. Be sure that the flanges are in good shape and have adequate flatness and surface finish. Loading needs to be sufficient to establish an initial seal but also maintain load to seal the joint over the long term, after the initial heat cycles.
How thick is your gasket? In most cases, the thinnest gasket you can use is the best choice. There are a few instances where you would want to increase the thickness (ex. compensating for flange conditions). Thinner gaskets have less chance for blowout since the load is concentrated over less volume, which provides higher shear strength.
6. Material Type
If you’re sealing fluids, be sure that the gasket material is compatible with the fluid and will not degrade over exposure time. Think of using a plastic bag to hold water vs a paper bag. Both will hold water, but the paper bag has a clock ticking.
Sometimes, none of the above gives you any insight into your problem. These are the difficult ones to fix. Unfortunately at this point, it tends to boil down to a less than ideal joint design and the difficulties associated with finding a gasket material to compensate for these issues. Obviously, if you have gotten this far in the process, changing the design probably isn’t going to be an option (unless it is really bad). It is up to you and your trusted gasket material supplier to find a material that is going to work. In most cases, you’ll find something that’ll seal. However, you may be in a situation where you find that you need to design a material to meet your specific needs. If your gasket material supplier isn’t willing to help walk you through your options, be sure to find someone that is.
What causes most of your blown gaskets?