Home > Knowledge > Content
Introduction to thermocouple and thermocouple components
Jan 31, 2020

What is a thermocouple?

Thermocouple is a kind of temperature sensor, which consists of two different metal wires, one end is connected together, the other end is connected to thermocouple thermometer or other equipment supporting thermocouple. After the correct configuration, the thermocouple can be used for temperature measurement in various temperature ranges.

What are the different thermocouple types? Thermocouples have different metal or "graduation" combinations. The most common types are j, K, t, e, and n "foundation" thermocouples. There are also special types of thermocouples, called precious metal thermocouples, including types R, s, and B. The maximum temperature thermocouple type is fire resistant, including C, G and D types.

How to choose thermocouple type?

The selection of thermocouples is usually based on the following conditions:

• temperature range


• process compatibility

(chemical and Mechanical)

• instrument compatibility

How do I know the type of connection point to select?

There are three types of connection points for metal Sheathed Thermocouples: grounded, ungrounded, and exposed

Bare wire thermocouple

Bare wire thermocouples are the most basic components provided. It is completely composed of two bead thermocouple wires to construct the thermocouple circuit. Omega can provide bare wire thermocouples of various even wire diameters, with a minimum diameter of 0.001 "and a maximum diameter of 0.128". Omega offers base metal indexing from stock

No.: J, K, t, e and N and precious metal graduation No.: R, s, B and C. Omega also offers a variety of insulation products for bare wire insulation, such as ceramic insulation sleeves and glass fiber braided tubes.

Insulated wire thermocouple

Omega uses internally manufactured thermocouple wires to produce finished insulated thermocouples. These temperature sensors are available in a variety of termination methods, insulation materials and lengths. In the market, Omega provides the largest number of insulated wire thermocouples and the most complete types. We produce all the components, so it's easy to customize the size and configuration, and fast delivery.

Surface mountable insulated wire thermocouple

For applications that are temporarily or permanently connected to any surface, Omega provides insulated wire thermocouples that cover the measuring connection points with insulating patches or mechanical washers. The patch can be installed with self-adhesive backing or bonded to the corresponding position with a natural setting adhesive of our company. The gasket type surface mounting can be fixed to the corresponding position with bolts. Surface mounted thermocouples have extremely fast response times. The sa1xl in the figure above has all the functions of self-adhesive and adhesive thermocouples, and the response time is less than 0.15 seconds.

Surface probe

Omega's unique surface probe line can produce more than 50 types of probes, measuring temperatures up to 760 ° C (1400 ° f) on stationary, rotating and moving surfaces. These probes can be manufactured according to the customized wire length and cable insulation layer, and can be made of a variety of handle materials. In addition, Omega uses proprietary component design to ensure reliable and durable sensors for customers.

Special metal thermocouple probe

For applications requiring temperature measurements above 1260 ° C (2300 ° f), graduations R, s, B, and C will be used, which are manufactured using a variety of special / precious metal and insulation combinations. These special metal thermocouple probes can be used at temperatures up to 2300 ° C (4200 ° f). Ceramic sheath is also provided for these graduation numbers.

M12 and M8 thermocouple probes

The new M12 and M8 thermocouple probes include integral metal threaded 12 mm x 1 or 8 mm x 1 connectors and thermocouple compensating pins. This design allows compact, safe, seismic sensors to be permanently attached to stainless steel and Inconel ® probe metal sheaths, providing the ideal solution for automation and process applications.

Quick release

The quick disconnect probe consists of thermocouple connector and MIMS probe. This design enables the probe to be quickly connected and / or disconnected from the measuring circuit. This style can provide probes with a variety of connector and sheath materials.

Transition connection type

The transition probe consists of a metal sheath probe and a built-in extension wire. Omega offers a wide range of off the shelf delivery probes, and can also easily customize almost any sheath material, graduation, wire insulation and cold end termination combination according to your application requirements

Section probe

The profile probe includes a plurality of small diameter thermocouples located in an outer sheath. It is very suitable for measuring the temperature of multiple points along a single axis, such as a belt furnace. Omega also provides innovative on-line profiler configurator, please visit cn.omega.com to help design profiler.

Hand held probe type

The probe has a user-friendly handle, which is also the transition between the metal sheath and the wire. The handle can be cast or mechanically assembled. This type of probe is usually used with handheld instruments such as omega supermeter. In this way, the operator can carry out spot check in the production line, metal smelting, food and beverage production, HVAC or any application. Sensor tips are available in a variety of styles for use in a variety of applications, such as a "hood" that protects the sensing connection point while allowing air flow, or a small tip with a large thickness of sheath material that reduces the size of the sensing tip to respond quickly. We provide a variety of styles to meet the needs of various applications.

Industrial protection head

Industrial thermocouple with metal sheath is usually used in liquid or gas fluid applications, such as oil refining, wastewater treatment and natural gas production. The probe has a metal sheathed thermocouple with a welded or brazed threaded joint which is connected to a plastic or metal coupling head. The coupling includes a terminal block and a wire outlet for connection with the temperature monitoring system. To "screw in" the probe, keep the tip of the sensor submerged in the media stream while maintaining the closed system.

Sanitary / CIP thermocouple

Sanitary / CIP 3A certified thermocouple sensors are available in flange sizes from 3 ⁄ 4 to 4 "diameter. The design includes industrial coupling, integrated M12 connector and thermowell configuration. The product line also includes Omega's unique and extensive wireless and amplification transmitter design. This design provides CIP special processing of highly polished 316 stainless steel surface to meet the needs of food, beverage and biopharmaceutical processing.