Tractorsport Flowbench Forum Archive

Posted: **Tue Jan 25, 2005 4:57 pm**

Ok, the bench is done, it is working VERY well thanks to this forum. I have made a couple hand made flow % scales, however I would like go get a machined scale.

Does anyone know if you can buy the Superflow backing plate for the Dwyer gauge like it? I actually have one of the gauges from Dwyer just like it for another project.

Or a nice machined CNC scale that can support the tubing.

Thanks guys!

Posted: **Tue Jan 25, 2005 8:17 pm**

I would contact a local place that does viynal (?) lettering and stickers and have one printed. I use K & M signs in Deerwood Mn. www.upnorthsigns.com
They can make you one easily.............

Scott

Posted: **Wed Jan 26, 2005 6:23 pm**

It would probably be possible to get something silk screened onto an aluminium strip.

If you can come up with a CAD drawing of the scale you require, that can then be photo-plotted to make a photographic negative. A silk screen printing process then completes the job.

Electronic circuit boards are made exactly that way. The problem is the length of the scale. If the scale only needed to be a foot long, that is easy. If it has to be three feet long, it might be very difficult finding someone that can photographically handle something that size.

The cost for a one off job might make your toes curl, but it would hardly cost any more to have a hundred scales printed than to print just one.

Posted: **Fri Apr 08, 2005 11:31 am**

Well, the vinyl shop I use said no way they could do it.... or, actually they can, but when I told them what was involved and took the measurements to them... they said nope.

What I would REALLY like is a machined ALUMINUM or STAINLESS steel gauge. I have seen some on here that others have used. I am willing to pay for it... just need to know where and who to contact!

I'll do a search here again and try contacting some of the people directly I guess. But if ANYONE has a lead on where I might get one... any help is appreciated.

Posted: **Fri Apr 08, 2005 12:23 pm**

Do you mean something like this one from .

Posted: **Fri Apr 08, 2005 1:44 pm**

Keep in mind the following:

1. Dwyer manometers are designed for the fluid to drop on the incline from 0 to 100% and rise in the well.

2. Take into consideration the specific gravity of what you're using for fluid as it plays into the formula when you calculate the scale.

3. The verticle rise and the exact dimension of the inclined leg must also be known.

All 3 pieces of criteria should be made clear to the person you purchase the scale from.

Larry

Posted: **Fri Apr 08, 2005 2:35 pm**

Posted: **Fri Apr 08, 2005 3:13 pm**

Thanks to this board and the fine people here.... I have all the calculations for just what you mention. I even have a nice spreadsheet I believe come from 86rocco that I laid my scale out with.

I have the scale made now.... but would like a little more "professional" look than white board with red Sharpie marks on it.

Mr. 86... that is EXACTLY what I'm talking about.

Posted: **Fri Apr 08, 2005 3:38 pm**

Posted: **Fri Apr 08, 2005 4:13 pm**

If designing a scale for an existing scale, there are 2 critical pieces of information needed, the length of tube between 0 and 100% and whether the scale runs from right to left or left to right.

Posted: **Fri Apr 08, 2005 6:10 pm**

I made my scale one metre long from the zero pressure point (well height) to the 100% flow point located 1,000 mm along the scale. It is then very easy to mark off the non linear flow divisions that way against a commercial steel ruler.

I used flat aluminium strip 1" by 1/8" and after removing any blemishes from the aluminium, marked off my flow scale with a black ink drawing pen using a set square. Black rub on lettering was used to add the calibration numbers. The whole thing was then sprayed with clear lacquer.

Maybe not the ultimate professional finish, but it cost almost nothing to make and does not look too bad.

Once you have the basic inverse square law flow scale, the high end can be raised to whatever calibration pressure you decide to use, and the same flow scale will be perfectly valid.

Posted: **Fri Apr 08, 2005 8:18 pm**

Posted: **Fri Apr 08, 2005 8:56 pm**

Posted: **Fri Apr 08, 2005 8:57 pm**

Your partly right. All else being equal, changing the angle changes the pressure at which your scale would read 100% and hence the calibration of your flowbench. So, if your change the angle of the scale you don't need to redo the scale but you do have to recalculate what 100% on your scale means.

The important thing to realize is that 100% on your scale in complete arbitrary, you choose the cfm value you want for 100% or, you choose the height and length of your scale and calibrate 100% accordingly.

For example: let's say you've got a 1.5" measurement orifice and you'd like 100% on your scale to be 100 cfm, that would require you to angle your scale so that it reads 100% at approximately 10.75" WC pressure difference exactly what angle is required to acheive that will depend on the construction details of the manometer and the density of the fluid you're using.
Now, let's say we switch to a 2.00" measurement orifice assuming the manometer is set up as above, a 100% reading for this orifice would be 178 cfm, the scale would have to be similarly calibrated for each of your orifices.

Posted: **Fri Apr 08, 2005 9:47 pm**

We had almost concurrent responses. My last response was to your previous post.
With regards to your most resent post: I had to go over to the Dwyer website to remind myself exact what the #246 is, to bring everyone else up to speed, with the standard red gage oil (.826 sp) the 246 reads 6" WC at full scale and the scale is 20" long. So to read 12" WC, ideally, you'd want to use a fluid with a specific gravity of 1.652, the closest gage oil I could find was Meriam 175 Blue gage oil so 12" WC would be 18.88" down the scale. So you would make a scale which has 100% at 18.88", the rest of the markings fall in line according to the inverse square rule i.e. half way down the scale would be 25% etc.

Tractorsport Flowbench Forum Archive

Machined Flow % Scale - Where can I find one?