May I ask how to determine the flange standard based on the flange dimensions?
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I would like to ask everyone: when I measure the dimensions of a flange on-site, can I determine what flange standard it belongs to based on those dimensions? If two different standards are found to give dimensions similar to those I measured, which one can be chosen arbitrarily?
The flange standards commonly used in our engineering work are HGT 20592~20635-2009 for steel pipe flanges, gaskets, and fasteners; these standards include both Chinese and American specifications for flanges. Standard flanges are basically all included here. It’s hard to say if it’s a non-standard flange. . .
More or less, it also depends on whether it is within the tolerance range.
Isn’t there a label on the flange? Is it non-standard? ? Should non-standard items also have their size indicated?
Yeah, the flange should have markings on it
Many of the flanges on the field equipment don’t have any markings; I need to measure them in order to determine the specifications and standard numbers, so as to decide on the appropriate connection flanges for the custom-made instruments
Measure the outer diameter, center it in the screw hole, and measure the inner diameter; you can find this information by checking the pipe material table.
Currently, there is indeed a lot of overlap between domestic national standards and industry standards. In the new version of GB, the first half is basically consistent with the European HG system as well as DIN and BS standards, while the second half is also similar to ASME SH and other standards. As a result, many flanges meet the requirements of multiple standards. How should such flanges be classified? When classifying industries, for example, in the chemical industry the industry standard HG is preferred; in the petrochemical industry, SH is the preferred standard; in the machinery industry, JB is preferred. For almost all other industries, GB is the standard used