Flow Meter Gas Vemmtec
General The vemm tec IGTM (International Gas Turbine Meter) is a highly accurate ﬂow meter,
approved for custody transfer measurement, equipped with electronic pulse outputs and a mechanical counter.
This document explains the dimensions, ranges, performance, calibration and outputs of the instrument.
It details the installation, safety requirements and material speciﬁcations.
The IGTM measures gas volume ﬂowing through an annular passage in the meter.
The ﬂowing gas volume is totalised on a local mechanical counter.
In addition, low or high frequency pulse signals are generated to infer the gas ﬂow and volume.
The indicated gas volume is the actual volume ﬂowing through the meter at the actual temperature and pressure.
The IGTM is available in two models: CT and IM. The IGTM-CT is used for high accuracy and custody transfer applications.
The IGTM-IM is an economically priced meter with a good accuracy.
Operation The operation of the International Gas Turbine Meter is based on the measurement of the velocity of gas.
The ﬂowing gas is accelerated and conditioned by the meter´s straightening section.
The straightening vanes prepare the gas ﬂow proﬁle by removing undesired swirl,
turbulence and asymmetry before the gas ﬂows to the turbine wheel. The dynamic forces of the ﬂowing ﬂuid cause the rotor to rotate.
The turbine wheel is mounted on the main shaft, with special high precision, low friction ball bearings.
The turbine wheel has helical blades that have a known angle relative to the gas ﬂow. The conditioned and accelerated gas
drives the turbine wheel with an angular velocity that is proportional with the gas velocity. The rotating turbine wheel drives
the index head with the eight digit mechanical counter via shafts and gears. The volume and ﬂow rate can also be indicated electronically.
A proximity probe generates a signal at each passing blade of the turbine wheel. With the device-speciﬁc K-factor and the number of pulses the passed volume can be calculated.
With the measured frequency the ﬂow rate can be determined.