Cessna Citation CJ4: Temperature Probes

Thermocouple probes utilize the reaction between two dissimilar metals to produce a voltage that changes as temperature changes. A thermistor is a resistive device with a change in temperature. In general, thermocouples offer a better temperature range and quicker response time than thermistors, which are typically more accurate.

Each thermocouple uses different metals and, therefore, has different characteristics. Here are some general guidelines:

• K-Type: Wide temperature range used in many digital thermometers. Identified by a yellow connector.
• T-Type: Narrower temperature range than J-type but more accurate than K and J types, which are used in digital thermometers. Identified by a blue connector.
• J-Type: Narrower temperature range than the K-type used in analog and digital thermometers. Identified by a black connector.

No. Since each thermocouple type uses different metals in its construction, each has different output characteristics. Using a J-type thermocouple in a K-type thermometer will cause measurements to be very inaccurate.

• Sub-Mini: This is an industry-standard connector type, allowing TPI probes to be used in any thermocouple thermometer with this type of connector. Sub-mini connectors are quick and easy to use – simply push in and out. A wide variety of economical probes are available with sub-mini connectors, enhancing the versatility and affordability of the temperature tester.

• Lumberg: This connector uses a screw collar to attach to the thermometer and is the most secure connection available. Lumberg connectors are designed for the rigors of food processing environments. Advantages include:

  • Strong connection: The stainless steel collar holds and protects the connection. The probe will not pull out of the instrument without unscrewing the collar.
  • Waterproof stainless steel will not rust and is ideal for wet, humid conditions.
  • Lumberg connectors are manufactured using ISO 9000 quality control guidelines.

The type of probe you use depends on your specific application. Here are some general guidelines for different types of probes:

• Penetration (F): This general-purpose probe is used for penetration and immersion. While it can be used for air, it is much slower than a typical air probe.
• Contact (C): Contact probes are used to measure surface temperatures. Penetration probes, with the exception of the chisel tip, are not capable of measuring surface temperatures.
• Air (G): Air probes measure the air or gas temperatures. They respond significantly faster than penetration or contact probes in air.

For each probe, you will need to select the tip type that best suits your application.