General purpose liquidinglass thermometers is rated 5. This paper describes a method for the calibration and. These thermometers are individually serialized and includes a statement of accuracy indicating accuracy traceable to nist. Report containing information of general interest to manufacturers and users of liquidinglass thermometers. When paired with a temperature scale, it is possible to use this occurrence to determine the temperature.
When the hollow sphere was heated, the air inside it expanded and bubbled through the liquid at. Liquid in glass thermometer thermometer mercury element. Scribd is the worlds largest social reading and publishing site. A liquid in glass thermometer consists of a capillary glass tube with a bulb at one end filled with a thermometric liquid, vacuumed and sealed. 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.
This paper describes a method for the calibration and recalibration of liquid in glass thermometers based on use at temperature. The more liquid there is, the more liquid will expand and rise in the glass tube. Apart from its industrial and laboratory use, it finds application in both domestic and medical fields. The coefficient of cubical expansion of mercury is about eight times greater than that of glass. As the temperature of the liquid in the reservoir increases, it expands and rises into the capillary tube. Compared to other thermometers, it is simple and no other equipment beyond the human eye is required. Nist traceable calibration 2 4 point liquid in glass. Liquidinglass thermometers lets start our story with one of the most common thermometers used today, the liquidinglass lig thermometer. International oiml r 3 recommendation edition 2002 e. This thermometer consists of a glass bulb and stem filled with a working liquid alcohol or mercury and an inert gas.
Glass thermometer an overview sciencedirect topics. Maintenance and validation of liquidinglass thermometers nist. A common range for liquidinglass thermometers is from 10 c to 110 c. Not sure how the same thermometer could be calibrated ok in 2011 but this year the high temp point was not. Jan 01, 2009 however, liquid in glass thermometers are subject to drift and change in calibration status as a function of time and use of temperature. 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. A desire to increase automation or to eliminate the use of mercury has prompted several astm committees to consider alternatives to astm liquid in glass lig. Designs can be classified as either the sheathed type or the unsheathed type. Some manufacturers use galinstan, a liquid alloy of gallium, indium, and tin, as a replacement for. It provided an exactly correct reading at 32 degrees f in an ice water bath. The glass thermometer must be the most familiar of all thermometers.
Nationalbureauofstandards division221,section01 marked. Liquid in glass thermometer principle instrumentation tools. Strouse national institute of standards and technology gaithersburg, md 208998363 abstract. Maintenance and validation of liquidinglass thermometers. These high precision liquidinglass mercury thermometers are hand blown, which bear graduations, numbers and letters etched into the glass and filled with and inert gas above the mercury. These high precision liquid in glass mercury thermometers are hand blown, which bear graduations, numbers and letters etched into the glass and filled with and inert gas above the mercury columngeneralpurpose liquid in glass thermometers feature black writing on clear tubes for easy reading, with some models having white backing for even easier reading. This may be a result of shipping and handling, or improper storage. However, the glass is used because it filters the temperature well. Thermometer faqs frequently asked questions how do partial and total immersion liquid in glass thermometers differ. A lig thermometer, by definition, is a glass capillary tube.
This particular material has excellent strength, impact and stiffness properties which makes it perfect forthe toughest applications. A liquidinglass thermometer is widely used due to its accuracy for the temperature range 200 to 600c. This may be a result of shipping and handling, or improper. Selection of alternatives to liquid in glass thermometers dean c. Not sure how the same thermometer could be calibrated ok in 2011 but this year the high temp point was not within calibration. The reason why this is one of the most famous is because mercury goes from being solidified to liquid quickly, therefore it expands more quickly and offers a. Liquid in glass thermometers thermcos precision liquid in glass thermometers are manufactured with the finest glass manufactured under iso2001 guidelines. A thermometer is a device that measures temperature or a temperature gradient. The case is nonsparking and has a 120ml capacity cup, which meets astm and api requirements. Mar 08, 2017 the liquid in glass thermometer uses the concept of thermal equilibrium to measure temperature. A procedure for the effective recalibration of liquidinglass thermometers author. P43 liquidinglass industrial thermometer u a u a t 1 w extension neck lag standard p43 liquidinglass industrial thermometer u a t 1 w extension neck lag standard.
