Leak Testing: Pressure Decay Explained

Cyan Tec Systems Limited (Cyan Tec) specialises in the integration of leak and flow test equipment which includes the supply of semi-automated and fully-automated systems into a wide range of different industry sectors. When talking specifically about leak testing, Cyan Tec has often adopted the pressure decay method to meet their customer’s demands.

bespoke-leak-test-tooling

Bespoke leak test tooling

The straightforward but effective technology that is well-known within the industry as pressure decay has now become a mainstay where high volume production testing is required and Cyan Tec has used its expertise in the design and manufacture of high-end automation systems to work alongside all the leading suppliers of leak test instruments to offer a quality solution. Strong working relationships with the aforementioned suppliers allow Cyan Tec to offer the end user the required after-sales support that is a key element in this type of project.

Pressure decay leak detection instruments are frequently associated with the checking of components that have relatively small volumes. The chamber is filled with air and the pressure transducer built into the specialist leak test instrument monitors the pressure for negative changes where any pressure drop indicates a leak.

automatic-leak-testing

Automatic leak testing

The pressure decay technique can also be referred to as gauge decay leak testing or absolute pressure leak testing. This is due to the method of leak testing simply measuring the drop in pressure on a gauge (transducer) during the leak test.

Although Cyan Tec is a UK-based company predominantly supplying leak testing equipment on home turf, having a strong reputation in this particular industry has also provided opportunities to supply leak testing machines to ‘Blue Chip’ companies on the continent. The product knowledge, reputable name and the high-quality end product associated with Cyan Tec gives the end user of the leak test equipment the confidence that the required skills are available in-house to offer expert advice no matter how simple or complex the automation.

Automotive Component Leak Testing

When a high-profile automotive supplier needed a suite of customised leak testing systems for their latest engine components, they had no hesitation in contacting Cyan Tec Systems who had previously provided several automation machines for their UK factory. In order to fulfil the customers’ requirements, Cyan Tec provided a total of six individual leak testing machines, each designed to suit specific engine components.

To verify the quality of high performance engines, it is necessary to perform accurate leak testing of components and assemblies, the most commonly used method being “pressure decay” which has been used for several decades to identify faults in sealing or component integrity. Using this method, air is injected into the test object which has been sealed to allow a build-up of pressure. The pressure is then monitored over time, any decay of pressure indicating a leak. In this case, it was the high-level testing of the casting integrity that was required.

Cyan Tec has established a track record in automated leak testing, using third party leak testing equipment integrated into the production lines of many clients.  In particular, Cyan Tec has a strong relationship with Ateq, a well-known supplier of differential pressure decay leak testing equipment.

After assessing the requirements of the customer, Cyan Tec provided the six machines based around a modular design. Each machine has a fabricated metal base frame, providing a rigid support structure for mounting of the various machine elements.

All the machines provided are manually loaded by an operator and wherever the parts are too heavy to be lifted, the operator is assisted by appropriate lifting equipment.  To simplify operation and eliminate human error, the operator uses a handheld scanner to scan the barcode on the component or assembly to identify and record the product variant which is to be tested.

 

All the orifices on the component under test are sealed by O-rings on the bespoke tooling which are closed onto the part using a combination of pneumatic cylinders and manual clamps. With the design and manufacture of such intricate tooling being a critical aspect of the leak testing process; the wealth of knowledge that Cyan Tec has in this area was absolutely vital to ensure that the project was a success.

Once the component is detected as “in place” and the variant is verified by the barcode reader, the automated leak testing process is initiated by the operator pressing the start button. On completion of the test sequence, the result is displayed as a green or red light (for pass or fail) as well as being displayed on the HMI (Human Machine Interface), located in front of the machine. Parts are then unloaded and new parts loaded by the operator.

Each machine is customised to suit one or more products, the machine construction providing a combination of guarding and safety light curtains to ensure that the operator is well-protected during the testing sequence.

Cyan Tec is an experienced manufacturer of laser processing systems, robotic automation and automated leak testing systems based in The Midlands, United Kingdom. Standard and custom systems are offered with a full service from design through manufacture, supported by a dedicated team of engineers.