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Thermocouples

Electroserv+ manufactures thermocouples Type K, N, T, J, R, S & B and RTDs 2-wire to 4-wire PT100, PTC and PT2. Our expert advisors will make sure you choose the most suitable one for your temperature sensing application, whether you’re working with plastic machinery applications, heat-treating furnaces, glass furnace control, food processing equipment, laboratories or industrial ovens.

The best temperature sensors distinguish real values from signal noise. Combine this with the advanced PID algorithms of the control equipment we offer to get optimum closed loop response.

We work very hard to ensure we consistently provide the best solutions, quality products and the highest level of customer service. Our quality system is approved to ISO9001:2008.

Electroserv+ stock numerous types of thermocouple cable. Our vast range includes single and multi-pairs ranging from two to twenty-four pairs. We offer cables with heat resistant PVC, flame retardant PVC, XLPE / LS0H, Mica / XLPE / LS0H, PFA / PTFE, fibre-glass or silicone rubber insulation. Bespoke cables can usually be manufactured or adapted quickly, and can also be supplied in small quantities to suit your application requirements.

Aerospace Thermocouples

At Electroserv+ we work to AMS 2750 E standard for the aerospace industry, which means that all our thermocouples produced for aerospace purposes are calibrated using the right methods, and shown to be within the defined limits. Each individual sensor in every batch is thoroughly tested to meet strict limits and this standard details the number of uses allowed before recalibration or replacement is required.

Electroserv+ manufacture temperature uniformity survey thermocouples specific to the oven/furnace dimensions and process temperature. These thermocouples can be made with fiberglass sheathing or mineral insulated (M.I). Our sales engineers all have the requisite knowledge within NADCAP requirements for thermocouple calibration and usage.

Food & Beverage Thermocouples

Certified technologies and maintenance are becoming increasingly important to food & beverage industry operations, as regulations for safety, quality and reliability become increasingly stringent. Everything has to be documented to provide traceability throughout your process operation, from production to maintenance.

At Electroserv+ we supply temperature sensor products to a number of food manufacturing companies for use in refrigerated transportation, food processors, dairy product processing, brewing process monitoring and confectionary production.

We also supply customers in the catering industry with dataloggers for monitoring refrigerators in transport, replacement sensors that have failed in catering equipment such as ovens, fridges, freezers, or vending machines, hand held probes/sensors including meat pyrometers, and infrared thermometers.

Base metal Thermocouples

Electroserv+ supplies base metal thermocouples for a variety of different industrial processes such as monitoring the temperature of ovens in food processing plants, measuring the temperature of furnaces, and checking the temperature when carrying out a smelting process on molten metals.

There are many types of thermocouples, each with its own unique characteristics in terms of temperature range, durability, vibration resistance, chemical resistance, and application compatibility. Type J, K, N, T & E are “Base Metal” thermocouples, the most common types of thermocouples.

Type J Thermocouple

This temperature sensor from Electroserv+ can be applied to many low-heat monitoring scenarios. Made of an iron-constantan alloy, it has a more restricted range than the type k thermocouple, but is more effective in terms of output and accuracy at the lower temperatures.

Type K Thermocouple

With a wide range of use and an operating temperature range that spans -200°C to +1350°C, this is the most commonly used thermocouple assembly from Electroserv+. Its chromel and alumel wires, which are welded together, create a voltage when the sensor wires experience a temperature gradient.

Type N Thermocouple

This is an effective temperature measurement sensor up to a maximum of around 1200°C, but is suited to lower temperature measurements and is more effective in terms of signal output at around 300-500°C than the type k thermocouple.

Rare metal Thermocouples

There are many types of thermocouples, each with its own unique characteristics in terms of temperature range, durability, vibration resistance, chemical resistance, and application compatibility. Type R, S, and B thermocouples are “Noble Metal” thermocouples, which are used in high temperature applications.

