Patent ID: 7179312

Claim:
A process vessel which includes a body defining an interior vessel surface; a catalyst bed in the body; and retaining means on the catalyst bed for retaining the catalyst bed in position, the retaining means including a generally horizontally extending layer of tiles or bricks laid on top of the catalyst bed, the layer of tiles or bricks allowing fluid to pass downwardly through the layer, the vessel including a plurality of spaced formations for trapping solid objects whirled about in an annular zone above the retaining means by a fluid passing through the vessel, which whirling solid objects can erode the interior vessel surface above the retaining means, each formation being defined by a tile or brick in the layer having an increased depth or thickness compared to the depth or thickness of other tiles or bricks in the layer and thus projecting above the other tiles or bricks in the layer, some of the tiles or bricks being regular hexagonal in plan view, some being trapezoidal and half of a regular hexagon in plan view, and some being pentagonal shaped in plan view, allowing the tiles or bricks to be laid out next to one another in abutting side by side relationship in a horizontal plane to form a roughly hexagonal plane figure in outline in plan view having extremities which fall on the outline of a hexagon and a circle.