запорный обруч(Bolt Ring Closure – A bolt ring is a closure ring that holds the cover on to the body of the container by encompassing the cover and the top of the container in a groove. This ring is then tightened by a bolt that pulls the ends of the rings together. A calibrated torque wrench is used to confirm proper closure (to meet UN Rating requirements) thecarycompany.com, gosthelp.ruFiriel)
быстродействующий затвор(quick opening closures are pressure retaining structures designed to provide access to pipelines and pressure vessels.) (синоним – байонетный затвор SergeyLetyagin)