Sensors

• CF, KF and custom flanged thermocouples for Vacuum

• Helium Leak certified

• Multi point
• Twisted Shielded Hi-Isolation

• Custom bends to tight tolerance

• Hyper Thermally conductive Tip
• 125 - .188 O.D.

• 1.5 X Faster than standard RTD
• Class A Din 385 Curve

• Useable under severe conditions
• Withstands temperatures up to metal melting point
• Withstands corrosive conditions limited only by the choice of sheath material
• Can be formed to a minimum radius of twice the sheath diameter without loss of integrity
• Can be welded, brazed or soldered to other metals when proper techniques are used
• Can be formed to a minimum radius of twice the sheath diameter without loss of integrity
• Available in a wide variety of diameters from .010” to .500”
• Available in standard and special limits of error
• Can withstand external pressures up to 50,000 psi
• Multiple element cable is available

In order to keep the two thermocouple wires apart from each thus causing a false junction, Wire is insulated with different types of insulation designed to work well with the particular application. PVC, Teflon, Polyamide, fiberglass and ceramic are the most common types of insulation used in thermocouples.

PVC, or Polyvinyl Chloride is typically used in lower temperature applications and also as extension or hookup wire to connect instruments together. Since its melting point is 221 degrees F, it cannot be used in high temperature applications. Teflon is the most common insulation used to make thermocouples. It is rated up to 550 degrees F° and has excellent chemical and abrasion resistive properties. Fiberglass is used in higher temperature applications and is rated up to 1000 degrees F°. It does not resist chemicals and is not good for abrasion. Wires can be braided with stainless steel and other insulation to make them more durable. Soft wire thermocouples can be crimped or potted in protection tubes made of ceramic or stainless as well as other sheath materials. Ceramics are used for bare wire and Nobel metal thermocouples.

This sensor has a more limited temperature range. Typically 600C is max, but due to epoxies and wire typically used, 500°F is standard. This is also a more accurate sensor than a thermocouple. RTDs come in different packages. The most common are thin film and Ceramic wire wound. Therm-x has thin film in a variety of sizes and tolerances. Wire wounds elements are available in special tolerances referred to as Bands 1-5. These are for application where the customer is looking for a product with higher accuracy than the industry standard.

Industry standards are defined by Curve, Resistance value and Class. The standard that we offer is the DIN 385 curve with 100 ohm resistance and Class B. There are other less common curves available. These curves refer to the resistance values read at different temperatures. These are defined in Temperature to resistance tables. The Class is typically either class A or B. This refers to the accuracy of the RTD. The resistance value is the resistance that the sensor reads at 0°C.

Thermistors are also a resistance temperature detector. They typically have a much higher resistance value such as 10K ohm at 25°C. Thermistors are also unusual in that they typically have a negative temperature coefficient. While RTDs resistance increases as the temperature rises, thermistors resistance decreases as the temperature rises. Thermistors are semiconductors and are known for their accuracy and repeatability. They are not typically used in industrial temperature applications because they are not very stable at high temperatures over 150°C.