Sheaffer White Dot
Military Clip Mint Condition Lifetime Nib No Scrapes, dents, or cracks Sheaffer introduced the plunger fill Vacuum Filling system in 1934, initially on second brands including the "Vacuum-Fil" pen and the WASP line. This sacless filling system used a long syringe-like plunger rod tightly fitted into a cylindrical ink chamber that on the downstroke creates a vacuum inside the ink chamber that draws ink into the pen through the feed. Sheaffer adapted this filling system to the Balance line in 1935 and advertised this system side by side with the proven lever filler. This type of filler was not unique, with Conklin, Wahl Eversharp and numerous second tier manufacturers using similar plunger systems in their pens.
The Vacuum Filler is actually counterintuitive in its operation. Many people are familiar with how a syringe works. Pull out the plunger and the liquid is drawn into the chamber, push the plunger in and the liquid comes out. Simple enough. The problem is in what to do about the plunger sticking out of the end of the barrel while using the pen. It makes putting the pen in the pocket a bit cumbersome as well.

When the plunger in the Vacuum Fill pen is pushed back into the barrel, this action pushes the air inside the ink chamber out, creating a vacuum that rapidly draws ink
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