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About
Temperature
This is an excellent article giving the basics about
temperature- Thanks to the University Corporation for Atmospheric Research.
4.11
The
Isotech Journal of Thermometry - This brilliant five part
journal is an excellent collection of technical articles dedicated
specifically to thermometry. It includes articles related to temperature
scales, different methods to realize them and practicle techniques used to
calibrate interpolation devices such as SPRTs, IPRTs, Thermocouples, Thermistors
and Pyrometers.
Welcome
to the Isotech Journal Of thermometry - Fundamentals of Thermometry, Part 1:
Temperature Scales - Practical Calibration of Thermometers on the ITS-90 -
Platinum Resistance Thermometers as Interpolation Standards for the ITS-90
Fundamentals
of Thermometry, Part 2: Fixed Points - Standard Platinum Resistance
Thermometer calibrations on the ITS-90, How to specify & order - International
Equivalence of thermometer calibration, testing & certification -
Improvements in Metrological Apparatus - Evaluation of the Gallium melting Point
by a two cell comparison - An MS-DOS computer program for the interpolation of
ITS-90
Fundamentals
of Thermometry, Part 3: Standard Platinum Resistance Thermometers - The
Platinum Resistance Thermometers of C.H. Meyers (Historic
Reprint) - Coiled Filament Platinum Resistance Thermometers - Open Cell,
Sealed Cells, & Slim Cells - The Heat Pipe and its use in Thermometer
Calibration - Isothermal Heat Pipes and Press Controlled Furnaces
Fundamentals
of Thermometry, Part 4: Standard Thermometers, Bridges &
Measurements - Cost of Calibration to ITS-90 at various institutions -
Uncertainties in Temperature Measurement - The Gallium Watchdog (in quality
assurance of measurement) - New Developments & Discoveries - High
Temperature Platinum Resistance Thermometers - Review: About Words - available
metrology vocabularies
Fundamentals
of Thermometry, Part 5: Industrial Platinum Resistance Thermometers -
Common Errors in Industrial Temperature Measurement - I Blame the Mother-in-law
(Evolution of a Fluid Bed Calibration Bath) - The Water Triple Point and Gallium
Point in Secondary Laboratories in Germany - Comparison Calibration at the
Boiling Point of Nitrogen or Argon - A Caution from Phil Metz - News of a new
Metrology Society (Slovak Metrological Society) - Melting Point and Triple Point
Measurements of Gallium on the IPTS-68 (Historic
Reprint)
8.10
Temperature
Measurement and Calibration: what every Instrument Technician should know -
Temperature may be the most commonly measured physical parameter. Yet there have
never been so many ways to measure it as there are today. With so many options
it’s natural to have a few questions. How do I measure temperature? How
accurate is my measurement? What temperature range is required? What type of
device best measures temperature? These are very common questions when
confronted with the need to measure temperature. A variety of measurement
devices may be used for temperature: liquid in glass thermometers (LIG),
thermocouples (TCs), thermistors, resistance temperature detectors (RTDs),
platinum resistance thermometers (PRTs) and standard platinum resistance
thermometers (SPRTs) - Thanks to Fluke and www.processonline.com.au
Challenges of Temperature Sensing - Measuring each of the "big four" process variables has its specific peculiarities, but temperature seems particularly controversial. In fact, this apparently simple task often gets complicated. This tutorial explains why- from Control Engineering Magazine and Moore Industries-Pacific, Inc.
Trends in Process Temperature Measurement -An Evolving Technology Segment Changes Focus to Meet End-User Needs - Mike Cushing - This article also covers the basics about resistance thermometers, thermocouples and the use of temperature transmitters - from www.flowcontrolnetwork.com
A useful degree C/F/Kelvin conversion tool - from Raytek
The Majority of the following links are compliments of http://www.temperatures.com , this website is excellent and provides comprehensive technical information on all temperature related instrumentation. ICEweb congratulates temperatures.com on the development of such a great resource.
The principle behind a bimetallic strip thermometer
relies on the fact that different metals expand at different rates as they warm
up.
Bimetallic
Thermometers and Thermostats
Emissivity - Emissivity: a mystery to some? But not to all! You can't live with it. You can't live without it - Emissivity is linked to Infrared Radiation Thermometry (or, if you prefer, pyrometry) . It's a mystery to many people, however, even to some who sell non-contact temperature sensors and thermal imagers.mPart of the mystery of emissivity is its spelling, it gets mangled more often than consistant; emmissivity, emistivity, emystery and emisomething are just a few. Seriously, it is the often misunderstood parameter that is always associated with IR temperature measurement and radiation heat transfer ("consistent" is the correct spelling, BTW and emissivity has always had only one 'm'). Heat transfer people have no problems with their emissivities. Are they better educated than some of the users of IR thermometers?
