Aspirator Ejector Pump for Vacuum filtration

thingiverse

This is a Aspirator/Ejector Pump for vacuum filtration. The STL model fits North American Garden hoses by default, and was tested on a resin printer. On line 218 there is a F5/quick-render issue in OpenSCAD documented. So one may need to press F6 to do the full-detailed render of the model to view in 3D. A Büchner funnel is also available for any sized paper: https://www.thingiverse.com/thing:4674108 Disclaimer: All numbers are approximate as this meter was flooded when the vacuum line returned to normal atmospheric pressure. Probably wise to add back-flow protection or a fluid trap to your apparatus. The design seems to work well, but to quantify how much it really sucks will ultimately be left to the reader. ;-) The vacuum gauge was likely rather inaccurate already, but we still check if the working fluid in the line remains under the vapor pressure limits of cold water. Pump Vacuum @4’C water temperature near sea level: -1.0 bar (meter scale) -29.5 inHg (meter scale) -14.5 psi (calculated) 0.014 atmospheres (calculated) A thermometer reading of the water temperature showed 4‘C average, and thus suggests a theoretical water vapor pressure limit of around 0.01 atmospheres minimum vacuum. Thus, the gauge data suggests the pressure remained 0.004 atmospheres above the theoretical minimum, or stated another way this suggests around 99.4% near the theoretical best vacuum for the design at this temperature. A rather dubious performance claim for any mechanism, and thus we conclude the design does indeed suck… but the vacuum gauge likely was inaccurate, and we must assume the performance will likely vary if you choose to test the design.