In many processing, medical and manufacturing applications, seals must be able to withstand high temperatures in order to meet safety codes and remain durable for a span of time. While there are different types of rubber seals designed to hold up to extremely high temperatures, there will typically be one kind that makes most sense for your application.
Materials Used for High-Heat Seals
Seals made for use in applications where they’ll be required to withstand extremely high temperatures consist of reliable materials such as neoprene, nitrile, PTFE, PEEK, silicone, flourosilicone. While mica can tolerate extremely high temperatures, it’s a porous material and isn’t flexible or moldable enough to create a precise seal. Graphite can withstand high heat and is a little more moldable, but it’s also porous, making it unfit for food and medical applications.
6 Challenges in High-Heat Sealing
Sealing in high-heat applications involving steam, hot gas or hot liquids and solids requires facing these six challenges.
1. Withstanding High Temperatures Without Outgassing
Seals designed for equipment used for processing substances at high temperatures should be made with materials that won’t cause harmful outgassing or leaching that contaminates the end product. The seal’s material should also be able to endure high temperatures for long-term periods without it taxing the structural integrity or altering its chemical composition.
2. Meeting Safety Compliance Codes
Industrial exhaust systems, processing plants and other facilities have strict codes business owners must follow. They also must demonstrate compliance with these codes in audits or inspections, according to local mandates.
3. Chemical Reactivity
Rubber is generally known to deteriorate when exposed to chemicals, but the right rubber materials used as rubber seals such as o-rings can withstand any chemical and resist corrosion, reactivity, leaching and outgassing. For example, nitrile, also know as Buna-N, is a material with ozone and weather resistance for applications such as car air conditioning systems that undergo a lot of exposure to various elements and chemicals.
In processes where water, food or medicine is processed, whether in liquid, solid or gas form, it requires containment and processing within materials that won’t cause contamination. For example, rubber o-rings used in food processing applications such as dairy processing are made with FDA-compliant, food-grade silicone, nitrile or ethylene propylene.
5. Long-Term Durability
While seals used in ambient or cool temperatures applications are relatively easy to create, ones used in high temperatures have unique challenges that make creating a reliable product challenging. They need to withstand temperatures of more than 400 degrees F and provide long-term reliability.
Materials that can check all the boxes above and still be molded into any custom shape are ideal for applications that need rubber seals to tolerate high temperatures without causing issues. Materials like ethylene propylene, silicone and fluorosilicone can be injection molded into any precise form you design, so it can be used in any unique product a company creates.
Some of the major challenges for seals are withstanding high temperatures, chemical reactivity, durability, compliance with safety codes and achieving precise custom form. While there are materials that can fit the full description, some are more suitable for certain applications than others, and they come at different price points.