Pantech Instruments manufactures Thermal Dispersion Type Flow Metering System, 845 T. Pantech Instruments is the manufacturer of Process Control Instruments. The Thermal Dispersion type Flow Metering system is in line with all the industrial and gas standards. It uses the principle of heat dissipation, where a heated sensor is inserted into the stream of gas flow. The cooling effect of the gas is measured, transduced and interpreted as flow. The cooling effect is a direct function of the heat transfer that takes place due to the flow of gas. The heat transfer in turn is a direct function of the velocity as well as density of the process gas. Hence, variations in temperature and pressure in the process gas are automatically compensated. The output signal obtained of the Thermal Dispersion type Flow Metering system is pressure and temperature compensated "massflow" signal. Thus the compensated flow independent of pressure and temperature variation is indicated without need for any separate transducers for the same. In areas of flow metering, where the process gas pressures are very low, conventional flow metering techniques present a no. Of limitations. In case of Thermal Mass Flow meter, upstream pressure required is very low because pressure drop across the sensor is negligible. It works in place where Orifice or Rotameter type flow meters have failed.