English
Zhongchi
Zhongchi
Zhongchi
Zhongchi
Zhongchi
Zhongchi
Zhongchi
Zhongchi
Zhongchi
The service life of a valve indicates its durability; it is a key performance indicator and holds significant economic importance. Given the wide range of applications, the variety of media used, and the differing levels of corrosion, there are two methods of expressing a valve’s service life: one is in terms of years of service, and the other is in terms of the number of opening and closing cycles required to maintain the guaranteed seal.
Generally, valve service life is expressed in terms of the number of opening and closing cycles. However, due to differences in operating conditions and testing methods, the number of cycles does not necessarily indicate the valve’s actual service life. Only when operating conditions, usage and testing methods are identical can a higher number of cycles or a longer period of use be considered indicative of a longer service life.
The sealing performance of a valve refers to the ability of its various sealing components to prevent medium leakage. There are three sealing points in a valve: the contact area between the closing member and the valve seat sealing surface; the interface between the packing, the valve stem and the stuffing box; and the connection between the valve body and the bonnet. Leakage at the first point is termed internal leakage, whilst leakage at the latter two points is termed external leakage, meaning that the medium leaks from inside the valve to the outside.
