Intro: Sterile Water Metering
This page provides instructions to create a metering device for the developing world that can withstand volume addition and accurately dispense five doses. This project was funded by Duke University Biomedical Engineering and was completed under the supervision of Robert Malkin, PhD.
Step 1: Acquire 10mL Syringe
Acquire a 10mL BD Syringe. ($0.25-$0.50 ea. depending on size of order)
http://www.coleparmer.com/Product/BD_syringes_non_... for ($0.40 ea.)
Step 2: Remove Printed Lines
Using a cloth or sponge rub against the printed lines of the syringe vigorously until the gradations are removed.
This may take a considerable amount of effort. Consider using a cleaning product or ethanol for ease.
Step 3: Draw New Syringe Lines
Using a permanent/water-proof pen draw new lines on the device in 2mL gradations.
The best way to do this is to:
(1) acquire a small medicine cup
(2) tare cup on scale
(3) add water carefully into cup until the scale reads out 2g (density of water is 1g/mL)
(4) take up the water in the cup with the syringe
(5) draw line at meniscus
repeat this four times (fifth time is unnecessary, but shouldn't lead to confusion regardless )
Step 4: Cut Styrofoam
Cut a piece of styrofoam to the following dimensions: 1.5"x1.5"x0.5"
In the center of the rectangular prism, cut a 0.7 cm diameter hole.
This is easiest to do by finding the center point by drawing lines from the diagonals across.
At the intersection of the two lines, place the tip of the syringe and slowly push in while twisting.
Do this until portion of styrofoam is removable. Clean with razor.
Step 5: Add Styrofoam Ring Onto Design
Slide the styrofoam prism up to the top of the syringe.
Step 6: Tape Tip Weights
Add makeshift weights.
Remove a piece of electrical tape (approximately 6 inches) and place 4 nuts (1.2 g ea.) on the sticky side.
Wrap the tape with nuts around the syringe tip.