How are the external dimensions of butterfly valves determined?
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The last edit to this post was made by manman2000 on 2012-7-5 at 10:57. I would like to ask everyone: how are the external dimensions of butterfly valves determined? Apart from the connection dimensions, structural length, and minimum wall thickness, how are standards established for other dimensions, such as the height of the valve? I’ve noticed that domestic manufacturers simply copy existing values for these dimensions, without having any method to determine them themselves
Once the main connection dimensions of butterfly valves, such as flange sizes, length, and wall thickness, are determined, there are no unified standards for the rest; each manufacturer designs them on its own.
Each manufacturer provides drawings of the valve’s appearance; you should use these drawings as a guide to choose the appropriate valve based on the size of your installation site. Generally, this doesn’t have much of an impact, as valves are standard products that can be used in most situations.
The sizes are indeed not the same; different manufacturers result in different dimensions. For example, the height of valves produced by Tianjin Watts and Shangdie is different. There isn’t much difference for newly installed valves, but more attention is needed in case of existing pipeline systems.
May I ask, is there any standard for the height of their valves, or is it determined by some factor to establish a minimum height value?
The structural length of a valve is the distance between the two end faces where the valve is connected to the pipeline; I believe the height referred to by the original poster is actually this structural length. When ordering butterfly valves, we usually only provide information such as the valve model and diameter, without specifying the length and dimensions of the valve; however, there are indeed standard values for the length and dimensions of such valves. GBT12221-1989 specifies the nominal lengths of wafer butterfly valves and flanged butterfly valves, while ASME B16.10-1992 also specifies the nominal lengths of some types of valves. Furthermore, I think the lengths of these structures merely provide some standards; manufacturers simply follow these standards when producing products, but errors may occur, resulting in variations in the height and dimensions of the valves
There are standards for the structural length, as well as for design and flange connections. What I would like to ask now is regarding the height of the valve: is there a minimum distance between the center of the valve and the upper flange of the butterfly valve? How can this be determined?