Abstract: A thermal sensor array includes a dielectric layer including a plurality of individual thermal sensors and a pattern of deposited electrical interconnections facing at least one surface of the dielectric layer for providing electrical connections from each of the plurality of individual thermal sensors, the dielectric layer and the pattern of deposited electrical interconnections being surface-conformable. The thermal sensor array can be used in a diagnostic tool that further includes: a scanning device coupled to the pattern of deposited electrical interconnections for obtaining sensor signals from the thermal sensors; and a computer for processing the sensor signals to estimate temperature distributions.

Abstract: This ceramic sheath type thermocouple has a long service life, an improved temperature measuring responsibility and an improved temperature measuring precision, and enables repetitive use. The ceramic sheath type thermocouple has its protective tube 1 formed of a heat resisting ceramics selected from silicon nitride, sialon and silicon carbide. In the protective tube 1 are installed a pair of W--Re wires that are connected to form a joint portion constituting a temperature measuring point 5. A filler made of Si.sub.3 N.sub.4 reaction-sintered ceramics is loaded into the front end portion of the protective tube to enclose the W--Re wires. Another filler made of SiC whisker with a heat conductivity smaller than that of the filler of the front end portion is loaded into the rear portion of the protective tube. An inert gas is sealed in the protective tube.

Abstract: A method of treatment by ultrasound comprises providing a first, ultrasound field intensity-to-voltage transducer sized for insertion into the vicinity of a treatment site and a second ultrasound treatment transducer. The free field intensities created by the second transducer in response to various second transducer exciting signal levels are determined. The first transducer outputs in the free field in response to various second transducer exciting signal levels are also determined. The first transducer is inserted into the vicinity of the treatment site, and the second transducer is positioned to create an ultrasound field at the treatment site. The distance from the second transducer to the first transducer is determined. An exciting signal is applied to the second transducer. The output of the first transducer is determined.

Abstract: A multi-wire self-diagnostic thermocouple having three thermocouple elements enclosed in a sheath and insulated therefrom. The three thermocouple elements are electrically connected to each other to form three thermocouple junctions. An electronic circuit response to the three EMF signals generated by the three thermocouple junctions generates an error signal when the ratio between the three EMF signals differs from predetermined ratios signifying that the calibration of at least one of the three thermocouple elements has changed. In the preferred embodiment, the sheath is a metal sheath and the three thermocouple elements are fused to each other and to the metal sheath.

Abstract: An apparatus and method for providing a topographical and thermal image of a semiconductor device. A probe (10) is made from a first ribbon of material (11) and a second ribbon of material (12) which forms a thermocouple junction (13). A probe tip (15) is then attached to the thermocouple junction (13) with an epoxy (14). In an alternate embodiment of the present invention, a probe (20) has a point region (17) which is formed by bending a portion of the thermocouple junction (13) and coating the point region (17) is coated with a thermally conductive material. An optical signal is then reflected off a planar portion of the first ribbon of material (11), the second ribbon of material (12), or the thermocouple junction (13) so the motion of the probe (10,20) can be monitored by an optical detector.

Abstract: A small bimetallic thermocouple probe device for use in scanning atomic force microscopy is mass produced by etching and oxidatively sharpening silicon points on a standard silicon wafer. The sharpened points are oxidized and the first thermocouple metal layer is deposited and patterned. The intermetal dielectric layer is deposited and removed in the area of the tip of the probe by a simple double spin photoresist process having a drying cycle between the two spins. The exposed tips have the dielectric etched, and the second thermocouple metal is deposited and patterned. The finished thermocouples are produced by etching the silicon from the back side of the wafer to free up the cantilevered structure which the probe are constructed upon. With such a procedure, large numbers of tiny, low thermal mass scanning atomic force microscope thermocouple probes may be inexpensively manufactured.

Abstract: A protective device for a thermocouple for immersion into a molten metal bath to measure the temperature in the bath includes an elongated exterior protective body, which has an axis and is formed of a refractory composition. An interior reinforcing member is contained within the protective body extending along the axis. The reinforcing member may be in the form of a hollow tubular body which is filled with a refractory cement. A hollow tube is located within the body for protectively housing a thermocouple. A thermocouple for measuring temperatures in a molten metal bath is positioned in the hollow tube.

