Use Of Thermometers Research Articles

Long Term Stability and Performance of Platinum Resistance Thermometers for Use to 1063° C

The design and performance of platinum resistance thermometers are evaluated for periods of up to 5000 h exposure between 1050 °C and 1100 °C. These thermometers are designed as interpolation instruments for the International Practical Temperature Scale (IPTS). Long term stability and high temperature insulation resistance measurements were of particular interest, and after an initial 500 h of high temperature exposure, drift rates measured at 0 °C were as low as 0.002 °C per 100 h.Insulation resistance was inferred from measurements between the sensing element and a fifth lead wire adjacent to and insulated from the element. An electrical analog was used to establish the correlation between this measurement and the true shunting resistance due to electrical leakage at high temperatures. These measurements suggest that the sensing element resistance could be increased up to a factor of two or three without causing errors greater than 0.001 °C due to insulation effects, thereby reducing the sensitivity requirements on null detectors.

Self-Supporting Carbon Resistance Thermometers for Use at Low Temperatures

Self-Supporting Carbon Resistance Thermometers for Use at Low Temperatures

Calibration and Use of Germanium Resistance Thermometers for Precise Heat Capacity Measurements from 1 to 25°K. High Purity Copper for Interlaboratory Heat Capacity Comparisons

The cryogenic apparatus and techniques used to calibrate 3 platinum-encapsulated 4-lead germanium resistance thermometers for use in precision calorimetry from 1 to 25°K are described. The calibration data for each thermometer were fitted with the aid of a digital computer by a polynomial expressing logR in terms of powers of logT. The sensitivity and temperature-cycling stability of these thermometers were adequate to recommend this type of temperature sensor for accurate low temperature calorimetry. A test of the temperature scale and of an isothermal type calorimeter was made by measuring the heat capacity of a sample of 99.99+% copper from the 1965 Calorimetry Conference Copper Standard and comparing the results with those obtained by other investigators. An equation to represent the heat capacity of pure copper from 1 to 25°K, based upon appropriate literature results and the present data, is offered as a convenient copper reference equation for intercomparison of heat capacity results from various laboratories.

The Development of an Acoustical Thermometer for a Graphite Matrix Nuclear Fuel Element

The development of an acoustical thermometer for use in graphite matrix nuclear fuel elements is described. Test results indicate that this thermometer accomplished the objective of automatically, accurately, and reliably recording temperatures of a number of sensors. The acoustical thermometer system offers a wider choice of signal transmission line and sensor materials than conventional thermometer systems, since it does not require the use of electrical insulators or the conductors in them. This advantage was the main reason for choosing the acoustical thermometer for use in the particular environment of interest. While the development of the thermometer was directly aimed at the solution of problems associated with a nuclear and carbonaceous environment, a number of observations are presented that should be pertinent to acoustical thermometer design in general.

A recording tele thermometer for use at airports

A recording telethermometer for use at airports, developed at the Instruments Division Meteorological Office Poona is described. The instrument designed for reliable and almost unattended performance over long periods, gives a continuous record of temperature at a remote location, with an accuracy of ±0.2°C. A rapid response time and high sensitivity render the instrument also useful for micrometeorological measurements and temperature profile studies.

A susceptibility thermometer for use at very low temperatures

Temperatures have been derived from measurements of frequency of a tuned circuit, the inductance of which encloses a quantity of paramagnetic salt. The expected linear variation of frequency with 1/T was observed (i) between 4° K and 0.1° K, using a single crystal of cerium magnesium nitrate, and (ii) between 4° K and 1.8° K with manganese ammonium sulphate.

Speer Carbon Resistors as Thermometers for Use Below 1°K

A survey has been made of the properties of certain resistors made by the Speer Carbon Company to determine whether they might be suitable for resistance thermometry below 1°K. It is found that resistors of grade 1002 in various nominal resistance values from 100–500 Ω are the most suitable for very low temperature work. Resistors of the same nominal size matched at room temperature and at 4°K have rather similar characteristics down to 0.02–0.03°K. The resistors may also be baked at a sufficiently high temperature to allow them to be sealed into apparatus using thermocuring epoxy resins. A magnetic field perpendicular to the axis of the resistors decreases the resistance at constant temperature.

Effect of Thermal Neutron Irradiation on Thermocouples and Resistance Thermometers

IV. Summary The purpose of this paper is to demonstrate for certain conditions that transmutation of elements can result in a temperature measurement error that is reasonably predictable. Methods are developed for estimating the errors for the purpose of: (1) Engineering judgment in selecting temperature measuring elements for application; (2) Obtaining the order of magnitude for expected error in nuclear applications; (3) Use as a guide in the evaluation of results from nuclear irradiation studies. Theoretical and experimental results show that the thermal emf of a Pt vs Pt-10% Rh is decreased (i.e., a temperature reading will be too low) when exposed to high neutron fluxes. The experimental results, together with theoretical considerations, indicate that the changes are due primarily to the transmutation of rhodium. Furthermore, the experimental results given here are in very close agreement with other irradiation data obtained independently by Oak Ridge National Laboratory. The results are believed to be sufficiently conclusive to permit an estimation of errors to be expected due to transmutations caused by nuclear reactions in this thermocouple. In order to evaluate the various resistance thermometers for use in nuclear reactors, from the transmutation point of view, the values arrived at for the numerical examples are listed below for room temperature.

