Tower of Power - Everything a bench should be...

[Mouse]

The FE series flow element design is based on the Pitot tube. However, the design also accomodates provisions for adding hot-wire sensors for measuring flow rates, or turbulance, and for adding sensors for measuring the temp of the gas flowing inside the tube.

John

[Thomas Vaught]

Thanks.

The Mass Air sensors tend to be sensitive to dust and trash possibly damaging the wire. Even with the front screen. They also are directional so you need to flip them around for intake vs exhaust testing unless you use plumbing to do it or two meters and then you have to shut the no functioning one off for air flow.

Your FP-1 looks better and better every day.

Tom V.

[Mouse]

Actually, a hot wire or temp sensor is not located in the air stream when installed into the Flow Performance flow elements. They only receive an air sample. So they could live a very clean and protected life. And the FE "can" work in either direction.

I should note that the "design" of the elements allow these items to be implemented. The actual units do not have the provisions for the sensors installed.

[Mouse]

Some changes on the Tower of Power. I put a solid front panel on the frame. This forms a backbone for the whole thing making it much more sturdy. It also cleans up the look and provides a surface to mout things onto, like the tablet PC shown in the photo. Also gone is the top cap. A panel will rest on top of the air box inside the frame intead. A shelf also adds support to the side panels. You can just see the PWM valve behind the flow element that controls test pressure in a bleed mode. Some doors on the front of the cabinet should look pretty good.



Rear shot shows the handles for moving the air box and the plastic flexable conduit carring the wires from the switch box to the vacuum motors. I have not finished the top yet. Need to add a brace and the top panel.



The Fujitsu tablet PC is very handy for this project. The software keyboard and touch screen eliminate the need for a real keyboard and a mouse (a pointing mouse, not the real Mouse).

[Thomas Vaught]

You ever think you might need a ledge on the back of the bench to keep the sliding box square, Mouse?

Really nice work.

Tom V.

[Mousehouse1]

Looking good John.

[Mouse]

Thanks you guys.

Thomas, The air box sits about 6" below the panel in the lower rear. That 6" high panel holds the box in place, I need to add one to the top. I can lift the air box out of the frame without the top panel, that's why I haven't installed it yet. Still tinkering.





I added a holster for a Casio Pocket PC to operate the FP1. This is the way to go if you do more sucking than cutting. Just touch one button and the FP1 is ready to flow test. Touch another button and you have your spreadsheet. Very fast.

[SuperRunner]

Just curious about your design, do you use a restrictor plate with a pitot tube? Could this be used with a restrictor plate, or would the PVC need to enter into a chamber under the port?

I really like the simplicity of your design for controlling airflow

[Mouse]

Thanks SuperRunner. The diagram above shows how an orifice style design would be implemented (on the right). What you do is build your box to fit right between the frame end panels. Install some cleats on the end panels to rest it on, and tack it in with a few screws. Planning on doing just that some day.

The ToP is really working well, I love this thing. And it looks good too. One other advantage in the design is strength. The small area of the panels in the air box makes it less apt to implode or explode with higher test pressures.



Here is a revised diagram of the air box. This vents out the top instead of the bottom as in the previous diagram earlier in this thread. A much better design.

John

[SuperRunner]

Wow, quick respons, you guys are great...and on the ball.

I just barely got the idea of making my own flow bench last weekend. Probably have put about 15 or so hours of reasearch into it since. I have already orded 8 motors.

I do have another question...which probably belongs in a different area...but...

Why would you choose pitot tube over orifice? Calibration? Electronic measureing devices(that you are using). I plan on having a working bench by this weekend or early next week, but I need to decide on a design so I can finish collecting parts.

[bruce]

[SuperRunner]

Ok, thanks, that is about what I expected .

I will just keep reading. Maybe another 10 hours or so of more research(mostly on this forum) and I should be good to start.

Thanks

[Mouse]

Pitot tube, orifice, there's been a lot of emotional debates over these two styles and a lot of missimformation on the Pitot tube being dispensed. But they both offer about the same accuracy. Orifices generally need much more space, and perhaps more air power since they create a pressure differential by causing a resriction in the air flow.

John

[larrycavan]

[DavidNJ]

Three questions:

1. What are the flaps for?

2. Would there have been any advantage of putting a plenum between the FR4 and the FE2?

3. Would there have been any advantage to placing the motors across two chambers to make two stages?

Thanks,

David