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Thermocouples are the most common, convenient, and versatile devices used to measure temperature. They convert units of heat into useable engineering units that serve as input signals for process controllers and recorders.

A thermocouple consists of a welded ”hot” junction between two dissimilar metals – usually wires – and a reference junction at the opposite end. Heating the hot junction in the working environment produces a temperature gradient that generates an electromotive force (EMF). The EMF appears across the free ends of the thermocouple wires where it is measured and converted into units of heat calibration. Through selection of appropriate thermocouple wires and sheath components, thermocouples are suitable to be used in temperature ranges from (-200 to 2316) °C [-328 to 4200] °F.


Resistance temperature detectors (RTDs), also known as resistance thermometers, accurately sense process temperatures with an excellent degree of repeatability and interchangeability of elements. The RTD is composed of certain metallic elements whose change in resistance is a function of temperature. In operation, a small excitation current is passed across the element, and the voltage–which is proportional to resistance–is then measured and converted to units of temperature calibration. The RTD measurement element is manufactured by winding a wire (wire-wound elements) or plating a film (thin-film elements) on a ceramic or glass core and sealing the element within a ceramic or glass capsule.

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A thermowell is a pressure-tight receptacle that protects and extends the life of a temperature sensor in processing applications where the sensor is not mechanically or chemically compatible with the process environment. Installed directly into piping systems, thermowells facilitate sensor replacement in high-pressure pipelines and eliminate the need to interrupt the process flow or drain the process system for sensor-maintenance functions. The use of standardized thermowells permits simple relocation of sensors throughout a plant.

Pyromation produces thermowells that have a proven track record in a wide range of industries and applications. Our product line includes threaded, Van Stone, socket-weld, weld-in, and flanged thermowells. Thermowells are available as separate components or as a part of complete temperature sensor assemblies.


Temperature transmitters make it possible to send a scaleable (4 to 20) mA signal from a temperature sensor to a control device without investing in long, expensive runs of thermocouple or RTD wire.

Pyromation carries programmable RTD and thermocouple temperature transmitters that can be mounted in the temperature sensor assembly connection head, or surface-mounted using a DIN rail mounting clip. Some units offer a visual digital display that shows the current measured value. All are PC programmable and convert various signals into a scaleable (4 to 20) mA analog output signal. We also carry transmitters programmable with HART® protocol for various signal inputs. Depending on type, some of Pyromation’s thermocouple and RTD temperature transmitters are UL-recognized components and/or FM- and CSA-approved, including styles that are intrinsically safe and approved for use in hazardous locations.

Pyromation temperature transmitters are used in many demanding industries, including pharmaceuticals, oil & gas, power generation, chemical, petrochemical, and food and dairy.

Connection Heads

Thermocouple and RTD connection heads provide a protected, clean area for mounting a terminal block or transmitter as part of the transition from temperature -ensor assembly to lead wire.

As a full-line manufacturer, Pyromation produces its own design-patented connection heads for its temperature sensor assemblies and other applications. The product line includes general-purpose (GP) aluminum, plastic, stainless-steel, and cast-iron connection heads, with NEMA 4X ratings for indoor or outdoor use. Pyromation’s redesigned explosion-proof (XP) aluminum and stainless-steel thermocouple and RTD connection heads are approved as individual components or as part of temperature-sensing assemblies used in hazardous locations. Most of the line consists of screw-cover connection heads; however, the company also carries a flip-top aluminum head for easy access, and a miniature-style connection head. Our thermocouple and RTD connection heads are designed to accommodate most terminal blocks and transmitters, including DIN Form B types. Specifications, ratings, and drawings for each connection head are located in the designated catalog pages (see links to pages below).

As an added benefit, Pyromation provides private-brand labeling of its thermocouple and RTD heads upon request. Connection heads are available as separate components or as a part of complete temperature-sensor assemblies.


Thermocouple grade wire is used in construction of a thermocouple temperature sensor. Thermocouple extension wire is used to carry the signal from the thermocouple sensor to the readout device while maintaining a high degree of accuracy. The extension wire material must match the material used in the positive and negative leg of the thermocouple type (e.g. type K) being used in the application. If a transmitter is installed within the thermocouple sensor assembly, copper wire is typically used in place of thermocouple extension wire to send the scalable (4 to 20) mA signal back to the process-control equipment.

RTD sensors use ordinary copper instrumentation cable to send the resistance signal back to the recording, readout, or control device. If a transmitter is installed within the RTD sensor assembly, copper wire is typically used to send the scalable (4 to 20) mA signal back to the process -ontrol equipment.

Pyromation stocks and sells a variety of sizes and gauges of thermocouple-grade and extension wire, as well as wire insulators. We also offer special construction thermocouple wire and RTD cable, including multipair thermocouple extension wire.

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Pyromation offers the support products needed to install and maintain your temperature-sensor assemblies. From jacks, terminals, and plugs to pipe nipples, clamps, bushings, and other fittings, we always have inventory available for shipment. Connection heads and transmitters are two of the larger accessories we carry in stock, but we also keep a variety of coiled cords, grips, and flexible armor on hand.