Takeover and flat cover welding structure
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This post was last edited by SDHZZXM on 2020-6-17 07:55. The manhole cover of a tank containing an explosive medium is equipped with multiple connections; it is difficult to achieve a fully penetrated welding structure for these connections and the flat cover (see figure). Is it possible to avoid a fully penetrative structure? If a fully penetrative weld structure is not used, how can one convince the inspection personnel? Welcome to participate in the detailed discussion...
What is the pressure level? Is it a special type of equipment?
GB/T150 specifies that in situations with rapid temperature changes or where it is prohibited by laws and regulations, non-full penetration structures cannot be used. . The thickness difference between the main pipe and the branch pipes is too large; consider other solutions and find a way to handle it with the connecting pipes. .
This post was last edited by SDHZZXM on 2020-6-17 08:52. The following are the provisions of TSG 21-2016; but does the manhole flange cover count as part of the shell?
A fully penetrative welding structure must be used, and the connection configuration between the lower nozzle and the cylinder can be altered
If a fixed installation is used, the extending pipe also has to be disconnected, which seems unreliable.
This is indeed rather troublesome. If the weld penetration requirements for the connections on the flange cover need to be met, the connection design between the pipe fittings and the flange cover should be changed to a socket-type structure.
Full penetration is required, as specified in the tolerance standards. I’m not sure if replacing the flange cover with a flange plus head would result in a thinner wall thickness, making welding easier. I just don’t know if it’s feasible.
The existing manhole cover is equipped with multiple connections, and it is unreasonable for the fittings on the newly added head to be located more than 80% of the head’s diameter away...
Actually, for this flange cover design, it differs from the usual connection between a housing and a pipe; it would be advisable to discuss this with the editorial board members.