What is a thermal conduction flow switch?
Thermal conductivity flow switch, the use of modern microelectronic heat exchange technology, high sensitivity, stable performance, suitable for modern centralized control technical requirements. With a switch, analog, digital and other status output. Nanping City Science and Technology traffic switch can detect non-directional flow state. Detection range: (W) Water 1 ~ 150cm / s (O) Oil 3 ~ 300cm / s (L) Air 1 ~ 30m / s Medium temperature range: -10 ~ +80 Protection class: IP67 Response time: 8s ... 20s switch Time: 2s / 2s installation torque: 100Nm shell material: 316L maximum voltage: 100bar (10Mpa) outlet: instrument dedicated 5P / M12 interface, wiring 2M (Note: there are analog and digital, dual interface output)
In general, the flow switch is divided into mechanical form and induction form according to the principle.
The thermal conductivity flow switch is the inductive form of the flow switch
Thermal conductivity flow switch is the use of heat transfer temperature difference to detect the principle of pipeline flow, it is by far the most complete application of the most widely used flow switch products.
FR thermal conductivity electronic flow switch is widely used in petrochemical, power, metallurgy, steel, paper, food processing, water treatment and other industries. When the flow exceeds or below a certain value, the output of a relay signal, the set point can be located anywhere in the range, with high reliability and repeatability.
The thermal conductivity flow switch is also called thermal conductivity type electronic flow switch.
Now use the FR series of electronic thermal conductivity flow switch to illustrate the thermal guide flow switch to explain the working principle:
The FR series thermal conductivity switch is made up of two temperature sensors, power supplies, signal processors and output relays or NPN / PNP transistor outputs.
The temperature sensor for this type of thermal conductivity flow switch is manufactured using special semiconductors.
The physical characteristics of these two sensors are very close, and separated by a certain distance, mutual heat can be ignored.
The sensor paired the temperature of the tracking media. The voltage drop of these sensors is proportional to the temperature and is accurate over a wide temperature range. One of the sensors (Sensor1) is heated to be higher than the medium temperature.
Another sensor (Sensor2) is the same as the medium temperature we have for the reference sensor.
The same constant current flows through the two sensors to produce a voltage difference that is inversely proportional to the amount of heat that Sensor1 takes away by the media.
As the medium flow rate and take away the heat is proportional to, so by measuring the voltage difference between the two sensors, we can see the flow rate of the media at this time, so as to know through the flow of media.
As shown in the picture ~!
