Axial Seals vs Radial Seals – A Guide

Jul 29, 2020

When it comes to seals, there might be a lot to think about, after all, it’s imperative that you get it right and that it works for your application. However, get it wrong and it could prove costly and cause a wide range of problems. Therefore, when it comes to static seals they are categorised as either axial seals or radial seals.

This categorisation is defined by the way in which compression is applied to the cross-section of the O-ring. So, what we aim to do is explain the difference between these two types of seals even though they might seem quite similar. The main difference between radial seals and axial seals essentially comes down to the direction in which compression is applied to the seal cross-sections. In the case of radial seals, compression is applied to the outside diameter and the inside diameter. In contrast to this, axial seals will have compression applied to both the top and the bottom of the cross-section of the seal. So, let’s delve deeper into the different properties and functions of both seals.

Radial Seal – What is it?

It is common to see radial seals used in bore, piston, cap and plug style applications. They then fall into one of two main categories known as dynamic radial seals and static radial seals. Dynamic radial seals are developed to be used in an environment where there is reciprocating, rotating or oscillating movements between two mating components. In contrast to this, static radial seals are traditionally used in those environments where there is very little or no motion between the mating surfaces that are being sealed. It is this specific reason that static seals are then considered to be more forgiving than dynamic seals. They have the ability to manage wider, larger gaps as well as surfaces that have a rough finish and higher pressures.

Axial Seal – What is it?

In applications where axial seals are used the top and bottom of the O-rings cross-section will be squeezed. Therefore, axial seals are the ideal solution for primary seals but also secondary seals in those applications where the primary seal is subjected to a significant amount of fluid or solid contaminants. This kind of seal is commonly used in face or flange type applications and they are a lot easier to manufacture when compared to static radial seals.

How Do You Pick The Right Seal?

As with any application, it is crucial that you choose the right seal. Therefore, it is imperative that you understand the different factors that might determine the seal that you need. It can also be of benefit to obtain professional advice and guidance as this will ensure that you get it right as if you fail to choose the correct seal then you are at risk of experiencing a wide range of problems depending on the industry that the machinery operates in. This highlights how important it is to understand the difference between seals and the benefits they offer.