Fig. 3. Cross-section illustration of the O-ring guided alignment and leakproofing at the end of a rotation.

a When the corner block is not rotated to the right position, a gap exists between two blocks that will cause leakage. b When the corner block is rotated to the right position, the O-ring embedded into the edge block will automatically fit into the concave on corner blocks, ensuring a self-aligned and leakproof connection of two blocks