Tractorsport Flowbench Forum Archive

Posted: **Fri Jun 29, 2007 9:42 pm**

Sorry for the delay getting the pics up.

But here it is.

This is the original configuration:

But after discussion on previous thread I decided to include a settling chamber:

Here's a pic of the sloped manometer scale, Does this look correct?

and the static probe I made:

As I stated in a previous thread I am interested more in relative flow measurement than precise flow numbers. So right now I've made no attempt at calibration. I have run several tests and can duplicate results within 1/2% everytime. I'm using 4 of the vacuum motors from surplus center and can pull almost 28" across a 2" orifice.

Here are the vacuum motors:

So tell me what you think.

Posted: **Sat Jun 30, 2007 7:14 am**

Based on what you are looking to accomplish with "relative flow measurement" rather than precise numbers, you're in business as long as the bench repeats readings.

Using that separate motor box is nice feature. You can grow the bench's capacity very easily with a larger box and more motors.

PS - The motors I purchased from Surplus Center have held up very well for well over a year now...or is it two...

Posted: **Sat Jun 30, 2007 9:25 am**

Now when I look at it I can see how the settling chamber could have been incorporated into the overall bench and would have been much larger. But because my woodworking skills are not so great I was afraid I would end up with a collosal leaking box so I wanted to keep it as simple as possible .

I went with the separate motor box just so that I could expand later if needed (really so that if I could not get the flow I wanted immediately I would not have to start all over)

Posted: **Sat Jun 30, 2007 10:39 am**

This is what the forum is all about!!

Being able to build it yourself, looks good!!

Posted: **Sat Jun 30, 2007 7:18 pm**

Yes I agree.

It is absolutely fascinating to actually see other peoples benches and ideas, and the thinking and philosophy behind the design.

I too rather like the modular blower box idea, as it opens up a whole range of possibilities as well as making construction simpler.

If I ever get around to building yet another bench, it would probably be a two box design with the blower system in one box and the test hole in the top of a vast settling chamber in the second box.

Vicoor, my woodworking skills are rather uncertain too, and because of possible corner leakage problems, and the very large mechanical forces involved, I chose a welded steel angle frame with bolted on wooden panels for my bench. I still do not trust myself to build an all timber bench.

Posted: **Sat Jun 30, 2007 10:16 pm**

I have to say that I am proud that I have no apparent leakage.

This is just shy of miraculous

Posted: **Thu Jul 05, 2007 11:38 pm**

I'm looking at the picture with the settling chamber added and, from the little I know, it appears the chamber is in the wrong place. My background runs more to windtunnels, but our equivalent to a settling chamber came before the flow element (test section). Here it looks like the measurements are made before the chamber. I'm building my pitot type bench right now and would like to know if the location makes a difference. Thanks, slracer

Posted: **Fri Jul 06, 2007 1:28 pm**

srracer,

I had to go back and look at the pics closely but in the first picture it appears the bench is an orifice in a pipe bench with a pressure tap on each side of the flanged part that you see in the straight run of pipe after the bend. You can see the hoses comming off of either side of the flange. It also appears from the motor box that the bench is a "suck only" bench.

It looks like in the other group of pics that he now has that flanged part at the exit point of the settling chamber (Intake flow), which would be correct.

Not saying that you could not do Exhaust flow testing but you would have to do it the way the Ford Motor Company did on their benches in the old EEE Building and make a fixture to suck on the exhaust and have a cylinder on the combustion chamber side of the head.

Very accurate to do it that way with a lot of data to support that statement. The temp variation is less too.

Tom V.

Posted: **Sat Jul 07, 2007 1:10 pm**

Thomas, That's exactly what I do for exhaust testing. I'll get a picture when I am back at the shop and post it.

You are exactly right on the orifice placement as well. I't's in the flange at the exit of the settling chamber.

Posted: **Mon Jul 09, 2007 10:07 am**

Hi Tom V. & Vicoor, Very busy weekend so I'm a little late in responding. I guess I'm not sure what I'm looking at. I had assumed the pickup at the flange leaving the settling chamber was measuring the depression and that the pitot and static for pressure velocity measurement are in the vertical tube next to the settling chamber (open in the pic). Looking at the pics again, I see there is no tube going to the connector at the upper end of that tube as there was in the first picture. From Tom V's answer, it would seem the tube coming from the settling chamber and going up the left hand side of the bench is for depression (better location than my assumption!) and the static(?) measurement is at the flange, leaving only the pitot attachment in the vertical tube. This seems to be pretty widely spaced for pitot - static as Bruce wants his to be 1/2 inch apart. Can you tell me where the pickups are? My concern with this is the arrangement for my own bench which is nearly complete and would be very difficult to change if I am doing something wrong. I'll try to post some pics (haven't had much luck in the past) for discussion without stealing any more time on this thread. Thanks all, Doug

Posted: **Tue Jul 10, 2007 1:50 pm**

Doug,
It's an orifice bench and there is no pitot measurement.

All of the measurement points are for static pressure at the different points. Just below the work, and just up and downstream of the orifice.

Posted: **Tue Jul 10, 2007 2:35 pm**

Thanks Vicoor, I thought I read your other post that you were going to add a pitot, but I just reread it and saw it was "add a settling chamber". That makes some difference! Sorry for the misunderstanding. -- Doug

Posted: **Tue Jul 10, 2007 7:27 pm**

Posted: **Tue Jul 10, 2007 8:12 pm**

I'm sure that testing under similar dynamic conditions as are present with a running engine would yield some very interesting data. But I can't think of any home made apparatus that would be able to replicate those conditions. So I'm stuck with a 28"h2o pressure differential. Now I guess the difference in charge density between pushing and pulling will have some effect But I'm gueesing that it is not enough for me to worry about.

here are pics of my exhaust test setup

I saw on another thread there were questions about sealing the work to the bench. In these shots you can see the craft foam that i use for gasket material.

Posted: **Tue Jul 10, 2007 8:31 pm**

Vicoor, I like that dial indicator holder/valve adjuster! Do you just turn it around for intake/exhaust or do you use a different one for each "type" of valve? Really simple!

Doug R.

Tractorsport Flowbench Forum Archive

Here's mine! - submitted for your approval???