Difference between internal and external leakage of valves
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During use, valves often encounter various types of failures, and leakage is one of the most common of these issues. Valve leakage can occur in two forms: internal leakage and external leakage! So, what is the difference between internal and external leakage in valves? The difference between internal and external leakage in valves Internal leakage in valves refers to the situation where, even after the valve has been fully closed, fluid still flows out, seeps, or drips from the outlet of the valve’s flow passage. In simple terms, it means the valve does not close properly and its sealing is inadequate! The cause of this fault is usually erosion and wear of the medium, or the presence of impurities. Even if the valve screw (valve stem) is tightened in place, fluid can still flow through since there is still a gap between the valve core and the valve body. External leakage of a valve generally refers to the leakage of fluid through the external sealing components of the valve’s packing, when the valve is completely closed or open. That is, poor sealing between the valve and the connection flange or threads, which leads to the medium leaking from the connection seals; poor sealing between the valve stem and the gland (i.e., the cover that presses the packing on the valve stem), resulting in medium leakage; external leakage caused by defects such as sand holes in the valve body blank; and external leakage resulting from wear of the valve body due to erosion by the medium.
Can it be understood this way? Internal leakage of the valve may be due to a problem with the product at the time of manufacture, or it may result from long-term use and issues caused by the medium ； External leakage of the valve is due to a problem with the product at the time of manufacture, or it may have been damaged by external forces.
I disagree with this view. The term \"inner\" in the context of internal leakage can only be used when there is an inner chamber present in a valve. For example, in the closed state of a fixed ball valve, an inner chamber is formed inside the ball; if there is internal leakage, it indicates that there is a problem with the upstream valve seat. However, gate valves and stop valves do not have any inner chambers at all, so the concept of internal leakage does not apply to them
1. Compared to external leakage, internal leakage in valves is visible whereas external leakage is not. 2. Internal leakage generally occurs when the valve core is in the closed position, and an amount of fluid exceeding the allowable limit leaks from the front side of the valve to the back side.
Seeing your answer, I wonder one thing: if the owner is answered in this way, will they explode on the spot?
1. If the valve disc of a gate valve is perforated, this situation should also be considered an internal leak. :Handshake 2. Internal leakage and external leakage are the ways in which leakage is expressed in our usual context.
What the original poster said is correct. Internal leakage of a valve means that it doesn’t close properly, while external leakage is usually caused by problems with the packing, the valve cover, or defects or corrosion in the valve body.