by 84-1074663779 » Tue Apr 13, 2004 4:55 am
My flowbench uses a two foot diameter wheel (turret) fitted with eight removable orifice plates.
My wheel is cut from melamine, that is the white coated particle board that they make kitchen cupboards from. It is very hard, flat, and as smooth as glass. It rotates against another sheet of melamine used as a bulkhead in my bench.
The centre bearing is a self aligning ball race, and light spring pressure of perhaps a couple of pounds on the shaft holds both surfaces flat together. A universal joint in the shaft allows the turret to sit completely flat. It is easy to rotate with the blower off, and air pressure clamps both surfaces together tightly without leakage with the blower going.
Eight holes were cut with a 3.5 inch hole-saw ( 88.9mm) through this turret. Some 90mm plastic stormwater end caps are a tight press fit into the turret holes. Various sized orifices were drilled or turned on a lathe.
Each plastic orifice plate can be levered out with a screwdriver and replaced without dismantling the turret assembly. An indexing system consisting of a spring loaded roller on the OD of the turret locates the orifice over a four inch hole located in the main supporting bulkhead.
The turret can be rotated by means of a car steering wheel at one end of the bench.
While the whole thing is pretty enormous, it does allow eight orifice plates of reasonable size, and I can change things around very easily.