How accurate are liquid in glass thermometers? Organic-Liquid-Filled Glass Thermometers contain nonhazardous liquid in a graduated scale tube which closely resembles their mercury predecessors. The accuracy of a typical glass thermometer is ±1 scale division.
How accurate are liquid in glass thermometers?
Organic-Liquid-Filled Glass Thermometers contain nonhazardous liquid in a graduated scale tube which closely resembles their mercury predecessors. The accuracy of a typical glass thermometer is ±1 scale division.
Which liquid is used in liquid in glass thermometer?
Mercury
Mercury, the liquid in the thermometer, is enclosed in a sealed glass bulb that expands into a fine bore present in the stem of the thermometer. A scale is etched along the stem of the thermometer that is used for reading the temperature.
Does liquid in glass thermometer need calibration?
High quality liquid-in-glass thermometers require only one complete calibration in their lifetime and it is possible to avoid the usual requirement for complete recalibration of the instrument by the recalibration of a single previously calibrated temperature.
What is the principle of liquid in glass thermometer?
Liquid-in-glass thermometers are based on the principle of thermal expansion of substances. A liquid in a glass tube (called a capillary) expands when heated and contracts when cooled. A calibrated scale can then be used to read off the respective temperature that led to the corresponding thermal expansion.
What are the disadvantages of liquid in glass thermometer?
Disadvantages. 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.
What is the most accurate tool to measure temperature?
Usually, an infrared thermometer offers an accuracy of +-2 degrees Celsius. The IEC 60751 for RTDs specifies classes from least accurate to most accurate. Thermocouple accuracy can vary widely, with the special versions as the most accurate, of course.
What is the advantage of liquid filled thermometer?
Following are the major advantages associated with the use of liquid-in-glass thermometers: They are comparatively cheaper than other temperature measurement devices. They are handy and convenient to use. Unlike electrical thermometers, they do not necessitate power supply or batteries for charging.
What are the two kinds of liquid found inside a thermometer?
You can identify the liquid in a thermometer based on its color. Silver liquid indicates that the thermometer contains mercury, while red liquid is alcohol to which red coloring has been added. Although uncommon in modern thermometers, a clear color indicates water.
How do you know if a liquid thermometer is accurate?
The measurement accuracy depends on the depth of immersion of the thermometer in the medium to be measured. A liquid-filled thermometer should be immersed up to a reference scale division or a specially applied line on the scale (partial-immersion thermometer).
How is a liquid thermometer calibrated?
Put the thermometer stem or probe into the ice water. Make sure the sensing area is under water. Wait 30 seconds or until the reading stays steady. Adjust the thermometer so it reads 32˚F (0˚C).
What are the advantages of liquid in glass thermometer?
Why are glass thermometers not recommended?
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.
Which is the best liquid in glass thermometer?
Thermco’s Precision Liquid In Glass Thermometers are manufactured with the finest glass manufactured under ISO2001 guidelines. Each thermometer is individually serialized and calibrated against standards traceable to NIST & DKD in our PJLA approved calibration laboratory.
Which is ASTM specification for liquid in glass thermometer?
ASTM has developed a specification for low-hazard precision LiG thermometers, ASTM E 2251, Specification for Liquid-in-Glass ASTM Thermometers with Low-Hazard Precision Liquids. This standard provides specific details on proper use of these devices, the repeatability of their measurements, and other limitations.
Why does liquid in glass thermometer leave film?
Organic liquids generally have inferior performance to mercury, and can leave a film on the glass as the liquid drains down the capillary wall. Separation of the fluid column is also known to be a common problem with spirit-filled thermometers.
What makes up the stem of a Lig thermometer?
The bulb is carefully designed to contain a calculated volume of liquid, based upon the length and diameter of the capillary (or stem), as well as the thermal expansion coefficient of the liquid. The stem, or capillary, of a LiG thermometer is made of annealed glass.