Wire-wound and Thin Film Resistance Temperature Detectors

The wire-wound platinum resistance thermometer was patented in 1924 and has since become the most popular device for measuring laboratory and industrial process temperatures. RTDs provide high accuracy, long-term stability, repeatability, and integration with electronic controls. As the temperature rises, so does electrical resistance in a very predictable manner. PRTs measure all sorts of processes, from industry to laboratory work. Additionally, the platinum resistance sensor has a linear resistance vs. temperature relationship over a wide operating range of -196°C to 850°C. 

Wire-wound and thin film sensing elements are the two most common forms of RTD sensing elements. Wire-wound sensing components apply in applications requiring high accuracy and long-term stability. The RTD sensor utilizes platinum wire wrapped around a ceramic core and offers various housings designed to give the optimum heat transfer and contact with the process, regardless of whether it is gas, liquid, or solid.

The thin film RTD sensor style is made by depositing a thin layer of platinum on a ceramic plate, then trimming a path with a laser or other techniques to create a narrow ribbon of platinum with a resistance of 100 ohms at 0°C. After that, the leads are joined and protected with glass. As a result, the sensor is relatively small and available in rectangular shapes in various sizes. They are inexpensive and, if properly packaged, can last for years. Long-term stability and repeatability are not as excellent as with wire wound sensors. 

Each sensor type for industrial applications meets the specifications of ASTM 1137 or IEC 60751. The specifications include an ice point (0°C) resistance and a temperature coefficient. The ice point resistance is calculated in a container using an ice bath made of ice and water. There is a tolerance called "interchangeability" associated with this measurement. Various interchangeability bands have label assignations such as A, B, or C, with A being the strictest and C being less tight.

The temperature coefficient of resistance, or TCR, is the amount of resistance change per degree Celsius change in temperature. The TCR of an industrial grade PRT is 0.00385 ohms/ohm/°C. In other words,  there is an average of 0.385 ohms of resistance per degree C of temperature change between 0°C and 100°C. The coefficients used for lab standards are 0.003925 and 0.003902, but the more widely used standard is now 0.00385 for industrial applications. For an accurate reading, you need to match the temperature coefficient and resistance of your PRT with the input requirements of the instrumentation you are using. Not doing this will result in a significant error.

For expert guidance specifying or applying RTD's in your application, contact:

Duro-Sense Corporation
310-533-6877
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Industrial Uses of Resistance Temperature Detectors (RTDs) Explained

Introduction: What is an RTD?

RTDs are sensors that measure the temperature of a material and provide an indication of its resistance to thermal changes.

An RTD is a sensor that measures the temperature of a material and provides an indication of its resistance to thermal changes. RTDs can be manufactured as either a wire or as a thin film on silicon.

The first RTD was developed in 1887 by German inventor Hermann von Helmholtz.

RTDs are typically used in industrial applications such as power plants, refineries, paper mills, and steel mills where they monitor temperatures of process fluids, gases, or equipment surfaces.

RTDs have also been used for years in home appliances like ovens and furnaces to control the temperature inside them.

What is a Typical Industrial Use of RTDs?

RTDs are used in industrial settings to measure the temperature of liquids and gases. This is done by measuring the resistance of a metal element which changes with temperature. RTDs have many applications in industry, such as controlling the temperature of devices, monitoring equipment, and testing for leaks.

Industrial use of RTDs can be found in a wide range of industries. For example, they are used to monitor the temperature of food processing plants and oil refineries. They are also used for quality control purposes in semiconductor manufacturing plants and petrochemical factories.

Other Industrial Uses of Resistance Temperature Detectors

Industrial use of RTDs is extremely common in the manufacturing industry. They are used in industrial processes to measure and control temperature, as well as to detect hot spots and cool spots.

RTDs are also used in many engineering applications such as process control, instrumentation, and automation for a variety of purposes.

Duro-Sense Corporation
310-533-6877
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Industry Leading Delivery Times for Thermocouples and RTDs

Customers dislike having to wait. Customer happiness and loyalty are directly related to how soon items are delivered. 

Lead time is a critical component of any effective supply chain. It is vital to a company's success to reduce lead times as much as feasible. Production lead time may be a significant factor in your company's success. Whether it's a poor movie or a dull and tiresome speech, shorter is usually better. Selecting the correct manufacturer is critical when determining the lead time.