Abstract: A probe (10) is formed to provide a topographical and thermal image of a semiconductor device. The probe (10) is made from a first ribbon of material (11) and a second ribbon of material (12) which forms a thermocouple junction (13). A probe tip (15) is then attached to the thermocouple junction (13) with an epoxy (14). In an alternate embodiment of the present invention, a probe (20) has a point region (17) which is formed by bending a portion of the thermocouple junction (13) and coating the point region (17) is coated with a thermally conductive material. An optical signal is then reflected off a planar portion of the first ribbon of material (11), the second ribbon of material (12), or the thermocouple junction (13) so the motion of the probe (10,20) can be monitored by an optical detector.

Abstract: A temperature sensor element in a temperature-measuring device using a thermocouple having excellent insulation property and having a simple assembly procedure is provided. The temperature sensor element comprises a temperature-measuring means consisting of a heat-resistant protective tube having a thermocouple inserted therethrough, compensating conduction means having connecting sections which connect a pair of extension sections of a thermocouple element extending from the protective tube respectively, and support means to join and hold mutually the temperature-measuring means and the compensating conduction means. The end of the protective tube and the compensating conduction means are held under the condition that they face the support means and that the extension sections of the thermocouple element and the connecting sections of the compensating conduction means are inserted into holding chamber means provided in the support means.

Abstract: A temperature sensing device includes a head piece having a solid metal body with a mounting surface and a recess within the mounting surface for receiving a thermocouple therein. The body has an attachment end, and hole extending through the attachment end which communicates with the recess such that a plurality of leads may extend through the hole and connect to the thermocouple. An insulating material of mica or metal oxide surrounds the leads and the conducting portions of the thermocouple so as to insulate them from each other and from the metal body of the enclosure. Several structures can be used to form the thermocouple fitted into the small enclosure. In one embodiment, a thermocouple is formed using thin strips of conducting material made of alloys suitable for forming a thermocouple. A thermocouple may be made by first removing the sheathing and insulation from the end of a thermocouple cable, exposing the leads and the leads are flattened or other wise shaped.

Abstract: A temperature sensor assembly for measuring ambient temperature and including a housing defining an enclosure. A temperature sensor is mounted within the enclosure. The housing includes a brass cap and a liner for conducting heat from the brass cap to the temperature sensor. The temperature sensor is mounted on the brass liner and is electrically insulated from the brass liner by a thermally conductive material.

Abstract: A thermocouple structure capable of measurement of a high temperature with a high accuracy is constituted of a protective pipe made of a heat-resistant ceramic; a pair of wires differing in kind and extending in the protective pipe from one end thereof to the other end thereof in the longitudinal direction thereof in a state of being spaced away from each other; a thin film constituting a temperature-sensing portion, made of a tungsten alloy, disposed on one end portion of said protective pipe, and connected to the wires; and a covering layer made of a heat-resistant ceramic and covering the thin film in such a way as to disallow exterior exposure of the thin film. The protective pipe is made of Si.sub.3 N.sub.4, and a filling member made of a powder mixture of Si.sub.3 N.sub.4 and TiN is filled in the protective pipe. Alternatively, a pair of printed strips differing in kind may be formed as wires in a protective pipe to provide such a thermocouple structure.

Abstract: Continuous temperature measurement for liquid steel has in the past been made only with a thermocouple with exponential drift. With a diameter ratio of about 2 between metal and ceramic wells and with exceptionally thin electrical insulation, a lower, calculable linear drift can be achieved thus giving a substantially longer service life.

Abstract: A semiconductor protection tube is a ceramic tube with a layer of silicon carbide covering at least a portion of the tube adjacent an open front end of the tube and extending forward of the open end to form a hollow, closed-end tip. The protection tube is formed by providing the ceramic tube, inserting a mandrel through the tube to extend forward of the front end, and depositing silicon carbide by chemical vapor deposition over at least a front portion of the ceramic tube and over the forward-extending portion of the mandrel. Subsequent removal of the mandrel completes the production of the protection tube.

Abstract: A rechargeable electric power supply device comprises a supply unit including a pair of electrodes spaced apart from each other embedded in a mixture of (a) fired fine pellets of an electron absorbing material consisting of Nb.sub.3 Sn and V.sub.3 Ge, (b) fine particles of a mixed electron absorbing material comprising V.sub.3 Ga, Bi, CuO, Sr and FeO.sub.2, (c) fine particles of a catalyst, (d) fine particles of C and FeO.sub.2 serving as a stabilizer, and (e) a plasticizer, and a casing for accommodating the pair of electrodes and the mixture therein so that the pair of electrodes are individually in intimate contact with the mixture. The device serves as a kind of capacitor with great charge power and the capability of emitting electrons over a long time.

