Dunk and Bubble Testing Systems


Dunk and bubble leak testing is a method of testing a part vessel or cavity for leaks. The test identifies leaks by submerging a gas charged part in a tank to see if a stream of air bubbles escapes from the part. Compressed air is commonly used for dunk testing and will test the part at various pressures and time. The size and of the bubbles and rate at which they can both signify the size of the leak.
Dunk Testing Systems

A Dunk and Bubble Test System performs a Pressure Decay Leak Test on the interior of the vessel and uses pressure drop over time to identify a leak. The dunk test system is not limited to leak testing, but can include:

  • Manual and automatic operation
  • Fixturing to secure the part for part handling (loading and unloading large parts)
  • Sealing the part for test pressures
  • Plumbing
  • Regulating compressed air
  • Booster air systems to achieve test pressure

Dunk testing requires a protective enclosure for the operator as some parts are tested under extremely high-pressure.

Dunk Leak Tests Are A Reliable Method of Product Quality Testing

Pressure decay dunk tests reliably test the tightness of sealed parts for compliance with industry specifications and to ensure product quality. Seal integrity is especially important for parts containing gases, fluids, and flammable or corrosive substances. Having a tight seal is also important for parts that could be damaged by the penetration of soapy water, fluids, or contaminants.
Dunk and bubble leak testing is used across a wide range of industries including automotive, medical, powertrain, consumer goods, HVAC/R, medical, and military. When integrated into the production line, dunk tests help identify leakage issues prior to final assembly. Dunk leak testing using the pressure decay method provides several benefits including:
  • Simple and effective testing method
  • High level of sensitivity for detecting small leaks
  • Reports pressure or flow loss
  • Determines leak rate based on pressure or vacuum

Using A Dunk Test System for Your Leak Testing Application

Dunk test systems are best for smaller components because of the tank size and to make it easier to monitor leaks. Because of the fluids involved, dunk tests should also not be used for components that are sensitive to moisture.
Extreme care must be taken when dunking the part into the tank to prevent air bubbles from being pulled down, creating the illusion of a leak. It is also important to maintain proper air and water temperatures during the test to allow for proper pressure stabilization and ensure accurate test results.

Custom Designed Dunk Testing Systems

CTS Dunk Test Systems are custom test solutions engineered to test parts to ensure they conform to manufacturer leak specifications and sized to meet production requirements. A custom designed Dunk Test System can be created to accommodate several part sizes, types and models with special fixtures to secure the part in the tank.
In some applications, the dunk leak test system will provide seal components to cover and seal large ports in the part, holding the test pressure without leaking. This type of system is custom designed to part design and used for: testing fitting, valves, weldments, fuel tanks, powertrain components, faucets, water heaters, gas cylinders, boilers and more. 

Contact CTS for Dunk Leak Testing Systems

For your next project let Cincinnati Test Systems will custom design a turnkey function test system for your parts. Contact us to discuss options for our customized dunk test systems and other leak testing solutions.