Pyrometers
Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
computer science crazy
Super Moderator
******

Posts: 3,048
Joined: Dec 2008
#1
07-04-2009, 10:35 PM


The Technique of measuring high temperature is known as pyrometry and the instrument employed is called pyrometer. Pyrometer is specialized type of thermometer used to measure high temperatures in the production and heat treatment of metal and alloys. Ordinary temperatures can be measured by ordinary thermometer, instead pyrometer is employed for measuring higher temperature.
Any metallic surface when heated emits radiation of different wavelengths which are not visible at low temperatures but at about 5400C radiations are in shorter wavelength and are visible to eye and from colour judgement is made as to probable temperature, the colour scale is roughly as follows.

Dark red - 5400C
Red - 7000C
Bright red - 3500C
Orange - 9000C
Yellow - 10100C
White - 12050C and above

The Technique of measuring high temperature is known as pyrometry and the instrument employed is called pyrometer. Pyrometer is specialized type of thermometer used to measure high temperatures in the production and heat treatment of metal and alloys. Ordinary temperatures can be measured by ordinary thermometer, instead pyrometer is employed for measuring higher temperature.
Any metallic surface when heated emits radiation of different wavelengths which are not visible at low temperatures but at about 5400C radiations are in shorter wavelength and are visible to eye and from colour judgement is made as to probable temperature, the colour scale is roughly as follows.

Dark red - 5400C
Red - 7000C
Bright red - 3500C
Orange - 9000C
Yellow - 10100C
White - 12050C and above

When a substance receives heat, change in pressure, electric resistance, radiation, thermoelectric e.m.f and or colour may takeplace. Any of these change can be used for measurement of temperature. Inorder to exercise provision control over the heat treatment and melting operation in the industry temperaturemeasuring device known as pyrometers are used. Also accurate measurement of temperature of Furnaces, molten metals and other heated materials
Use Search at http://topicideas.net/search.php wisely To Get Information About Project Topic and Seminar ideas with report/source code along pdf and ppt presenaion
Reply
seminar presentation
Active In SP
**

Posts: 582
Joined: Apr 2010
#2
30-05-2010, 07:56 AM


.ppt   pyrometer.ppt (Size: 763 KB / Downloads: 307)


Optical pyrometer

can only be used for measuring high temperatures, but different types of radiation pyrometers are available that between them cover the entire spectrum of temperature

Optical pyrometer is designed to measure the temperature / temperature where the peak emission of radiation, there is the red part of the visible spectrum, ie a certain place which is measured shining red color according to temperature.
This tool is for measuring temperatures above 600 ° C.
Optical pyrometer contains a tungsten filament is heated in the optical system. Current in the filament will be increased to the same color with the heat of the object.
Temperature measurements obtained in relation to the current flowing in the filament.

Calibration of optical pyrometer emissivity should be adjusted according to target because they have the brightness / darkness of different objects at a certain temperature.
Manufacturers provide tables emissivities materials to help with this standard.
Inaccurate measurement of optical pyrometer 5 ° C. However, it can be more due to operator error 10 ° C
Able level of accuracy of measurement with an optical filter with a wavelength of 0.65 µm
Ponderable temperature of 5000 ° C in the instrument without the filter up to 10 000 ° C.


This tool can not be used in automatic temperature control scheme for human operator's eyes is an important part of the measurement system.
Until now this tool to measure the temperature in the furnace industry and similar industries.

Radiation thermometer (also known as radiation pyrometers) to measure this radiation in order to calculate the temperature of the object. Total level of radiation emission per second is given by:
E = KT4



Why you should use an infrared pyrometer to measure temperature


Infrared Pyrometers allows users to measure temperature in applications where conventional sensors can not be used. In particular, in cases associated with moving objects (eg, rollers, moving machinery, or conveyor belt), or where non-contact measurement is required because of contamination or hazardous reasons (eg high voltage), in which the distance is too large, or where the measured temperature is too high for thermocouples or other contact sensors.


Focusing energy on objects emit

Filament and removes the eye is replaced with metal detectors such as the eye lens
Principle, can measure the temperature - 36000c 1000c sd
Thermal radiation detector that measures the blackbody temperature rise at the focal point optical system or a photon detector
Thermal detectors respond to the same for all wavelengths in the spectrum of frequencies and consist of thermopiles, resistance thermometers or thermistors


Having a few milliseconds time constant for heating temperature blackbody and respond to the change of time sensor
Selective photon detector in response to a certain range the full spectrum. Usually the type of photoconductive or photovoltaic.
Photon detectors respond to changes in temperature which is very much faster than the atomic thermal detector because it involves processes and typical time constant measurement in a few microseconds.
Optical fiber technology is often used in high temperature measurement applications by collecting and sending the incoming radiation into a detector and electronic processing that is located far

