Will the external heat tracing coil affect the container classification?
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The heat tracing tubes on the outer wall of the atmospheric-pressure vessel (full-length tubes, not those welded to the outer wall in a semi-length format) have a pressure of 0.4 MPag and a diameter of 25 mm; they are wound around the vessel in multiple loops. Should the coiled tube be taken into consideration when classifying? Should such containers be classified in Category 1 according to the new regulations? Can the design of the heat tracing tube be based on 150?
The heat exchange tubes do not affect the classification of the container
For pressure vessels with an inner vessel at atmospheric pressure and accompanying pipes, the classification must take these pipes into account; such vessels are classified as Class I. The relevant standard specifications should be indicated in the technical characteristics table: for the inner vessel, refer to NB/T47003.1, and for the accompanying pipes, refer to GB150 (including Amendment No. 2)
Regarding the device you mentioned, it is not classified. If the nominal diameter of the accompanying pipe is greater than 25 mm, it can be considered as a pressure pipeline.
The heat tracing tube on the outer wall of this atmospheric-pressure vessel is a full-length tube (not one that is welded to the outer wall in a semi-length format); its pressure is 0.4 MPag and its diameter is 25 mm. Since its inner diameter is less than 25 mm, it constitutes an atmospheric-pressure vessel. If it’s a half-tube container, then it falls into that category