Abstract: The invention provides a contact temperature sensor consisting of a planar contact plate, a thermocouple element attached to the contact plate for determining the temperature of the contact plate, and a deflectable and tiltable holding system. The connection lines to the thermocouple element are wound around a tube. By vulcanisation with a rubber-elastic material, a one-piece elastic formed body is produced which connects together the contact plate, holding piece and inner tube. Through the rubber-elastic spring action and the deflectability and tiltability of the contact plate with reference to the surface of the object of measurement, and improved flow of heat to the contact plate and improved measurement results are achieved.

Abstract: A coaxial thermoelement having a thermocouple wire coaxially disposed in a tubular metal sheath. A ceramic powder electrically is disposed in the tubular metal sheath to insulate the thermocouple wire from the tubular metal sheath. A thermocouple is formed by fusing the thermocouple wire to its metal sheath in each of two coaxial thermoelements and joining the fused ends of the two coaxial thermoelement to form a thermocouple junction.

Abstract: A temperature measuring device for measuring the temperature of an abrasive particulate material of the type found, for example, in rotary calcining kilns and the like. The device comprises a temperature sensor producing an indication of a temperature to which the sensor is exposed, circuitry or the like for connecting the temperature sensor to remote equipment for converting the indication to a recognisable form and a protective element shielding the temperature sensor from damage by the abrasive particulate material. The protective element comprises a layer of ceramic material having a matrix of alumina reinforced with 5 to 50% by volume (based on the total volume of the ceramic material) of particles of silicon carbide having an average size, at least in two dimensions, within the range of about 5 to 60 microns. The protective element provides good abrasion, heat-shock and mechanical resistance while exhibiting sufficient thermal conductivity to avoid undue inaccuracies in the temperature measurements.

Abstract: A temperature sensor uses a type R thermocouple wire element in a ceramic sheath to sense temperatures up to 3,200.degree. F., and is particularly suitable for flexible insulations. The sensor includes a thermocouple wire embedded in a sheath having two sections disposed at right angles to each other. The junction of the thermocouple is located at one end of one of the sections and the lead wires extend from the other section. The section which includes the junction is secured to a flexible surface with ceramic cement.

Abstract: A temperature-measuring instrument especially for measuring high temperatures in pressure reactors. It comprises a sheathed thermocouple which is mounted in an inner ceramic element which is closed at one end. This inner element is inserted into a molybdenum element which is also closed at the same end and is surrounded in turn by an outer ceramic element. The annular space between the molybdenum element and the ceramic element is filled with a pressed ceramic mass. A flanged joint joins the molybdenum element to a ball joint which is in turn joined via bellows to a pressure-resistant bushing.

Abstract: An assembly for permitting temperature measurements at a large number of locations within a vessel, which assembly has a spreader-reducer for compacting a significantly large number of thermocouple cables into a relatively small volume so as to permit passage through one or more vessel nozzles. The thermocouple cables each has a heat expansion portion as well as a seat, thereby permitting a series of horizontal arrays of thermocouple junctions positioned at different depths within the vessel.

Abstract: The present invention is a device for measuring the temperature of a molten metal. The device includes a thermocouple element, a housing consisting of a heat-resistant material and a retainer member for receiving the thermocouple element. The retainer member has an open end and a closed end. The thermocouple element has a hot junction located proximate the closed end of the retainer member. The retainer member is positioned within the housing and is smaller in size than the housing to define a cavity therebetween. The cavity is substantially filled by a protective material which includes a metal oxide component and an oxygen reducing component.

Abstract: A thermocouple connector for measuring the temperature of a surface includes a heat conductive casing having a hollow interior and a linear ridge on one side. The apex of the linear ridge forms a contact zone with the surface. A pair of thermocouple leads extends into the hollow interior of the casing, and are attached to the casing at and parallel to the linear ridge. The contact zone is sufficiently wide in relation to the distance of the contact zone from the leads such that welds along the side of the contact zone penetrate the contact zone, but do not penetrate so far as to burn the leads.

