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Valves are very common in various chemical processing activities and are often referred to as the \"throat of pipelines.\" However, they tend to be problematic, suffering from various types of failures that cause headaches for their users. Leaks, production disruptions, and serious accidents resulting from issues with valve performance and quality result in immeasurable losses to the normal operation of industrial production, as well as to human safety and property. It is therefore essential to strengthen the maintenance and care of valves. The importance of valve maintenance: In chemical production, significant losses often arise due to issues with valve performance and quality, so this aspect must be given due attention. In 2005, when the catalytic cracking unit of a petrochemical plant was started up, the gasket on the cover of the gate valve suddenly failed, causing a large amount of hot oil slurry to leak out and generating thick clouds of smoke. In 2012, a malfunction occurred in the inlet valve of a fuel tank at a company in Shenzhen; the valve gate separated from its linkage, resulting in the leakage of over 1,200 tons of gasoline from the valve. One maintenance worker died as a result of suffocation due to the oil and gas fumes during the efforts to deal with the incident. In 2014, a 20-ton natural gas tank truck on the highway leaked due to a broken valve. Causes of valve failures and maintenance I. Leaks at the gasket area Reasons for leaks at the gasket area ● The gasket is not resistant to corrosion, high pressure, vacuum, high temperatures, or low temperatures. ●Unstable operation causes fluctuations in valve pressure and temperature. ●The clamping force of the gasket is insufficient. ●The gasket is not properly assembled, resulting in uneven stress distribution. ●The gasket surface is rough and contains foreign objects. Maintenance for leaks at gaskets ● The material of the gasket should be selected based on the operating conditions. ●Carefully adjusted for smooth operation. ●The bolts should be tightened evenly and symmetrically. ●The gaskets should be fitted under even stress; overlapping gaskets are not allowed, nor is the use of multiple gaskets. ●Be careful to keep it clean when installing the gasket; clean the sealing surface with kerosene. II. Reasons for the detachment of the closing element ● Improper valve operation causes the closing element to get stuck or go beyond the top dead center, leading to damage and breakage at the connection points. ●The closing element is not firmly connected and loosens, falling off. ●The wrong material was chosen for the connectors, which cannot withstand corrosion from the medium and mechanical wear. Maintenance ● The connection between the closing element and the valve stem should be proper and secure, and a backstop should be provided at the threaded connection. ●The fasteners used to connect the closing element to the valve stem must be resistant to corrosion by the medium, and they should also possess sufficient mechanical strength and wear resistance. Although the separation of the closing element is rare, it is a very dangerous fault. ●To operate correctly, do not apply too much force when closing the valve, and do not open it past the top dead center; after the valve is fully open, turn the handwheel slightly in the opposite direction.