Valve leakage and sealing technology
Introduction
As valve technology develops, engineers are constantly striving to reduce leakage, especially in applications that require a greater degree of accuracy and reliability. This paper will discuss the various technologies used to reduce and eliminate valve leakage, and how those technologies have been applied to specific types of valves.
Overview of Valve Leakage
Leakage is a common problem for many types of valves, though the sources and types of leakage vary depending on the type of valve being used. The most common types of valve leakage includes: incomplete seating, pressure, temperature, corrosion, and wear. Incomplete seating is caused by an improperly fitted valve seat, improper installation, or an obstruction in the valve passage preventing it from fully closing. Pressure leakage, also known as dynamic leakage, occurs when the pressure of a liquid or gas passing through the valve exceeds the closure force of the valve, resulting in a small amount of fluid passing through the seal. Temperature leakage is caused by the thermal expansion or contraction of the valve, resulting in a gap between the valves mating surfaces. Corrosion can also cause a leak by eroding the valve seals, resulting in an imperfect seal. Finally, wear can occur over time, resulting in a gap between the valves mating surfaces.
Valve sealing technology
To reduce or eliminate leakage, engineers utilize a variety of technologies and techniques to achieve a tighter fit between the valves mating surfaces. These technologies include precision finishing techniques, differential pressure techniques, and environmental sealing techniques.
One of the most common techniques used to reduce valve leakage is precision finishing, which is a process that is used to achieve a high-level of surface accuracy and tight fitting seals. The process involves grinding and polishing the valves mating surfaces to a mirror-like finish, allowing for a tighter fit when the valve is closed. This process is most commonly used on metal valves, though plastic valves can also benefit from this technique.
The differential pressure technique is another common method used to reduce valve leakage. This technique utilizes different levels of pressure on either side of the valve to maintain a tight seal. By measuring the pressure differential between the inlet and outlet of the valve, any increase or decrease in pressure can be accounted for, ensuring a stable and tight seal.
Environmental sealing techniques are also employed in order to reduce and eliminate valve leakage. These techniques include the use of o-rings or gaskets, which are designed to create a barrier between the valves mating surfaces and the surrounding environment. O-rings and gaskets are particularly useful when working with valves in harsh and corrosive environments, as they provide an additional layer of protection against leaking fluids.
Conclusion
Leakage is an important issue for many types of valves, and engineers are constantly looking for ways to reduce and eliminate this problem. By utilizing the various technologies and techniques outlined in this paper, both metal and plastic valves can be engineered to provide a tighter and more reliable seal, aiding in the prevention of leaks and other related issues.
