Classification Of Temperature Measuring Instruments

The temperature classification describes the threshold temperature for the hazardous area.

Classification of temperature measuring instruments.

The value of minimum ignition temperature is classified from t1 to t6. The liquid in glass thermometer is one of the most common instruments used today to measure temperature. It was created by the german scientist daniel gabriel fahrenheit in the early 18th century and adapted its measurements standards from a previous scale created by ole roemer. Temperature measuring sensors come in a wide variety and have one thing in common.

The liquids chosen for thermometers expand and contract significantly. For measuring temperature we use different methods and devices. Till now many methods have been developed for measuring temperature. Attempts at standardized temperature measurement prior to the 17th century were crude at best.

For instance in 170 ad physician claudius galenus mixed equal portions of ice and boiling water to create a neutral temperature standard. The seven basic types of temperature measurement sensors discussed here are thermocouples resistive temperature devices rtds thermistors infrared radiators bimetallic devices. Of the many different methods of temperature measurement available the instrument engineer in the process industry is only likely to encounter a handful. Following are the most commonly used temperature measuring devices.

The magnitude of one of the quantity is unknown and it is compared with the predefined value. The modern scientific field has its origins in the works by florentine scientists in the 1600s including galileo constructing devices able to measure relative. Atop the bulb is a stem that has a scale marked for measuring the temperature. As the name suggests the instrument consists of a glass bulb containing a special liquid.

The term measurement means the comparison between the two quantities of the same unit. What is temperature classification. Temperature classification also known as temperature class or t class defines the maximum surface temperature that a product destined for use in a potentially hazardous atmosphere is allowed to operate at relative to an ambient temperature of 20 c to 40 c. This classification of temperature identifies a temperature that an instrument will produce at ambient environment temperature 40ᵒ c.

Almost all the methods depend upon the measuring some physical property of a working material that varies with temperature. Classification of measuring instruments the instrument used for measuring the physical and electrical quantities is known as the measuring instrument.