Overview
A thermocouple consists of two dissimilar metals, joined together at one end. When the junction of the two metals is cooled or heated a voltage is produced that can be correlated back to the temperature. Most thermocouple alloys are commonly available as wire.
Thermocouples are manufactured in different combinations of metals and/or calibrations. The calibrations most regularly specified by Ultra’s customers are J, K, T and E. High temperature calibrations include R, S, C and GB. Each calibration has a different temperature range and environment, although the maximum temperature varies with the diameter of the wire used in the thermocouple.
While the thermocouple calibration defines the temperature range, the maximum range will also be a factor the diameter of the thermocouple wire. Therefore, a very thin thermocouple may not reach the full temperature range.
Since thermocouples measure wide temperature ranges and are relatively rugged, they are very often used demanding industrial automation and process control applications. In selecting a thermocouple, the following criteria are key considerations:
- Temperature range
- Chemical resistance of the thermocouple or sheath material
- Abrasion and vibration resistance
- Installation requirements (may need to be compatible with existing equipment;existing holes may determine probe diameter)
Typical thermocouple applications
- Test stands
- Medical equipment
- Aerospace markets
- Packaging equipment
- Semiconductor processing
- Food processing equipment
- Heat treating and processing
- Engine and turbine exhaust gas
- Plastic injection molding machinery
| Model (PDF) | Description |
|---|---|
| 101 & 103 | General purpose |
| 110 | Field cuttable |
| 120 | Hand-breakable |
| 201 & 203 | With welded fittings |
| 301 | Spring loaded for use with cast iron explosion-proof housings |
| 302 | Spring loaded without transmitter for general purpose housing |
| 305 | Spring loaded, 1/2″ NPT hex hipple |
| 312 | Spring loaded (for use with type 1 general purpose head) |
| 452 | Spring loaded sanitary temperature sensor |
| 3142B | Sanitary flush mount tank temperature sensor |
| 3226A | Food piercing temperature sensor |
| 3304A | Flexible stick-on surface temperature sensor |
| 3312A | Autoclave temperature sensor |
| 3332A | Embedded temperature sensors for rotating machinery and turbines |
| Bearing temperature | Sensors for the measurement of bearing temperatures |
| Bayonet fitting design | Spring loaded bayonet fitting temperature sensors |
Thermocouple General Specifications
Thermocouples
Mineral Insulated (MgO) thermocouple assemblies are metal sheathed, magnesium oxide insulated temperature sensing elements. These small, compact units are moisture proof, non-porous, and pressure resistant. They are available with single or dual elements and are noted for accuracy and fast response. These thermocouple assemblies come in a large variety of sheath materials and calibrations. Installation is made easier because Mineral Insulated thermocouple assemblies are bendable to practically any contour. The metal sheath is made of durable alloys and can be welded. These thermocouple assemblies have consistency that is assured by excellent quality control in manufacturing.
Key selection criteria:
- What is the temperature Range Required?
- What is the Thermocouple Type?
- What Connection Type?
| Model | Configuration |
|---|---|
| 701 | MgO – Plain Stripped Ends |
| 716 | MgO – Standard Plug |
| 718 | MgO – Heavy Duty Plug |
| 721 | MgO – Standard Jack |
| 723 | MgO – Heavy Duty Jack |
| 751 | MgO – Steel Plug & Aluminum Screw Cover Head |
| 753 | MgO – Steel Plug & Cast Iron Screw Cover Head |
| 761 | MgO – 1/2″ x 1/2″ Hex Fitting & Aluminum Screw Cover Head |
| 763 | MgO – 1/2″ x 1/2″ Hex Fitting & Cast Iron Screw Cover Head |
| 782 | MgO – Thermocouple w-Extension Leads, Bare Strip |
| 783 | MgO – Thermocouple w-Extension Leads w-Plug |
| 784 | MgO – Thermocouple w-Extension Leads w-Jack |
| 785 | MgO – Thermocouple w-Stainless Steel OverBraid Extension Leads, Bare Strip |
| 786 | MgO – Thermocouple w-Stainless Steel OverBraid Extension Leads w-Plug |
| 787 | MgO – Thermocouple w-Stainless Steel OverBraid Extension Leads w-Jack |
| 792 | MgO – Thermocouple w-Flex Armor Extension Leads, Bare Strip |
| 793 | MgO – Thermocouple w-Flex Armor Extension Leads w-Plug |
| 794 | MgO – Thermocouple w-Flex Armor Extension Leads w-Jack |
Nobel Metal Thermocouple Elements
All elements are provided to match the ITS 1990 curve. 24 ga. (0.020″) wire is standard – other gauges are available. Spools of bare platinum wire are available.
