Boiler manhole
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Is the thickness of the splice not specified in the boiler manhole standards? How to choose? Thank you!
When placing the order, specify that the material standard for the tube sections should be 20 (GB/T9948-2013). Otherwise, the boiler material is used by default. In this way, when performing calculations in the software, the boiler material is not shown. Or use other algorithms.
Refer to the General Parts Catalog for Industrial Boilers. There are relevant data in this album.
My understanding is not 19mm. 19mm refers to the width of the sealing surface. For example, if a manhole without a reinforcement ring is used on the head and the thickness of the head is less than 19 mm, then a sealing ring made of the same material as the head is usually fitted (welded) on the outside of the manhole’s flange, after which the sealing surface is prepared. So I have the same question as the original poster. The thickness of the reinforcement ring for the handhole section in this standard is also not specified.
No, every boiler factory has a copy of this catalog. In previous boiler drawings, components such as furnace doors could be referenced directly using the diagram numbers from the atlas, without needing to be drawn separately. In strength calculations, the nominal reference thickness of the stiffening ring is taken from the atlas. In the manufacturing of components such as manholes, manufacturers not specified by standards also produce them according to the thickness indicated in the drawings, unless a different thickness is specified by design; for example, setting the thickness of the reinforcement ring to 30 mm for a pressure of 25 kilograms.
This issue exists not only with boilers, but also there are no clear specifications regarding the thickness of all open-ended connections in containers. The reason is that the drafters of the national standards believe that as long as the thickness of the perforated pipe meets the reinforcement requirements, it will certainly satisfy the strength requirements for the internal pressure of the medium. Therefore, no regulations are needed. But in reality, ASME does not think in this way; therefore, clear provisions are made in Volume I, PG-43. Additionally, the manholes on boilers are usually designed with internal flanges and no short sections; what type of boiler is this?
The manholes on the cover are usually flanged, though there are also some cases where the holes are made directly. When manholes are installed on the cylinder, those with reinforcing rings are always used.