Vacumatic

From Penpedia

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Parker's Vacumatic pen was introduced (under another name) in 1932, and claimed to abolish the rubber sac as a pen reservoir. This is not entirely honest, as the filling mechanism relied on a partially inverted rubber sac, but as the pen's barrel was effectively the reservoir it's a claim Parker could squeak through. The Vacumatic is in essence a bulb filler with complications, using a breathing tube to allow the displacement of air at the top of the reservior when the mechanism is operated, while drawing ink in through the channels of the feed (the different density of air and ink making it easier to drive out the air than the ink). The whole barrel could this be filled, up to slightly above the level of the breather tube, whose length was limited by the space required for the working of the mechanism. This filler was also fitted to some models of Duofold and to the earlier models of "51". The Vacumatic model of pen was officially discontinued in the late 1940s, although production outside the US persisted into the early 1950s.