Themocouple

A thermocouple is a sensor that measures temperature. It consists of two different types of metals, joined together at one end. When the junction of the two metals is heated or cooled, a voltage is created that can be correlated back to the temperature. Thermocouple alloys are commonly available as wire.
Thermocouples are widely used in science and industry; applications include temperature measurement for kilns, gas turbine exhaust, diesel engines, and other industrial processes. Thermocouples are also used in homes, offices and businesses as the temperature sensors in thermostats, and also as flame sensors in safety devices for gas-powered major appliances.

Temperature range

Category

Code

Temperature Range

Ni-Cr-Si----Ni-Si-Mg

N

0°C ~ 1200°C

Ni-Cr----Ni-Si

K

0°C ~ 1200°C

Ni-Cr----Cu-Ni

E

0°C ~ 800°C

Fe----Cu-Ni

J

0°C ~ 750°C

Cu----Cu-Ni

T

0°C ~ 350°C

Pt-Rh13----Pt

R

0°C ~ 1600°C

Pt-Rh10----Pt

S

0°C ~ 1600°C

Pt-Rh30----Pt-Rh6

B

0°C~ 1700°C

Measuring junction

 

Type

Features

Outer diameter of universal sleeve

Single couples

Double couples

1

Ungrounded

1 It responses more slowly than that of the case-connected type.
2 Long service life
3 Resistance to electric interference

Φ0.5 ~Φ8.0

Φ3.0 ~Φ8.0

2

Grounded

1 Rapid response
2 Not suitable in case with interference

Φ0.25 ~Φ8.0

Φ3.0 ~Φ8.0

3

Exposed

1 Rapid response
2 Suitable to measure the temperature of gas, such as engine exhaust
3Poor mechanical strength in contact with other measuring structures

Φ0.5 ~Φ8.0

Φ3.0 ~Φ8.0

Thermocouple and RTD

Hand-Held Thermocouple

The two most common ways of measuring industrial temperatures are with resistance temperature detectors (RTDs) and thermocouples. Choice between them is usually determined by four factors. Temperature: If process temperatures are between −200 to 500 °C (−328.0 to 932 °F), an industrial RTD is the preferred option. Thermocouples have a range of −180 to 2,320 °C (−292.0 to 4,210 °F), so for temperatures above 500 °C (932 °F) they are the only contact temperature measurement device.
Response time: If the process requires a very fast response to temperature changes—fractions of a second as opposed to seconds (e.g. 2.5 to 10 s)—then a thermocouple is the best choice. Time response is measured by immersing the sensor in water moving at 1 m/s (3 ft/s) with a 63.2% step change.
Size: Class A RTD sheath is 3.175 to 6.35 mm (0.1250 to 0.250 in) in diameter; sheath diameters for thermocouples can be less than 1.6 mm (0.063 in).
Accuracy and stability requirements: If a tolerance of 2 °C is acceptable and the highest level of repeatability is not required, a thermocouple will serve. RTDs are capable of higher accuracy and can maintain stability for many years, while thermocouples can drift within the first few hours of use.

  • THERMOCOUPLE & RTD WIRE

    Insulation material: fiberglass, PTFE, PVC, silicone
    Thermocouple Type: K,J,T,E,,N,R,S,B
    RTD Type: Cu50,Cu100,Pt100
    Size: from AWG 8 to AWG 40

  • THERMOCOUPLE & RTD CONNECTOR

    Used for thermocouple and RTD circuits.

  • THERMOCOUPLE & RTD HEAD

    Body Material: Aluminum,SS304,SS316
    Material of terminal block: ceramic or Bakelite
    Form of terminal block:2P,3P,4P,6P