Electroserv+ supplies quality rare metal thermocouples - the perfect solution for measuring high temperatures up to 1700°C. Our thermocouple assemblies contain rare metals including Platinum and Rhodium, which form an alloy. These metals are used in the platinum wires within our rare metal thermocouples.

Our knowledgeable Electroserv+ team will be happy to guide you through the factors to consider when ordering your rare metal thermocouples such as the material you require for your metal sheath (Recrystalised Alumina – 1750°C, Silicon Carbide – 1600°C, Sillimantite 60 – 1600°C, Pythagoras – 1500°C, Quartz – 1500°C, Syalon 101 – 1000°C), element diameters, shank length and head type you may require depending on the purpose of the rare metal thermocouple.

Type R and Type S Thermocouple

These thermocouples from Electroserv+ are used for temperature measurements in environments where the temperature is up to or around 1600°C and oxidizing or inert gas atmospheres are present, such as gas production processes or petrochemical manufacturing.

Precision measurement and monitoring is provided using voltage from an alloy of Platinum and Rhodium. When protected with a mineral insulation and outer sheath they are able to function for longer periods up to their maximum working temperature.

Both Type R and Type S Thermocouple achieve better accuracy than most other assemblies when used in higher temperature processes such as furnaces or kilns.

Type B Thermocouple

This is one of the best assemblies for high temperature monitoring and control on the market today - suited up to a very high temperature of 1800°C.

At Electroserv+ all our Type B designs are bespoke to the application process.

Accurate and durable in applications where the environment is extremely hot, our Type B Thermocouples are mainly used in Glass and Steel manufacturing, foundries and some university laboratories. They retain their durability and stability for longer periods of time than other assemblies and we apply metal sheaths and mineral insulation to our thermocouples in order to protect the sensor when it is in use.

Mineral insulated (MI) Thermocouples

Electroserv+ manufactures a range of bespoke mineral insulated thermocouples for industrial processes. The durability of these thermocouples means that they are ideally suited to industry - they can handle stress and strain in challenging environments and have the flexibility to twist and bend. They can also withstand high temperatures (from -250°C to 1250°C) and high external pressures.

The mineral insulated thermocouple with pot seal & flexible tails is our most frequently purchased configuration, and is available with various options - with head, with block, with transmitter, with permanently attached cable and with DIN plate for use with your existing transmitter.

At Electroserv+ we deliver a personal approach and custom build our mineral insulated thermocouples on site to create a bespoke application to your exact specification. This means that each of our temperature sensors is fit for its exact purpose. You can order mineral insulated thermocouples from us in both simplex and duplex formats.

An external metal sheath houses the conductors, which are insulated in a magnesium oxide powder. This protects the mineral insulated element from damage, expanding its life capacity. The magnesium oxide is flexible before use and becomes more rigid during application, making it easier to fit. The assembly can also be sealed to give the conductors extra protection from the external environment.

We can also provide compensating cables, sockets, and compression fittings.

Thermocouple sheaths

At Electroserv+ we can use a variety of materials in our sheaths:

Mild Steel

These protection sheaths are rarely used because of their low temperature limit.

Basic Composition: Iron and Carbon (Fe,C)

Temperature Limit: +550°C

International Standard: Seamless Pipe

Density: 7.9g/cm³

446, 4C54, Ferritic

Ferritic provides resistance to oxidation in air and is a very good material to use when it comes to resisting sulfurous gases and salts.

446 performs better than austenitic steels in sulfurous reducing atmospheres but nitrogen concentrations can result in early failure. Hot gases containing hydrocarbons and carbon monoxide can cause carburisation. 446 requires oxygen to be present in order to form an oxide layer, otherwise failure occurs quickly.

Basic Composition: Cr 26.5%, Mn 0.8%, Si 0.5%, N 0.2%, C 0.2%, P 0.03%, S 0.15%, Bal Fe

Temperature Limit: +1100°C in oxidising conditions

International Standards: 1.4749, 446-1

Density: 7.9g/cm³

Specific Heat: 460 – 670 J/Kg°C

Thermal Conductivity: 17 – 28 W/m°C

Kanthal AF, Kanthal APM

Kanthal provides great sulphur resistance and can resist carburisation at higher temperatures than most materials. It also gives better heat transfer than ceramic.

