Diatom sampler - prototype 1

thingiverse

One of my colleagues is studying diatoms in lakes in Antarctica. To make this possible without getting wet in harsh Antarctic conditions, we developed a sampler that lets users scrub and siphon diatoms from almost 1m below the surface without touching the water. The hardware used is relatively inexpensive to produce, requiring only a handful of m3x20mm bolts and 2 m5 x 75mm bolts. Stainless steel hardware is recommended for durability. The poles are made from extruded aluminum with diameters of 16 and 25mm and lengths of 1m. Standard 50ml syringes with centered nozzles are used. This is our first prototype, and we have a long list of improvements to be incorporated into future versions. Some key areas for improvement include: • Reducing the overall size to make it easier to transport. Currently, the outer diameter is around 125mm, making it difficult to fit inside a protective tube. Ideally, we'd like to get this down to around 90mm so that it can fit in a PVC tube and reduce the amount of plastic required. • Improving access to the syringe inlet for cleaning and ensuring it's free from obstructions. • Making toothbrush clamps more adaptable, as the current design limits the width of the toothbrush and doesn't work well with angled brushes. • Using a rubber seal with mechanical attachment instead of glued foam. • Adding an outlet so that the sample flows out in a controlled manner when the syringe is pressed. • Creating a tool-free way to replace the syringe. To build this sampler: • Print all components, including two pole clamps and each toothbrush clamp. • Trim around 80mm from the 25mm aluminum pole, fine-tuning the measurement if necessary for the scrubber handle locking pin to fit. • Clamp the outer shield and pole clamps together, then slide a gasket onto the 25mm pole. • Clamp the scrubber onto the 16mm pole and attach the syringe clamp to the other 16mm pole. • Attach the second syringe clamp to the outer shield using m5 bolts. • Slide the poles together, clamp the scrubber handle to the top of the scrubber, and the syringe handle to the top of the syringe pole. Fine-tune the handle position if necessary for a secure fit. • Bolt the toothbrush clamps with open ends facing outwards, then slide in some toothbrushes and tighten the clamps. • Glue foam to the base of the shield so that it can seal against rocks. Some sanding may be required due to tight tolerances on some components.