The link you provided seems to be a kind of complex system. I have seen other surge devices that are much simpler and have very few moving parts.
The above is an article written by the Director of the Waikiki Aquarium in HI. They have a huge surge device on one of their outside aquariums. A simple diagram is included in the article.
The above link shows you a much smaller version of the same surge device design.
This is a great way to reproduce natural currents in your tank. If you have been snorkling or diving in a reef you know that the currents while they are strong do not always come from 1 single direction. A surge device will send a predticable surge of water/energy thru the system. The net result is high flow with random direction.