4 Factors To Select the
Correct Rubber Material
The four factors that determine the type of rubber seal you need are:
- Medium
- Temperature
- Pressure
- Time
Medium: What Your Seal Touches?
A rubber seal comes into contact with various substances. When the machine is running, but also during the cleaning process, for example. Not every compound can tolerate all media, so this factor plays an important role in making the right choice.
Media consists of 3 main categories:
- Liquid
- Gas
- Solids
Each kind of rubber reacts differently to different substances when it comes to abrasion resistance, gas permeability, swelling, etc.
When choosing a suitable material always consider all media the seal will come into contact with. For example cleaning materials, lubricants and any media in the immediate vicinity of your application.
Temperature: Hot & Cold
The temperature is also of great influence on the functioning of a seal and tends to vary due to internal (application of the machine) or external influences (climate or cleaning with hot steam). Does the seal come into contact with high or perhaps extremely low temperatures? To what extent and how often does the temperature change? The answer to these questions will bring you closer to the ideal seal.
However, temperature is not an isolated entity; the combination of temperature, time and media is usually the determining factor.
Pressure: Max and Operational?
Specific rubber seals can, once fitted, withstand very high pressures of up to hundreds of bar. Not all materials perform at the same level under high pressure. This results in the risk that the seal will no longer function properly or that it will wear out quicker than expected. Also, consider how often and for how long the seal will be under pressure. In order to find the material you prefer, you have to know the pressure exerted on a seal.
Higher pressure often goes hand in hand with a higher hardness of the material you need. Medium, temperature and time often determine the choice of the polymer type, but pressure often determines the hardness of the polymer type.
Just like with temperature, the combination of pressure and time plays an important role.