Issues with non-standard manholes
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Some time ago, I received a drawing from a client; it was an old design for a buffer tank. The designed pressure was 1.0, the temperature 200 degrees, and the medium involved was steam. However, the client requested that the manhole be of DN400 size with a vertical lifting lid. But the new standards do not provide manholes of this size with vertical lifting lids. There are two options: one is to create a custom part drawing for the manhole, and the other is to use a manhole according to the old standards. Which option is feasible and why? Thank you all for your attention! xuanze Last edited by yuchenjoy2008 on 2009-3-5 08:29 ]
Create a custom manhole part drawing based on the old standard, as the standard has been replaced.
I don’t understand why the moderator deducted my points; it’s so discouraging! ! Please give me an explanation!
I think either one will do, because the old standard has been in use for many years; since there is no new standard, the old one can be used. However, the components used must be changed to the new standards currently in use.
Since the old standard is no longer available, a part drawing for a non-standard manhole should be created.
Let’s go with something non-standard then. But why make it 400? It’s not convenient either. It’s recommended to change it to 500 or 600
Or refer to the design for 450; it shouldn’t be complicated~
In HG/T21514~21535-2005 \"Steel Manholes and Handholes\": GH/T21520-2005 \"Manholes with Vertical Lids, Necked Butt-Welded Flanges\", the pressure range is from PN1.0 to PN1.6, and the applicable temperature range is from -20° to 500° (although this depends on the material used for the container). You should be able to use this standard.
1. Follow the old standards; 2. Design a non-standard structure of 400 based on the new standards; 3. Replace the DN400 size with DN450 or DN500 according to the new standards. All three options are viable, but personally I recommend the third option.
It is possible to create a non-standard manhole by referring to the dimensions of manholes specified in a new standard. It is quite common to provide drawings for manholes; usually, for manholes on high-pressure equipment, which do not have such high nominal pressures, non-standard designs are required. In this case, it is necessary to use pipe flanges of the appropriate pressure rating, along with connecting pipes; suspension columns or rotating shafts can be attached in accordance with the standards for manholes. This post was last edited by ripdover on 2009-3-9 at 09:12.]
I designed it myself; the old standards cannot be used directly. It’s actually quite simple – just a flange plus a flange cover, along with components for an additional rotating lid