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Resistance temperature detectors (RTD) accurately sense temperature 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 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 RTDs 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 -328 to 1202 °F.

Pyromation manufactures RTDs for many industry applications. From single- or dual-element RTDs to PT100's to Sanitary CIP types, we have the right sensor for your job. If what you need is not available from our catalog, our product engineers will design an RTD for your specific application, including temperature sensor assemblies that require connection heads, thermowells and/or transmitters.

Miniature Temperature Sensors

For Miniature Bearing and Babbitt Bearing Applications:

  • General purpose and ATEX-certified designs available
  • Supplied in multiple case styles
  • Custom designs on request
  • Rugged construction
  • RTD and Thermocouple Types available
  • Pass throughs, elastomer fill and accessories
  • Standard four day delivery
  • Application proven

Pyromation's miniature sensors are designed to measure the critical temperature of the metal bearing shoes operating in generators, turbines and other rotating equipment. Monitoring the bearing temperature of rotating equipment is very important in preventing machine failures caused by the breakdown of the lubricating oil when it becomes too hot. Pyromation not only provides a cost-effective line of miniature sensors for these applications, they have experienced sales and engineering support available to assist you in finding the best way to measure temperature in your equipment.

(FD01) Water-Tight CIP RTD Assemblies w/Optional Series 450 Integral Transmitters

 

The Water-Tight CIP RTD Assembly houses an optional integral Series 450 Temperature Transmitter (no connection head is required) that is ideal for monitoring temperature in small areas such as tanks and pipes. The water-tight construction meets NEMA 6P requirements. Assemblies are supplied with a surface finish that meets or exceeds 32µin Ra. Surface finishes of 15µin Ra or better are available upon request. Standard units include a M12 process connection housing. The transmitter is a 2-wire unit with an analog output. It has measurement input for Pt100 resistance thermometers (RTD) in 4-wire connections. Transmitters can be ranged from (-51 to 160) ºC [-60 to 320] ºF with a 10 ºC [18 ºF] minimum span requirement. Ambient temperature limits for the M12 connector are (-40 to 85) °C.

 

(FD02) CIP Sanitary-Connected RTDs

 

General-purpose CIP sanitary-connected RTD temperature sensors are used in food, dairy, beverage, pharmaceutical, and chemical processing applications where sensor corrosion and product contamination are critical factors. The sanitary caps listed are those most commonly used in such processes. Sanitary caps are welded to the sheath and to a heavier support tube, all made of stainless steel, and then ground and polished to a finish that exceeds the No. 4 minimum finish required by the 3-A Sanitary Standard 74 - . Assemblies are supplied with a surface finish that meets or exceeds 32µin Ra. Surface finishes of 15µin Ra or better are available upon request. The process contact surfaces are free of pits, crevices, and pockets thus preventing corrosion and bacteria growth. The 3-wire constructed sensor assembly consists of a high-accuracy platinum element sealed inside a 316 stainless steel sheath, and is provided with a FDA-compliant white thermoplastic gasketed connecting head. The complete assembly provides excellent washdown protection. It is recommended that once customer connections are made, the connecting terminals be further protected by applying a coating of moisture-proof sealant over the connections.

 

(FD03) RTDs w/CIP Sanitary-Connected Wells

 

These RTD sensors are constructed with the CIP sanitary-connected cap thermowell, which is then mounted into the process with a clamp and mating sanitary cap. A 3-wire spring-loaded RTD element and sheath is then screwed into the back of the thermowell. This construction method allows for easy removal of both the well and/or the sensor assembly. The well and sanitary cap in contact with the process are all ground and polished to a finish that exceeds the 3-A Sanitary Standard 74- . Thermowells are supplied with a surface finish that meets or exceeds 32µin Ra. Surface finishes of 15µin Ra or better are available upon request.

 

(FD04) Miniature Sanitary CIP RTD Sensors

 

Miniature CIP sanitary RTD temperature sensors are provided with 16AMP sanitary caps to fit 1/2" and 3/4" tube size sanitary fittings. They are used in pharmaceutical, chemical, biotech, R & D laboratory, and food process applications. The sanitary caps are welded to the sheath and to a heavier support tube, all made of 316 stainless steel, and then ground and polished to a finish that exceeds the No. 4 minimum finish required by the 3-A Sanitary Standard 74- . Assemblies are supplied with a surface finish that meets or exceeds 15µin Ra. The process contact surfaces are free of pits, crevices, and pockets thus preventing corrosion and bacteria growth. All leads are Teflon® insulated to further provide moisture and chemical resistance. The listed sheath lengths provide assurance that the sensing element is properly placed in the flowing medium when used with typical sanitary tees and tube fittings, and the small sheath diameter provides fast temperature response times.

