It has one input pipe for water and oil per column and it has 1 output pipe for gas and HO per row and 1 output pipe for LO per column. This means that there is an upper limit to how big a block of these things can be before saturating the pipes but once you reach it you will have a monstrous throughput anyway.
pics: http://imgur.com/a/AqNDS
Real life setup:
Water and oil come in from below and are divided among the columns. Then gas and HO are output to the right by each row separately and come together into a single pipe but you can of course keep the outputs of each row separate to fully utilize the throughput. LO goes up and is output by each column separately.
The directions of the oil, water and the products do not matter of course. It's up to you on which side of a block you collect the products.
The blueprint is a block of 1x3 refineries as outlined in the picture below.
A close-up:
blueprint