Future Advancements in Sealing Technology with a Focus on O-Rings

Future Advancements in Sealing Technology with a Focus on O-Rings

Author: Ron Bargman

Almost all types of O-ring seal designs today are based on the toroidal geometry patented by Neils Christensen. This seal, which was primarily utilized in military applications, gradually found its place in the hydraulic sector, and is today used in almost all applications ranging from indoor plumbing to the space shuttle. Although there has been no major changes in the basic shape of an O-ring, improvements in the sealing technology, material development, characterization, and testing areas has taken a new dimension. The use of nano-technology rubber is one such example of technological advancement. As O-rings are majorly used in the field of material science and chemistry, any advancement or development in nano-technology has a greater impact on the O-ring industry.

Material Enhancements

Nano-PTFE
Nano-PTFE is a specialized formulation developed through nanotechnology with multi-functional characteristics. Such materials along with nano-carbon, when filled into elastomers result in O-rings with anti-scratch, fire resistant, anti-UV, super hydrophobic, and several other properties. When reinforcing agents, inert fillers like mineral fillers, and carbon black are added, the physical properties of O-rings are improved. Use of carbon nano-tubes makes the O-rings suitable for electrostatic dissipative applications. Nano-PTFE utilized in semiconductor application provides improved abrasion resistance, decreases permeation, and reduced friction.

Plasticizers
Material enhancement using plasticizers not only decreases the stiffness of the O-ring, but also enhances its low-temperature properties. Recently, special additives like flame-retardants and pigments are also utilized for enhancing the O-ring performance.

Anti-degradants
Anti-degradants are special compounds used to inhibit deterioration or aging of rubber compounds. Such compounds when utilized along with the O-ring materials reduce the unwanted chemical reaction at the time of compounding and help in fast construction of finished parts.

Special Compounds
A combination of accelerators, activators (zinc oxide and stearic acid), and curing agents improve the vulcanization rate of an O-ring component.

Advancements in Analytical Characterization and Testing
In the recent past, there has been a major change in the analytical characterization of elastomers. The use of fillers, such as carbon black, prevents electrical arcing and static spark formation within the rubber material to provide electrostatic dissipation of rubber. Such charge dissipation of rubber along with additives imparts flame resistance to the final O-ring product.

On the other hand, there have been gradual advancements in the testing processes of various O-ring elastomers. Stress-relaxing tests and seal lifetime analysis are some recent developments in testing that envisage potential failures accurately and at an earlier stage.

Seal Configurations
Today, low-leakage designs are one of the popular choices to develop seal configurations. However, recent developments have resulted in the emerging of zero-leakage designs, which are far more cost-effective and of high performance. In addition, there are several software packages available currently to assist in robust designing of O-rings. AutoCAD is one such popular software used to design O-rings efficiently.

Utilization of finite element analysis is another recent improvement in enhancing seal configurations. The finite element analysis results in early identification of non-linearity in elastomers.

Future O-rings
Although there has been a tremendous increase in emerging technologies, the scope for future developments remains open. In the future, new materials can be applied for reliable and consistent operation even under extreme conditions. In addition to designing, the application of CAD and Simulation for performance prediction would provide efficient operations at minimized costs. Technology needs to be modified for providing reduced maintenance and ability to offer modularized package of seal along with condition monitoring. This condition monitoring is considered one feasible way of increasing the efficiency and reliability at a low maintenance budget.

Article Source: http://www.articlealley.com/article_1822940_22.html

About the Author: Ron Bargman, president of Zycon.com, has been fascinated and involved with the engineering and manufacturing processes required to turn ideas into products for over 30 years. Mr. Bargman is a regular contributor of manufacturing theme articles, and his rich industry history provides insight into manufacturing and engineering events and changes that are timely, poignant, and relevant. Through Zycon, he is able to transfer his passion for the industry by assisting engineers, designers and inventors find the services, parts and components that they need to succeed.

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