In the event that emas is not working, appropriate liquid in glass thermometers e. In order to promote public education and public safety, equal justice for all, a better informed citizenry, the rule of law, world trade and world peace, this legal document is hereby made available on a noncommercial basis, as it is the right of all humans to know and speak the laws that govern them. Supplement demonstrate understanding of sensitivity, range and linearity describe the structure of a thermocouple and show understanding of its use as a thermometer for measuring high temperatures and those that vary rapidly describe and explain how the structure of a liquid inglass thermometer relates to its sensitivity, range and. Us environmental protection agency office of pesticide. Thermometers will be trerice bx9 series or approved equal. Liquid inglass industrial thermometers for pipeline, duct or tank mounting bx9 series thermometers will be a blue reading liquid inglass adjustable angle type, 9 scale, cast aluminum case with cured polyester powder coating, clear acrylic window and brass separable thermowell. Report containing information of general interest to manufacturers and users of liquidinglass thermometers. A liquid inglass thermometer is said to be linear if the liquid expands by the same amount for every degree celsius rise in temperature. It is used almost everywhere, and its principle of operation is very simple. Liquid in glass thermometer free download as powerpoint presentation. If the liquid did not expand uniformly, the scale would be nonlinear. Appendix 2 format of the calibration protocol for liquidinglass thermometer12. The principle used to measure temperature is that of the apparent thermal expansion of the liquid.
Scribd is the worlds largest social reading and publishing site. List of astm nonmercury alternatives to liquidinglass. Liquidinglass thermometers lets start our story with one of the most common thermometers used today, the liquidinglass lig thermometer. Temperature readings are recorded every 5 minutes and can be found in a table within the txt. Partial immersion thermometers are immersed in the fluid to the specified immersion depth. See epas about pdf page to learn more list of astm nonmercury alternatives to liquid inglass thermometers pdf 1 pg, 71 k. This type is the oldest and most common kind of thermometer. One of those types is a liquid inglass lig thermometer, which includes both mercury partial and total immersion and organic total immersion filled. A procedure for the effective recalibration of liquid inglass thermometers author. In order to promote public education and public safety, equal justice for all, a better informed citizenry, the rule of law, world trade and world peace, this legal document is hereby made available on a noncommercial basis, as it is the right of all humans to. Methods temperatures in degrees celsius were taken simultaneously using the four thermometers in 207 patients at the casualty department of a malaysian hospital. A lig thermometer, by definition, is a glass capillary tube with a liquidfilled bulb at one end. Importantelementsofthermometerdesignarediscussed,andfactorsaffectingtheuseof common types ofliquidinglass thermometers are includedtogetherwith tablesoftolerances and reasonably attainableaccuracies.
Wise thismonograph,whichsupersedesnbsmonograph90,containsinformationofgeneralinterest tomanufacturersandusersofliquidin. Calibration and verification of temperaturemeasuring. An enlargement at the top of the capillary into which the liquid can flow if the thermometer temperature exceeds the scale limit. Liquid inglass thermometers are based on the principle of thermal expansion of substances. A liquid inglass thermometer designed to indicate temperatures correctly when just that portion of the thermometer containing the liquid is exposed to the temperature being measured. A procedure for the effective recalibration of liquidinglass. When this occurs, the thermometer will not read correctly. A procedure for the effective recalibration of liquidin. Methods of reading liquid inglass thermometers 227 combines the objectivity of readings and automation of data processing, 6. Thermometer, this is an instrument of extreme accuracy and rugged dependability. Although they are decidedly low tech devices, ligts of extremely high accuracy and precision can be constructed today.
Userfriendly guidance on the replacement of mercury thermometers. Primary view of object titled liquidinglass thermometer calibration service. Thermometry thermometry is the science and practice of temperature measurement. To check the temperature sensor read the temperature of the meter against a nist thermometer and record the two temperatures. Glass stem thermometers the glass stem thermometer was the. The coefficient of cubical expansion of mercury is about eight times greater than that of glass. The increase in volume is thus due to a change in height of the liquid within the column. Liquidinglass thermometer calibration service nist page. In the lig thermometer the thermally sensitive element is a liquid contained in a graduated glass envelope. Ccd camera illumination calibration bath with a window reference thermometer ligt under test image acquisition modul processing software metal equalising block figure 5.
Instructions explaining how to submit a thermometer to the national bureau of standards for calibration are provided, and the techniques and equipment, such as stirred liquid comparison baths, used in the calibration procedures are described. The glass thermometer must be the most familiar of all thermometers. Some ranges and types are more readily susceptible to separation than others. Publication 1088, maintenance, validation, and recalibration of liquid inglass thermometers, january 2009 as the linkage of a measurement back to primary temperature standards also referred to as metrological. The pdf file provides a daily summary of temperature activity selectable. Thermometer faqs frequently asked questions how do partial and total immersion liquid inglass thermometers differ. In other words, as long as a glass thermometer is not mechanically destroyed, it remains accurate for the duration of its service life. Pdf the thermometerfrom the feeling to the instrument. Calibration of liquidinglass thermometers unt digital. Maintenance, validation, and recalibration of liquidin. Liquidinglass thermometers 1 applies only to the french text. It consists of mercury as a liquid filled in a glass tube. Liquid in glass thermometer principle instrumentation tools.
