"瓮染料制剂桶" can be translated as "vat dye preparation barrel" or "vat dye formulation container".
“Vat dye” refers to a type of dye that requires reduction in an alkaline solution (vat) before it can be applied to the fabric.
“Preparation” or “formulation” indicates the process or result of mixing the dye with other necessary components to make it ready for use.
“Barrel” or “container” describes the physical vessel used to hold the dye preparation.
In context, if emphasizing the industrial or manufacturing aspect, "vat dye preparation barrel" might be more appropriate. If focusing on the general storage or transport aspect, "vat dye formulation container" could also be used.