National standard gate valve refers to a gate valve that complies with the Chinese National Standard (GB). Its closing element (gate) moves vertically along the centerline of the passage and is only used to fully open or close the pipeline medium, and cannot adjust the flow rate. This type of valve is usually made of steel structure, which has the characteristics of low fluid resistance, reliable sealing, and compact structure. It is suitable for industries such as petroleum, chemical, and power, and can handle media such as water, steam, and oil. The working pressure range is 1.6-32.0MPa, and the temperature coverage is -29 ℃ to 570 ℃. There are differences in unit system and flange parameters between its design specifications (such as GB/T 12234), structural length (GB/T 12221) and American standards.