Cover for porthole in container wall

摘要

The cover has a flange (18), which engages over a collar (12) around the porthole. It also has an insert, formed as a ventilated hollow body. This projects into the collar, and completely fills the aperture. The body interior communicates with the container interior via a ventilation pipe, pressure relief pipe, etc. A seal (28) is located between insert and collar, to seal the insert on the level of the container wall. Collar and insert are cylindrical. The seal engages into the rounded transitional sections of container and insert.