100-Ohm Platinum RTD Temperature Sensors

RTDs (short for Resistance Temperature Detectors) are temperature sensing devices that change resistance value as its temperature changes. The most popular RTD is the 100-ohm platinum sensor, used for many years to measure temperature in laboratory and industrial process applications. 100-ohm platinum RTDs (PT100) have a reputation for accuracy, repeatability, and stability.

Most RTD element designs include a length of finely coiled wire wound around a ceramic or glass bobbin. The inherent system is fragile, so it is typically placed inside a sheathed metallic tube to protect from shock and vibration. RTD sensing elements are made from a material with a very predictable and repeatable change in resistance. This predictability and stability is the basis for its widespread application.

The 100-ohm platinum RTD provides accurate temperature readings with reasonable accuracy, excellent stability, and repeatability. They are also significantly immune to generated electrical noise, and as such, they are well suited for temperature measurement in industrial plants, near motors, generators, and high voltage equipment.

There are two 100-ohm platinum RTD standards, the American and the European (known as the DIN or IEC standard), with the IEC standard considered the default for PT100. The IEC751 standard requires the RTD to have an electrical resistance of 100.00 O at 0°C and a TCR (temperature coefficient of resistance) of 0.00385 O/O/°C between 0 and 100°C.

Because 100-ohm platinum RTDs use resistance to measure temperature, the lead wires, connectors, and measuring devices introduce additional resistance. These must be compensated for by configuring the RTD circuit to null out these outside resistances by incorporating a third or fourth lead wire to offset the introduced error.

For more information about 100-ohm platinum RTD temperature sensors, contact Duro-Sense Corporation. Call them at 310-533-6877 or visit their website at https://duro-sense.com.

Temperature Sensors Used for Power Generation

In an electrical generating plant, most temperature measurements are performed with RTDs (resistance temperature detectors) and thermocouples (T/Cs). 

RTD's are sensors that produce a measurable change in electrical resistance, while thermocouples have a change in mV signal in response to temperature change. 

RTD's consist of a thin conductor (nickel, platinum, copper) wrapped around a glass or ceramic bobbin, placed into a protective sheath, and backfilled with an electrically inert material but thermally conductive. 

Power plants use 100-ohm platinum, 100-ohm nickel, 120-ohm nickel, and 10-ohm copper RTDs. Though offering excellent accuracy and long-term reliability, RTDs are vulnerable to mechanical shock and vibration in a generating plant. They are more costly than thermocouples and are generally limited to about 1110 ° F. A very appealing feature for RTDs is their electrical noise immunity, a significant advantage over thermocouples. Finally, inexpensive instrument wire is all that is required to connect the RTD to the measuring instrumentation. 

A thermocouple consists of two wires made of dissimilar alloys, joined at both ends. One junction is coined the "hot junction," the other is the "cold junction" (or reference junction). When the hot junction experiences temperature change, a voltage is produced proportional to the temperature difference between hot and cold junctions. 

T/Cs are made of various alloy combinations and "calibrations" for different temperature ranges. Type J, K and N are the most common thermocouples for power generation applications below 1800 ° F; R and S types are common for applications above 1800 ° F. Besides the evident higher temperature capacity, thermocouples have a quicker response and greater endurance to shock and vibration. However, thermocouples are more susceptible to conducted and radiated electrical noise due to the minute signals generated. Another problem with thermocouples is their deterioration over time when used at high temperatures, hence being less stable than RTDs. One final concern is running an expensive thermocouple extension wire of the same type as the sensor-measuring instrument thermocouple.

Duro-Sense Corporation
310-533-6877
https://duro-sense.com

Temperature Sensors for Aerospace and Space Exploration

Duro-Sense Corporation provides the precision temperature sensors to the aerospace, aviation, and space industries and has a reputation for manufacturing the finest quality temperature sensors available. 

Robert J. Collier Trophy

Duro-Sense engineers bring proven solutions to your most difficult problems. The company has a long history of supplying thermocouples and RTDs to the top manufacturers in the aerospace industry. The Duro-Sense R&D department is staffed with some of the industry's most qualified people, working in the most modern facilities to help advance the state of the art in temperature measurement. 

