What you need to know about low-temperature sealing
Sealing components are used in a wide range of industries. Aerospace manufacturing, oil and gas, petrochemicals, pharmaceuticals and food are but a few of the sectors that could not operate without this rarely discussed — but quite critical — technology.
Specifically, all these sectors are reliant on the low-temperature performance of sealing components. Simply put, they need materials that not only function in typical environments, but that can also stand up to extreme conditions and continue working optimally.
But how do you know which materials to use when low temperatures may come into play?
Understanding Low-Temperature Data
Machine Design offers an authoritative breakdown of how different rubbers and materials are able to withstand various temperature ranges.
The analysis reveals some fascinating results. Specifically, polyurethane is the worst performer and reliable in only the narrowest temperature range, while silicon — with a temperature capability from -150 degrees Fahrenheit to 500 degrees Fahrenheit — easily spans the greatest range.
Flurocarbon is the other measured material that performs admirably. As a sealing material, it can also withstand temperatures up to 500 degrees Fahrenheit. Its low-temperature capability, however, only goes down to -40 degrees Fahrenheit, making it significantly inferior to silicon.
Flurosilicone has the second-best low-temperature capability, at -100 degrees Fahrenheit. But, again, this is still significantly inferior to silicone, and flurosilicone also can only resist temperatures of 400 degrees Fahrenheit at the high end.
Why Silicon Is King
In presenting the data, the publication also breaks down the general guidelines regarding how low temperatures affect sealing components.
Low temperatures can reduce the resiliency of hydraulic seals, and make them stiff, hard and shrink their size. To avoid these outcomes, designers and engineers need to balance four crucial factors when choosing the seal material: seal shape, hardness, thermal contraction and low-temperature resilience. This means that low-temperature performance can make or break a final application. So you have to get it right.
Given the data illustrated here, it is no wonder that silicone o-rings are the first choice from professionals working in the highly technical and highly competitive industries previously mentioned. If you absolutely cannot risk a seal failing or leaking, you are going to want to use silicone.
By contrast, the other materials analyzed (while they can have a place as sealing components in some applications) are not always up for the task. They can become inflexible and brittle when the mercury drops well below zero. This ultimately results in deformations and leaks — two unacceptable outcomes when so much rides on the seal holding firm.
Minimizing Risk and Making the Right Decision
The sealing components you chose can impact the bottom line. If failures occur, you may be looking at real downtime — or worse. Damage can occur, and the next thing you know a blown seal turns into a much larger and longer-lasting nightmare that has actual business implications.
It is imperative to have someone on the team who understands the importance of minimizing risk and understanding how to make the right decision. It may seem small, but the implications of the wrong call can be huge.