O-Rings

A simple device like an o-ring can make or break your sealing efforts. O-rings are the most common method of preventing a leak. Making the correct choice in materials critical. It makes the difference between an o-ring that goes unnoticed because it works, or one that makes the news at 11:00.

O-rings made simple

Understanding how an o-ring works is simple, it blocks a leak path. What must be considered is what happens to that o-ring while it is in service. Does it see movement? Does it get exposed to acids or caustics? You must not only consider what the o-rings sees in while in general service but also what it sees in routine maintenance operations such as system flushing.

O-Rings for heat

Is the o-ring going to see temperatures, low or high? Or is that o-ring going to see a range of temperatures? NASA experience a catastrophic failure in Challenger. Disintegration of the shuttle stack began after an O-ring seal in its right solid rocket booster (SRB) failed at liftoff. The O-ring failure caused a breach in the SRB joint it sealed, allowing a flare of pressurized hot gas from within the solid rocket motor to reach the outside and impinge upon the adjacent SRB attachment hardware and external fuel tank. The SRB breach flare led to the separation of the right-hand SRB's aft attachment and the structural failure of the external tank, dumping the liquid hydrogen fuel load all at once and causing a massive explosion as this fuel was immediately ignited by various present flame sources. While it's unlikely you are considering an application as critical as this the potential leakage of many gases, and chemicals can be just as deadly. The rule of thumb in o-rings is: if there is any potential for temperature or pressure excursion, always design for the worst case scenario.