Leaking is a common issue for fluid systems and their components. Technically, it’s impossible for systems or products to be completely leak-free. However, in high purity applications, even a minor leak can have a detrimental effect on the smooth running of systems, thus raising high requirements for the leak rate.

Types of leaks

Leaks are divided into internal leakage and external leakage by way of leaking.

Internal leakage, also known as across-seat leakage, refers to the leakage that occurs inside a piping component when there is a barrier in the internal flow path of the piping component and the closing function of the barrier completely prevents the flow of the medium, such as medium leaking through the seat of a closed valve.

External leakage is a leak between a piping system or piping components and the external environment and can be categorized into inboard leakage and outboard leakage. Inboard leakage refers to a leak from the external environment to the internal when the internal pressure of the piping system or piping components is lower than that of the external environment.

Outboard leakage, on the other hand, refers to a leak from the internal to the external environment when the internal pressure of the piping system or piping components is greater than that of the external environment. Below is a figure of the FITOK high purity pressure regulator for reference.

leakage testing high purity valves

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