In the process of daily use of valves, we often encounter a variety of failures, and valve leakage is one of the most common of the many failures. Even valves labeled as "zero leakage", or "bubble tight", are not necessarily completely leakage-free. The leakages of valves generally are internal and external leakage. So, how to distinguish the two leakages?

The internal leakage of the valve, generally refers to when the valve is completely closed, there is still media from the valve flow out of the mouth. In general, it is not closed tightly, which is usually due to the media wear, or impurities and other reasons. Even if the stem is screwed into place, the medium can still flow through because there is still a gap between the valve clack and the valve body.

External leakage of the valve, generally refers to when the valve is completely closed or opened, there is leakage of media in the external sealing parts of the valve packing. The valve and the connecting flange or threads between the seal is not tight, resulting in the media out of the sealing surface. The bad sealing between the stem and gland results in media leakage. The sand hole in valve body blank causes external leakage, and the external leakage of the valve body wear due to media impact.

Zhejiang Dongchen Valve Technology Co., LTD