Pressure decay or rise test

Verborg Engineering B.V. has realised several pressure decay/rise tests for several different products over the years.

How it works

In a vacuum room, the open top of the product is pushed against a rubber ring on the “ceiling”, the air in the product is now completely seperated from the air outside of the product in the room. The air pressure can be measured outside of the product. The original air pressure in both of these areas is approximately 1 bar atmospheric pressure.

A vacuum is made in the air outside of the product, for example all the way down to 5 mbar. The air in the product stays the same. If there is a leak in the product, the air from the inside of the product will “escape” from the drum to the vacuum chamber. If the pressure sensors detect a raise of the 5 mbar outside of the drum, a leak is detected.

The same principal can be applied to a product without an opening, this will only remove the sealing-step from the process.

Working principal sketch:

Pros:

• Product stays clean during test.
• No operators required, fully automatic solutions available.
• No tracer gas required.
• A cheap solution for an automated zero defects line.

Cons:

• Relatively inaccurate (max 10^-2 mbar*l/s).
• Lower throughput then (for example) helium testing, due to stabilizing time of pressure values. Especially applicable with larger products, because of their larger volumes.
• No pinpointing of leak location.
• Vacuum required, not applicable for every product.
• Susceptible to environment changes (e.g. temperature or humidity).
• susceptible to mechanical instability, especially if the product is not ridgid (when under pressure, the volume of the product can change, causing misleading results).

Verborg Engineering B.V. Project examples