 

(FD05) Thermometer Replacement RTDs

 

Thermometer replacement RTD temperature sensor assemblies are used when converting instrumentation from older direct reading thermometers to electronic instruments requiring RTD inputs. These RTD assemblies replace the filled system capillary actuating bulbs and will fit into the old existing bulb wells as listed below. These 3-wire constructed sensor assemblies consist of a high-accuracy platinum element sealed inside a spring-loaded 316 stainless steel sheath and are supplied with a FDA-compliant white thermoplastic gasketed head. Each sensor is supplied with a free-rotating stainless steel mounting fitting with the appropriate threading for the wells listed below.

 

(FD06) Weld-In RTD Assemblies

 

These Weld-In RTD temperature sensor assemblies are commonly used in the food, dairy, beverage, pharmaceutical, and chemical processing industries. The complete assemblies are provided with a 3-wire platinum RTD element sealed inside a 1/4" O.D., spring-loaded, stainless steel sheath, and with a heavy wall sanitary protection well. Thermowells are supplied with a surface finish that meets or exceeds 32µin Ra. Surface finishes of 15µin Ra or better are available upon request. The well is to be welded into a tank or vat with a full crevice-free fillet-weld to prevent corrosion, bacteria growth, and product contamination. Assemblies are provided with a FDA-compliant white thermoplastic-gasketed connection head. The complete assembly provides excellent washdown protection.

 

(GP01) Fixed Sheath RTD Assemblies w/Connection Heads

 

Fixed-Sheath RTD Assemblies with General-Purpose Connection Heads are provided with head mounting fittings that are welded or brazed to the sheath for direct immersion into a process. The RTD assemblies are supplied with a 316 stainless steel sheath in several diameters. They are available in various tolerances and temperature ranges.

 

(GP03) Spring-Loaded RTD/Thermowell Assemblies w/Connection Heads

 

Spring-Loaded RTD/Thermowell Assemblies with General-Purpose Connection Heads are designed for use with various thermowell types. These sensors are supplied with a 316 stainless steel sheath and are available in various tolerances and temperature ranges as noted in the tables below. Note: The "S" dimension will measure 1/4" longer than specified when the spring is in the relaxed position. The "S" dimension is calculated when the sensor is compressed or in the installed position. This design allows 1/4" spring compression to ensure positive contact with the bottom of the thermowell.

 

(GP05) Spring Loaded Replacement RTD Elements

 

Thermocouple and RTD spring-Loaded Replacement elements are designed for spring-loaded thermowell assemblies. The RTD assemblies are supplied with a 316 stainless steel sheath and are available in various tolerances and temperature ranges as noted in the tables below. The MgO-insulated thermocouple assemblies are supplied with a 316 stainless steel sheath, various calibrations, and as standard limits of error.

 

(GP07) Fixed Sheath RTD Assemblies w/Miniature Connection Heads

 

Fixed-sheath RTD assemblies with miniature heads are offered with mounting fittings that are welded or brazed to the sheath for direct immersion into a process. The miniature heads offer a compact design and are ideal for laboratory applications or applications where space is limited. The RTD assemblies are supplied with a 316 stainless steel sheath in several diameters. They are offered in various tolerances and temperature ranges.

 

(FD09) Non-Intrusive Tank Sensors

 

These non-intrusive tank sensors are designed to mount flush with the interior tank wall for maximum product contact. This allows the wiping or mixing blades to properly mix the product within the tank without damaging the temperature sensor. The temperature sensors are manufactured of highly polished stainless steel and use various mounting methods for simple installation. These sensors are supplied standard with a 100 Ω, Platinum RTD sensing element. These RTD assemblies are constructed of 316 stainless steel and all wetted parts are supplied with a surface finish that meets or exceeds 32µin Ra. Surface finishes of 15µin Ra or better are available upon request. These RTD assemblies have an operation temperature of (-50 to 200) ºC [-58 to 400] ºF.

 

(PL02) General Purpose Plastic Industry RTDs

 

The RTDs described below are those most commonly used in the plastic process industry. These assemblies can be used in many general applications where a 1/8" NPT fitting is preferred by utilizing either a compression fitting or a bayonet adapter. These assemblies are supplied standard using 316 stainless steel sheath material and a 100 Ω platinum element with a temperature coefficient of 0.003 85 ºC-1 (IEC Class B). Elements of other materials, values, and tolerances are available upon request.

