Copper Pipes

Fill Copper Grates with water to create pipes.

Item Transport

Dispense items into the grates to transport them around.

Use bubble columns to push/pull items up/down the pipes.
Downward bubble columns will pull items into the pipe.

Heated Pipes

Use a campfire to fill the grates with smoke.

The grates will heat up, damaging any mobs standing on them.

This can be combined with water to create pipes that collect dropped items in mob farms.