TC21 Nozzle Thermocouple with Lead Wire

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TC21 Nozzle Thermocouple with Lead Wire

Threaded Surface Thermocouple for Accurate Metal Surface Temperature Measurement

To obtain accurate surface temperature measurements, it is necessary to use a sensor that remains firmly in place. The TC21 Threaded Surface Thermocouple is designed to ensure reliable temperature monitoring by maintaining direct contact with hot metal surfaces via its threaded mounting system. This secure fit contributes to better measurement stability, reduces temperature variations, and secures consistent performance in tough industrial conditions. Due to its rugged MgO mineral insulated construction, the TC21 is capable of resisting vibration, thermal cycling, and mechanical stress, which makes it suitable for continuous use on heated platens, molds, dies, machine parts, process equipment, and OEM machinery. The TC21 is available with configurable thread sizes, probe lengths, lead-wire insulation, and termination choices, thus delivering a reliable and customizable solution for OEM manufacturers, machine builders, and maintenance professionals who need accurate long-term surface temperature measurements.

Secure Threaded Mounting

Threaded mounting ensures secure installation and consistent surface contact for accurate, repeatable temperature measurement in industrial equipment.

Rugged MgO Construction

MgO mineral insulated construction withstands vibration, thermal cycling, and harsh industrial operating conditions for long-term reliability.

Fast Surface Response

Optimized sensing tip delivers rapid heat transfer for fast, stable surface temperature measurement and improved process control.

Multiple Termination

Available with bare leads, standard, miniature, or high-temperature connectors for easy integration with existing control systems

High Mechanical Durability

Stainless steel construction resists mechanical wear, corrosion, and continuous production environments for dependable long-term performance.

Custom Configuration

Configure thread size, probe length, lead wire, insulation, termination, and mounting options to match your OEM application.

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Quick Specifications

Thermocouple Type Type J
Mounting Thread Threaded Bolt Surface Mount
Junction Type Grounded
Sheath Material SS304 or SS316 Stainless Steel
Thread Size 1/4"-20 UNC, M6 × 1.75, or Custom
Lead Wire Options PTFE (260°C), Fiberglass (510°C), SS Braid, or SS Armor
Ideal for
Plastic Injection
Plastic Extrusion
Heated Dies & Tooling
Packaging
Automotive Engine
Industrial Process
OEM Machine
Rubber Molding
The TC21 Nozzle Thermocouple and its lead wire are designed to accurately measure the surface temperature of heated parts where secure sensor contact and mounting are essential. Unlike clamp-on or surface-mounted sensors that may shift during use, the TC21 integrates the thermocouple into a threaded bolt, providing a permanent mounting solution that maintains consistent contact with the measured surface. This design improves temperature stability, reduces measurement variation, and ensures reliable operation in demanding industrial environments.
Manufacturers, maintenance engineers, and process engineers commonly use the TC21 to monitor the temperature of heated platens, molds, manifolds, dies, nozzles, machine components, and other metal surfaces where precise temperature control is critical. Its robust stainless steel construction allows it to withstand vibration, mechanical stress, and continuous industrial use, making it suitable for equipment operating under severe conditions.
The TC21 is offered as a Type J thermocouple with a grounded junction, providing robust construction and reliable thermal transfer for general industrial applications. Engineers can specify various thread sizes, bolt lengths, lead wire lengths, insulation materials, and termination options to simplify installation on new or existing equipment. Optional features such as stainless steel overbraid, flexible armor, strain relief springs, wire clamps, silicone connector boots, and a range of connectors enhance durability and protect the lead wire in harsh environments.
Each TC21 is made in accordance with ASTM E608/E608M and the temperature tolerances comply with the requirements of IEC 60584 and ANSI MC96.1. Calibration services can be obtained if required for cases in which documented measurement traceability and quality assurance are needed.
Whether you are replacing an existing bolt-style thermocouple, specifying a threaded surface temperature sensor for new OEM equipment, or seeking to improve the reliability of an industrial temperature monitoring system, the TC21 provides a durable and customizable solution for long-term use. For further engineering guidance, consider visiting the following pages: Surface Temperature Measurement, Bolt-Style Thermocouples, Grounded Thermocouple Junctions, Thermocouple Response Time, Type J Thermocouples, and ASTM E608 Thermocouple Standards. These resources offer valuable technical information and support SEO, AI discoverability, and user experience.

