As is obvious from my previous questions, i'm very curius to learn as much as i can about Leibniz's inventions, simply because i think his inventions contain that kind of technological ingenuity that enabled later technical developements to emerge. This queustion asks what were the original ideas that Leibniz introduced in the design of the pumps of this fountain - i read that in his time this fountain was the highest in europe, with it's water reaching a height of 40 meters.
In fact, Leibniz is the father of the fountain. He supplied the decisive ideas in 1696 but died before the fountain could be finished.
Leibniz first recognized that enough water has to be supplied. This was realized by a channel from the nearby river Leine which had to be damed by a weir. The heart of the device is a two storied Wasserkunst (something he also had improved for the mining industry in the Harz mountains) consisting of a water wheel and four water pumps, two of which had to pump the water into a 12 m high container. The other pumps had to pump the water into a completely new invention: the Windkessel, a device to compress air such that finally the fountain should reach a hight of 35 m, according to Leibniz' calculations. (And we can state that he was better than Euler whose construction of the fountains in the garden of Sanssouci Frederick the Great always gave reason to complaints.)
Leibniz ideas have been applied and even improved after his dead by Johann Christian Böhme, such that a hight of 67 m was reached. Today, with electric power, even 82 m are reached.
For facts and photos see technikatlas.