Abstract: A thermocouple assembly includes a protective housing, preferably made of glass, a thermocouple suspended in the housing, and a thermally conductive material that fills the space between the inner wall of the housing and the thermocouple. In a preferred embodiment, a compressible ring is used to both confine the thermally conductive material and prevent damage to the thermocouple assembly caused by thermal expansion or contraction.

Abstract: A thermocouple probe for use in an autoclave has two conductive wires spaced apart and supported in parallel relation by fluoropolymer insulation material. The structure is air-tight which eliminates vacuum and/or steam leakage along the wire and is relatively flat so as not to disrupt the seal where the thermocouple passes through the autoclave. A method is also provided to produce the thermocouple in a single extrusion step that ensures uniformity, proper calibration and reliability of the thermocouple.

Abstract: An insulated ceramic coated wire with a relatively thin ceramic coating allowing flexibility. The insulation is non porous and is particularly useful for thermocouples. The application all describes thermocouple made with such wires.

Abstract: It is useful to be able to place a thermocouple in a plug in a spacecraft heat shield without disturbing the heat flow to the thermocouple. The thermocouple wire is ceramic coated before placement in the plug and a thin metal disc is placed in the bottom of the hole. The thermocouple wire is pressed into the disc to obtain good thermal contact.

Abstract: Several embodiments of improved thermocouples that can be formed without necessitating welding of small diameter wires. In each embodiment, the thermocouple is formed by depositing strips of dissimilar materials on an insulating base with the ends of the strips in contacting relationship to form a junction.

Abstract: A thermocouple assembly and method of making it wherein a pair of wires formed of dissimilar metals extend through electrical insulating material in a thin flexible stainless steel sheath. A forward portion of the sheath containing the wires is snugly received in a nickel alloy casing which is then bent to form an opening to receive a screw therethrough to accurately secure the forward end of the thermocouple assembly in place. The casing is made strong enough to maintain the circular shape and bending the sheath and casing together securely retains the sheath in the casing.

Abstract: The invention concerns a measurement sensor for the detection of temperatures in metal or alloy melts. This measurement sensor consists of a thermocouple (41) surrounded by a ceramic capillary (24) which is closed at its end by means of an adhesive (45) or the like. This measurement sensor is directly, i.e. without further sheathing, introduced into the melt (FIG. 3a).

Abstract: This invention concerns thermocouples for the measurement of temperature of molten metal which have a bimetal junction located in a closed outer end of a length of quartz glass tube with the wire ends separated around a plug in the open end of the tube and connected to the compensating conductors of the thermocouple.

Abstract: A thermometer probe comprising a temperature sensing element for sensing temperature of an object to be sensed, a conductor connected to the temperature sensing element for transferring the sensed temperature, an insulator for coating the conductor, and a water-resistant sheath for enclosing the temperature sensing element, the conductor, and the insulator. The opening end of the sheath is welded for enclosure of the temperature sensing element.

Abstract: A threaded average temperature thermocouple 11 is provided to measure the average temperature of a test situs of a test material 30. A ceramic insulator rod 15 with two parallel holes 17 and 18 through the length thereof is securely fitted in a cylinder 16, which is bored along the longitudinal axis of symmetry of threaded bolt 12. Threaded bolt 12 is composed of material having thermal properties similar to those of test material 30. Leads of a thermocouple wire 20 leading from a remotely situated temperature sensing device 35 are each fed through one of the holes 17 or 18, secured at head end 13 of ceramic insulator rod 15, and exit at tip end 14. Each lead of thermocouple wire 20 is bent into and secured in an opposite radial groove 25 in tip end 14 of threaded bolt 12. Resulting threaded average temperature thermocouple 11 is ready to be inserted into cylindrical receptacle 32. The tip end 14 of the threaded average temperature thermocouple 11 is in intimate contact with receptacle 32.

Abstract: A temperature sensor using a thermocouple, optimum for measurement of temperature of an object heated to a high temperature such as the tip of a soldering iron. Comprising a thermocouple formed by mutually bonding dissimilar metal materials, the junction of the dissimilar metal materials of thermocouple is covered with a good conductive metallic sleeve, and the measuring part is formed. Therefore, if an object high temperature contacts with the measuring part, the metal materials composing the thermocouple are not directly heated, and heat conduction to the metal materials is also excellent. Therefore, oxide coating due to heating rarely occurs in the measuring part, and the measuring performance of high precision may be maintained for a long period.

