Hi Pen Fans!
I always love it when a customer approaches me with new ideas, designs, filling systems, and challenges to consider.
I had a customer speak to me about a blow filler.
This is a filling system that was used very early in the history of pens. I'm not sure that it was a real lucrative filling system, as I've never seen one live, but it turned out to be very interesting and certainly fun.
With a blow filler, there is a sac attached to the section or housing which holds the ink. This is just like any other typical pen incorporating a sac as the reservoir, such as a lever filler, button filler, crescent filler, etc.
Each of these sac filled pens incorporate some way of compressing the sac. When you dip the pen in ink, compress the sac and then release, the result of the sac returning to it's shape will cause a vacuum resulting in ink being drawn into the sac.
In the case of a lever filler, there is a pressure bar that compresses the sac, activated by a lever. With a button filler, there is a pressure bar activated by a button on the bottom of the pen, with a crescent filler, the same applies, and you can guess what activates the pressure bar. 
So this pen fills the same way, but with an incredibly simple method of compressing the sac.
How does this pen fill?
There is a very small hole drilled into the bottom of the barrel, which is visible in the photos below.
The section threads are made very precise, to the point of where they are airtight.
This seals the barrel internally.
So to fill the pen, you insert the nib into an ink reservoir, and blow into this hole on the back of the barrel.
Since the interior of the barrel is sealed, blowing into the barrel increases pressure, causing the sac to compress.
When you stop blowing, the sac decompresses, drawing ink into the sac.
Two or three cycles of blowing into the back of the barrel will fill the pen completely.
The blowfillers of the past would typically not have an ink window. The customer who ordered this pen wanted some kind of way of knowing where the ink level was. We went with an ink window, and also a clear sac. This makes it easy to determine when it's time to refill.
This pen was also made from original Sheaffer Crimson stock. Very hard to find.
This was a seriously fun pen to make. It was really nice to revive a design from a very long time ago!
Brian at Edison