Mercury in Steel Basic principals from the Glossary of Meteorology
Standards for Liquid in Glass Thermometers - Glass thermometers are among the oldest and still the most widely type of thermometer used in laboratory work and in households to determine fever temperature in humans.The first standard issued by ASTM on thermometery was standard E1.
8.10
Choosing
the Right Temperature Sensor - Mick Carolan - Temperature
sensors are an effective way to measure temperature, but which should you use,
and for which application? Thanks to www.pacetoday.com.au
Selecting a Temperature Sensor - Choosing a temperature sensor can often be very straightforward, sometimes tricky, but always worth doing well. That's because these sensors, especially in science and engineering uses, can spell the difference between repeatable results and nonsense numbers. The name of the game in measurement is to measure with an amount of inaccuracy or uncertainty that is acceptable. So, the first thing you need to know is how well you need to know the value of the temperature numbers you expect to get. A simple series of questions, when answered, will usually get you started.
How To Select And Use The Right Temperature Sensor - Ron Desmarais - This paper answers the question "How do I determine which sensor to use in my application?” After a brief review of how RTD’s and thermocouples are constructed and used to measure temperature, it discusses what differentiates these sensors from one another. It covers the topics of temperature range, tolerance, accuracy, interchangeability and relative strengths and weaknesses for each type. After reviewing these topics you will have a better understanding as to when each type of sensor should be used and why. From Pyromation, Inc.
Choosing a Temperature Transmitter -From Moore Industries International - While there are many practical and economic advantages to using temperature transmitters, the most basic are to ensure measurement integrity and to convert a temperature sensor’s low-level (ohm or millivolt) signal to a standard 4 to 20 mA current signal that can be readily accepted by a monitoring and control system. Advancing technology has made the use of temperature transmitters affordable even in cost-sensitive applications. Here are few things to consider when choosing one. Thanks to Process Heating Magazine
Sensor Types - Big differences exist between different temperature sensor or temperature measurement device types. Using one perspective, they can be simply classified into two groups, contact and non-contact. The two links in this article take you to descriptive pages on each type with a breakdown by more specific, detailed types.
Temperature Sensor Uses, Measurements or Applications - Measurements are where temperature sensors meet the "real world" where results prove that one understands their properties and has selected a sensor well enough to do the job within the desired measurement uncertainty. This link is where the real fun begins for anyone trying to make a serious temperature or dewpoint measurement. It highlights web sources for this information.
Resistance
Thermometers - What are RTD's? -Resistance
Temperature Detectors or RTDs for short, are wire wound and thin film devices
that measure temperature because of the physical principle of the positive
temperature coefficient of electrical resistance of metals. The hotter they
become, the larger or higher the value of their electrical resistance.
Resistance
Tables - Thanks to Emerson Process Management
All
you want to know about Resistance Thermometers - A 53
page document from Eurotherm
Standard
Platinum Resistance Thermometers - Frequently Asked Questions - From
ISOTECH
Questions
and Answers on Infrared Thermometers - A useful technical
information sheet from our sponsor Zedflo
Australia
Radiation/IR Thermometers/Pyrometers
Infrared
Thermometers - from Omega.com
Principles of Non-Contact Temperature Measurement
- This manual focuses on the practical operations of non contact
temperature measurement devices and IR thermometry, and answers important
questions that may arise - from Raytek
Emissivity
- This is the measure of an object's ability to emit infrared
energy. Emitted energy indicates the temperature of the object. Emissivity
can have a value from 0 (shiny mirror) to 1.0 (blackbody), this technical
article provides further information on this including emissivity tables for
metals and non metals - from Raytek
Thermocouple
Millivolt Tables - Thanks to Emerson Process Management
Thermocouple -
A good introduction from Wikipedia, the free encyclopedia
Thermocouples
All
you want to know about Thermocouples - A 53 page document
from Eurotherm
Thermocouple
Tables
Thermocouple
Theory and Practice -
W. Dhavepatana Co., Ltd, a neat site this one.
Thermocouple
Compensating Cables- See Pages 7 to 9 of this comprehensive document from
Eurotherm
Thermocouple
Extension Cable Tables - Data and colours from Raychem Thermocouple
Wire- Some of the questions answered by Omega
Traps
and Colour Confusion in Thermocouple Wiring - A
useful reference from Arthur Holland and Eurotherm
Thermocouples
- Greg Passler answers the following
questions: What is a thermocouple and how does it work?
Why do we use thermocouples? What
is thermocouple extension cable? From Shawflex
Taking
Thermocouple Temperature Measurements- From NI
Instruments
The
Care and Feeding of Thermocouples
- Richard D.
Smith, P.E - This is a absolutely superb paper.
Thermistors
Thermistor
Resistance Table - from Minco
Following are a number of technical articles on the new Thermowell Design Standard ASME PTC 19.3 TW-2010, the correct design of thermowells is very important especially in respect of stress failures - this standard addresses this.
