pressure measurement in air duct system with U-tube manometer
pressure measurement in air duct system with U-tube manometer
(OP)
Dear all,
I want to measure the air pressure in an air duct system both on the head and suction side of a big air ventilator. The channel is square 1.5 x 1.5 meter, air velocity is around 10 meter/sec. The motor is 100 kiloWatt.
Now I want to apply a good old U-tube manometer to measure the air pressure. Does anybody have experience with this method? How to avoid pressure readings induced by speed (p = 0.5 rho x V^2) and carburetter-like sucction effects?
What pressure readings I can expect (approx), I mean what pressures are typical for this size of ventilators?
Please let me know,
MVD
I want to measure the air pressure in an air duct system both on the head and suction side of a big air ventilator. The channel is square 1.5 x 1.5 meter, air velocity is around 10 meter/sec. The motor is 100 kiloWatt.
Now I want to apply a good old U-tube manometer to measure the air pressure. Does anybody have experience with this method? How to avoid pressure readings induced by speed (p = 0.5 rho x V^2) and carburetter-like sucction effects?
What pressure readings I can expect (approx), I mean what pressures are typical for this size of ventilators?
Please let me know,
MVD





RE: pressure measurement in air duct system with U-tube manometer
RE: pressure measurement in air duct system with U-tube manometer
The catalog also has good technical sections on how to take various velocity and pressure measurements. As for guessing what you'll get for pressure measurements, not enough info.
RE: pressure measurement in air duct system with U-tube manometer
http://www.dwyer-inst.com/htdocs/airvelocity/qsprestipsandfit.cfm
RE: pressure measurement in air duct system with U-tube manometer
I agree with BRT549. You only need a static pressure gauge for the application. At the velocity/area values provided I would only expect pressures in the range of 0-10 inches of water.
Pharo of Thermo
RE: pressure measurement in air duct system with U-tube manometer
static pressure measurements can be made with a connection that is flush with the plenum wall.
There are also special insert fixtures that accomplish the same.
You can also take a pitot reading and subtract out the velocity term.
Manometers are fine but have been replaced by electronic types.
If you are in a hurry a plastic tube filled with water works great. In practice the velocity effects are not that great unless to direct the tube suarely into the flow.
RE: pressure measurement in air duct system with U-tube manometer
You are great!
Thanks for all the information. I'm going for the web-link you gave me. Thanks for all the tips.
: )
MVD
RE: pressure measurement in air duct system with U-tube manometer
Pressure head: +9 cm water
Pressure suction -3 cm water
Cheers,
RE: pressure measurement in air duct system with U-tube manometer
RE: pressure measurement in air duct system with U-tube manometer
I'm checking the air mass balance of a sausage drying tower. Mass In = Mass OUT and the air mass flow [kg/sec] is dependend on pressure , temperature and the volume flow [m3/sec].
Here's some equations I used:
http://home.hccnet.nl/m.dijk/pressure_drop_calculator/calcs/calcs.html
(=Physical Properties of Water and Air.)
Greetings from Holland,
MVD
RE: pressure measurement in air duct system with U-tube manometer
Greetings from Wyoming, USA.
BRT-549
RE: pressure measurement in air duct system with U-tube manometer
http://www.carf-engineering.com/
Cheers,
C.