Abstract: A process for oxidation retardation in nickel-base thermocouple alloy comprises the step of initial heat-treatment of thermoelement wires at high temperatures in an atmosphere of very low oxygen partial pressure. The preferred nickel-base alloy is a type K or a type N alloy. The preferred atmosphere is a gas mixture selected from the group consisting of hydrogen/water vapour, and oxygen/argon.

Abstract: A level measuring device comprises an electrical heater, a metallic sheathed thermocouple cable with two thermoelectric elements, a negative temperature coefficient electrical insulant interpositioned between each thermoelectric element and the sheath material of the thermocouple cable such that the thermoelectric elements are not mechanically in contact with each other; an outer cylindrical metallic sheath with one closed and one open end wherein the resistance heater and thermocouple cable are contained; a constant current power supply and a digital millivoltmeter connected to the ends of thermoelectric elements protruding from open end of the outer cylindrical metallic sheath for measuring the loop resistance of the thermoelectric elements; a microprocessor system for computing a length of cable corresponding to the resistance measured using the constant current source and the digital millivoltmeter; and, a power supply for supplying an electrical current to the heater cable.

Abstract: To make a jacketed thermoelement, two metal wires, one of which is pure platinum, preferably of at least 99.9, and even higher purity, and the other being a platinum/rhodium alloy are included in a ceramic element. The wires are first threaded into capillary openings of a cylindrical ceramic element which is jacketed by a jacket of platinum-rhodium alloy or INCONEL (TM). The initial assembly is hammered, thereby crashing the ceramic, and drawn to reduce the outer diameter of the metal jacket tube to fit the inner diameter of an auxiliary tube, for example of a copper-tin alloy which is fitted over the metal jacket tube. The thus formed composite is then passed through a sequence of drawing dies, preferably in a single drawing pull, in which each die reduces the cross-section by about 9-10%, until the desired outer diameter of the metal jacket tube (4) is reached; this diameter may be in the order of 0.3 mm, after starting with an outer diameter of just under 5 mm.

Abstract: A thermocouple assembly for attachment to surfaces by welding which includes a solid metal head formed with a knife edge and receiving sheathed thermocouple conductors, the ends of which are disposed at the knife edge and are junction welded. The head is economically fabricated on a mass-production basis, and the sheathed conductors are attached in a simple manner to minimize the overall production costs of the assembly. The disposition of the junction and the connection between the sheath and the solid head coacts with the weldments mounting the assembly on a surface to control the heat energy path such that the effective junction permits the junction to accurately function with respect to sensing the temperature of the surface on which the assembly is mounted.

Abstract: A thermocouple assembly including a thermocouple probe having facilities mounted thereto to protect the probe, e.g. from the hostile environment of a mounting hole provided through a refractory wall of a glassmaking furnace into which the probe extends for measuring the temperature of molten glass contained by the furnace. The facilities to protect the probe include an outer sleeve disposed in surrounding relation to a selected portion of the probe to form a first annular space between the outer surface of the probe and the inner surface of the sleeve; facilities for sealing the first annular space from atmosphere outside thereof; and, facilities for continuously moving a corrosion-inhibiting gas into, through, and out of the first annular space to thereby flush any infiltrating oxygen an/or alkali-sulfate corrosives out of the first annular space.

Abstract: The object of this invention is to provide a rapid response thermocouple which is removably affixable to the surface whose temperature is to be measured, and a method of making such a thermocouple. The thermocouple of this invention comprises a thermocouple assembly 24, a first film 10 having an adhesive coating on one side, a second film 50 having an adhesive coating on both sides, a third film 30 and a tab 40, wherein the adhesive coated side of the first film is adhered to one of the adhesive-coated sides of the second film with the thermocouple assembly interposed between them, and further wherein the third film is removably adhered to the remaining adhesive-coated side of the second film with the tab disposed between them so that it partially extends beyond the edges of the second and third films to facilitate removal of the third film from the second film.

Abstract: A thermocouple system has been nicknamed the "Binocular" thermocouple assembly because the terminal housing has a configuration similar to a pair of binoculars, with the chromel and alumel terminals mounted in spaced circular openings in the terminal housing. A thermocouple probe extends outwardly from the terminal housing, and is provided with two peripheral grooves, into one of which the terminal housing is secured by swaging. The second groove in the thermocouple probe is spaced away from the terminal housing by a short distance along the probe, and a washer is securely swaged into this second groove. A nut having external threads is mounted between the terminal housing and the washer for securing the thermocouple probe to its sensing location, for example, mounted adjacent a turbine engine.