A platinum resistance thermometer for use at high temperature

A platinum resistance thermometer for use at high temperature

Low-Temperature Thermal Noise Thermometer

The design for a relatively simple noise thermometer for use at low temperatures is presented. This thermometer has been used to measure temperatures as low as the lambda point of liquid helium with a least accuracy of 10%. Some of the properties of thermal noise are discussed.

An airborne radiation thermometer

An airborne radiation thermometer for use in measuring sea surface temperatures from aircraft is described. Infra-red radiation from the water surface is compared to the radiation from a black body at known temperature within the instrument. The sensitivity is about 0·01°C. Errors attending such measurements are discussed, and several applications to oceanographic research are cited.

Distant Reading Electrical Air Temperature Thermometer for use on Aircraft

An electrical resistance air temperature thermometer for use on aircraft is described, capable of measuring air temperatures, at all levels in the atmosphere attainable by aircraft, to an accuracy better than ± ½ C. (This accuracy is usually the highest accuracy which has any meaning in the upper air.) The element resembles a Muller calorimetric resistance thermometer and is in the form of a flat plate with its edge into the airflow, a form which has many advantages. The indicator is a Wheatstone Bridge, balanced manually for each reading, the point of balance being indicated by a small two pivot moving-coil galvanometer. Suitable mechanical arrangements make the balancing operation very easy while the use of a null method obtains many advantages, the most important of which is adequate scale length.

Temperature Surveys in Oil Wells

Temperature measurement in wells is an old practice and geothermal gradientshave been of interest to geologists for many years. Their application to theoperation of oil wells is a more recent practice. It has long been recognizedthat temperature anomalies occur in drilling and producing wells butthermometers that could obtain a satisfactory record of the anomalies were notavailable. The normal geothermal gradient is considered as being about one degreeFahrenheit for each 60 ft. of depth. This "normal" gradient varies indifferent areas, but whatever it may be in an area there is little variationfrom the surface to as deep as the drill penetrates. The normal gradient isappreciably changed by gas expanding from the reservoir into the borehole or bythe movement of fluid through a borehole while drilling, producing, orcirculating. It is the resulting anomalies and abnormal gradients from whichconditions in wells can be interpreted. Some of the applications of suchinterpretations are locating the position of oil or gas sands, permeable stratain a reservoir zone, gas-oil contact, source of water, casing leaks, and thetop of cement behind casing. Thermometers A thermometer for use in wells must be sensitive and have a low thermal lag.The sensitivity should permit recording 0.2?F. or less for differentialtemperatures although the actual temperature need not be more accurate thanIOF. The thermal lag should be as low as rugged construction will permit in order to allow surveysto be made in a minimum of time. Of the several kinds of thermometers, theserequirements are most easily obtained with the vaporpressure, expansion, andelectric-resistance types. Thermometers for use in wells may beself-contained-that is, the complete instrument is lowered into the well and arecord made of the temperature---or the thermal element only may be loweredinto the well and the temperature recorded at the surface. The vapor-pressureand expansion types are more adaptable for a self-contained instrument whilethe electricresistance thermometer is more suitable for surface recording oftemperatures. The self-contained instrument can be run against high pressure on a single wireline with only one operator required. The instrument and its hoisting equipmentis easily portable and can be mounted on a small car. The disadvantages are asomewhat greater thermal lag and the necessity of completing a run before anytemperature or temperature anomaly is known. A surface-recording thermometer has the advantage of being somewhat moresensitive and of having a lower thermal lag. T.P. 1258

Mercury recording thermometer for use over long periods of time

This recorder was developed for the purpose of recording temperatures of experimental tanks, also for hydrographic survey, etc. The record is obtained by casting the shadow of a flat section mercury column of a thermometer on to bromide paper or film, by a feeble source of light.

Phosphorbronze resistance thermometers for temperatures below 1°K, and carbon and ink thermometers for use in high magnetic fields between 1 and 4°K

The resistance of a few phosphorbronze thermometers was measured as a function of the Curie temperature of gadolinium sulphate in liquid helium down to 0.25°K, and showed a nearly exactly linear dependence on that temperature between 1.5 and 0.25°K. Several carbon and ink resistances were measured between 1 and 4°K in different magnetic fields. Those made from a kind of glass-ink appeared to be the most suitable for measurements in magnetic fields, because they change regularly and considerably with temperature and are very slightly affected even by strong magnetic fields.