gage fluid

[coulterracn]

I measured the Inch marks on my Dwyer 36" meter with my digital caliper. They are 1.087" apart. The tube ID is 0.190" and the well is 0.750" ID. This model uses .826 red gauge oil.

Ray

[johno]

Hi there mate, i got a manometer fluid recipie from a old flow-bench build by Peter Saueracker (this thing had 16 Grainger motors shoe-horned into it!!!!) which goes; 1 pint of distilled water with 1 drop of dishwashing liquid and 4 drops of rose/ red food colouring.

[Eagle Eye]

Hello everybody. I'm going to build a vertical manometer now that asked you about months ago. I will make the resivoir 1000 times the area of the fluid in the tube as you told me to do. After reading this fluid info. I am understanding that using the same pressure will raise different fluids a different height in the tube depending on the s.g. Is that correct? My question is should I use water or marvel mystery oil and is an inch of rise really an inch? Thanks for your help everyone. Jim

[86rocco1]

Normally an inch of rise isn't an inch. For distilled water (or any fluid with 1.0 s.g.), one inch of rise equals one inch + the amount of drop in the reservoir. But in your case, since the surface area of the reservoir is so big compared to that of the the tube, the drop in the reservoir will be negligible and you can happy pretend that an inch of rise is indeed an inch of pressure.

Now, if you're using a fluid other than water, you need to take the specific gravity of the fluid into account. in the case of Marvel mystery oil the specific gravity is 0.876. So, in your manometer with a 1000:1 reservoir to tube ratio, a one inch rise of MMO would be something like 0.8769 inches of pressure.

[jfholm]

Ed,
Since the MMO is lighter shouldn't it rise higher with the same pressure? I thought that the inch mark with MMO should be around 1.14" since MMO will rise higher with same pressure that it takes to raise water as MMO has a lighter specific gravity.

John

[86rocco1]

You're right, my mistake, I forgot to take the reciprocal of 0.876 to should have been a one inch rise of MMO would be something like 1.143 inches of pressure.