Place the cylinder of the thermometer in melting pure water and mark the point where the fluid in the. Glass thermometer an overview sciencedirect topics. This type of thermometer was developed by a german based physicist named daniel gabriel fahrenheit. Our glass thermometers conform to the international temperature scale of 1990 its90. The main difference between partial and total immersion thermometers is the application in which they should be used.
Factors affecting the use of common types of liquidinglass thermometers are included together with tables of tolerances and reasonably attainable accuracies. Liquid inglass thermometers are pervasive throughout industry. Instructionsexplaininghowtosubmit athermometertothenationalbureauofstandardsforcalibrationareprovided,andthetechniques. When the temperature changes, the liquid expands or shrinks. Liquid inglass thermometers can be used to measure atmospheric temperature, semisolids, or liquids. As an alternative to conducting pointcheck of liquid in glass thermometers in the event of an emas failure, digital thermometers section 11 may be used to measure the. This thermometer consists of a glass bulb and stem filled with a working liquid alcohol or mercury and an inert gas. This study assessed the concordance of the temperatures of the digital, liquid crystal forehead and digital infrared tympanic thermometers with the mercury in glass thermometer. There are two major types of liquidinglass thermometers which are mentioned below. Mercuryinglass thermometer franks hospital workshop. Reuniting separated thermometer columns sigmaaldrich. Alcoholometers and alcohol hydrometers and thermometers. Liquid inglass thermometers everyone is familiar with liquid inglass thermometers ligts.
List of astm nonmercury alternatives to liquid inglass thermometers. International oiml r 3 recommendation edition 2002 e. The liquid in glass thermometer, is the most commonly used device to measure temperature and it is inexpensive to make and easy to use. Reuniting separated thermometer columns al221 mercuryfilled thermometers this technique applies to most mercury thermometers regardless of temperature range, except deep immersion types. As we saw above, the first known thermometers were of the ligt type. A mercuryinglass thermometer, also known as a mercury. As the temperature of the liquid in the reservoir increases, it expands and rises into the capillary tube. Mechanical thermometers can be constructed to use liquids, solids, or even gases as the temperaturesensitive material. Liquid in glass thermometer principle the liquid in glass thermometer, is the most commonly used device to measure temperature and it is inexpensive to make and easy to use. Liquid in glass thermometer thermometer mercury element. The nist certificates for the master thermometers should be kept on file for.
Verification regulation of liquidinglass thermometers for. If the depth of the test sample is shallow, a partial immersion thermometer. Liquid inglass separation all liquid inglass thermometers are subject to separation of the liquid column. Liquid in glass thermometers tend to be fragile and hence easily broken, can only be used where the liquid column is visible, cannot be used for surface temperature measurements, cannot be read from a distance and are unsuitable for high temperature measurements. Mercuryfilled liquid inglass thermometers have a long history of use in. Racgp a comparative study on the accuracy of noninvasive. A liquidinglass thermometer measures temperature based on the thermal expansion of mercury or spirit alcohol in a glass container. Liquid inglass thermometers winters instruments tel.
Gregory strouse, dawn cross, wyatt miller and dean ripple national institute of standards and technology gaithersburg, md 20899. Choose a glass thermometer by the length that will be immersed in the liquid or gas. Types of liquidinglass thermometers automationwiki. Liquidinglass thermometer calibration service unt digital library. Report discussing important elements of thermometer design. These thermometers are individually serialized and includes a statement of accuracy indicating accuracy traceable to nist. These thermometers provide a convenient method for measuring temperature over a broad range of applications with reasonable stability and accuracy. Hold the thermometer in an upright position and gradually immerse the bulb in a. However, like all thermometers, liquid inglass thermometers are subject to drift as a function of time and maximum temperature of use. A calibrated scale can then be used to read off the respective temperature that led to the corresponding thermal expansion. As the temperature of the liquid in a thermometer increases, its volume increases.
A liquid in a glass tube called a capillary expands when heated and contracts when cooled. You may need a pdf reader to view some of the files on this page. The national institute of standards and technology nist industrial thermometer calibration laboratory itcl is responsible for calibrating several different types of industrial thermometers. It is the basis of the design and operation of thermometers. The liquid is enclosed in a tall, narrow glass or plastic column with a constant crosssectional area. Userfriendly guidance on the replacement of mercury. Wise thismonograph,whichsupersedesnbsmonograph90,containsinformationofgeneralinterest tomanufacturersandusersofliquidinglassthermometers. This means that the scale will be marked in degrees of equal size as below. A typical liquid inglass thermometer is shown in the figure below. Liquid inglass thermometers 1 applies only to the french text.
158 281 297 1460 929 1159 610 208 553 1185 165 1287 1182 1131 1412 148 1376 645 854 919 709 654 635 1142 447 671 1097 1254 1173 116 532 1107 1224 1496 1323