Am1880 standard platinum resistance thermometers sprt interpolates temperature in the range from 200c to 670c on the international temperature scale of 1990 its90. Thermometers, thermal physics from alevel physics tutor. Platinum resistance thermometer an overview sciencedirect. The platinum resistance thermometer is a versatile instrument for temperature measurement in the range from 200 to c. The resistance thermometer uses a sensitive element made of extremely pure metals like platinum, copper or nickel.
The temperature measurement through platinum resistance thermometer is easier as compared to the gas thermometer. The platinum sensing resistor is highly stable and allows high accuracy temperature sensing. The resistance change is not linear, particularly over a large range of temperatures, but the linearity can be improved by using an active circuit with a. The resistance of the metal is directly proportional to the temperature. The platinum resistance thermometer was develop ed into a successful and accurate instrument by callendar. Morris, reza langari, in measurement and instrumentation, 2012. Mar 08, 2019, the resistance thermometer has different accuracy classes. Available in the following models and more, please contact our technical sales team for more details or to place an order. Platinum resistance thermometers chamois metrology ltd.
It discusses the major issues linked to platinum resistance thermometry for the realization of the international temperature scale of 1990 in the temperature range from 24. Two, three, or four leads are connected to the element. Fluke corporation, hart scientific division how to calibrate an rtd or platinum resistance thermometer prt 3 table 2. For best accuracy with modern equipment choose characterization. The warranty period is 1 year for the platinum resistance thermometer. Off using platinum resistance thermometers, control mode switch 5. Industrial platinum resistance thermometer sensors from sai global. With decades of experience in metrology, our team has a passion for making great products using the most cuttingedge technology available. A biographical note by his son appears on he facing page. The figure below shows the platinum resistance thermometer. The metal of choice is platinum as a result of its high melting point1773 o c and large resistance temperature coefficient. Standard specification for industrial platinum resistance.
A working form of resistance thermometer sensor is defined in iec and din specifications and this forms the basis of most industrial and laboratory electrical thermometers. View and download fluke 56265628 user manual online. The thermometer has a wide range from 200 to 1200 celsius. Many rtd elements consist of a length of fine wire wrapped around a ceramic or glass core but other constructions are also used. An investigation into the stability of industrial platinum resistance thermometers 262.
The primary reference standard instrument for calibration at the top of the calibration chain is a helium gas thermometer, a platinum resistance thermometer, or a narrowband radiation thermometer according to the temperature range of the instrument being. Platinum resistance thermometers within a limited range several metals and alloys have an approximately linear resistivity alteration depending on temperature. Secondary platinum resistance thermometers thermoworks. The platinum resistance thermometerin which the principle of measurement is the variation in the resistance of a platinum wire as a function of temperatureis. The its90 is realized in the sprt laboratory entirely by fixed points over the range from the ar tp to the ag fp. In particular, he showed that the clay used for the former, or some. Hightemperature standard platinum resistance thermometer. Platinum resistance thermometry at high temperatures. Standard platinum resistance thermometer sprt model. Standard platinum resistance thermometer calibrations from. Industrial grade platinum resistance thermometers were calibrated in the temperature range from 200 c to 700 c. The more accurately a resistance thermometer should measure, the more limited its permissible measuring range is. Resistance thermometer transducers, also known as rtds resistance temperature detectors depend on the change of resistivity of any material when the temperature changes, and this change in the resistivity causes a change of resistance. Methods for evaluating the condition of platinum resistance thermometers.
If the off the shelf range will not suit the needs the thermometers can be supplied custom manufactured to almost any specification. Replacing the sheath with alumina and the support mandrel with synthetic sapphire seem obvious changes, whilst keeping the bias and aspiration features from the quartz thermometer research. The hightemperature platinum resistance thermome ter has long been advocated as a standard interpolating instrument for a practical temperature scale up to the gold point, in place of the standard thermocouple. Mostly, platinum is used in resistance thermometer. The r vs t relationship is defined as the amount of resistance change of the sensor per degree of temperature change. This article discusses the development and construction of resistance thermometers and their uses in a wide range of industries. Platinum sensing resistors are available with alternative ro values, for example 10, 25 and 100 ohms. The platinum sensing resistor, pt100 to iec 751 is dominant in europe. In this ptr, the double wire of the platinum is wound on the strip of the mica. How to calibrate an rtd or platinum resistance thermometer. Heliumthermometerattemperaturesbelow100,andforthe measurementoftemperaturesintheintervaloto200,itis. The prt is used with a readout device to detect temperature changes or actual temperature.
Ac ceptance of the resistance thermometer for this purpose is likely to come only when sufficient information is. The platinum resistance thermometer is a standard type, calibrated from the ultimate but inconvenient temperature reference of a gas expansion thermometer. For equipment that does not allow characterization, tolerance testing may be your only choice and this is a common situation in industry today. The platinum resistance thermometer prt is very widely used below 500 c as a thermometric sensor. Troemner was founded over 160 years ago by henry troemner.
