Get our free book (in Spanish or English) on rainwater now - To Catch the Rain.

Straw Filter

From Appropedia
Jump to navigation Jump to search
MOST Delta filament as guide.JPG This page was part of an MTU course MSE4777 OA and MSE4777 OB/MSE5777/EE4777/EE5777: Open-source 3-D printing

Please leave comments using the discussion tab. The course runs in the Fall semester. It is not open edit.


Straw Filter[edit]

Project developed by Brad Revett (talk)
Status
This OSAT has been designed but not yet tested - use at own risk.
This OSAT has been prototyped.

You can help Appropedia by contributing to the next step in this OSAT's status.

Abstract[edit]

Having an instant source of drinking water anywhere you can find water is a hard thing to come by in the developing world and while out backpacking in nature. This 3D printable straw filter should allow for cheaper and more readily available access to clean water at a lower price as most of the components of a water filter are things we come across every day. The main components of most survival water filters today are gravel, sand and activated carbon. These three things in addition to a cloth of some sort to keep the described things from going into our water are what make up a water filter that will filter out most of the harmful things.

Fig 1: Assembled Straw Filter  
Fig 1a:Straw Filter 3D printed parts  
Fig 1b: Straw filter 3D slicer/print orientation  

Bill of Materials[edit]

  1. 3D printed bottom of the straw: Estimated cost is $0.62 based on 20$ for a 1kg roll of filament and an approximate use of 31g for the print.
  2. 3D printed top of the straw: Estimated cost is $0.30 based on 20$ for a 1kg roll of filament and an approximate use of 31g for the print.
  3. 1 inch O-ring $0.11 from amazon [1]
  4. Sand from the beach sterilized with hot water $0.00
  5. Small pea gravel sterilized with hot water $0.00
  6. Activated carbon: Estimated cost $0.38 based on $6.52 cost for 255g from Walmart and an estimate use of 15g. Alternative cost should be $0.00 from burning wood.
  7. Piece of cloth to keep materials in straw: $0.00 any piece of cloth laying around should work. Alternatives could include coffee filters or a purchased washcloth. 100 coffee filters for $1.50 from Walmart. Washcloths could be ordered from amazon $15 for 24 washcloths and only a small piece of the washcloth would be needed so the cost would be less than $0.10 per straw. [2]

Source Files[edit]

Source files can be found on youmagine here: [3]

Tools needed for fabrication of the Straw Filter[edit]

  1. MOST Delta RepRap or similar RepRap 3-D printer
  2. Fire for boiling water sterilization of parts and creation of activated carbon

Skills and Knowledge Necessary to Make the OSAT[edit]

  • If you used special skill – link to relevant wikipedia or wikiversity articles/courses

Technical Specifications and Assembly Instructions[edit]

Rinse all materials in boiling water before adding them to your filter.

Step 1 add pea gravel to bottom of straw  
Step two add sand to straw  
Step 3 add activated carbon to straw  
Step 4 roll up cloth of some kind  
Step 4 roll up cloth of some kind  
Step 5 insert cloth into straw  
Step 6 Add O-ring to straw top  
Step 6 Add O-ring to straw top  
Step 7 screw in the top to the bottom and enjoy  
  1. Print time estimate: 3.5 hours total, 2.25 hours for bottom and 1.2 hours for the top.
  2. Assembly time estimate once all materials have been gathered: 3-6 minutes.

Print Settings[edit]

Filament feed rate: 105% Print temperature for PLA 210C

*Top of straw filter

  • Layer height: 0.2mm
  • Wall line count: 4
  • Top and bottom layers: 4
  • Infill density 25%
  • Overlap percentage 10%
  • Print speed: 50mm/s
  • No print support needed
  • Build plate adhesion: brim or skirt

*Bottom of straw filter

  • Layer height: 0.2mm
  • Wall line count: 4
  • Top and bottom layers: 4
  • Infill density 100%
  • Overlap percentage 10%
  • Print speed: 50mm/s
  • No print support needed
  • Build plate adhesion: brim or skirt

Common Problems and Solutions[edit]

  • In slicing software rotate the top of the straw filter 180 degrees so that the threads are facing up to allow for a perfect print.
  • Also in slicing software scale the top to 98% to allow a 2% tolerance for the threads.

Cost savings[edit]

  1. Estimated cost of total device: $1.41 from the Bill of materials above.
  2. Commercial equivalent costs $19.99 from Dicks Sporting goods [4]
  1. $19.99 - $1.41 = Cost Savings of $18.58 and a 92.94% savings.

Benefited Internet Communities[edit]

  • Charity: water [5]
  • Water.org [6]
  • Columbia water center [7]
  • WATERIsLIFE [8]
  • The water project [9]

References[edit]