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Thermocouple

Product catalog summary

Introduction to Thermocouples
Thermocouples are devices that measure temperature by converting thermal energy into electrical voltage. They are favored in industrial applications for their durability and low maintenance.

Temperature Measurement
Temperature is measured in Kelvin or degrees Celsius, with the International Temperature Scale (ITS 90) as the standard. It is based on the laws of Boyle-Mariotte and Gay-Lussac.

Thermoelectric Effect
The principle behind thermocouples is the thermoelectric effect, discovered by Seebeck, where a voltage is generated when two different metals are joined and exposed to a temperature difference.

Standards and Specifications
Thermocouples are standardized under IEC 584 and EN 60584, which define temperature-specific voltages, deviations, and material compositions. Color coding is used for easy identification.

Measuring Inserts and Protective Tubes
Measuring inserts are flexible modules that include a thermocouple, designed to withstand high mechanical stresses. Protective tubes, typically made from stainless steel, protect the thermocouple and must be chosen based on pressure, velocity, and temperature loads.

Types of Thermocouples
Thermocouples are categorized by metal combinations and color codes, such as Type T (Cu/CuNi), Type J (Fe/CuNi), and Type K (NiCr/Ni), each with specific temperature ranges and voltage outputs.

Ordering and Customization
Thermocouples can be ordered using catalogue numbers, with options for modifications. A questionnaire is available for custom requirements.

Basic Values and Deviation Limits
Basic values for thermoelectric voltage are provided for different temperature ranges, with a reference junction temperature of 0°C. Deviation limits are specified for different types and classes of thermocouples.

Conclusion
Thermocouples are essential for temperature measurement, offering a wide range of applications and customization options. Understanding their specifications and standards is crucial for accurate and reliable temperature monitoring.

Specifications
The measuring insert is designed with a mineral insulated sheathed cable, bendable and made of stainless steel, operating from -100 °C to 600 °C. It complies with DIN 43772 Form 4 and features an exchangeable insert. The connection head is type B, made of light metal, with a cable gland M 20 x 1.5 as per DIN EN 50446. The neck tube is 11 mm in diameter, made of stainless steel 1.4571, and 165 mm long. The weld-in thermowell has a diameter of 24 h7 mm and is made from specified materials. Thermocouples available are NiCr-Ni (Type K) or Fe-CuNi (Type J), in simplex or duplex configurations with insulated measuring points, adhering to DIN EN 60584 class 2 tolerance. Connection is via a ceramic terminal block with connection pins.

Spare Weld-in Thermowells
Specifications align with the standard design, with various lengths and materials available, and specific order numbers for different configurations of Type K and Type J thermocouples.

Options and Ordering
Various connection head types and head transmitters are available, with specific order numbers. A questionnaire is available online for custom requirements if a suitable option is not found.

Key Materials
Materials for thermowells include 1.0460 (C22.8), 1.5415 (15Mo 3), 1.7335 (13CrMo 44), 1.7380 (10CrMo 9 10), and 1.4571 (X6CrNiMoTi 17-12-2).

Additional Information
Couplings are available for inserts with diameters of 6 mm and 8 mm, with various threading options. Clamping rings are available in Teflon.

Procedures
Connection is facilitated via a ceramic terminal block with connection pins. Options for head transmitters include programmable types with electrical insulation and EEx versions. Customers can specify their requirements using a questionnaire if standard options do not meet their needs.

Standards and Norms
The document adheres to DIN EN 50446 for connection heads, suitable for mounting terminal blocks or head transmitters. The protection class for materials used in connection heads is IP54.

Recommendations
For specific configurations not listed, customers are encouraged to fill out a questionnaire to specify their needs. A DAkkS-calibration laboratory is available for precise temperature and density measurements, ensuring compliance with international standards.