On input k jl temperature range selected using switch 1,000 900 800 700 600 500 400 300 200 100 0 999 600. The platinum sensing coil is enclosed inside a bulb which is either made of glass or pyrex. A platinum resistance thermometer prt is a thermometer constructed from a high purity platinum element wirewound coil or thin film placed in a tube of metal or glass and sealed with an inert atmosphere andor mineral insulator. Platinum resistance thermometer thermocouple thermistor sensor platinumwire wound or flatfilm resistor thermoelement, two dissimilar metalsalloys ceramic metal oxides accuracy typical values 0. The 5627a may also be used as a temperature standard for calibration of industrial sensors. Jul 19, 2019 iec industrial platinum resistance thermometers and platinum temperature sensors. Resistance thermometers are sensors that allow determining temperature by measuring the electrical resistance of the sensor, assuming that it is in thermal equilibrium with the medium to. Both wirewound and thinfilm sensorbased thermometers were investigated. Evaluation of some hightemperature platinum resistance. Thermoworks selection of calibration platinum resistance thermometers prts are highly resistant to corrosion and stable over wide temperature ranges. As a case study, propagation was calculated for the case where the reference thermometer was a standard platinum resistance thermometer conforming to the its90 equation and the thermometer under calibration was an industrial platinum resistance thermometer conforming to an equation defined in standard iec751.
If youre using block calibrators, furnaces, or temperature points above normal prt platinum resistance thermometer temperatures 420 c, then these two prts are for you. Calibration of industrial platinum resistance thermometers up. The rtd wire is a pure material, typically platinum, nickel, or copper. The thermometer measures the temperature over the range of 200c to1200c. The traditional sensing element of a resistance thermometer consists of a coil of small diameter wire wound to a precise resistance value. It works on the principle that the resistance of platinum changes with the change of temperature. These thermometers operate on the principle that electrical resistance changes in pure metal elements, relative to temperature.
It is designed as a primary or secondary standard thermometer to calibrate other thermometers andor to measure temperature precisely in primary and secondary laboratories. The platinum resistance thermometer johnson matthey. This wide temperature range requires several thermometer types, which are included as part of the 162 series shown in table 1. Platinum resistance thermometer calibration procedures are similar whether the method selected is characterization or tolerance testing. Common rtd sensing elements constructed of platinum, copper or nickel have a repeatable resistance versus temperature relationship r vs t and operating temperature range. The property of metals that their resistance is temperaturedependent makes them ideal as thermometers. The platinum thermal resistance uses platinum for determining the temperature. The company started as a manufacturer of scales and weights. Ag fp, the interpolation instrument is a platinum resistance thermometer constructed with a strainfree platinum resistance element and meeting certain performance criteria. Data sheets showing similar products and accessories. Platinum resistance thermometer calibrations nvlpubsnistgov.
Platinum resistance thermometer pprt calibration laboratory provides calibrations based on the international temperature scale of 1990 its90 1 to government owned facilities, industry and secondary calibration laboratories. Calibration by comparison of platinum resistance thermometers. It works on the principle that the resistance of platinum. The platinum has high stability, and it can withstand high. The platinum thermal resistance ptr uses platinum for determining the temperature. Resistance thermometers, also called resistance temperature detectors rtds, are sensors used to measure temperature. It is used both for precision measurements of the highest accuracy and for routine industrial work. John ancsin suggests that the quartz support for the platinum winding forms a eutectic at 830c. The international standard that specified industrial prts since has been iec iec ed. Here the double wires are used for reducing the inductive effect. Rtd precision thermometer, fluke 5627a temperature probe. Construction and application of platinum temperature. Am19601950 standard platinum resistance thermometer users.
Platinum resistance thermometers prt characteristics. The meter gives the precise reading of temperature. Resistance thermometer an overview sciencedirect topics. The last international agreement, cgpm181987, adopted the so called international temperature scale, its90, which extends upwards from. Guide to the realization of the its90 platinum resistance thermometry 3 56 5. Resistance thermometers may be called rtds resistance temperature detectors, prts platinum resistance thermometers, or sprts standard platinum resistance thermometers. Platinum resistance thermometer prt selection guide. The dominant standard adopted internationally is the pt100 which has a resistance value of 100.
Resistance thermometers utilise a high precision sensing resistor, usually platinum, the resistance value of which increases with temperature. The insulator deposit on the surface of the glass tube is also used for sensing the temperature. Interpolation from an rtd calibration resistance ratio w table. Accumac corporation designs and manufactures digital thermometer readouts, platinum resistance thermometers prts, and thermocouples. The relative change in resistance temperature coefficient. The platinum resistance thermometer prt models 5627a is designed to be a secondary standard interpolating instrument converting temperature to resistance. Platinum resistance thermometer input models multiinput thermocoupleplatinum resistance thermometer models using thermocouple sensors, control mode switch 5. The reference thermometer ctp5000 provides a full range platinum resistance thermometers prts for use in every application from standards calibration to site temperature measurement. Platinum sensors can now be obtained in thinfilm or thickfilm forms of various shapes and sizes, at much lower cost than the older platinum wire types. Resistance thermometer sensing resistors are 2 wire devices but the 2 wires will usually be extended in a 3 or 4 wire configuration according to the application, the associated instrumentation and.