Thermocouple Temperature Sensors

Thermocouple Temperature Sensors

Dwyer Instruments, Inc. offers many temperature measuring products that use thermocouples as the sensing element, and also manufactures a wide variety of thermocouples.

A thermocouple is made of two dissimilar metal wires, which product a voltage as a function of temperature change. Thermocouples are based on the Seebeck effect, which is a thermoelectric effect where continuous current is created in a circuit where the junctions of two dissimilar conductive materials are kept at different temperatures. The measuring end of the sensor is created by joining the two metal wires together into what is called the hot or measuring junction. Continue reading “Thermocouple Temperature Sensors”

RTD Temperature Sensors

Temperature Sensors

Dwyer Instruments, Inc. offers a wide variety of temperature sensors that use RTDs as the sensing element.

RTDs are based on the principal that the electrical resistance of the wire is a function of the temperature, with the resistance increasing as temperature increases. The resistance varies nearly linearly with temperature per the Callendar Van-Dusen equation. The wire used in RTDs as the sensing element is usually constructed of platinum, copper, or nickel.  Platinum is the best material for this element, as it has the widest useful temperature range of these materials. It also has a very repeatable and linear temperature to resistance correlation. Continue reading “RTD Temperature Sensors”

Condensation Issues in Instrumentation Enclosures and How to Prevent Them

Many Dwyer Instruments, Inc. electrical products are connected to the receiver and power supply with wires that are run through electrical conduits. Often, the conduit passes through multiple ambient temperature zones in the building or plant installation.

These temperature changes can cause water vapor condensation inside the conduit.

If this condensation flows into or forms in the instrument, it can create electrical shorts or lead to corrosion that can create an instrument failure. Continue reading “Condensation Issues in Instrumentation Enclosures and How to Prevent Them”

Bimetal Thermometers

Dwyer Instruments, Inc. offers many temperature measuring products that use bimetal sensors as the sensing element.

Bimetal Thermometers measure temperature based on the differences in thermal expansion properties of metals. Pieces of metals with different thermal expansion coefficients are attached to each other in an assembly.

As the temperature applied to the metal sensor assembly increases, the metal strip with the larger temperature coefficient of expansion expands more.  Continue reading “Bimetal Thermometers”