Plumbing time!
Alright, as you know the intent on dealing with the cyclical changing stand height dimensions and the plumbing was - to use flexible hose.
The hose was to be generally bent into a 360 degree loop that would be free to change its radius as the tank rises or descends. Since I'd have several feet involved the individual tiny bits of hose would each only have to deform slightly over the entire cycle. Hence, the tensions involved would be small.
Why do we need small since we have serious large forces available? Because ultimately those forces will be resolved in the fittings at the most rigid locations. That's the bulkheads and pump ports. Neither are good spots for repetitive stress cycles.
Unfortunately.... One touch of the 2" hose and it was OBVIOUS that it was waaaaay too stiff.
The advertising sputum shows it tied in a small knot and states some incredibly small bending radius which faked me out totally. I didn't realize that to get it into that tight a radius you would need two trucks or a backhoe.
Sadly I bought many feet at over $13 a foot to make a large loop. To have small enough stresses with this stuff I'd have to have a 10 foot diameter loop which would cause problems with the shear weight of it all - not to mention no room for it.
The beast hose lurking in wait:
Bring up Plan B - STAT!
Well, if the pump didn't move relative to the the stand then the flex issue would be mute. Plan B is to mount the BIG closed loop pump on the stand.
Since this eventuality was never even considered in the stand build, here's the only position I can work with.
To actually hold the pump in space at a skew angle I need a platform. So I made one out of cardboard and had a friend hold it all up while checking things out. Once that was looking OK I cut a rough duplicate out of the bottom marine plywood from my aborted tank build.
Notice how I have to avoid my gear reduction plate etc. A pain in the...
This is the wood mock-up in place. You can see the suction bulkhead to the left and the discharge one on the right and where the pump mount will reside.
Once I had the mockup hacked the way I needed it I sat down and CADDed up a drawing with nice radiused corners that will prevent barked arms and faces in the event of any contact.
Then I fed the CAD drawing to my CNC router and threw another hack out of my aborted tank bottom on it.
This is the result.
Once that was done I decided I didn't want just a piece of low tech plywood visually obvious under my stand. That would be like stripes and poke-a-dots on the same person... It dawned on me I could cover the top with acrylic and have a waterproof surface too. I had a chunk of black. I reset the CNC to cut only 1/4" and ran the same program over my black acrylic. I then painted the plywood cheery yellow to match my stand top extensions.
Here's the resulting setup.
I wish there was someone around I could hire to do it.. :rolleye1:
