- #1
frascati
- 25
- 0
Hello.
I am not skilled in math or physics. I'm interested in building an inclined manometer accurate only enough to measure water column (w.c.) inches scaled to .5 w.c to about 10 percent accuracy.
A very basic manometer can be built to measure inches of water with a utube of small diameter clear plastic hose. Set the zero about 7 to 10 inches from bottom of loop and mark off a one inch increments above it. I don't know if this would measure even within my range of accur. Accurately determining within .5 w.c. is what I'm after. Don't want to buy a 60 dollar digital manometer from ebay since I'm only using this twice and then may not use it again for five years.
I'm wondering if there is a simple calculation to adjust that scale according to the incline of the tubing? "Inclined" u-tube manometers I've seen on the web generally maintain the plane of the unit horizontally while inclining the tube itself approx 70 degrees to the left of the vertical axis of that plane (the board that the tubing is attached to).
Can one assume that the same effect could be had by inclining the basic u-tube manometer backwards 45 degrees and adjusting the scale accordingly? I only ask because it would seem easier to build accurately.
Inclination of the tube results in finer (though narrower overall) useful adjustment, no? Again, I'd like to make an inclined manometer that measures 0 to 15 w.c. scaled to .5 w.c with perhaps 10 percent accuracy.
Plans on the web would be ideal but I can only find plans for the standard w.c. manometer.
Lastly, It's often mentioned in these diy designs that the liquid used is not terribly important. One inch of mercury is equal to approx 13.6 inches of water weighed against atmospheric pressure. So while the weight of most other oils and fluids at hand to fill a manometer are generally equal, are the differences in weight between them appreciable enough to care about in my homemade manometer? Water, hydraulic fluid, light motor oil, etc? Viscosity would not be a concern I'm guessing. That might only affect a damping factor but the measurement would remain constant.
I'm measuring a stable steady pressure so damping is not important. Tinted water may just be ideal.
Thanks for any comment.
I am not skilled in math or physics. I'm interested in building an inclined manometer accurate only enough to measure water column (w.c.) inches scaled to .5 w.c to about 10 percent accuracy.
A very basic manometer can be built to measure inches of water with a utube of small diameter clear plastic hose. Set the zero about 7 to 10 inches from bottom of loop and mark off a one inch increments above it. I don't know if this would measure even within my range of accur. Accurately determining within .5 w.c. is what I'm after. Don't want to buy a 60 dollar digital manometer from ebay since I'm only using this twice and then may not use it again for five years.
I'm wondering if there is a simple calculation to adjust that scale according to the incline of the tubing? "Inclined" u-tube manometers I've seen on the web generally maintain the plane of the unit horizontally while inclining the tube itself approx 70 degrees to the left of the vertical axis of that plane (the board that the tubing is attached to).
Can one assume that the same effect could be had by inclining the basic u-tube manometer backwards 45 degrees and adjusting the scale accordingly? I only ask because it would seem easier to build accurately.
Inclination of the tube results in finer (though narrower overall) useful adjustment, no? Again, I'd like to make an inclined manometer that measures 0 to 15 w.c. scaled to .5 w.c with perhaps 10 percent accuracy.
Plans on the web would be ideal but I can only find plans for the standard w.c. manometer.
Lastly, It's often mentioned in these diy designs that the liquid used is not terribly important. One inch of mercury is equal to approx 13.6 inches of water weighed against atmospheric pressure. So while the weight of most other oils and fluids at hand to fill a manometer are generally equal, are the differences in weight between them appreciable enough to care about in my homemade manometer? Water, hydraulic fluid, light motor oil, etc? Viscosity would not be a concern I'm guessing. That might only affect a damping factor but the measurement would remain constant.
I'm measuring a stable steady pressure so damping is not important. Tinted water may just be ideal.
Thanks for any comment.