Why are valve flanges smaller than standard flanges
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The standard chemical industry flange has a diameter of DN150 and PN63, with an outer diameter of Φ345; whereas the flange for valves with DN150 and PN64 standards also follows these industrial standards, but its outer diameter is Φ340
Because the outer diameter of the flange for the DN150 PN64 valve, according to the old mechanical industry standards, is Φ340
HGT 20592-PN63-DN150: the outer diameter of the valve’s flange is also Φ345
The standard for flanges in the Chemical Industry Department is HG/T 20592-2009. What is the chemical industry standard for the flanges of valves you are referring to?
It’s probably due to different implementation standards
1. If the same standard number, grade, and specifications are used, the dimensions will match. 2. “Chemical industry standards” do not necessarily mean the use of the same standard number; for example, there are European and American series within chemical industry standards. 3. When there is a mismatch in dimensions, it is likely that the standard numbers are different
It seems you bought the wrong valve. . . .
That is, the flange of the valve does not meet chemical industry standards; if it were to be in accordance with such standards, its outer diameter should be 345, right?
If the flange standard for the valve is based on chemical industry standards, it should be 345, right?