hand sanitizer bottle dispenser

A project log for Hands-Free

hacks to avoid touching shared surfaces in public spaces

John OpsahlJohn Opsahl 04/11/2020 at 17:220 Comments

In response to the Coronavirus pandemic distilleries have begun to offer hand sanitizer in one liter plastic liquor bottles. This log describes a hack to add a self sanitizing dispensing mechanism to these bottles for less than $5. Simply mount the bottle upside-down and tap to the bottom of the mechanism to dispense hand sanitizer.

I designed a 3D printed part to fit around the existing bottle cap. It provides a surface that the spring can be loaded against and clearance from the bottle cap for the rubber stopper to travel within during the dispensing motion. Sanitizer flows through the slotted holes of the part.

A hole is drilled in the bottle cap the size of the tapered rubber stopper. The spring pulls the rubber stopper against the bottle cap (via the the bolted connection) to create a water tight seal. The seal is broken and hand sanitizer flows through the hole in the bottle cap when the user presses on the head of the bolt and compresses the spring.

The build was successful but I found a few things I would consider on the next revision. The rubber stopper absorbs the alcohol and swells so I had to cut it down a little to get it to seal against the bottle cap properly. It took maybe two or three tries to get the right rubber stopper shape. I will consider extending the clearance from the cap to the 3D printed part and different ways to cut the stopper to make it work the first time. Additionally, after a dispense, the alcohol continues to drip for three or four drops from the head of the screw. Not a big issue since alcohol evaporates and doesn't create a wet spot below the dispenser, but it's also not ideal. I will consider extending the slotted holes in the 3D printed part towards the tip so there is a more direct flow path to the head of the screw and less opportunity for the sanitizer to pool behind the tip and flow slowly through the bolt hole.