From RS Pro a range of Type J and Type K thermocouple temperature sensors conforming to IEC 584 standards with a grounded hot junction for a fast response time. These durable type J and Type K thermocouples have a 2 m long cable with flexible glass fibre insulation and a rugged stainless steel braid. The probe has a stainless steel sheath which is surrounded by an adjustable spring loaded bayonet connector which enables the thermocouple to fitted securely

A thermocouple is a sensor used to measure temperature in a range of different processes and consists of two wire legs made from different metals joined together at their two ends to form two junctions. The hot, or measuring junction is connected to the body whose temperature is going to be measured. The cold junction or reference junction is connected to a body of known temperature. When the measuring junction is placed on something hot a voltage or potential difference between this and the reference junction occurs. This voltage can then be converted into a temperature measurement using thermocouple reference tables. This process is also known as the Seebeck Effect

In a welded grounded junction the two thermocouple wires and sheath are welded together to form one junction at the probe tip. These thermocouples have a fast response time because all the thermocouple is making contact with the sheath allowing the heat to transfer easily.

The probes of these thermocouple sensors have an adjustable screw threaded spring 175 mm long with a slotted bayonet fixing cap. The bayonet cap screws along this spring and allows the immersion length of the thermocouple probe to be adjusted. Once in place the bayonet cap is secured to a bayonet adapter (which must be purchased separately - see stock number 621-2243) allowing the thermocouple to be firmly held in place within the recess. The advantages of this method of fixing are;

• Immersion depth can be adjusted easily
• Secure connection within machine recess
• Positive pressure at the thermocouple tip and full immersion in process

• Conforms to IEC 584 Standards
• Adjustable spring loaded bayonet connection
• Grounded hot junction for fast response time
• Rugged glass fibre insulated cable with stainless steel overbraid
• Stainless steel probe sheath for resistance to corrosion
Standard tolerence TC "K" class1:
‐40°C < t°< 375°C = ± 1.5°C
375°C < t°< 1000°C= ±0.004. [t]

hese J-Type and K-Type thermocouple temperature sensors are designed for direct installation into the process. The bayonet fitting makes them suited for applications where the thermocouple sensor tip is fitted directly into a drilled hole or recess in machinery. Typical applications include the plastics and rubber industry where they are used in extrusion and moulding machinery