The Principle of Thermal Mass type Air Velocity Transmitte

The Air Velocity Transmitter feature thermal dispersion technology in which the temperature difference is greatest in a no-flow condition and decreases as flow increases, cooling the heated RTD. Changes in flow velocity directly affect the extent to which heat dissipates and, in turn, the magnitude of the temperature difference between the RTDs.

 

An electronic control circuit converts the RTD temperature difference into a DC voltage signal. Both of these signals are provided at output terminals and are used to drive two adjustable-setpoint alarm circuits. Both alarms are independently field configurable for flow, liquid level/interface or temperature operation.

 

Thermal Mass Air Velocity Sensor is a speed measuring instrument that converts the flow velocity signal into an electrical signal. It can also measure fluid temperature or density. The principle is that a thin metal wire that is electrically heated is placed in an airflow, and the amount of heat dissipation in the airflow is related to the flow rate. The amount of heat dissipation causes a change in temperature and a change in resistance, and the flow rate signal is converted into an electrical signal. It has two working modes:

1. Constant current type. The current passed remains the same. When the temperature changes, the resistance changes, so the voltage across the two ends changes, thereby measuring the flow velocity.

2. Constant temperature type. The temperature is kept constant, such as 150 ° C, and the flow rate can be measured according to the required applied current. Constant temperature type is more widely used than constant current type.

 

GE-374 Air Flow Velocity Transmitter

GE-374 Air Flow Velocity Transmitter is designed for air velocity measuring, CE certificate, ATEX Explosion Proof is available, monitoring and controll.

Features

● Capable of temperature compensation

● High-speed, high-precision measurement, fast response

● Thermistor measurement sensor

● LCD display air velocity and temperature value

● Switch multifunction physical quantities：[m/s]、[ft/s]、[km/h]、[mph]、[kont]

● DIP SWITCH function and RS-485 function

● Calibration physical quantities, measuring range, analogue output, station, and zero-point OFF SET function

EX Thermal Flow Switches

GE-325 series Thermal Flow Sensor is designed as Explosion Proof type,...