by blaktopr » Fri Oct 23, 2009 8:22 pm
Ok, so here is where the bench is now.
For one, the attachment needs a design change for measuring accuracy, but does a good job of capturing liquid. There is a pipe that exits into the bottom chamber totally srewing with the CFM and depressions. Same kind of issue as with the orifice in a pipe.
EX.. Calibration plate on main bench reads 285@28. No head adapter. Calibration plate on attachment 331@28" read through main bench. Somewhere down the line I will figure something out.
I went back to the "old faithful" bench. Tossed out the "wet" settleing box that was on top of the bench along with the old shop vac motor box. Built the new motor box and reconfigured the benh to work the opposite direction. What used to be the inlet chamber for the motors is now my settleing chamber under the head. The motor box is connected trough a new hole on the side of the bench.
I also went digital. Used 2 plates for the DM. One in each direction of flow testing with a blank. This allows me to use both plates in one direction if I have to. Right now, it is just move the blank. As I wrote in the baffle thread, I went to a round, radiused 21" disk. This is in betwen the chamber opening and the plates. 9" to each direction. (pic below)
So, there is a about 6 cu/ft settleing chamber fed through a 6X6 hole to the chamber on one side of the plate (9 cu/ft) with the same on the other.
This is the best the bench has ever been. No leaks anywhere (except motor box slider plate). Lots of internal volume plus the large baffle netted me with a .605 DC for the bench. Every plate I throw on the bench is right on or 1.5 cfm off. It was calibrated with a 285 and a 350 plate, both are right on. The lower numbers are the ones off (210).
The motor box needs a little work. A little to overboard with design but still faulted. All and all, still can reach in the low 400 @28 and reaching to 366@34.
I made room for a second motor box if the need comes.
Chris Sikorski