Trevor:
1.) The idea of Coef. of Friction improving a bit with increased pressure probably has to do with material flow and creep; with the Teflon material flowing to the contact surfaces under compressive pressure. It’s been a long time since I’ve looked at that data, I’d talk with a supplier who you would buy from. I’d be inclined to go with the std. CoF and try to deal with the forces that causes, unless the product manuf’er. gave me a very compelling explanation and data on this coef. improvement, for this low/slow motion condition. Because on the one hand you have to design for sliding at 12k reaction, but then also contend with a 60k static reaction for 90% of the time. I would also want my brg. pads to be large enough in width and length to be sorta self equilibrating during the sliding action. Thus, my earlier 6" wide (across the tank) by 12-16" long (along the tank length). I’d have very low brg. pressures, but know that the sliding brgs. were very stable. The exact size is, of course, an engineering judgement call, so 6x16 may be larger than needs be. The outer stability brg. pads actually have a .25" +/- gap with the found. leveling plate, no Teflon, so they can be washed out during cleaning. They just prevent the tank from rolling too much.
2.) This was the reason for my earlier comment about skirts all around the bearing pads, in my second post, #4.), 3JUL, 13:54. My problem is usually keeping dust, grit and rain water out of the bearing, not bacterial growth or build-up and high pressure washing solution out. I would think you would want to try to keep this material out of the bearing, but you still probably want it to drain too. And, you probably want to be able to open it up fairly easily for inspection and periodic cleaning. There are wipers, similar to a window washer’s squeegee. You’ll see these in various forms on machine tool beds and the like. There is rubber sheet material for skirting. It is held to the two surfaces with some sort of steel bar flange, screwed down. Or, imagine something akin to... a bicycle inner tube inflated btwn. the two surfaces, how you put a new one in is another matter. What about long rod/sq. stock of 2" square closed cell rubber foam material, compressed and fitted into the space btwn. the two surfaces, bottom saddle pl. and found. leveling pl.? This would just shear and roll with tank movement, but be easy to remove for cleaning. Maybe the easiest solution would be a rubber sheet skirt around the entire 21" x 120" saddle bottom pl., hanging down over the found. leveling pl. This could easily be lifted for cleaning. It might just sit on the bottom saddle pl. with some gasketing at that pl. and hanging down over the found. leveling pl.
3.) A.B’s = Anchor Bolts, in my world. Sorry about the abbreviations, because I sure bitch about them and acronyms often enough. This kind of design is fun design for Struct. and Mech. Engineers, at least I really enjoy it. I like the mix of struct. and mech. and it’s much better than just picking parts out of a catalog, watching parts come off a production line or some such, and calling that engineering and design.
