Explosion-Proof, Fixed-Element RTDs are made for use in U.S. and Canadian hazardous areas. They are designed to extinguish flames inside the device, eliminating the potential for ignition of flammable mixtures in the surrounding atmosphere. FM and CSA approved assemblies, dependent on connection head type, meet XP Class I Division I & II; Groups A, B, C, D; DIP Class II Division I; Groups E, F, G; Class III; Type 4/4X. They may be installed directly in the process without being inserted into a thermowell. The assemblies feature 316 stainless steel sheaths in various diameter sizes. They are available with or without process mountings and with aluminum or stainless steel explosion-proof connection heads.
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.
Since most resistance temperature detectors and resistance thermometers have a low initial resistance, often 100 ohms, and have a small change in resistance per unit of temperature range, the resistance of the lead wire is often compensated for with a three or four wire bridge configuration built into the measuring devices. By selecting the proper elements and protective sheathing, RTDs can operate in a temperature range of (-200 to 650) °C [-328 to 1202] °F.
Pyromation manufactures resistance temperature detectors and resistance thermometers for many industry applications. From single- or dual-element RTDs, PT100s-PT1000s, to Sanitary CIP configurations, we have the right RTD type for your job. If what you need is not available from our catalog, our product engineers will design an RTD measurement device for your specific application, including temperature sensor assemblies that require connection heads, thermowells and/or transmitters.