Basic Composition: Cr 22%, Al 4-6%, Fe Balance

Temperature Limit: 1400°C

Density: 7.1g/cm³

Specific Heat: 460 – 670 J/Kg°C

Thermal Conductivity: 12-32 W/m°C

321 SS

Often used for MI sheathing on type J and Pt 100 sensor assemblies, 321 SS, also called 18/8, is corrosion resistance and remains ductile.

Basic Composition: Cr 18%, Ni 9%, Mn 2%, Si 1%, C 0.1%, Bal Fe

Temperature Limit: 800°C

International Standards: BS 970 321 S31, W No 1.4541

Density: 7.9 g/cm³

Melting Range: Approx 1400°C

Specific Heat: 500 J/Kg°C

Thermal Conductivity: 14.7 W/m°C

310 SS

Commonly known as 25/20, 310 SS displays good oxidation resistance and resistance to sulphur and reducing atmospheres. It is used as a high temperature sheathing material and is not recommended for use continuously between 550°C and 850°C.

Basic Composition: Cr 25%, Ni 20%, Mn 2%, Si 2%, C 0.02%, Bal Fe

Temperature Limit: 1100°C

International Standards: BS 970 Grade 310 S31, W No 1.4841

Density: 7.9 g/cm³

Melting Range: Approx 1400°C

Specific Heat: 500 J/Kg°C

Thermal Conductivity: 14.7 W/m°C

316 SS

At Electroserv+ this is one of our most popular sheath material choices and is commonly found in chemical plant temperature sensor applications. It has very similar characteristics to 321 SS but provides better acid resistance and effective corrosion and pitting resistance.

Basic Composition: Cr 17.5%, Ni 12.5%, Mn 2%, Si 1%, Mo 2-2.5%, C 0.03%, Bal Fe.

Temperature Limit: 800°C

International Standards: BS 970 Grade 316, W No 1.4401

Density: 7.9 g/cm³

Melting Range: Approx 1400°C

Specific Heat: 500 J/Kg°C

Thermal Conductivity: 14.7 W/m°C

353 MA ®

Often used in the PetroChemical industry, during the ammonia cracking process, 353 MA displays good resistance to most combustion gases and carburisation, in particular nitriding gases.

Basic Composition: Cr 25%, Ni 35%, Si 1.6%, Mn 1.5% Max, N 0.16%, C 0.05, P 0.04 Max, S 0.03 Max, Ce 0.05, Bal Fe

Temperature Limit: 1175°C

International Standards: UNS S 35315

Density: 7.89 g/cm³

Specific Heat: 450 – 670 J/Kg°C

Thermal Conductivity: 11-28 W/m°C

253 MA ®

This is similar to 353 MA and displays good oxidation resistance as well as protecting vital components effectively against carburisation.

Basic Composition: Cr 21%, Ni 11%, Si 1.7%, Mn 0.8% Max, N 0.17%, C 0.08, P 0.04, S 0.03, Ce 0.05, Bal Fe

Temperature Limit: 1150°C in air, oxidation and carburisation.

International Standards: 1.4835, S 30815, W Nr 1.4893

Density: 7.8 g/cm³

Specific Heat: 440-690 J/Kg°C

Thermal Conductivity: 14.5-29 W/m°C

Alloy 600 (Inconel®)

Alloy 600 Inconel is a strong oxidation resistant material at high temperatures, particularly with cycling, and resists sulphur compounds and carbon dioxide at moderate temperatures.

