DIY Inclined Manometer

[Rick360]

[MikeyFIN]

[color=#000000]How about Mercury as a fluid in Manometers?
At least they are stable and easy to see plus don

[86rocco]

There are a couple things wrong with mercury, first, it's heavy so it takes a fair bit or pressure to move the column a short distant thus reducing the sensistivity of the manometer and second, it's a hazardous material so you don't want to allow any of it to vapourize and escape into the air.

[MikeyFIN]

[color=#000000]Well how much actuall do you have to pull to get the mercury moving compared to others...it

[86rocco]

The density of mercury is more than 13.5 times that of mercury, in a typical flowbench, the inclined manometer will measure a 6 or 7" water column at full scale and we are usually interested in pressure changes which are measured in fractions of an inch W.C. A mercury column under the same conditions would be about a 1/2" full scale and the small changes would be very difficult to see.

[84-1074663779]

I agree, mercury has absolutely nothing going for it for a flowbench application.

Water is almost ideal, but commercial manometer oil is always going to be the best fluid available. The only real disadvantage of water is that it evaporates slowly, can freeze, and bugs and bacteria can grow in it.

I use distilled water with a tiny trace of bleach, a tiny trace of detergent, and a bit of green food colouring dye. The bleach kills the bugs, and the detergent reduces surface tension so the water does not stick so well to the inside of the manometer tube through capillary action.

[MikeyFIN]

[color=#000000]Agree that it

[bruce]

Marvel Mystery oil (MMO), read the MSDS for real manometer fluid and MMO and they are almost the same thing. Real manometer fluid probably has a little more red dye in it.

[gaz]

I'm currently using car engine antifreeze. It's density is 1.12 (took a phonecall to the company that suplies it) and its color is red. because it felt kind of "oily" (too thick) so I made a solution 50:50 with water and it seems like the fluency improved.

[106-1194218389]

[106-1194218389]

Here is the copy of the MSDS