“How much pressure can this seal handle?”
The answer to this question depends on a number of parameters and conditions. But the principle limiting factor in the pressure handling of any seal system is the extrusion gap.
Commonly referred to as the “E-Gap,” the extrusion gap is one of the most critical design aspects in any high-pressure application. Seal design, type, and material are all influenced by the extrusion gap and the desired pressure handling capability.
What exactly is an extrusion gap, and why is it so important in the successful design of a sealing system? Let’s find out.
The Basics: What is an Extrusion Gap?
In terms of sealing systems, the extrusion gap is defined as the clearance between the hardware components.
In a piston configuration, this would be the clearance between the piston and bore. In a rod configuration, this is the clearance between the rod and housing it’s passing through.
The extrusion gap can be expressed in terms of radial or diametral clearance, which can lead to some confusion. Our partners at Eclipse define the E-Gap by stating it as the radial clearance. The radial clearance is equal to the diametral clearance divided by two.
It’s important to note that while hardware components might be machined to have a specified clearance, this gap might not be perfectly realized or maintained. Continue reading Why an Extrusion Gap is Important