What parameters are required for non-standard customized thermocouples?

Custom thermocouples require the following key parameters based on the specific application scenario and measurement requirements to ensure performance, compatibility, and reliability:

1. Thermocouple Type

Grading: Examples include K-type (nickel-chromium-nickel-silicon), J-type (iron-constantan), and S-type (platinum-rhodium 10-platinum). Different graduations correspond to different temperature ranges and materials.

Choice Selection: Based on the temperature measurement range, accuracy requirements, and ambient media (oxidizing/reducing properties).

2. Temperature Range

Operating Temperature: The minimum and maximum temperatures, as well as the temperature range for long-term stable operation, must be clearly defined.

Short-Term Temperature Limit: Whether the thermocouple needs to withstand occasional overtemperatures (e.g., for overload protection).

3. Dimensions

Diameter and Length:

Hot-end diameter (e.g., 1mm, 3mm) affects response speed.

Insertion depth (e.g., 50mm, 100mm) must match the measured media.

Total length (including protective tube and lead wire). Shape: Straight, curved (90°, 135°, etc.), tapered, or special shapes.
4. Protective Tube Material
Material Options:
Stainless steel 304/316 (for medium and low temperatures, generally corrosive environments).
Ceramics (such as alumina, suitable for high temperatures >1000°C).
Hastelloy, Inconel (for highly corrosive environments).
Sealing Requirements: Explosion-proof, waterproof, or vacuum-sealed.
5. Wiring Method and Wires
Junction Box Type: Explosion-proof, waterproof, open, etc.
Wire Length and Material:
Compensating wire length (such as 2 meters, 5 meters).
Requirement of a shielding layer (for electromagnetic interference suppression).
High-temperature wire (such as fiberglass-coated) or flexible wire.
6. Mounting Method
Fixing: Threaded mounting (such as M6, M12), flange connection (DN15/DN25), ferrule, or welded.
Mounting Orientation: Horizontal, vertical, or at a special angle. 7. Special Environmental Requirements
Pressure/Corrosion Resistance: For use in autoclaves, acidic/alkaline environments.
Vibration/Shock Resistance: For use in mobile equipment or industrial vibration environments.
Explosion-Proof Certification: For use in flammable and explosive environments, such as ATEX and IECEx.
8. Output and Signal Processing
Transmitter Required: Integrated temperature transmitter (4-20mA output).
Cold Junction Compensation Requirements: Internal or external compensator.
9. Other Custom Requirements
Response Time: Fast response (such as thin-film thermocouples) or standard.
Calibration Requirements: Whether a third-party calibration certificate is required (such as the ITS-90 standard).
Multiple Thermocouples: Whether dual or multiple independent measuring units are required.