How to determine if a valve is leaking internally or externally?

In the daily operation of valves, one of the most common issues encountered is leakage. Valve leakage generally manifests in two forms: internal leakage and external leakage. Understanding the difference between the two is essential for effective troubleshooting and maintenance.

gate valve

What is Internal Leakage?

Internal leakage refers to the situation where a valve, despite being fully closed, still allows the medium to flow out, seep, or drip through its flow path. In simpler terms, it means the valve does not seal properly, and the valve fails to completely close. This type of leakage typically occurs due to factors such as erosion and wear from the medium, or the presence of impurities in the fluid. Even if the valve stem is tightened, a gap between the valve core and valve body can still allow the medium to pass through, leading to leakage.

Cryogenic gate valve

What is External Leakage?

External leakage, on the other hand, occurs when the sealing components outside the valve—such as the valve packing or seals—fail to prevent the medium from leaking. This can happen when the valve is either fully closed or fully opened. External leakage may occur at the connection between the valve and its flanges or threaded connections, resulting from poor sealing between these components. It can also happen when the seal between the valve stem and packing gland is inadequate, leading to leakage around the stem. Additionally, external leakage may occur due to casting defects like sand holes in the valve body or wear caused by erosion of the valve body, which creates gaps where the medium can escape.

At Haihao Group, we specialize in providing high-quality pipeline components and have extensive experience in the field. Our products are designed to meet stringent quality standards, ensuring reliable performance for our customers. If you require assistance with valve leakage problems or other pipeline solutions, feel free to contact us! Email:sales@haihaogroup.com