Positive Pressure Liquid Leak Test

A leak is an undesirable flow of gas or liquid from the wall of a container due to a defect such as a hole, crack, or bad seal. Leaks require a pressure difference to create the flow. Gases or liquids generally always flow from high pressure to low pressure.

Typically, leaks are considered to move from positive pressure to atmospheric pressure. Positive pressure is inside an object, atmospheric pressure is outside.

The key questions at the beginning of any leak testing requirement are: What is the size and internal volume of the component? What is the leak limit? Are there any hidden internal volumes that affect leak measurements? Are the parts clean and dry? Is there access to the interior, or is it a sealed unit? Is the sealed unit rigid or flexible? Are the parts at ambient temperature? What is the surface quality of any sealing surfaces?

The generic system for tightness testing is pressure/vacuum testing. The test piece and reference volume are simultaneously pressurized (or evacuated) to a preset pressure. The air in the system is then allowed to stabilize with the supply valves closed and the differential pressure transducer resets automatically. After stabilization, the pressure change in the test piece is compared with the pressure change at the reference volume using a transducer. The volume difference is measured and the difference increases if a leak is detected. The accuracy and precision of the system is defined by the way the preset pressure is set, together with the quality and type of control valves and differential pressure transducer.

There are several reasons for positive pressure fluid leak tests:

• Economical (done to avoid material loss that interferes with system operation)
• Safety (made to prevent fire, explosion and environmental pollution)
• Reliability (done to detect unreliable components and components with leak rates that exceed standards)

Leak testing is an important process to determine the reliability of the system under test. This test may indicate a fundamental fault of the system and high leak rates may be detected in certain areas (for example, the gasket may be misaligned or the valve connections may be misaligned).

Our organization also provides positive pressure liquid leak test services with its trained and expert staff and advanced technological equipment, among the numerous test, measurement, analysis and evaluation studies it provides for businesses in various sectors.