Our bench design - Our bench design

[Thomas Vaught]

It appears that you will have about 1100 cfm capacity if you are using the 115923 motors. SF 1020 has 12 motors, SF 1200 has 16 Motors.

You also should have the ability to read very accurate flows anywhere
in that range with the three Pitot tube array.

I am not sure how you are doing the suck vs blow valving in your design
but assume that when the valve is in one position the center chamber
feeds the motor arrays and the exhaust from the motors goes somewhere.

Same deal for the Exhaust testing.

I have seen the rotary valve work with a two chamber box but not a three chamber box.

More info please.

Tom V.

[Griffin]

Weird - I had this posted before and it disapeared. Anyways heres the motor box with the valving:

[Griffin]

The range select valves up at the top are going to be slide valves. The vent valve at the bottom will either block the pressure side and open the vacuum side to atmosphere, or block the vacuum side and open the pressure side to atmosphere. The pressure / vacuum select valve will either block the pressure side and open the vacuum side to that distribution box, or block the vacuum side and open the pressure side to the distribution box.

So in suck mode the pressure vent valve would be wide open on the pressure side and blocking the vacuum side. The pressure/vacuum select valve would be upen ot the vacuum chamber and blocking the pressure side. And then the range valve for the appropriate range will be open.

[Little Rocket]

Fabbing started today. We hope to get the motor box fabbed tomorrow. I will post up some pics as things progress.

[Griffin]

well, the metal frame is now built, the motor box panels are all cut, and we just need to finish sizing them and weld the nuts for the service panels to the frame, and then its on to the plumbing and settling box.

We took a break form the bench because we both had some other projects, trips, personal stuff etc. that got in the way.

The designs has changed slightly in that we now will no longer have only one valve top and one valve bottom. We wliminated the bottom pressure transfer box and changed to a 9 valve design. 3 valves at the bottom of the 3 chambers (1 vacuum and 2 pressure), 3 valves at the top of the 3 chambers, and 3 range select valves at the top of the main pressure box under each of the valves.

So theres still a lot of work to go, but we're actually working on it actively now so hopefully it will be done in a week or two.

[Griffin]

Oh - heres a picture of the frame while we were buildign it:

[Griffin]

And heres the tentative design for the settling box fixture:

[Griffin]

This is the revised motor box drawing:

[Thomas Vaught]

Amazing how the mind works.

I did a common center chamber (with outside motors chambers)
some years ago and needed to make the same chamber valve
adjustments that you did, but the bench worked very well. I used manual slide valves to open each motor chamber (as needed) where you have incorporated the "automatic" flapper valve technology that Mouse used in his Tower of Power. One good thing about your design is that the motors
boxes see small surface areas and with a metal support structure are
very strong. Your drawing doesn't show support to the outer walls of the chambers on the exhaust side of the motors but I think in your actual metal framework you may have that support designed in. One of our members used a rectangular "hoop" design to allow the air to go between the supports and still hold the chambers rigidly in place. You could use that "hoop" design in the upper vacuum chamber too between the three valves.
Are the inlet and outlet valves going to be sliding parts or could you use the Beckman Port holes (cover on or off) to do the same thing? A 8" access port and three 6" actual "ports/valves" would work well. The automated bleed valve should take care of control issues so the valves need only be "off" or "on" parts.

Tom V.

[Griffin]

The valves are on or off slider valves we fabricated from MDF - here are some updated pictures:

Early fabrication:







Floors and Flapper Panels Installed:







Closeup of part of sliding valve assembly in pressure box:





Current state - Motor panels installed:



The blower box panels will all be held on by liquid nail and screws, or for the serviceable panels, bolts, washers, and silicone.

[Griffin]

Oh - the frame was sandblasted and painted with 2 coats of rustoleum clean metal primer. We're going to have to sand the sides down to give a flush fit for all out panels and then we will re-paint. All of our MDF panels are getting a coat of KILZ oil based primer and then an oil based paint to help seal out moisture and ensure complete sealing of the air surface.

I am a TAD worried about the pressure boxes when in blow mode. Do you think additional fastening or retention measures need to be taken?

[Thomas Vaught]

Based off of the pics, yes, I think you are going to need additional reinforcements in the boxes. You have a lot of area in the end panels and a goodly amont of area in the front and back panels. Take another look at your design and try and not have over a 12"x12" area of unsupported panel.

28" of water = 2" of mercury. 2" of Mercury = 1 psi. 12"x12" = 144"
of area times 1 psi = 144 lbs of force on just that 1 square foot section.

Looks to me like some of your areas are a lot bigger than 1 square foot of area. If you can provide some actual dimensions the calculations would be a lot easier.

Tom V.

[Erik]

Thomas

I have notised that you know a lot about Superflow benches.
When I lookt at the specs for the Sf 1020 they say that it will flow 1000cfm@65" water.
Is this posible to get that number with only 12 motors?
When I look in the specs of the 115923 motor I com up with
56cfm@62,9" water for one motor times 12 adsup to 672cfm.
What am I missing?
Do you know some other flow numbers for the SF1020 bench ?

Erik

[Griffin]

[Thomas Vaught]

Better have at least 90 amps of power per leg at
your location. The SF 1200 that I use on occasion at a suppliers shop originally had less amps available and burned up 8 of the 115923 motors and one of the SF circuit boards. SF fixed the circuit board but the company had to buy new motors.

16 motors will draw a lot of power.

Quote:

"The bench is 22" deep. The motor boxes are 12" high"

So basically on a given external motor panel you have about 264 pounds of force trying to blow it out. I would add a vertical piece of square tubing in the middle of the outside framework of each motor box so that each panel is supported in the middle. Pic #4 Post on March 1, 2007

Tom V.