Duro-Sense products are time-tested and proven to be ultra-reliable, accurate, and of extremely high value. 

Contact Duro-Sense Corp. today with you aerospace or space exploration temperature sensing requirement. Call them at 310-533-6877 or visit their website at https://duro-sense.com.

Engine-Compressor Thermocouples for Offshore Platform Generators

Providing power to a broad range of sophisticated equipment on offshore oil and gas platforms requires a large amount of uninterrupted electricity. Pumps, valve operators, essential communications, turntables, engines, and safety devices are just a subset of the environment of drilling and processing that needs a reliable power source. A large amount of electrical power, not unlike a small town, is required. Electric generators provide comfort heating, cooling, water desalination, food storage, and even waste processing. 

On offshore platforms, conditions are harsh. Equipment and components must be robust to function correctly and decrease the need for regular maintenance. 

Temperature is one of the compressor's most critical measurement parameters and its accuracy can directly affect compressor efficiency. Analysis reveals that errors in temperature calculation account for over 80% of efficiency errors. More aspects of compressor temperature measurement and improved methods of temperature measurement are required.  Thermocouples are used to measure inter-stage gas compressor temperature and outlet gas temperature.  

A specialized temperature sensor known as an 'engine-compressor thermocouple' measures temperature in these applications. These are heavy-duty, specially built temperature sensors that monitor a variety of parameters including exhaust gases and lubricant temperatures. Such sensors are time-tested and designed to withstand the harsh mechanical and environmental conditions of offshore marine conditions. The thermocouple's prime requirement is to be robust enough to withstand a high vibration and corrosive environment and still be accurate and fast responding.

The engine-compressor thermocouple provides oil and gas platform technicians with precise measurements, excellent accuracy, and rapid response times. These thermocouples are also easily checked for calibration, removed, and replaced if necessary.

Duro-Sense Corporation
310-533-6877
https://duro-sense.com

Happy Labor Day from Duro-Sense!

 

Duro-Sense Thermocouple Wire and Thermocouple Extension Wire

Insulated thermocouple wire is single pair wire that can be made into a thermocouple. Thermocouple wire is made from two dissimilar metals conductors that are joined (welded) together at the sensing end. Different metal wires are used for the various types of thermocouple types (J, K, T, E, etc). These dissimilar metals produce a millivolt electrical signal at the cold junction that is proportional to the change in temperature at the sensing end. Thermocouple wire has two grades; standard and Special Limits of Error. Special Limits of Error wire is made of the same metals as standard wire, but uses a higher grade with increased accuracy and higher expense than standard thermocouple wire.

Thermocouple extension wire is a single pair wire that cannot be made into a thermocouple, but is used to carry the signal form a thermocouple to the recorder, controller, or instrument reading the signal. Extension grade wire usually has lower ambient temperature specifications. It is used to carry signal representing the higher temperature seen by the sensing location, but extension wire cannot be generally cannot be exposed to those higher temperatures. Extension wire cannot be used to make a thermocouple, but thermocouple wire can be used as extension wire. Insulation is typically PVC, but other option are available.

For more information about Duro-Sense thermocouple wire, visit their website here.

Duro-Sense is currently having their annual wire sale (while supplies last). Here is a list of inventory that is on sale now. Call 310-533-6877 with questions.

Check Out the Duro-Sense Annual Wire Sale!

Duro-Sense Corporation is a high quality manufacturer of thermocouples, RTD's, and other custom temperature sensing assemblies. Every year, Duro-Sense provides access to their "shorts and overrun" wire inventory for public sale. Offered at very attractive prices, this is perfect quality product in odd lengths or has special design characteristics. You can download the Wire Sale Inventory List from this link. Products are available on a first come, first served basis while supplies last. For more information or to place an order, call 310-533-6877 or email sales@duro-sense.com.

SEE THE DURO-SENSE WIRE INVENTORY LIST HERE