The installation hole dimensions and overall dimensions of flanges HG20592-97 and HG20592-2009 are different
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It was recently discovered that for flanges HG20592-97 and HG20592-2009, even at the same pressure rating and with the same specifications, the sizes of their mounting holes as well as their overall dimensions differ; it’s quite confusing
HG20592-2009 replaces the HG20592-97 standard; the standard flange to be used can be selected as needed. Additionally, modifications to the old standards are proposed in the new standards, which can be referred to.
The standards for HG20592-2009 PN0.25-PN1.6 are not available online; only those for PN2.5 and above exist. What’s going on?
Because the specifications specify steel pipe flanges and flange covers suitable for nominal pressures of PN2.5 to PN160 Kg. In standard 97, it applies to steel pipe flanges and flange covers with pressures ranging from 0.25 to 25 MPa. The required unit has changed, but the connection dimensions remain essentially the same
97 uses the MPa unit, while 2009 uses the bar unit. In fact, 2.5 in 2009 is equivalent to 0.25 in 97, right? Let’s learn about this together
In the old standards, PN is expressed in MPa, while in the new standards it is expressed in bar, which is equivalent to the previous Pg. This is chaos created artificially; it is recommended to write it as PN2.5MPa