Test Pressure Tube Relocation - After mods to MSD type bench top

[larrycavan]

John, Tom V., Bruce etc.


I finaly got my aluminum top plate back from being cut on the water jet. A diagram is attached showing how I ended up modifying the top of my MSD bench to install a baffel plate.

What I ended up doing was adding the new 3.75" top section. I left the original 4" discharge hole and mounted a baffel over it with 4 angle brackets. The baffel is 16" long [L to R when facing the bench] and about 9" wide.

Now, the quandry is where to place the static pressure pick up now. I have it located on top of the baffel because right now I feel that's the proper place for it. Time will tell.

What's troubling me a bit is that now the air can flow in all directions rather than just straight past the pick up tube. Readings may be faulty as a result.

In the diagram I drew a circle to represent looking straight down the test fixture from above and divided it into quadrants. The pickup tube is represented in red. I have it located in quadrant 1 at at 45* angle to 2 & 4. This is basically the old location before adding the baffel plate. I would greatly appreciate input on this.

How did anyone handle this situation? How does Superflow handle it on their 300 and 600 units?

Many Thanks,
Larry

[Mouse]

I would place the pick up against the very top surface, at least a few inches away from the top discharge hole.

John

[larrycavan]

After waiting for the silicone caulk to dry over night and I ran a couple of tests this evening. Some totally unexpected things happened.

I installed the SF110 calibration plate and sealed both holes to test for any leaks. I tested in my lowest range, 28cfm. Much to my surprise, when dialing up test pressure, the inclined manometer began to flow backwards.

Remove the rubber plug from the calibration plates large hole and the fluid in the inclined manometer travels in the right direction [down the tube and rises in the well].

Plug the large hole again and leave just the .312" hole open.[supposed to be 4cfm @10"] The fluid again starts out going the wrong way again.

I removed the very top of the bench [leaving the new upper section in place] removed the baffel and installed the top. Tested again and the same thing happens.

I had been testing with 3 of the six motors running because the other 3 need brushes replaced. I thought maybe I was getting back flow through them when the top of the bench was sealed [ it never bothered before installing the new top section] so I sealed the openings for the three unused motors with duct tape. Tested again. Same results. Inclined Manometer flowing backwards again.

Do I need to open up the old 4" discharge hole now with the new top section added? That and the baffel are the only changes I made. Removing the baffel didn't cure anything.

Larry

[Mouse]

It looks to me lthat your second, or original discharge hole is creating a pressure differential perhaps. Either way, I don't think you want that original discharge hole in your design.

John