Tractorsport Flowbench Forum Archive

Posted: **Sat Nov 26, 2005 5:47 pm**

I'm trying to do the leakage test on my bench this weekend and must confess that things are not going well so far.

My first problem is trying to fill my homemade U shaped vertical manometer.

Can someone who has been through this tell me what is the secret to adding the fluid to precisely the right point without air bubbles? And if you have air bubbles, what is the technique for getting rid of them? By the way, I'm using acrylic tubing with a 1/8" ID if that matters.

I may also have a problem with the pickup points for my probes for the inclined manometer but I'll solve one issue at a time.

Will appreciate any suggestions.

Thanks.

Dom

Posted: **Sat Nov 26, 2005 6:39 pm**

Posted: **Sat Nov 26, 2005 7:03 pm**

Agree with Larry about the movable scale, impossible otherwise.

The well type manometers require some scale correction UNLESS you use a large well. With a large well surface area you will be so close to the actual number that if you wanted to test at, for example, 28" of test pressure a .040" error would be meaningless, as long as you consistantly tested at the same reading each time.

Rocco's spread sheet can really make constructing a vertical well manometer easy to accomplish.

Remember on your "U" tube deal that the reading is BOTH legs, or 14" down and 14" up for 28" total. The zero will be in the middle.

Tom V.

Posted: **Sat Nov 26, 2005 7:12 pm**

Thanks Tom and Larry.

You've given me some good suggestions on how I should re-engineer things. I chose to make a U manometer because it seemed like an easy, low cost way to get started. But its obvious now that I'm getting some first hand experience and aggravation a design change is in order.

Ultimately, if the bench works well, I will probably look into going digital.

Dom

Posted: **Sat Nov 26, 2005 7:36 pm**

Dom,

You'll likely find that it's always the test pressure manometer that causes the grief. Dwyer makes slacktubes that are pretty reasonably priced. If you end up going digital down the road, you can use the slacktube with your pitot...

Larry

Tractorsport Flowbench Forum Archive

Homemade Vertical Manometer - What Is The Secret To Filling It?