This is a The Simplo Filler I never saw one before or even heard of it.
I believe is from around 1912, it has a bar inside the barrel and a hole to press the bar and the sac (a system similar to the Waterman that used a coin) through a fixed extension on the cap top... The barrel imprint: The Simplo Filler and in a second line Pat. Aug 2 and impossible to read the year.
I believe is worth to see it, so some images for you...