Molded hollow concrete unit e.g. septic tank, has lateral walls with one wall comprising opening that is sealed by removable rigid gate which maintains shape and position of joint and protects lip of joint

摘要

The concrete unit (1) has lateral walls (3) with one of the walls comprising an opening (4) provided with an annular joint (6) and sealed by a removable rigid gate (9), where the joint assures sealing with a tube (5) to be connected to the unit (1). The gate cooperates with the joint for forming an annular chamber in which a lip of the joint is housed. The gate maintains the shape and position of the joint during the fabrication of the unit (1) and protects the lip. The joint has two edges that are arranged to axially move the gate into the unit (1) to free the joint.