Shear clips design

The shear clip must be designed to break away from the vessel wall at some predetermined stress. Otherwise, a powerful pressure surge could deform the wall of the vessel itself. However, if the shear clips can be designed to be strong enough to withstand a AP across the tray deck of about 0.6 psi (i.e., about 2 ft of hydrocarbon liquid) the downcomers would blow clear before the shear clips would fail. Hence, the downcomers would act as a partial safety bypass and protect the tray decks from damage. 

Bolt the trays to the tray ring, or use back-to-back trays with shear clips (see my book. Process Design for Reliable Operations, for mechanical details). This will help to avoid tray failures due to pressure surges caused by high liquid levels. 

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