This is to prevent exposure / exposure of an electronic process for potential damage due to high temperatures. Fiber-optic radiation pyrometer is also used to apply these principles in a very difficult application, such as measuring the temperature inside a jet engine by collecting radiation from the engine and transmission out.
Object size is measured by the radiation pyrometer is limited by optical resolution, which is defined as the ratio of the size of the target distance. A good ratio of 1:300,
This means that will allow measurement of the temperature of an object the size of 1 mm in the range of 300 mm.
With a large distance / target size ratio, it is very important dg accurate aiming and focus of the pyrometer at the target object.
How does an infrared pyrometer selection for each application
comparison

What should be in consideration of the application settings when selecting an infrared pyrometer

Critical considerations for any infrared pyrometer as follows:
Field of View / Field of View (target size and distance),
Surface Type the measured / Surface (emissivity considerations),
Spectral Response (for atmospheric effects or transmission to the surface),
Temperature Range and Model (portable or Fixed-Mount).
Another consideration is the response time, the environment, the limitations of the model, view ports or windows applications, and processing the desired signal.


Field of view / Field of View is the angle of view in which the instrument operates, and is determined by the optical unit. To get an accurate temperature reading, measurable targets should really fill the field of view instruments. Because infrared devices determine the average temperature of all surfaces in the field of view, if the temperature is different from the object background temperature, a measurement error can occur.

Many instruments are used for long distance or a small spot size also includes coverage of the review to improve focus.
Field of view diagram is available for most instruments to help estimate the size of the spot at a certain distance.


Emissivity is defined as the ratio of energy emitted by an object at a given temperature to the energy emitted by a perfect radiator, or blackbody, at the same temperature.

Emissivity of the blackbody is 1.0.

All values of emissivity fall between 0.0 and 1.0.

Emissivity can not be ignored, an uncontrollable factor in infrared temperature measurement, the value is also the main / important


Total energy, the total emissivity, transmission and reflection is equal to 1: ETR = 1.0
Reflection ®, a measure of the ability of an object to reflect infrared energy,
Transmission (T), the size of the object the ability to pass or transmit the infrared energy
All energy radiation must be emitted (E)
The higher emissivity of an object, the easier it is to get an accurate temperature measurement using infrared

What spectral responses / Response Spectrum and how they affect the reading

Spectral response is the width of the infrared spectrum which was the cover.
Generally (for temperatures below 1000 ° F) using wideband 8 sd14 micron filter.
This range is preferred for most measurements, because it will allow measurements to be taken without atmospheric disturbance (because of the atmosphere affect the temperature reading of the instrument).

How to take into account when selecting and installing the infrared measurement system

First, the instrument must respond fast enough to process the change accurate temperature recording or control.
Typical response times for an infrared thermometer in the range of 0.1 to 1 second. This tool must be able to function in the environment, at ambient temperature.
Use Search at http://topicideas.net/search.php wisely To Get Information About Project Topic and Seminar ideas with report/source code along pdf and ppt presenaion
Reply
harsh_fast
Active In SP
**

Posts: 1
Joined: Jul 2010
#3
05-09-2010, 11:50 AM

plzzzzzzzzzzzz i want ppt,pdfs of radiation pyrometer
plzzzzzzzzzzzz helppppppppp me i want ppt,pdfs of radiation pyrometer
thanksssss
Reply
study tips
Super Moderator
******

Posts: 10,180
Joined: Feb 2013
#4
17-08-2013, 04:49 PM

Pyrometers


To measure temperature of a very hot body
Where thermometers cannot brought into contact or
Where hot bodies are moving
Measurements done by measuring energy radiated by a hot body or by comparison of colour

Lens – for focusing targets

Uses selective materials to prevents absorption by them
Thallium iodide – more suitable for high temp with shorter emission
fused silica -High temp with shorter wavelength – b/w 250 to 1900 C
Pyrex

Advantages

Abitity to measure high temp
No need for contact
Fast response speed
High o/p
Moderate cost

disadvantages

Non linear scale
Emmisivity of target affect measurement
Errors due to interleaving media

Optical pyrometer- working
disappearing filament type


Radiation received by objective lens- focus on filament- viewed through a microscope system- filament appears in background.
red cadmium filters makes the radiation appear momchromatic
Reply

Important Note..!

If you are not satisfied with above reply ,..Please

ASK HERE

So that we will collect data for you and will made reply to the request....OR try below "QUICK REPLY" box to add a reply to this page

Quick Reply
Message
Type your reply to this message here.


Image Verification
Please enter the text contained within the image into the text box below it. This process is used to prevent automated spam bots.
Image Verification
(case insensitive)