6.11
New
Standard for Thermowell Design - ASME PTC 19.3 TW - 2010 - The long
awaited PTC 19.3 TW-2010 is a completely new standard that establishes the
practical design considerations for thermowell installations in power and
process piping. This code is an expanded version of the thermowell section
contained in the PTC 19.3-1974, and incorporates the latest theory in the areas
of natural frequency, Strouhal frequency, in-line resonance and stress
evaluation. ASME responded to changing industry demands for a more comprehensive
set of thermowell evaluations. Key enhancements over the 1974 edition include:
Expanded coverage for thermowell geometry;
Natural frequency correction factors for mounting compliance, added fluid mass, and sensor mass;
Consideration for partial shielding from flow;
Intrinsic thermowell damping;
Steady state and dynamic stress evaluations;
Improved allowable fatigue limit definition
PTC 19.3 has been the standard used by piping designers since it’s release and has been highly successful in the industry. The new, expanded PTC 19.3 TW edition—developed by end users and manufacturers—builds on decades of industry and research data to make it the new worldwide authority for thermowell design safety. Intended for piping designers, instrument engineers, instrument designers and plant I/C engineers/designers, plant engineers, plant safety engineers, process engineers, thermowell manufacturers, instrument manufacturers, anyone who assembles thermowell bids or design specifications, and regulatory agencies.
6.11
Thermowell
Calculations - A white paper from Emerson Process Management - Dirk
Bauschke, David Wiklund. Andrew Dierker and Alex Cecchini - Thermowells
are essentially a circular cylinder installed like a cantilever into the process
piping. They allow a temperature sensor to be located within a process flow
while providing a process seal and protecting the sensor from the process fluid.
As a process fluid passes around the thermowell, low pressure vortices are
created on the downstream side in both laminar and turbulent flow. The
combination of stresses, generated by the static in-line drag forces from fluid
flow and the dynamic transverse lift forces caused by the alternating vortex
shedding, create the potential for fatigue-induced mechanical failures of the
thermowell. Until recently ASME PTC 19.3-1974 has been the standard by which
most thermowells are designed. For the most part, though, ASME PTC
19.3-1974 was used successfully in both steam and non-steam applications.
Several key factors caused ASME to re-form the committee in 1999 to completely
rewrite the standard; advances in the knowledge of thermowell behavior, a number
of catastrophic failures (Monju among them) and the increased use of Finite
Element Analysis for stress modeling. When combined, these factors caused many
in the industry to move away from the rudimentary methods and simplified tables
laid out in ASME PTC 19.3-1974 in favor of more advanced methods for predicting
the thermowell natural frequency and calculating the forced frequency. Rather
than simply update the existing version of ASME PTC 19.3-1974, the committee
decided to release a new standard due to the significant changes associated with
the effort. The thermowell calculation portion of ASME PTC 19.3-1974 was 4
pages. By comparison, the new standard, known as ASME PTC 19.3TW-2010 (“TW”
for thermowell), is over 40 pages due to the explanations of theory and the
sheer complexity of the process. By February 2010, ASME PTC 19.3TW-2010 was
approved through all applicable committees and it was finally released in July
2010.
6.11
Thermowell
Design Standard ASME PTC 19.3 TW-2010 - An explanatory video - from
Emerson Process Management
6.11
Typical
Thermowell Calculations Report per ASME PTC 19.3TW-2010 - From Emerson
Process Management
6.11
Velocity
Collars: No Longer Best Engineering Practice - A velocity collar is a
metal ring machined into the shank of a thermowell and installed tightly in to
the standoff of a pipe. Due to the nature of thermowell vibration behavior,
installation practices, and ASME’s position, Emerson does not recommend
velocity collars as a best practice for means of reducing vibration-related
failure. Emerson also feels that other installation methods that attempt to
reduce unsupported length in a similar fashion to velocity collars, such as DIN
Weld-in style thermowells, are not a best practice.
What
is a thermowell? From-Trerice
About
Thermowells -A super page from Temperatures.com
covering most aspects including the one most forgotten related to velocity constraints.
Thermowell
Wakes, Vortices, Vibrations & More- Another top rate
page from Temperatures.com covering most aspects
Introduction
to Thermowells - From Newport
Thermowell
Materials Selection Guide - From Azom.com
Temperature
Scales and Conversions
Calculate
temperature and millivolt tables for Thermocouples based on NIST Monograph 175
- From MINCO
Calculate
temperature and resistance tables for Minco's RTD Elements -
From MINCO
Temperature Regulators - The characteristic feature of self-operated temperature regulators is their compact design, including a sensor, a valve and a capillary tube. Their simple operating principle is based on fundamental mechanical, physical and thermodynamic laws. Thanks to our valued sponsor Samson Controls.
Temperature Sensor Calibration Resources