 

(PL04) Spring- or Armor-Adjustable Immersion RTDs

 

This RTD spring-adjustable immersion sensor has a bayonet cap on an 8" spring (standard) to allow for immersion depths of 1/2" to 7". This assembly is used in a variety of applications (with a bayonet adapter) where ease of installation and quick disconnect is preferred. Standard and metric size bayonet caps and adapters are available. These assemblies are supplied standard using 316 stainless steel sheath material and a 100 Ω platinum element with a temperature coefficient of 0.003 85 ºC-1 (IEC Class B). Elements of other materials, values, and tolerances are available upon request.

 

(PL06) Melt Bolt RTDs/p>

 

The melt-bolt RTD sensor illustrated below is used on extruders and injection molding machines to directly measure the melt temperature of plastic as it moves down the extruder barrel. This sensor is made of 300 series stainless steel and is constructed using a 100 Ω platinum element with a temperature coefficient of 0.003 85 ºC-1 (IEC Class B). Elements of other materials, values, and tolerances are available upon request.

 

(PL09) Threaded Nozzle RTDs

 

The threaded nozzle RTD illustrated below is generally used to measure the temperature of the nozzle of an injection molding machine. This style is not in direct contact with the molten plastic. Due to the relatively small size of this sensor, other general areas of use include mounting in bearing housings, sealing bars, heat plates, and other limited space applications. These assemblies are supplied standard using a 100 ohm platinum element with a temperature coefficient of 0.003 85 ºC-1 (IEC Class B). Elements of other materials, values, and tolerances are available upon request.

 

(PL11) Ring RTDs

 

The ring type assembly pictured below has the RTD element embedded into a brass ring. Various ring sizes are available to measure the surface temperature of nozzles, extruder barrels, die heads, molds, and many other applicable surfaces. This assembly is supplied standard using a 100 Ω platinum element with a temperature coefficient of 0.003 85 °C-1 (IEC Class B). Elements of other materials, values, and tolerances are available upon request.

 

(PL15) Flexible RTD Extensions

 

The flexible RTD extensions illustrated below are constructed using stranded copper wire with various insulations. They are used as extension cords to provide suitable connections between sensors, jack panels, or instrumentation.

 

(RT01) Single and Duplex Element RTDs

 

The RTD elements illustrated and described on this page are designed to measure temperature in a variety of process and laboratory applications. These RTDs are specifically designed for use in two different process temperature ranges and will provide accurate and repeatable temperature measurement through a broad range. Low range RTDs are constructed using Teflon® -insulated, silver-plated copper internal leads with potting compounds to resist moisture penetration. High range RTDs are constructed with nickel internal leads inside swaged MgO insulated cable to allow higher temperature measurements at the RTD element and provide higher temperature lead protection along the sheath. The following tables allow customer selection of standard element materials, tolerances, sheath diameters, mounting fittings and terminations. Custom-built assemblies with non-standard specifications are available upon request.

 

(RT02) Single and Duplex Element RTDs

 

These RTD elements are designed to measure temperature in a variety of process and laboratory applications. These RTDs are specifically designed for use in two different process temperature ranges and will provide accurate and repeatable temperature measurement through a broad range. Low range RTDs are constructed using Teflon® -insulated, silver-plated copper internal leads with potting compounds to resist moisture penetration. High range RTDs are constructed with nickel internal leads inside swaged MgO insulated cable to allow higher temperature measurements at the RTD element and provide higher temperature lead protection along the sheath. Custom-built assemblies with non-standard specifications are available upon request.

 

(RT03) Water-Tight RTD Assemblies w/ Optional Series 450 Temperature Transmitters

 

These RTD Assemblies house an optional Series 450 Temperature Transmitter (no connection head is required) that is ideal for monitoring temperature in small areas such as tanks and pipes. The water-tight construction meets the NEMA 6P, IP68 Protection Rating requirements. Standard units include a sensor, an M12 process connection housing, and optional transmitter. The transmitter is a 2-wire unit with an analog output. It has measurement input for Pt100 resistance thermometers (RTD) in 4-wire connections. Transmitters can be ranged from (-51 to 160) ºC [-60 to 320] ºF. With a 10 ºC [18 ºF] minimum span requirement. The ambient temperature limits for the M12 connector is (-40 to 85) ºC.