Basic Composition: Ni 72% Min, Cr 14-17%, Fe 6-10

Temperature Limit: 1100°C

International Standards: W No 2.4816, UNS N06600

Density: 8.472 g/cm³

Melting Range: 1354-1413°C

Specific Heat: 444 J/Kg°C

Thermal Conductivity: 15-27 W/m°C

Alloy 800 HT (Incoloy®)

Alloy 800 HT displays good resistance to high temperature corrosion with reasonable effectiveness against sulphur resistance at moderate temperatures.

Basic Composition: Ni 30-35%, Cr 19-23%, Fe 39.5%

Temperature Limit: 1100°C

International Standards: W No 1.4876, UNS N08811

Density: 7.945 g/cm³

Melting Range: 1357-1385°C

Specific Heat: 460 J/Kg°C

Thermal Conductivity: 11-32 W/m°C

Pyrosil

Pyrosil is commonly used in mineral insulated thermocouple sheathing, especially in Type K and N sensor assemblies.

Basic Composition: Ni Cr Si

Temperature Limit: 1250°C

Hastelloy C276

This can be an effective material to use in severe environments and displays good corrosion resistance in reducing and oxidising atmospheres.

Basic Composition: Ni 57%, Mo 16%, Cr 15.5%, Fe 5.5%, W 3.8%

Temperature Limit: 1040 ° C

International Standards: UNS N10276

Density: 8.9g/cm³

Melting Range: 1325-1370°C

Syalon 101

This is a strong and thermal shock resistant material for use in molten metals with little wetting or dross build up.

Basic Composition: Silicon Nitride, Aluminium Oxide

Temperature Limit: 1000°C (1250°C in controlled conditions)

Density: 3.26 g/cm³

Thermal Conductivity: 16.7 W/m°C

Quartz

Quartz provides good high shock resistance.

Basic Composition: SiO 2

Temperature Limit: 1500°C (Then flows under own weight)

Density: 2.2 g/cm³

Melting Range: 1683°C

Specific Heat: 670 J/Kg°C

Thermal Conductivity: 1.4 W/m°C

Silicon Carbide (Clay Bonded)

Clay Bonded Silicon Carbide tends to have a thick wall to improve strength. It displays good thermal shock resistance and high thermal conductivity.

Basic Composition: SiC 70 – 90%

Temperature Limit: 1400°C

Density: 2.4 g/cm³

Thermal Conductivity: 28.0 W/m°C

Silicon Carbide (Recrystalised)

Recrystalised Silicon Carbide has great thermal shock resistance.

Basic Composition: SiC 99%

Temperature Limit: 1600-2000°C dependant on atmosphere

Density: 2.6 to 2.7 g/cm³

Thermal Conductivity: 30.0 W/m°C

Sillimanite 60

Sillimanite 60 is a porous material with good thermal shock resistance.

Basic Composition: Al 2O 3 73 to 75%

Temperature Limit: 1600°C

International Standards: DIN VDE 0335 C530

Density: 2.35 g/cm³

Thermal Conductivity: 1.4 W/m°C

Recrystalised Alumina (Alsint)

Used with R, S and B thermocouples, Recrystalised Alumina is a pure and tough ceramic exhibiting hardness and vacuum tightness.

Basic Composition: Al 2O 3 99.7%

Temperature Limit: 1750°C

International Standards: DIN VDE 0335 C799

Density: 3.9 g/cm³

Melting Range: 2072°C

Aluminous Porcelain (Pythagoras)

Pythagoras Porcelain is commonly used with J, K, N and E conductors.

Basic Composition: Al 2O 3 60%

Temperature Limit: 1500°C

International Standards: DIN VDE 0335 C799

Density: 2.6 g/cm³

Platinum

Platinum is commonly used in glass manufacturing processes.

Basic Composition: Pt

Density: 21.45 g/cm³

Melting Range: 1769°C

Thermal Conductivity: 74 W/m°C at 20°C

Platinum 10% Rhodium

This platinum alloy gains strength at higher temperatures and is therefore used in molten glass processes and heat treatment.

