Regarding the “opening for connecting jacketed equipment,” can a sleeve be omitted?
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This post was last edited by Douman on 2018-5-18 07:58. The opening structure for connecting the sleeve equipment is as specified in the standards; however, in one of the drawings, no sleeve is provided – instead, the connection pipe is welded directly to the inner and outer cylinders, as shown in the diagram on page 2. (The image failed to upload correctly when the post was first posted.) ) This is theoretically feasible, but how is lofting done in actual manufacturing? I wonder if those who work in the production field have done this before? Is this structure on the 2nd floor reasonable? Give some advice.
There are no restrictions on such a structure in terms of standards, but the welding of the take over to the inner shell can only be done from the inside, while welding to the outer shell can only be performed from the outside. It is not suitable for materials with large differences in linear expansion coefficients, as it results in high additional stresses.
First, weld the nozzle to the inner cylinder, then weld it to the jacket, and finally weld the nozzle to the pipe flange.
This structure is generally not used, as it has poor constructability and high thermal stress.
In the first case, I have seen it being processed by equipment manufacturers, with heating and hammering being carried out on-site
However, it is feasible from a manufacturing perspective, but the structural design is unreasonable; with the connections located in the middle part of the jacket, issues such as stress, corrosion, and leakage arise, and these problems are difficult to address.
The first type of structure is quite common; if the inner cylinder is made of stainless steel and the jacket is made of carbon steel, a gasket ring is added. I’ve never heard of a situation where this cannot be done.
Is the method shown in the pictures on the 2nd floor quite common?