PTS Flowbench Forum

Greetings to all,
Nice to be around others with a shared intrest in air flow thru engine componets. As a toolmaker/designer/anything powered by engines enthusiest, I hope to aquire or build a flow bench soon. There is much accumulated experience here and I look forward to learning and shareing ideas and thoughts regarding the flow bench.

I see some flowbench kits on the internet that interface to a laptop, use a vacuum cleaner for a signal, then correct the output values to 28". Are these fairly accurate? Whate are the advantages/dissadvantages to these type of units? Is a person better off building a bench from scratch? I grasp engineering principles pretty well, and have machine tools. I've built simple manomometers to evaluate restrictions / pressures on automotive applications. I see there are two basic types of benches, orfice plate and pitot tube. Orfice plate seems more popular, may I ask why?
regards,
Ken

Hi ken!
Welcome!

Is a person better off building a bench from scratch?

Using Bruce's flow bench plans.......YES!

Orifice plate seems more popular, may I ask why?

Others can explain better but, basically air pressure, is all around you, and constantly changing, and will affect the flow ## with a Pilot tube design
with the orifice plate design, you don't have to add a bunch more math the changes.

You need a weather station to keep up with figures with a pilot tube...........orfice plate the affects are equal on both side of the plate there for cancel each other out.

There is every thing to build a pro bench for change..........compared to the high dollar pro bench's
Bruce's flow bench's are quality design and built......You just have to build assemble and calibrate.
And there are Grate people here to help you do all of that!!!!!!!

Thanks for responding Flash.
I'll look over the plans. How accurate are the orfice benches once calibrated?
regards,
Ken

Ken,
Welcome aboard! Most of us use orfice benchs because it a ratiometric measurement and is not affect by temp or barometer changes. Like Gordon said, it will save you a lot of grief to just buy the plans from Bruce. You can build your own manometers, but Bruce also has a digital manometer that works great. It feeds directly to your computer so it makes life good. Has an included software also. I am building the water manometers to go with my digital, just for fun.

John

klrskies wrote:Thanks for responding Flash.
I'll look over the plans. How accurate are the orfice benches once calibrated?
regards,
Ken

I feel they are the easiest to calibrate and the most accurate and they "stay" calibrated

John

jfholm wrote: I am building the water manometers to go with my digital, just for fun.
John

John, I can think of a lot of other ways to have fun!!!

I would put my PTS Orifice Flowbench up against any of the other flowbenches on the market for accuracy and repeatability!

The PTS Design was developed using many ideas proven in other homebuilt flowbenches. I took all those ideas and condensed them into a very user friendly design in construction and use. It has one movable part (slider plate) which has no effect on flowbench accuracy. If you follow the plans and take your time in construction you will have a very professional flowbench in the end at a fraction of the cost!

Brucepts wrote:

jfholm wrote: I am building the water manometers to go with my digital, just for fun.
John

John, I can think of a lot of other ways to have fun!!!

hee hee, nothing is funner than a 12" rise angle manometer

John

I ordered a set of plans, and will begin gathering parts.

Has any one ever built a large varible speed centrifical blower to generate vacuum / pressure signal? I have a book with such a blower used to force feed a large volume of air/gas thru a kiln, and wonderd if it would be a good thing to consider...should be quieter?
I have a machine shop at home and could make one, scaled, up or down. Is the bench plan designed for a certain set of blowers?

thanks for all the responses & best regards,
Ken

Ken,

I see there are two basic types of benches, orifice plate and pitot tube. Orifice plate seems more popular, may I ask why?

To answer this question, the orifice bench is what is called Ratiometric, the air on each side of the measuring device is the same air thus is unaffected via atmospheric changes. Thus unlike the smaller SF benches and Pito (Vacuum cleaner Tube device) your flow calculations are not effected via changes in air density (Temp, Humidity, Barometric Pressure).

Don’t get me wrong I think Pito tubes have a great place in R & D but for what we are doing her the Orifice Bench is the way to go, that said you did good by purchasing Bruce’s plans. Build it to the plans don’t cut any corners and you will have one hell of a bench.

Rick

PS. Did I mention GO DIGITAL, Pts DM