Seeking help with gate valves and flanges issues
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Questions: 1. If there is pressure in both sides of a regular gate valve, does the valve achieve double-sealing or single-sealing once it is closed? 2. What do the technical specifications for flanges mean? For example, does a flange specified as 80 refer to an inner diameter of 80? And what does 30 kilograms per square centimeter mean regarding flanges? Thank you
Answering your second question: the 80 for the flange refers to the nominal diameter, not the inner or outer diameter. Common ordinary steel pipes include those with dimensions of 89*4.5; the value of 30 kilograms refers to the nominal pressure. Each type of flange has a specific pressure rating, and for the same type of flange but at different pressures, certain parameters may vary, such as the flange thickness, the number of bolt holes, and the hole spacing. When selecting or using it, it is essential to strictly follow the standards; otherwise, it may not be usable after purchase.
Answering your first question: it should be double-sealed, because whether there is pressure at one end or at both ends, it is designed with two sealing surfaces
Answering your second question: DN80 refers to the nominal diameter. Different types of flanges are welded to steel pipes in different ways, and their inner diameters also vary. 30 kilograms represents the nominal pressure of the flange, which is approximately 3 MPa; the nominal pressure of the flange is chosen based on the operating pressure of the medium
DN80 refers to the nominal diameter, while 30 kilograms denotes the nominal pressure of the flange, which is approximately 3 MPa. The nominal pressure of the flange is chosen based on the operating pressure of the medium
I’ve learned some new knowledge again; thanks to the original poster
Gate valves have double-sided sealing, while globe valves have single-sided sealing.