 

(RT04) M12 Molded and Field Wireable Cables

 

M12 Molded and Field-Wireable cables are available for connection to Pyromation Water-Tight Assemblies with Optional Series 450 Transmitters. The M12 quick disconnect plug eliminates all external screw connections, simplifying the electrical installation process and solving the problems caused by moisture, loose connections, and corrosion. They are easier to install and more secure than conventional field-wired connections. Both are available in 2-, 3-, and 4-wire connection options, and in straight or 90º angle styles. Molded cables are PVC insulated and meet NEMA 1, 3, 4, 6P and IEC IP68. Field-Wireable Cable insulations are listed below and meet IP67 requirements. Cable lengths are manufactured to customer specifications. All M12 Molded Cables are supplied as 4-wire and are terminated as specified in part number.

 

(SP02) Teflon®-Coated RTD Assemblies

 

These assemblies are designed for a broad range of applications that require resistance to corrosion and chemical attack. They provide very good temperature measurement and service life in plating, pickeling, and acid bath applications. The stainless steel sheath is coated with FEP Teflon ® and includes a fused Teflon® tip for excellent corrosion resistance.

 

(SP03) Heat Tracing Temperature Sensors

 

Heat-tracing temperature sensors are made for use in systems that measure the surface temperature of process pipe that is carrying products whose temperatures must be controlled to prevent freeze-up, or to maintain a viscosity level so that the inner medium will flow. These sensors are offered with either Thermocouple or RTD sensing elements inside 316SS sheaths, and with a 3/4" Radius stainless steel mounting pad. Cold legs are available in customer-specified lengths to accommodate pipe insulation thickness.

 

(SP06) RTD Averaging Sensor

 

The averaging RTD sensor listed below measures the temperature over the entire sheath length to provide an average temperature measurement of the cross sectional area of air ducts, room gradient temperatures, and other low temperature averaging applications. The sensing element has a resistance output that conforms to a 100 Ω platinum element with a 0.003 85 ºC-1 temperature coefficient within a measurement range of (0 to 100) ºC [32 to 212] ºF. The RTD sensors are available in copper or 316 stainless steel sheath materials and can be supplied in various lengths up to 828 inches. All RTD sensors 48 inches and longer will be shipped in a coiled configuration.

 

(SP07) Thermostat Temperature Sensors

 

The Pyromation thermostat temperature sensors are provided with the sensor, or the sensor and a (4 to 20) mA temperature transmitter, mounted on a subplate within a standard size thermostat housing. The thermostat housing measures 2 3/4"h x 4 1/2"w x 1 5/8"d and can be mounted either horizontally or vertically on a 2" x 4" electrical handibox. The cover is vented on two sides to provide for airflow over the sensing element, regardless of mounting position. The standard temperature sensing elements are available as a Teflon® insulated thermocouple or a three-wire RTD. Matching transmitters are available for all configurations and output ranges.

 

(SP08) Variable Length RTD Sensors

 

These sensing elements can be cut to any desired length over 3" long by using an ordinary tubing cutter. All sheaths are provided in 316 stainless steel.

 

(XP01) Hazardous Location Explosion-Proof Approved Fixed-Element RTD Assemblies

 

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 1, Group A, B, C and D; DIP Class II, Division I, Groups E, F, G, and Class III, Division 1. 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.

 

(XP03) Hazardous Location Explosion-Proof Approved RTD Assemblies w/Thermowells

 

Explosion-Proof RTD Assemblies with Thermowells 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 1, Group A, B, C, and D; DIP Class II, Division I, Groups E, F, G and Class III, Division 1. The required thermowell is available in standard, heavy-duty, and flanged constructions. The assemblies feature 316 stainless steel sheaths. They are available with aluminum or stainless steel explosion-proof connection heads.

 

(XP05) Hazardous Location Explosion-Proof Approved, Spring-Loaded RTD Assemblies

 

Explosion-Proof, Spring-Loaded 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 1, Group B, C and D; DIP Class II, Division I, Groups E, F, G and Class III, Division 1. Pyromation provides sensors for installation into your existing thermowell or provides the required thermowell as part of the assembly. Refer to the Thermowell Section of this catalog for product selection. The assemblies feature 316 stainless steel sheaths. They are available with aluminum or stainless steel explosion-proof connection heads. Note: The "S" dimension will measure 1/4" longer than specified when the spring is in the relaxed position. The "S" dimension is calculated when the sensor is compressed or in the installed position. This design allows 1/4" spring compression to ensure positive contact with the bottom of the thermowell.