Thermoplastic bottle with welded-on metal seal - notched at the neck, so that an imperfect weld will easily reveal itself

摘要

Thermoplastic bottles are closed at the neck with a metal seal held in place by thermoplastic welding. The neck of the bottle is notched. The weld must then go deep enough to take the seal to the level of the bottom of the notches; failing this, a notch will be left open, and a test of the bottle by trying to pour out its contents will reveal the faulty weld. This is a protection against faulty machine action for bottles with corrosive contents, and as preventing the detachment of loosely fixed duty-paid seals for fraudulent re-use.