Key Data from Tables
Tables provide detailed part numbers for various insert lengths and diameters for both Type K and Type J thermocouples in simplex and duplex forms. Additional specifications for head transmitters, including supply voltage, isolation voltage, and temperature spans for different thermocouple types, are provided.

Critical Information
The document emphasizes the importance of specifying the measuring range when ordering head transmitters and provides detailed input and output specifications for different types of transmitters. It also outlines the service performance of Ludwig Schneider's calibration laboratory, which includes calibration to fixed points and comparison measurements for various thermometer types.

Catalog excerpts

LUDWIG SCHNEIDER

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TABLE OF CONTENTS HOW TO ORDER ELECTRICAL TEMPERATURE MEASUREMENT WITH THERMOCOUPLES Temperature Temperature scale Thermoelectric effect Standards for thermocouples Measuring inserts Thermowell THERMOCOUPLES ACC. TO DIN 43772 FORM 1-4 TE-BA TE-BE TE-BB-ko TE-BB-k TE-BB TE-BC TE-BF TE-BE (R) TE-BB (R) TE-BC (R) TE-BF (R) TE-BD THERMOCOUPLES WITHOUT ADDITIONAL THERMOWELL TE-BL-ME 40 MEASURING INSERTS FOR THERMOCOUPLES ACC. TO DIN 43735 BASIC VALUES DEVIATION LIMITS

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In addition to the meter, kilogram, second, mole, candela and ampere, the temperature is a basic unit within the metric system of units (SI) and is represented by the formula sign T. In addition to the temperature scale to Kelvin, measurement in degrees Celsius is very common. The following correlation exists between the two units: 0 K = –273.15 °C All thermocouples in this catalogue are exactly described in their technical execution and correspond to valid standards and prescribed manufacturing methods. All thermocouples in standard design have an own catalogue number, which is sufficient for...

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The functional principle is based on the effect described by Seebeck in 1821 that a current flow arises when two metal conductors made of different materials are connected with each other and a temperature change takes place at a connection point. The connected conductors are designated as thermocouples and the physical process is defined as the thermoelectric effect. The thermoelectric voltage, meaning the voltage at the thermocouple, increases as the temperature increases. Thermocouples have some advantages compared to resistance thermometers: Smaller construction forms are possible, they have...

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Put generally, the thermoelectric voltage/K is higher, the greater the difference in the metals of both legs is. Of the thermocouples listed, the NiCr/CuNi element (Type E) has the highest electromotive force (EMF). By contrast, the thermocouple Pt30Rh/Pt6Rh (Type B) has the lowest EMF, since the two thermo-legs differ only in the rhodium alloy content. The thermoelectric voltages as a factor of the temperature were calculated as the basic values and defined in the standards IEC 584 or EN 60584 respectively. These values all reference a reference junction temperature of zero degrees Celsius....

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DEVIATION LIMITS ACC. TO IEC 751 RESP. DIN EN 60751 According to EN 60584 thermocouples are divided into three tolerance classes. These reference thermoelectric wires with a 0 0.25 to 3 mm and refer to the state of delivery. Possible aging during operation cannot be taken into consideration, since these are application-specific. The specified temperature ranges do no contain any limits for the application. These are ranges within which the described tolerances are defined. DEVIATION LIMITS ACC. TO DIN EN 60584 Type SUMMARY OF THERMOWELL AND INSERTS TE-BA

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TE-BA INSERTIBLE THERMOCOUPLE ACC. TO DIN 43772 FORM 1, WITH EXCHANGEABLE INSERT SPARE INSERTS AT BENDABLE DESIGN SPECIFICATION: + Measuring insert with mineral insulated sheathed cable (bendable) at stainless steel + Temperature range -100 °C to 600 °C COMPLETE INSTRUMENTS SPECIFICATION OF THE STANDARD DESIGN: + Connection head Type B at light metal with cable gland M 20 x 1,5 (acc. to DIN EN 50446) + Thermowell at stainless steel 1.4571 + Thermowell 0 and nominal length according to table + Measuring insert with mineral insulated sheathed cable (bendable) stainless steel sheath with constant...

