Cap for Venus to reduce tearing liner

thingiverse

To avoid tearing the liner when folding it over the sides I made a cap that holds the liner with a couple o-rings. *** The STL is for a round tube. The square tube just makes it easy to see. *** The f360 file has some user parameters to make it easy to change the size, but I didn't put any constraints on the parameters and I really don't know what I'm doing in CAD. The main purpose of this was to test out a method to not have to fold the liner over the edges of the tube, which uses extra liner and also seems to be a point where the liner can tear easily. To prevent the liner being pulled off, two o-rings are used. First, pull the liner over the holder part of the cap. Put an o-ring over and fold the liner back down. Put a second o-ring over this, between the first o-ring and the lip. The end result reduces tearing at the top, uses less liner, prevents the liner from collapsing, and make the size of the liner independent of the tube size. I use 1/8" push button valves rather than the one way valve that comes in the receivers. This removes possibility of clogging while allowing me to control air coming in or out while remaining closed otherwise. Just time opening the valve with the stroke direction, there's no reason for a one way valve. I have a video about making / modifying receivers: https://youtu.be/GtFdMjno4mw