Occlusion Testing

Occlusion testing is a crucial component of leak testing systems, particularly for products with open passages or flow paths. This method is designed to detect blockages or obstructions that could impede the proper functioning of devices such as catheters, IV sets, tubing sets, or injection molded components.
 
The first occlusion method involves measuring the pressure rise at a specific point during the fill step. A part that isn’t occluded will have a steady, predictable rise in pressure. An occluded part or port will have excessive back-pressure and a steeper rise in pressure. This condition causes the leak tester to reach its fill pressure prematurely when pressurized, indicating excessive blockage based on min-max occlusion pressure limits applied.

Basic setup is relatively simple. After some product sampling, production timers and high/low pressure limits to pass the occlusion test are established. The occlusion limits are then applied in conjunction with the min-max fill limits. If the occlusion test is set up correctly, there is no cycle time penalty to a normal test sequence as the test is performed during the fill step.

For the second method, a complete test sequence is performed. One end of the product is attached to the leak tester test port and filled with a gas (usually air or Nitrogen) to a desired setpoint pressure. The other end of the product is left open to vent to atmosphere. Once pressurized, the leak test instrument monitors the decay rate of the pressure. A test part that is functional and open will lose most or all of the pressure in a predetermined time frame. A test part that is  occluded will retain a higher amount of pressure in a predetermined time. The final pressure loss value is determined and compared to the setpoint limits to determine a pass/fail condition.

From our first leak tester design, LeakMaster has been offering Occlusion leak testers for manufacturers, helping to ensure the parts they manufacture aren’t previously blocked or occluded in the manufacturing process. LeakMaster provides many leak tester options for occlusion testing including our Guardian, Defender, and Stealth leak tester, providing a variety of enclosure sizes and secondary test methods for your unique occlusion application.

The Guardian is our flagship leak tester preloaded with Occlusion testing. The Guardian is configurable for many test methods and is equipped with our latest sensors and communications for top performance. The instrument also comes pre-configured for Occlusion testing, providing steady, highly accurate Occlusion results over a wide range.

The Defender is the most cost-effective pressure or vacuum decay leak tester that can also perform an Occlusion test as well. Compact yet powerful, the Defender's high speed 64-bit processor and 24-bit digital pressure transducer provide stable, repeatable Occlusion results. Standard options include real time & historical graphing, and built-in data collection make the Defender an excellent value.

The Stealth leak test module is the newest member of the Occlusion family. Modular, compact and lightning-fast describes the Stealth. Its compact design, onboard Occlusion programming and low cost per channel make Stealth a great value and ideal for multi-channel applications.

Key Benefits of Occlusion Testing

• Non-Destructive: Occlusion testing does not alter or damage the component, making it ideal for sensitive or expensive parts.
• Simple and Fast: The process is relatively quick, with results often available in just a few seconds.
• High Sensitivity: This method is sensitive enough to detect small blockages, which is crucial in applications where even tiny obstructions can compromise performance or safety of the product.
• Versatile: Occlusion testing can be performed with a Pressure Decay, Differential Pressure Decay, or Mass Flow leak test instrument. This method is widely used across industries such as catheters, IV sets,  tubing sets, or injection molded components (to ensure molded parts are not over molded or blocked).
• Quantitative Results: The test provides numerical data, making it easy to determine the severity of the occlusion and to make precise decisions about part integrity.

Occlusion testing with a leak testing instrument is a reliable, accurate, cost-effective, and efficient method for detecting occlusions or partial blockages in a product. Its non-destructive nature, coupled with its ability to provide quick, quantitative results, makes it a popular choice for quality control and assurance in manufacturing. Whether it is ensuring the integrity of a catheter or a tubing set, occlusion testing offers a prominent level of precision and sensitivity that contributes significantly to product quality and safety.

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