Developing sealing solutions for all types of applications and industries is a key strength of Novotema. However, the real value of a sealing specialist comes with performance testing to ensure the high performance of a sealing solution. This is particularly critical for industries where seal failure would be catastrophic in terms of safety, time and money.
A typical customer will approach our experts with drawings and other details of their sealing requirements. When pneumatic applications are involved, a number of specific considerations need to be taken into account.
In some cases, a gasket may need to be tested in an environment which simulates that of the final application, ensuring that the gasket performs reliably in situ and in conformance with relevant industry standards.
For pneumatic applications, a compression set test will measure the selected elastomers’ ability to return to its original thickness after prolonged compressive stress. Gaskets are under constant pressure in hydraulic and pneumatic applications, so compression set is a measure which is vitally important.
Elastomer treatments for pneumatic sealing
Friction is an important factor within pneumatic applications, caused by fast and frequent movements within the system affecting the sealing components. Making the right material choice is a crucial step in solving these issues. Polytetrafluoroethylene (or PTFE) is one option for friction-resistant moulded rubber seals - and is also available as a surface treatment.
A PTFE surface treatment involves the application of a thin film, using a specialist drum that will reduce the friction and allow the pneumatic application to perform to the highest standard.
Main sealing challenges of pneumatic equipment?
The main challenge that consistently causes issues within the industry is when buyers value engineer the seals to reduce the overall costs. If a seal is value engineered to lower quality elastomer, it may not perform well in the pneumatic application causing future problems in efficiency and costs.
Choosing a cheaper supplier can be a lot more expensive in the long run if seal failure and contamination occurs. Not only will the seals have to be replaced, it will also incur additional costs for machine downtime, lost productivity and clean-up costs if leakage has occurred. There is the potential for lengthy downtime if replacement seals are not readily available. In addition, failed seals and/or leakage have significant safety and environmental implications, which might vary in severity depending on the application and industry.
If o-rings are being used in an application that will need to resist oil and operate in high temperatures, there are elastomeric sealing materials which can achieve this level of required resistance. Alternatively, a sealing expert can advise on a system of two o-rings, using different elastomers - one example being an NBR for hydraulics and resistance to oil, and an FKM for operation in high temperatures.
In a multiple o-ring system, while the seals are operating in the same application, this may lead to the misconception that the diameter can remain the same. In reality, the two elastomers will have different reactions to their environments and geometries can change quite significantly. These variables and many others besides make detailed testing across a wide range of parameters highly important for a high performance, reliable sealing solution. Likewise, the experience and expertise of your sealing partner is of core importance - so be sure to choose wisely!