Duro-Sense has over four decades of manufacturing experience and has developed essential solutions for reducing lead times without sacrificing quality. Allow us to show you.

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Noble Metal Thermocouples

Two categories of thermocouples are base metal and noble metal. Base metal thermocouples are types E, J, K, T, and N and use inexpensive metals such as nickel, copper, and iron. Noble metal thermocouples B, R, and S are platinum-based, tolerate higher temperatures, and provide greater accuracy than base metal thermocouples. 

A typical application for noble metal thermocouples would include jet engines, rocket engines, turbines, exhaust gas sensing, glass manufacturing, heat treating, laboratory research, nuclear environments, power stations, and vacuum furnaces.

Noble metal thermocouples have widespread applications involving high temperatures in oxidizing or inert environments but require a ceramic protective tube. These sensors are often brittle, and their use in reducing atmospheres or metallic vapor-containing environments is inadvisable. 

Insulators and protective tubes come in a variety of materials and forms. Typically, Alumina and Mullite. Mullite has excellent thermal shock immunity but low mechanical shock resistance. Alumina has good thermal and mechanical shock resistance and is resistant to gases up to 3,200°F.

In the harshest and most demanding conditions, noble metal thermocouples selection criteria include the temperature operating range, ambient atmospheric or media, the size and form, precision, and response time. For more information, or for assistance selecting the right noble metal thermocouple, contact:

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

Custom Temperature Sensor Manufacturing

Build-to-order components, one-offs, short production runs, and customization are all examples of the types of temperature sensor production that fall under the umbrella of "custom temperature sensor production." Additionally, This term refers to the design, engineering, and manufacturing process based on the specific requirements of a customer. It is pointless to have a concept for a product if you cannot manufacture it. To produce your product effectively, you need to have a solid grasp of the design, the materials, the application, and the budget. 

On the other hand, there are a lot of unknowns, which may both push up costs and cause confusion. There is often a knowledge gap between the design and engineering, the materials and applications, and the manufacturing and installation phases of a project. We can add a knowledge layer that fills in these essential gaps because of the unique combination of design, application engineering, product experience, and collaboration that we bring to the table at Duro-Sense. We can get more value to any project by making it more straightforward for engineers, designers, manufacturers, and customers to interact with one another and collaborate on accomplishing project goals. Call Duro-Sense with your next custom temperature sensor application.

Duro-Sense 100 OHM Platinum RTD Temperature Sensors

RTDs (Resistance Temperature Detectors) are temperature detecting devices that vary their resistance value when surrounding temperature changes. RTD sensing elements use well-known materials that change resistance in a predictable and repeatable manner. Their popularity and general use are outcomes of the RTD's predictability and stability. 

The most common type and material of RTD is the 100-ohm platinum sensor. Its use is ubiquitous in the laboratory and industrial process applications going back many decades. The precision, reproducibility, and stability of 100-ohm platinum RTDs (PT100) are well known. 

For the most part, resistance temperature detectors (RTDs) fall into two main categories. Thin-film elements are one form of RTD, and wire-wound elements are the other. Each type provides advantages in certain situations and purposes. The more common design, wire-wound, is a length of tightly coiled wire wrapped around a ceramic or glass bobbin. Because the wire and wrapping are delicate, it is usually enclosed in an encased metallic tube to protect them from stress and vibration. 

The 100-ohm platinum RTD provides accurate temperature readings with excellent stability and repeatability. They are also very resistant to electrical noise, making them ideal for temperature monitoring in industrial facilities near motors, generators, and high voltage equipment. 

The American and European (known as the DIN or IEC standard) 100-ohm platinum RTD standards are the same, with the IEC standard considered the default for PT100. According to the IEC751 standard, the RTD must have:

•  The electrical resistance of 100.00 O at 0°C 
• A TCR (temperature coefficient of resistance) of 0.00385 O/O/°C between 0 and 100°C. 

Because resistance is used to measure temperature in 100-ohm platinum RTDs, the lead wires, connections, and measurement devices contribute extra resistance, requiring external compensation to offset the error. A solution is found by inserting a third or fourth lead wire inversely proportional to the external resistances.

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