Se ti interessa guardare il nostro video in lingua italiana clicca questo link:
• Come funziona una Term...
• Find out more about our project:
www.jaescompan...
• Here are some products installed by our technicians:
www.jaescompan...
JAES is a company specialized in the maintenance of industrial plants with a customer support at 360 degrees, from the technical advice to maintenance, until final delivery of the industrial spare parts.
Linkedin: / jaes-srl​
Facebook: / jaescompany
The thermocouple is a very simple and cheap instrument, which can measuredifferent degrees of temperature; thanksto its simplicity it is used in many industrial sectors. The basic principle that uses the thermocouple for its operation was discovered by the physicist Thomas Johann Seebeckin 1822. Hediscovered that in a closed circuit composed oftwo conductors of different nature and subjected to a temperature gradient,apotential differenceis established , that is proportional to the temperature differences.In this video we will discover how a Thermocouple works, its characteristics and all its variants.Jaes, leader in the spare parts industry for over 10 years, offers in its catalog every type of thermocouple from the leadingmanufacturers.This is a Thermocouple. It is a probe made up of 2 different metal wires, welded at one end, this part, called HOT JUNCTION, will be positioned in the space tobe measured. On the other end, we find the COLD FUNCTION, from here the2 metal connections, generally made by copper, will then be connectedto a measuring instrument to detect the temperature perceived by the probe.But how does a Thermocouple work?Imagine holding a copperbar with your hand fromone end, while the opposite side is exposed to a source of heat, a flame for example. The heat will begin to spread along the entire length of the bar until it reaches our hand. This is because the heat excites the molecules and atoms present in the copper bar, which in turn will makefree electrons to move easily reaching the cooler part and heating it. This happens because there is a TEMPERATURE GRADIENT, that isa difference in temperature from one point to another, in our case from the hottest to the coldest point of the copper bar. If we look closely at the images we will notice that the colder part now has more negative charged electrons, while the hot part deprived of its electrons will be positively charged, thanks to this difference we can measure the electric potential present in the copper bar, obtaining one specific voltage. Now let's grab our Thermocouple and remember that to measure the temperature we need a potential difference. If the Thermocouple wasmade up of 2 equal metal wires, the heat will arrangein the same wayalong the wiresand there would be the same number of electrons. By measuring the voltage, the result will be 0, sincethere is no potential difference in a circuit consisting of 2 equal metal wires.In fact, Thermocouples are composed of 2 wires of different metals, for example copper and iron, which conduct heat and free electrons in a different way, thus creating a potential difference. This difference isonly generated when the thermocouple circuit is closed, 2 copper wires, called compensated cables, are connactedto the respective cold junctions on one side and to a multimeter on the otherone, it is possible to convert the potential difference into temperature.For an accurate measurement, the cold junction must be in an environment with a known temperature, to compare it to that of the hot junction; ideally in the laboratory the cold junction was immersedinside a
liquid solution of water and ice, therefore at a constant temperature of 0 ° C, but since this solution isn’tvery practical, scientistshave found a way around thanks to technology.Inside the multimeter, asensor is installed to detect the cold junction temperature; The cold junction is extended, thanks to the extendedcables, inside the multimeter nextto the temperature sensor. The purposeof the sensor is to detect the cold junction temperature andtocompensate the automatic cold junction temperature. To put it in other words,it processes a conversion to ensure that the cold junction is always at 0 ° C(or 32 degrees Fahrenheit), as in the laboratory.The equalization takes place thanks to a specific algorithm designed for this situation; the processor of the instrument measures the electrical voltage of the joints and itadds it upto the temperature of the cold junction, in this way we obtain a number expressed in millivolts (mV) which is laterconverted by the device itself into degrees Celsius, thus...