Open the catalog to page 7

SPARE INSERTS AT BENDABLE DESIGN SPECIFICATION: + Measuring insert with mineral insulated sheathed cable (bendable) at stainless steel + Temperature range -100 °C to 600 °C COMPLETE INSTRUMENTS SPECIFICATION OF THE STANDARD DESIGN: + Connection head Type B at light metal with cable gland M 20 x 1,5 (acc. to DIN EN 50446) + Thermowell at stainless steel 1.4571 + Thermowell 0 and nominal length according to table + Measuring insert with mineral insulated sheathed cable (bendable) stainless steel sheath with constant diameter + Thermocouple NiCr-Ni (Type K) or Fe-CuNi (Type J); simplex or duplex...

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TE-BB-ko SCREW-IN THERMOCOUPLE SIMILAR DIN 43772 FORM 2G, INSERT NOT EXCHANGEABLE COMPLETE INSTRUMENTS SPECIFICATION OF THE STANDARD DESIGN: + Connection head type B at light metal with cable gland M 20 x 1,5 (acc. to DIN EN 50446) + Thermowell at stainless steel 1.4571 + Mounting bush G 1/2 at stainless steel 1.4571 + Immersion length EL and thermowell 0 acc. to table + Thermocouple NiCr-Ni (Type K) or Fe-CuNi (Type J); simplex or duplex Tolerance acc. to DIN EN 60584 class 2 + Measuring point insulated + Connection via ceramic terminal block with connection pins + Range -100 °C to 600 °C ORDER:...

Open the catalog to page 9

SPARE INSERTS AT BENDABLE DESIGN SPECIFICATION: + Measuring insert with mineral insulated sheathed cable (bendable) at stainless steel + Temperature range -100 °C to 600 °C COMPLETE INSTRUMENTS SPECIFICATION OF THE STANDARD DESIGN: + Connection head Type B at light metal with cable gland M 20 x 1,5 (acc. to DIN EN 50446) + Thermowell at stainless steel 1.4571 + Mounting bush G 1/2 at stainless steel 1.4571 + Immersion length EL and thermowell 0 acc. to table + Measuring insert with mineral insulated sheathed cable (bendable) stainless steel sheath with constant diameter + Thermocouple NiCr-Ni...

Open the catalog to page 10

SPARE INSERTS AT BENDABLE DESIGN SPECIFICATION: + Measuring insert with mineral insulated sheathed cable (bendable) at stainless steel + Temperature range -100 °C to 600 °C COMPLETE INSTRUMENTS SPECIFICATION OF THE STANDARD DESIGN: + Connection head Type B at light metal with cable gland M 20 x 1,5 (acc. to DIN EN 50446) + Thermowell and neck tube at stainless steel 1.4571 + Mounting bush G 1/2 at stainless steel 1.4571 + Immersion length EL and thermowell/neck tube 0 acc. to table + Neck tube length HL = 145 mm + Measuring insert with mineral insulated sheathed cable (bendable) stainless steel...

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SPARE INSERTS AT BENDABLE DESIGN SPECIFICATION: + Measuring insert with mineral insulated sheathed cable (bendable) at stainless steel + Temperature range -100 °C to 600 °C COMPLETE INSTRUMENTS SPECIFICATION OF THE STANDARD DESIGN: + Connection head Type B at light metal with cable gland M 20 x 1,5 (acc. to DIN EN 50446) + Thermowell and neck tube at stainless steel 1.4571 + Mounting bush G 1 at stainless steel 1.4571 + Immersion length EL and thermowell/neck tube 0 acc. to table + Neck tube length HL = 145 mm + Measuring insert with mineral insulated sheathed cable (bendable) stainless steel...

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Thermocouple

Thermocouple

Catalog excerpts

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