Basic Composition: Pt 90%, Rh 10%

Temperature Limit: 1700°C

Density: 20.00 g/cm³

Melting Range: 1840-1870°C

Thermal Conductivity: 31 W/m°C at 20°C

At Electroserv+ our platinum materials are available with grain stabilisation to reduce degradation at higher temperatures.

Platinum Resistance Thermometers (PRT)

There are two kinds of platinum resistance thermometers – wire wound (WW) and thin film (TF).

TF temperature sensors are smaller than the WW versions and have better vibration resistance. However, they are generally only used for temperature measurements in ranges below 400°C due to a deviation of the resistance/temperature characteristic from the standard characteristic of IEC 60751 at high temperatures. The tight limit values of tolerance category A as per IEC 60751 can only be observed with TF sensors at temperatures up to approximately 300 °C.

TF platinum resistance thermometers contain a very thin, ultrapure platinum layer, approximately 1 μm thick, which is vaporized in a vacuum on a ceramic substrate and then structured photolithographically. The platinum conductor paths formed in this way create the measuring resistance. Additional covering and passivation layers are applied and reliably protect the thin platinum layer from contamination and oxidation.

WW platinum resistance thermometers contain a double coil of fine, high-purity platinum wire in a ceramic support, which is then sealed top and bottom with a ceramic protective layer. They facilitate very reproducible measurements and offer good long-term stability of the resistance/temperature characteristic within temperature ranges up to 600 °C. However, they are relatively large in size and are comparatively sensitive to vibrations.

Thermocouple Consumables

Sensor Accessories

As temperature sensor experts, Electroserv+ supplies a range of sensor accessories to use in new or existing sensor assemblies. Plugs and sockets, compression fittings, glands, transmitters, cables and more are included in our range.

Plugs and Sockets

Plugs and sockets are a popular choice with our Electroserv+ customers as they allow you to easily replace your sensors when new ones are required. Our industry standard designs are commonly used in a number of different assemblies.

At Electroserv+ we supply standard plugs (with round pins) and miniature plugs (with flat pins). We offer two-way plugs and sockets for thermocouples and three-way sets for resistance thermometers. Sockets can be arranged in a number of forms including panel mounted or attached cable depending on their application.

The IEC colour code matches a particular thermocouple to its matched plug and socket:

  • Type J – Black
  • Type K – Green
  • Type T – Brown
  • Type E – Purple
  • Type N – Rose
  • Type R/S – Orange
  • Type B – Grey

Compression Fittings

At Electroserv+ we can supply compression fittings to use with your existing assembly, manufactured using 316 SS. Often applied to mineral insulated thermocouples, compression fittings are a popular choice when measuring temperature in a pressure or vacuum environment. Our high quality double ferrule compression fittings apply a tight pressure seal.

Glands

Glands are commonly supplied with thermocouples for use outside as they provide a weatherproof connection, allowing the cold end of a probe to enter a termination box or instrumentation case.

Our Electroserv+ glands are typically made from brass and can also be nickel plated for added resistance against the elements.

Non Integral Sheathing

Electroserv+ can provide high quality separate sheathing to protect an element. We supply individual sheaths, with or without a thread, which you can attach to your existing assembly. Our ceramic sheaths are a popular choice in high temperature environments or we offer metal as a low cost option for added protection to your assembly.

Transmitters

When sited in a head or instrument panel, temperature transmitters eliminate the need for a large amount of compensating cable along long runs and can be used to convert sensor outputs into linear signals to transmit around plants. Typical loop power for a transmitter is 24V.

Terminal Heads

At Electroserv+ we regularly stock ALA, SD-BK, BUZ and KNE terminal heads and will happily hunt out the right terminal head for your temperature sensor to protect your transmitter or DIN block.

Temperature Sensor Cable

Quality cable is of paramount importance in temperature sensor manufacturing. Electroserv+ offers a wide range of cable including compensating, extension, cables for all varieties of thermocouples, 2,3,4 wire for RTD, and we also offer a choice of insulating material, stranding shielding and armouring.