Abstract: This invention relates to a tubular element provided with a temperature sensor, in particular for measuring overtemperatures in the tube bundle of superheaters in thermoelectric power plant steam generators, comprising a pair of concentric tubes forcibly locked one into the other by a mechanical plastic deformation process, at least one of the two tubes comprising in the mutually contacting surfaces a series of longitudinal grooves into which temperature sensors are inserted.

Abstract: A heat sensitive cable capable of generating a temperature representative measurable voltage. The cable includes a pair of thermoelectric conductors disposed in contacting side-by-side relation together with an electrical insulation for passively self-generating a temperature representative measurable voltage between the conductors when the cable is exposed to ambient temperature. A flexible outer jacket formed of an electrically non-conductive material is provided to completely surround the conductors. The electrical insulation causes a change in the temperature representative measurable voltage with an increase or decrease in temperature at every location along the jacket. A change in the temperature representative measurable voltage under such condition is representative of a change in ambient temperature. The electrical insulation also causes a change in the temperature representative measurable voltage with an increase in temperature above the prevailing ambient at any location along the jacket.

Abstract: A heat sensitive tape capable of generating a temperature representative measurable voltage. The tape includes an elongated flexible strip of electrically non-conductive material. A pair of thermoelectric conductors extend along the strip in spaced apart side-by-side relation. The tape also includes an electrical insulation capable of passively self-generating a temperature representative voltage between the conductors when the tape is exposed to ambient temperature. The insulation causes a change in the temperature representative measurable voltage with an increase or decrease in temperature at every location along the strip. A change in the temperature representative measurable voltage under such condition is representative of a change in ambient temperature. The insulation also causes a change in the temperature representative measurable voltage with an increase in temperature above the prevailing ambient at any location along the strip.

Abstract: Flexible conduit fixturing, as for a thermocouple, where the coupling cap is spring equipped so as to lie between adjacent convolutions of the flexible conduit and be gripped thereby to prevent rotation of the flexible conduit.

Abstract: In a means for supporting an elongated heavy thermocouple assembly the weight of the assembly is carried by a rigid support at an intermediate point along its length instead of by a long lever arm exerting a substantial torque at the point of attachment to the reactor vessel shell as in the conventional design.

Abstract: A heat sensitive cable operable over a temperature range of between approximately -20.degree. F. and 1650.degree. F. The cable includes a tubular metallic sheath which is substantially temperature resistant and moisture impervious. It also includes a mass of compacted insulation material filling the sheath and having an insulation resistance variable with temperature in the range of between approximately 100 and 50,000 ohms. The cable further includes at least one thermoelectric conductor positioned within the insulation material filling the sheath. A method of manufacturing the cable includes the step of preparing the insulation material and advancing the thermoelectric conductor through a given region. It also includes the step of advancing a strip of flat metal material past apparatus for forming and welding a tubular sheath surrounding the given region.

Abstract: A flexible coaxial thermocouple wire comprising an insulated inner thermoelement and a braided outer thermoelement surrounding the insulation covering the inner thermoelement. The braided outer thermoelement, in addition to forming one conductor of a thermocouple pair, also serves to protect and contain the insulation. Also encompassed is the formation of a thermojunction at one end of the coaxial thermocouple wire and connection of a termination to the other end.

Abstract: A noise thermometer of the type in which a resistive sensing element is exposed to elevated temperatures and has a measuring circuit connected thereto so that the noise voltage output of the sensing element is detected. According to the invention this element is a rectangular parallelopiped, elongated or cubical, of lanthanum chromite, LaCrO.sub.3.

Abstract: An improved thermocouple and method for making the thermocouple and installing same on the fireside of heat exchanger tubes or the like for monitoring surface temperature which includes a thermocouple assembly made from mineral oxide insulated metal sheathed thermocouple wires where a pair of thermocouple wires or conductors extend through a metal sheath in spaced apart and insulated relation from each other and from the sheath and are connected together at an end to define a hot junction member adapted to be mounted in engagement with the surface being measured, which hot junction is defined by a disk or bar-shaped member extending from the end of the sheated conductor assembly beyond the insulation and sheath but not in contact with the sheath. Installation on a heat exchanger tube includes welding the sheath to the tube which pressurizes the hot junction against the temperature measured surface and defines a heat energy path that bypasses the hot junction.