Alumina is recommended above 2400ºF and is supplied as a standard. Mullite causes silica contamination of the platinum element above this temperature. Fishspine insulators and copper sleeves are supplied as standard termination. Standard insulator = 3/16″ O.D. and 1/16″ bore. Other diameters available. A collar should be used in all vertical applications.
| Model | Configuration |
| 25X | Bare Wire Element |
| 26X | Insulated Wire Element |
| 27X | Insulated W-Collar Wire Element |
Noble Metal Thermocouple Assemblies
Noble Metal thermocouple assemblies consist of a Platinum or Tungsten Rhenium Elements with a protection tube(s) and a termination head. Elements are Types R, S, B and C and are available with Ceramic, Inconel, Stainless Steel, Molybdenum Protection tubes in standard and customer lengths. Termination heads are available in aluminum & cast iron screw covers and also in various open terminal heads.
| Model | Configuration |
|---|---|
| 591 | Nobel Metal – Open Terminal Head |
| 592 | Nobel Metal – G7 Open Terminal Head |
| 593 | Nobel Metal – Screw Cover Head w-Nipple |
| 594 | Nobel Metal – Screw Cover Head w-Hex Fitting |
| 595 | Nobel Metal – Open Terminal Head – w-SiC & Support Casting Assembly |
| 596 | Nobel Metal -Screw Cover Head – w-SiC & Support Casting Assembly |
| 597 | Nobel Metal -Screw Cover Head – w-SiC & WeatherProof Cover Assembly |
Vacuum Thermocouples
Vacuum thermocouples are designed for use in vacuum furnaces and other applications requiring high temperature measurement in controlled atmospheric conditions. Our high temperature thermocouples generally operate in a temperature range of 1800ºF. (982ºC), through 4200ºF. (2300ºC). The construction style consists of a high purity alumina (or Hafnia) insulated 24 gauge element inside Alumina, Molybdenum, or Inconel sheath with a plug. Many are argon back filled and sealed for use in vacuum applications. Special drawings and construction designs can also be made to meet customers needs.
Base Metal Thermocouples
Base Metal Thermocouple Elements, Ceramic Insulators, Metal Protection Tubes and other Base Metal Thermocouple Hardware and Supplies. Standard calibrations include E, J, K, N and T. Available in a wide variety of wire gauges, lengths and configurations – customized to your specifications. Contact us with your requirements.
| Model | Configuration |
|---|---|
| 1XXY | Base Metal – Bare Wire Element (XX = Wire Gauge 8,11,14,20, Y=Type J,K,N,etc) |
| 2XXY | Base Metal – Insulated Wire Element (XX = Wire Gauge 8,11,14,20, Y=Type J,K,N,etc) |
| 3XXY | Base Metal – Angled Insulated Wire Element (XX = Wire Gauge 8,11,14,20, Y=Type J,K,N,etc) |
| Straight | Base Metal – Assembly w-Protection Tube Head |
Nonferrous Molten Metal Thermocouple Tips and Lance Handles
Nonferrous Molten Metal Thermocouple Tips are designed for intermittent temperature sensing below 2300°F for use in molten brass, copper, aluminum lead and other nonferrous metals. They are available in a variety of tip lengths. Lance Handles are available Curved, Angled, or Straight. Contact us today with your requirements, and we will be delighted to assist.
| For Use w-Covered Lance Handle | ||||
| Part # | X Length | Y Length | Length | Part # |
| MT-8-Y | 8″ | 36″ | 31″ | LH-31 |
| MT-12-Y | 12″ | 49″ | 43″ | LH-43 |
| MT-15-Y | 15″ | 61″ | 55″ | LH-55 |
| MT-20-Y | 20″ | 79″ | 72″ | LH-72 |
| MT-24-Y | 24″ | 103″ | 96″ | LH-96 |
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