….so as to cause violent water hammering of the drum inlet line…..
This does not sound like a good idea.
Your inlet line should be clean after the steamout to fractionator & blowdown.
Do you inject steam before the drum switch ?
Since you have a “hat”, I guess that you remove the bottom head (manually or remotely) to remove the coke from the drum. You should be able to inspect it to see if it is plugged.
Regards,
CG