A procedure for the effective recalibration of liquidin. By reading the position of the liquid level on a scale, a temperature value can be obtained. Rated 5 out of 5 by richard from long thermometer in degrees f i am. Wise instituteforbasicstandards nationalbureauofstandards washington,d.
The temperature t indicated by the thermometer is the mercury temperature which will only equal t f. In an open container filled with colored alcohol, he suspended a long narrowthroated glass tube whose end was shaped into a hollow sphere sort of like an upsidedown thermometer. A glass thermometer containing mercury that indicates the temperature being measured. Report containing information of general interest to manufacturers and users of liquid in glass thermometers. Although it is normally an instrument of only moderate accuracy, the very best of them, when used with sufficient attention to detail, have. Liquidinglass 65 astm tank gauging thermometersscoopmaster cup case thermometer total immersion thescoopmaster thermometer is molded from heat resistant.
These and other features of a solidstem thermometer and of an. Selection of alternatives to liquidinglass thermometers dean c. I let them know i had questions on my evaluation but to date, no contact from the company. For this reason, liquid thermometers have a reservoir to increase the amount of liquid in the thermometer. A typical liquid in glass thermometer is shown in figure 25. Ligts are one of the earliest forms of thermometers, 1. It has been used in medicine, metrology and industry. Too much liquid, however, would cause the thermometer to react very slow to temperature changes, as the heating of the liquid will take longer and the liquid.
They have been developed for the use in the range from 190 ocupto600c, including the measure. The liquid in glass thermometer has a glass bulb attached to a sealed glass tube also called the stem or capillary tube. One side of this is a magnifying glass, which makes reading easier. In an open container filled with colored alcohol, he suspended a long narrowthroated glass tube whose end was shaped into a hollow sphere. A liquid in glass thermometer uses the expansion of a liquid with increase in temperature as its principle of operation. Astm liquidinglass mercury thermometers, partial or.
When the temperature changes, the liquid expands or shrinks. Liquid in glass thermometers consist of a liquid contained in a glass envelope. In this section, we give a brief description of various types of liquid in glass thermometers see refs. A procedure for the effective recalibration of liquid in glass thermometers author. Liquid in glass thermometers ligts are analogue measuring instruments, where the height of the liquid column inside a glass stem is proportional to the exposed temperature. A liquidinglass thermometer consists of a capillary glass tube with a bulb at one end filled with a thermometric liquid, vacuumed and sealed. The range of a thermometer is the difference between the maximum and minimum temperatures that the thermometer can read. However, liquidinglass thermometers are subject to drift and change in calibration status as a function of time and use of temperature. Thermometer, this is an instrument of extreme accuracy and rugged dependability. Liquidinglass 65 astm tank gauging thermometersscoopmaster cup case thermometer total immersion thescoopmaster thermometer is molded from heat resistant plastic, impervious to the chemical action of petroleum products and hydrocarbons. The lig thermometer is one of the earliest thermometers. By reading the position of the liquid level on a scale, a.
Liquid in glass thermometer free download as powerpoint presentation. Figure 1 provides an illustration of thermometer features and pictures of various. A lig thermometer, by definition, is a glass capillary tube with a liquidfilled bulb at one end. Rated 5 out of 5 by richard from long thermometer in degrees f i am quite happy with the liquid thermometer showing temperature in degrees f for checking my various digital indooroutdoor thermometers, which do not always agree. The liquid in any glass thermometer, regardless of type e. Apart from its industrial and laboratory use, it finds application in both domestic and. The range of a liquidinglass thermometer is limited by the length of the thermometer and can be increased by. This particular material has excellent strength, impact and stiffness. Galileo is credited with inventing the thermometer, circa 1592. Manual of petroleum measurement standards chapter 7. Mercuryinglass thermometer 3 phase out today, many mercuryinglass thermometers are still widely used in meteorology. Because the body of glass is considered delicate and very fragile, it is imperative to take care of extremely strong drops or grips, because it could rupture and leak the liquid. Maintenance, validation, and recalibration of liquidinglass. In this section, we give a brief description of various types of liquidinglass thermometers see refs.
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