Coaxial Sensor Back Cover for the AP Diving Inspiration Vision Rebreather

prusaprinters

Print it yourself or order from Shapeways!When using a 4 or 5 cell holder like this one on an AP Diving Inspiration Vision rebreather, the coaxial cables to connect to the sensors used for external monitoring often come without a back cover to fit onto the back of the cell.I designed this cover with dimensions matching the original (blue) cell cover that is installed by AP Diving on the original sensor connectors. I experimented with versions in PETG and TPU. The TPU version is a nicer fit, and easier to install, but in the end I went for PETG, because it is food safe and does not degrade with exposure to moisture.The overhangs are designed to make it printable without supports if printed with the side towards the sensor up.Important: This cover is only intended to stop condensation drops from entering the back of the sensor, not to seal it off. As the air space at the back of the sensor needs to be able to equalise to the ambient pressure,do not glue this cover on, or make it air tight in any other way.Update: After some discussion about the importance of the back of the cell being sufficiently ventilated, I have added a version that has an air vent on the side of the SMB connector. Please use this if you are printing in soft material, or if you are worried about not having sufficient ventilation.From Martin Parker / AP Diving:To check whether there is sufficient gas transfer, take the lid to 1.35 - 1.4 bar using a cell validator then release the gas quickly from the lid while watching the PO2 display.If you leave one cell open and the other cells with your new covers you’ll soon see the difference, if there is any. If there is a difference in reaction to the pressure drop you will need to have bigger air channels.Update 2:I have added inspiration_coax_cell_back_cover_ventilated_small.stl - in this design the diameter of the part that goes into the opening at the back of the cell is 0.5 mm smaller. This makes it just slide in and out when printed in hard plastic, making it easier to install / remove.Update 3:After some frustration and fiddling when trying to get connectors and covers off the cells, I have changed the design of the small cover (for hard plastic) to have a 1 mm lip extending over the body of the cell - this makes it easier to grab the cover with your fingers and pull it and the connector off without prying and wriggling. The new design is inspiration_coax_cell_back_cover_ventilated_small_improved.stl.Update 4:Slightly reduced the height of the dome in order to allow shorter SMB connectors to fully fit into the plug.Category: Sport & Outdoors