Ben McAlonie

Background

As an avid backpacker and engineer, I am always looking for ways to make the outdoors more accessible and easier for all. Clean water is vital to any outdoor adventure, but miles into the wilderness most water sources contain particles and bacteria that can be dangerous for human consumption. Current water purification methods commonly include UV Lights, Charcoal Pumps, Iodine Purification Tablets, and Squeeze Filters. However, these come with challenges for backcountry use. UV Lights do not filter out particulates and take a long time to work, Charcoal Filters are complex and heavy, and Iodine Purification Tablets taste strange, do not filter particulates, and take a long time to work. For these reasons, squeeze filters are by far the most popular way to purify water on the trail. They are also the cheapest, lightest, and longest-lasting purification method.

The Problem

The process of using a current squeeze filter is as follows: First, dip a pouch into water to fill it. Then, screw on a filter, and squeeze the water through it and into a bottle. Or, screw the filter directly onto the bottle and drink through it. The problem? These two methods take a long time (4 fill-squeeze-bottle cycles for just 2L of water). This is usually a 10-15 minute process that could be only a couple as a Sawyer Squeeze model has a flow rate of almost 2L/min. In the winter, touching cold water can also pose a risk of frostbite or hypothermia.

Engineering Solution

To eliminate the issues associated with Squeeze Filter use, a pump apparatus was designed to work with the squeeze filters. This pump utilizes the effects of pressure differences with a check valve to suck in water, then push it through the filter. To use it, simply screw it onto a Sawyer filter, and pump the handle in a reciprocating motion. Benefits of this design include:

An overall reduction in water filtering time.

Reduced contact with water sources, significantly reducing the possibility of injury due to cold exposure or bacterial infection.

Fewer components are needed as compared to charcoal or UV filters resulting in a more robust and lightweight design.

Instantaneous clean water, no need for a cleansing period like with a UV light or purification tablets.

Use Case

Although this concept is designed for recreational outdoor use, I hope that it could also be used for humanitarian aid as it essentially turns a slow-flowing, awkward filter into a fast-flowing, easy to use clean water source. This design is small and lightweight and could be shipped all over the world. It would be an easy way to inexpensively provide clean water to a large group of people, with the only power input being human muscle.

Current State

As of 1/1/2024, the design has been completed and I have presented the idea to some of my professors and engineering mentors. Due to the material surface requirements, the main body of the pump must be smooth and uniform. Ideally, I would resin print a prototype for testing, but I do not have access to that technology. When I do, I will resume this project and complete testing and design iteration.

Next Steps

The first model is complete, and the next phase of development will be prototyping with a 3D-printed case and handle, and the rest of the parts sourced from online distributors. After a working prototype is created, field testing will be next. Then, depending on the results, more design iteration may be required. This will be continued until a final product is completed.

Wilderness Clean Water Filter