diff --git a/docs/project_notes.md b/docs/project_notes.md index 424cb19f..09f28c98 100644 --- a/docs/project_notes.md +++ b/docs/project_notes.md @@ -12,11 +12,11 @@ PIOC was taken apart to diagnose issues in the previous iteration. During testing the spool valves started to stick. They were disassembled which revealed significant zeolite contamination! The valves were cleaned and reassembled. An attempt to use the valves without lubrication was unsuccessful so a thin coat of silicone oil was used to lubricate the spools. The spool valves will be replaced with poppet valves in the next iteration. -![valve-contamination](docs/img/valve_contamination.jpg) +![valve-contamination](/docs/img/valve_contamination.jpg) A compact and low-cost intercooler was built from 1 meter (3 feet) of copper gas pipe and a 120mm 12V fan. The surface area of the copper that is exposed to the fan was maximized using a spiral shape. Droplets of water were observed after the intercooler which demonstrates that the water vapour is still present after the coalescing filter. The water is directed into a reservoir with a 2/2 valve on the end - this should be replaced with an automatic drain in the future to minimize maintenance. -![intercooler](docs/img/intercooler.jpg) +![intercooler](/docs/img/intercooler.jpg) Various configurations of the equalizing valve have been tried and the low pressure of the circuit may allow for the 2 brass valves to be reduced to 1. @@ -26,27 +26,27 @@ Some small improvements have been made to the tanks; one end of the threaded rod The latest build is shown below: -![build-004](docs/img/pioc-build-002.jpg) +![build-004](/docs/img/pioc-build-002.jpg) **1 November 2020** It's alive! Running for the first time PIOC reached 95% O2! VentMon is being used to monitor the O2 output, pressure and flowrate. Unfortunately the single stage water filter let enough water vapour past that after a few hours the concentration dropped to 35% - the water separator was half full with a small puddle underneath it. PIOC has been made by hand without much effort to be exacting as to test the idea of manufacturing in an automotive or small engineering workshop - tolerances are +-millimeters not fractions of a millimeter. Next steps are to dry out the zeolite and build a simple chiller and desiccant drier to remove any excess water vapour - some digital pressure sensors will then be installed to tune the system and test various configurations. -![build-002](docs/img/pioc_firstrun.jpg) -![build-002](docs/img/ventmon95o2.jpg) -![build-003](docs/img/pioc_circuit.jpg) +![build-002](/docs/img/pioc_firstrun.jpg) +![build-002](/docs/img/ventmon95o2.jpg) +![build-003](/docs/img/pioc_circuit.jpg) **22 October 2020** The system is now mounted to the board! Some changes have been made during the build to simplify it - the sieves now use 1/4" NPT barb fittings as a step towards making an all metal "sealed for life" sieve that can be heated to 300C to regenerate the zeolite without opening the sieves. Standardizing the end plates also helps to make manufacturing easier and remove the need to drill and tap 3/8" BSPT which is costly and requires a drill press. The pneumatic circuit has been modified to shorten the overall height. The valves have been tested manually and the overall operation appears to be correct. Next steps are to finish the driver circuits and fill the sieves. -![build-001](docs/img/pioc-build-001.jpg) +![build-001](/docs/img/pioc-build-001.jpg) **19 October 2020** First build is almost ready for testing! Parts of the system have been tested independently. Next is to complete assembly for a full pressure test. Then fill the sieves with zeolite and start tuning the control system. -![mockup](docs/img/pioc-mockup.jpg) +![mockup](/docs/img/pioc-mockup.jpg) ## Project Structure