Valves are control components in fluid transport systems. They can be used in fluid control systems to control the flow of various types of fluids, including air, water, steam, various corrosive media, mud, oil, liquid metals, and radioactive media. Standards for Determining Internal Leakage in Valves The method for determining internal leakage in valves is as follows: After the valve has been closed for 4-6 hours, use an infrared thermometer to measure the metal temperature at the valve stem (near the valve body) or 150mm downstream of the valve body. If the temperature exceeds 70℃, it is considered an “internal leak.” This method is applicable to most valves with internal leaks.

With increasing global awareness of environmental pollution in recent years, countries and the world are striving to develop clean energy to gradually replace polluting traditional energy sources, providing impetus for development. In particular, liquefied natural gas (LNG) and liquefied petroleum gas (LPG) are rapidly emerging as new energy sources worldwide. This has led to the development of more similar cryogenic operating media, with LNG, CNG, liquid oxygen, liquid nitrogen, and liquid hydrogen being the most widespread.

Gate Valve Definition: A gate valve is a valve that opens and closes by moving its gate perpendicular to the direction of media flow (channel axis). Among various types of valves, the gate valve is the most widely used. Gate valves are mainly used in pipelines to cut off the medium, i.e., fully open or fully closed. They are suitable for low temperature and low pressure as well as high temperature and high pressure, and can be used for various media depending on the valve’s material. Component Names and Terminology: A gate valve mainly consists of a valve body, valve cover, bracket, valve stem, valve stem nut, gate, valve seat, stuffing box, sealing packing, upper sealing seat, packing gland, and transmission device. Characteristics of Gate Valves: Gate valves have the following advantages: ♦ Low fluid resistance: The media channel inside the valve body is straight, and the medium does not change its flow direction when flowing through the gate valve. ♦ Lower torque required for opening and closing; ♦ Can be used in ring network pipelines where the medium flows in both directions, i.e., the flow direction of the medium is not restricted. ♦ Relatively simple structure, easy to manufacture. ♦ Good sealing performance: minimal erosion of the sealing surface when fully open.