Special Thermocouples: An Overview

Special thermocouples are designed for demanding and highly specific industrial applications where standard configurations may not suffice. These sensors are engineered with enhanced protection, customized assemblies, and application-focused materials to ensure accuracy, reliability, and longevity under extreme conditions. Whether operating in molten metal environments, fluidized beds, or specialized furnaces, special thermocouples are built to meet the unique thermal, mechanical, and chemical challenges of the process.

Working Principle

Like standard thermocouples, special thermocouples operate based on the Seebeck effect. Two dissimilar metals form a thermoelectric circuit; when the two junctions are at different Temperatures, a voltage is generated that corresponds to the Temperature difference. This voltage can be measured and converted into Temperature using standard calibration data. What distinguishes special thermocouples is their robust construction, protective assemblies, and optimized materials suited to extreme industrial applications.

Type R thermocouples consist of a Platinum (Pt) and Platinum-13% Rhodium (Pt-Rh) combination. They are used extensively in high-Temperature environments (0°C to 1600°C) and offer exceptional accuracy (±0.25%) and stability. They are ideal for use in metallurgy, glass, and ceramic industries due to their resistance to oxidation and thermal shock.

Type B thermocouples are made of Platinum-30% Rhodium and Platinum-6% Rhodium. Designed for extremely high Temperatures (up to 1800°C), they are commonly used in high-Temperature furnaces and molten metal applications. They have excellent long-term stability and an accuracy of ±0.50%, making them suitable for continuous use in extreme environments.

Type S thermocouples are composed of Platinum and Platinum-10% Rhodium and offer similar performance to Type R. They operate accurately up to 1600°C and are commonly used in laboratories, metal processing, and pharmaceutical environments where high accuracy (±0.25%) is essential.

Platinum Thermocouple for Coke Oven Furnace with Double Ceramic Protection Tube Assembly

Ajmer Thermotech Pvt. Ltd., an ISO 9001:2015 and CE certified company, manufactures the Platinum Thermocouple under its Special Thermocouples category, engineered specifically for the demanding conditions of coke oven furnaces. This model features a noble metal thermocouple housed within a double ceramic protection tube assembly, designed to withstand extremely high Temperatures and corrosive atmospheres commonly found in metallurgical and furnace environments.

The double ceramic sheath construction offers exceptional thermal insulation, mechanical integrity, and resistance to chemical attack, making it ideal for continuous high-Temperature operation. It supports Type R, S, or B configurations and is optimized for reliable and stable measurements in coke oven chambers and high-heat industrial processing zones.

Ajmer Thermotech provides customization options such as wire gauge, insulation material, lead wire length, terminal styles, and mounting arrangements to suit specific industrial requirements.

Platinum / Rhodium Thermocouple is built for precision, durability, and safety, ensuring long service life even under the most severe thermal conditions.