25-01-2013, 04:46 PM
HOW TO HANDLE PYROMETERS
[attachment=48527]
Introduction
The word pyrometer is derived from the Greek word “Pyro” which means fire and “meter” means measurement so it means measurement of fire.
Pyrometer is a device used to measure the temperature of molten metal.
The thermocouple pyrometer that utilizes interchangeable thermocouple tips on immersion temperature measurement applications.
Principle of Operations
It works on the principle of Seeback Effect.
The Seeback effect is a phenomenon in which a temperature difference between 2 dissimilar electrical conductors produces a voltage difference between the 2 substances or in other words The Seeback effect is the conversion of temperature differences directly into electricity.
When heat is applied to one of the two conductors heated electrons flow towards the cooler one. If the pair is connected through an electrical circuit, direct current flow through that circuit.
If the temperature difference is large enough, some Seeback effect devices can produce a few milli Volts.
Operations
Immersion pyrometer consist of metal housing, Electronic Measurement Circuitry (EMC), metal lance, Thermocouple connected to the circuitry by means of compensating cables which passes through the lance.
When thermocouple dip into the molten metal, it gives milli volts output. These milli volts are carried to the EMC, where the signal (mv) is amplified and processed to give direct digital output. The processing of the signal is done by various techniques. Peak latching, Plateau Detection, Continuous tracking are some of these techniques.
Continuous tracking
In this technique temperature is displayed continuously as it senses. So you do not get stable display of temperature. So it is difficult to know, when to remove lance.
Temperature recording is fully dependent on operator skill and it can not separate out hot spot temperature and true temperature. So it is not suitable for ferrous foundries.
[attachment=48527]
Introduction
The word pyrometer is derived from the Greek word “Pyro” which means fire and “meter” means measurement so it means measurement of fire.
Pyrometer is a device used to measure the temperature of molten metal.
The thermocouple pyrometer that utilizes interchangeable thermocouple tips on immersion temperature measurement applications.
Principle of Operations
It works on the principle of Seeback Effect.
The Seeback effect is a phenomenon in which a temperature difference between 2 dissimilar electrical conductors produces a voltage difference between the 2 substances or in other words The Seeback effect is the conversion of temperature differences directly into electricity.
When heat is applied to one of the two conductors heated electrons flow towards the cooler one. If the pair is connected through an electrical circuit, direct current flow through that circuit.
If the temperature difference is large enough, some Seeback effect devices can produce a few milli Volts.
Operations
Immersion pyrometer consist of metal housing, Electronic Measurement Circuitry (EMC), metal lance, Thermocouple connected to the circuitry by means of compensating cables which passes through the lance.
When thermocouple dip into the molten metal, it gives milli volts output. These milli volts are carried to the EMC, where the signal (mv) is amplified and processed to give direct digital output. The processing of the signal is done by various techniques. Peak latching, Plateau Detection, Continuous tracking are some of these techniques.
Continuous tracking
In this technique temperature is displayed continuously as it senses. So you do not get stable display of temperature. So it is difficult to know, when to remove lance.
Temperature recording is fully dependent on operator skill and it can not separate out hot spot temperature and true temperature. So it is not suitable for ferrous foundries.