3 Reasons for Oil Seal Failure and Their Solutions Discussed

Jul 04, 2019 Industrial seals | Oil Seals

The oil and gas industry is one of the most challenging industries due to adverse conditions and demands involved. A few engineered components such as oil seals are required to perform in these adverse conditions, where they may be exposed to various extreme conditions. Although most of these seals are precision designed for a long-term performance, they may fail due to several reasons. This post gives a brief insight into the challenges that the seals are exposed to, and explores various reasons behind their failure.

Oil Seals

An Overview on the Challenges Endured by Gas and Oil Seals
Mechanical seals are always designed in adherence to the conditions of a particular application where they may be used. Oil and gas seals are designed to resist the following:

Aggressive Corrosive Chemicals
Sour Gas (H2S)
Decomposition
Explosive Conditions
Extreme Pressures and Temperatures

Analyzing the Top 3 Reasons for Failure of Oil Seals and Corrective Actions
Like any regular mechanical seal, oil seals fail due to several reasons or one of these reasons. Here, the failure reasons are also followed by their solutions.

Chemical Attack: As said, the oil seals are exposed to several types of chemicals. The seal may exhibit a variety of signs ranging from cracking, blisters, and discoloration to a change in hardness levels. Why does this happen? The material of your seal is not compatible with the chemicals it is being exposed to. This chemical attack will affect its cross-link density, increasing or decreasing it. The seal material becomes hard and brittle when this cross-link density increases and becomes softer when the cross-link density decreases.
Solution: Selection of the right sealing material is important for ensuring the compatibility of the seal with chemicals. This chemical incompatibility leads to chemical attacks, which accelerate at high temperatures or pressures. So, check the compatibility of the elastomer seal material before choosing it for your application.
Extrusion and Nibbling: At times, the oil seals may have a chipped or nibbled appearance. In extreme cases, the surface of these seals may peel on its own, thereby lending it a shaved appearance. What is the cause of extrusion and nibbling? Stress induced by high pressure is one of the main reasons for extrusion and nibbling. This stress widens the clearance gap between the mating edges, where the seal may get entrapped, and it leads to severe physical damage.
Solution: Many industry experts suggest using backup devices to avoid the formation of clearance gaps between the mating edges. The selection of a properly sized oil seal is also important to avoid extrusion and nibbling.
Out-gassing: This is one of the common causes of oil seal failure, which happens due to the volatility of any of the constituents of the elastomer. These constituents may be the part of elastomer formulation, or gases may get trapped in the elastomer during the process of molding. Although the oil seals may not show any visual indications of out-gassing, at times they may shrink due to extreme out-gassing. The out-gassed molecules may cause contamination in wafer processing in several semiconductor applications, and also it can affect vacuum performance in industrial applications.
Solution: Use the materials that are rated to the temperature of application. Also, ensure that the elastomer used is free from volatile ingredients such as waxes, plasticizers, and so on. Both these will help you avoid the chances of outgassing.

The above mentioned are only the top three causes of oil seal failure; however, there can be several other reasons for the same. In addition to these solutions, it is important that you source these seals from some trusted manufacturer such as SSP Seals. The company provides customized oil seals in different specifications to its clients in the oil and gas industry.