A manhole issue encountered in the design
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One manhole encountered in the current design: Conditions: PN9.5MPa, design temperature 200 degrees Celsius； Manhole DN500, medium: syngas; shell DN2000, material: 304L+Q345R composite plate ； Design: Custom manhole; the flange connection surface requires an RJ design. Issue: The RJ connection surface is problematic – if surfacing is used, a very thick layer is needed to accommodate the grooves; whereas if no surfacing is used, according to pipe flange standards, if the flange material is 304L, then ASME B16.5 WN-RJ flanges and flange covers of size 20” and 1500BL must be used. Just the manhole flange and flange cover weigh over 1800 kg, resulting in high costs (all made of 304L) and significant weight. Question: Are there any good solutions available without modifying the RJ surface?
Compared to those made entirely of stainless steel, even if grooves need to be made in the RJ connection surface, a thick weld layer is required; therefore, using welding is much more cost-effective