Product Specifications

Review the standard specifications and available configuration options for the TC21 Thermocouple. Sheath diameter, insertion length, thermocouple type, lead wire, insulation, connector style, temperature rating, and optional features may vary depending on the selected configuration and application requirements

Thermocouple TypeType J
Mounting ThreadThreaded Bolt Surface Mount
Junction TypeGrounded
Sheath MaterialSS304 or SS316 Stainless Steel
Thread Size1/4"-20 UNC, M6 × 1.75, or Custom
Lead Wire OptionsPTFE (260°C), Fiberglass (510°C), SS Braid, or SS Armor
Termination OptionsBare Ends, Standard, Miniature, High-Temperature Plugs & Jacks
Optional AccessoriesStrain Relief Spring, Wire Clamp, Silicone Connector Boot
ApplicationSurface Temperature Measurement on Heated Metal Components

Spare Parts & Accessories

Complete your installation with compatible mounting accessories, connectors, and replacement components for the TC21 Thermocouple.

Product Videos

Watch product overview, installation, and application videos for the T21 Thermocouple

Temperature Transmitter | Tempotech Controls Inc

PT2M44S

A temperature transmitter takes the temperature data from a sensor, like an RTD or thermocouple, and converts it into a standard signal, usually 4-20mA or 0-10V. This signal can be sent to control systems, PLCs, or monitoring equipment to keep track of temperature in real-time.

Read transcript

Video Transcription: Temperature Transmitter Technology & Application
[00:05] A temperature transmitter is a critical component in industrial automation that converts low-level sensor signals into standardized outputs. This ensures accurate, reliable, and long-distance signal transmission for complex control systems.

[00:14] Thermocouple and RTD sensors are the industry standards for measuring the temperature of processed media. However, in challenging environments—characterized by high temperatures, electromagnetic interference (EMI), or long cable runs—the raw signals from these sensors can degrade.

[00:33] This signal degradation, often caused by wire resistance and electrical noise, can lead to inaccurate readings. To mitigate these issues, temperature transmitters are used to amplify, condition, and convert sensor data into a standardized 4-20mA output, ensuring high-integrity data across the plant.

[00:59] Several signal types are used depending on the application:

4 to 20 mA Analog Signal: The most common standard, highly resistant to noise and ideal for long distances.

0 to 10V: A common analog option, though more susceptible to signal loss over length.

Digital Signals (HART & Modbus): Used for advanced remote communication and diagnostics.

RS485/RS232: Essential for integrating transmitters with PLCs and SCADA systems.

[01:35] The Tempotech TT367 series temperature transmitters are engineered for versatility. They offer precise sensor-transmitter matching and robust protection against interference. Configurable via the HART protocol, these units allow for easy setup and reliable field operation.

[01:56] Key reliability features include open/short-circuit detection, incorrect wiring alerts, and NAMUR NE43 failure standards. The TT367 supports RTD, TC, Ohm, and Millivolt inputs, making it a universal solution for your instrumentation needs.

[02:26] With integrated dot-matrix displays and easy configuration options, our transmitters provide the precision you can trust. Contact our technical sales team today to find the best transmitter for your application.

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Frequently Asked Questions

Find answers to common questions about the TC21 thermocouple

How do I select the correct thread size for the TC21 Threaded Surface Thermocouple?+

The TC21 is available with 1/4"-20 UNC, M6 × 1.75, and custom thread sizes. The thread should match the existing mounting hole to ensure proper seating, reliable thermal contact, and secure installation without modifying the equipment.

Is the TC21 suitable for high-vibration industrial equipment?+

Yes. The TC21 is designed with a threaded bolt mounting that keeps the sensing element securely positioned against the measurement surface. Combined with optional stainless steel overbraid or armor, it is well suited for machinery exposed to vibration and continuous industrial operation.

Which lead wire insulation should I choose for my application?+

The TC21 is available with PTFE (260°C) and fiberglass (510°C) insulation. PTFE is commonly selected for general industrial environments, while fiberglass is preferred where the lead wire is exposed to higher ambient temperatures. However wire rating does not reflect operating temperature range, Please check with our Sales team.

Can the TC21 be manufactured to replace an existing OEM sensor?+

Yes. The TC21 can be customized with different thread sizes, bolt lengths, sheath materials, lead wire lengths, insulation types, and connector options, allowing it to replace many OEM threaded surface thermocouples without requiring equipment modifications.

How can I achieve the most accurate surface temperature measurement with the TC21?+

For the best measurement accuracy, install the TC21 using the correct thread size and tighten it according to the equipment manufacturer's recommendations to maintain full contact between the sensing tip and the heated surface. Proper mounting, selecting the appropriate lead wire insulation, and protecting the cable from excessive mechanical stress all contribute to stable, repeatable temperature measurements and longer sensor life.

How tight should I install the TC21 Threaded Surface Thermocouple for accurate temperature measurement?+

The TC21 should be tightened securely to ensure full contact between the sensing surface and the measured component without exceeding the recommended torque for the mounting thread. Insufficient tightening can create air gaps that reduce heat transfer and affect measurement accuracy, while excessive torque may damage the sensor or the mounting threads.