Accuracy of Micro Motion Meter


Thread Starter


We have faced several problems relating to micro motion meter accuracy specifically when gas is present in the fluid being measured. Can any one give me information about calibration curve that will give accuracy of the meter with respect to different concentrations of gas in the liquid ( say from 0.01% to 10% of gas)? Is drive gain of the micro motion related to this issue...?

Micro Motion meter are extensively used in process control applications for measurement of density and flow rate etc. But when these meters are used in Petroleum industries there is every chance of gas in the fluid being measured and this is unavoidable. Thus comes the question of uncertainity of the measurement being made. A calibration curve or a curve indicating the instruments accuracy at different concentrations of the gas being present in the fluid will be very helpful in making accurate measurements?

The MM meter is an excellent mass meter. SO, gas will reduce mass of fluid and thus meter reading.

You need something to tell you gas content or a second flow meter, a volumetric meter and then subtract reading to get true flow.

Good luck,


lonnie henderson

MM meters are excellent mass flow devices but entrained gases throw them a curve as the density varies significately thus as they measure
density directly is the problem. They use density for thier volumetric determination so the error is introduced. I suggest a gas entrainer, a device to remove gasses prior to the measurement of the flow stream. These are common in industry and many manufactures are found. The only other way, if this is impractical, is the common orifice meter with pressure and temperature compensation for the determination of mass flow. Remember that any major entrainment of gas in the liquid stream will throw off your mass flow. You cannot calibrate this out and as the gas content increases your error will grow. Micro Motion will help, you just have to ask, but the real answer in my opinion is to remove as much gas as possible or increase the pressure to keep gasses in solution when being measured.