RTD or Thermocouple for Your Temperature Measurement Application?

Temperature Sensor Assembly
Wika

Proper temperature sensor selection is key to getting useful and accurate data for maintaining control of a process. There are two main types of temperature sensors employed for industrial applications, thermocouple and resistance temperature detector (RTD). Each has its own set of features that might make it an advantageous choice for a particular application.

Thermocouples consist of a junction formed with dissimilar conductors. The contact point of the conductors generates a small voltage that is related to the temperature of the junction. There are a number of metals used for the conductors, with different combinations used to produce an array of temperature ranges and accuracy. A defining characteristic of thermocouples is the need to use extension wire of the same type as the junction wires, in order to assure proper function and accuracy.
Here are some generalized thermocouple characteristics.

• Various conductor combinations can provide a wide range of operable temperatures (-200°C to +2300°C).
• Sensor accuracy can deteriorate over time.
• Sensors are comparatively less expensive than RTD.
• Stability of sensor output is not as good as RTD.
• Sensor response is fast due to low mass.
• Assemblies are generally rugged and not prone to damage from vibration and moderate mechanical shock.
• Sensor tip is the measuring point.
• Reference junction is required for correct measurement.
• No external power is required.
• Matching extension wire is needed.
• Sensor design allows for small diameter assemblies.

RTD sensors are comprised of very fine wire from a range of specialty types, coiled within a protective probe. Temperature measurement is accomplished by measuring the resistance in the coil. The resistance will correspond to a known temperature. Some generalized RTD attributes:

• Sensor provides good measurement accuracy, superior to thermocouple.
• Operating temperature range (-200° to +850°C) is less than that of thermocouple.
• Sensor exhibits long term stability.
• Response to process change can be slow.
• Excitation current source is required for operation.
• Copper extension wire can be used to connect sensor to instruments.
• Sensors can exhibit a degree of self-heating error.
• Resistance coil makes assemblies less rugged than thermocouples.
• Cost is comparatively higher

Each industrial process control application will present its own set of challenges regarding vibration, temperature range, required response time, accuracy, and more. Share your process temperature measurement requirements and challenges with a process control instrumentation specialist, combining your process knowledge with their product application expertise to develop the most effective solution.

Installing Heat Tape - Instructional Video

BriskHeat manufactures a broad range of heating equipment and componentry. Their heat tape is routinely applied across many applications involving heating of gases, liquids, and solids. The video included below provides simple and well illustrated guidance for selecting and properly installing heat tape to provide for safety and longevity.

Heat tape is flexible in its application, inexpensive, and easy to use. The video shows the three basic types, along with their application limitations and basic selection criteria. Instruction is provided on how to properly prepare the installation surface. The tools and materials needed for installation are also shown.

Share your process, pipe, and valve heating challenges with application specialists. Combining your process or application knowledge with their product expertise will produce a good match between product and application.

BriskHeat Joins the M.S. Jacobs Lineup

M.S. Jacobs is pleased to announce its new representation agreement with BriskHeat Corporation. The industrial heaters manufactured by BriskHeat complement many of the other quality products handled by M.S. Jacobs.

BriskHeat manufactures a broad line of heaters, insulators, and controls for almost every industrial application.

• Cloth Heating Jackets and Insulators
• Heating Tapes
• Heating Cable
• Laboratory Heaters and Equipment
• Etched Foil Heaters
• Silicone Rubber Heaters
• Drum Heaters
• Tote Tank / IBC Heaters
• Gas Cylinder Warmers
• Enclosure Heaters
• Hopper Heating Systems
• Personal Comfort Heating Solutions
• Hazardous-Area Heaters
• Plastic Bending Heaters
• Resistance Wire
• Temperature Controllers
• Temperature Controllers for Outdoor Use
• Insulators
• Heaters and Controls with Canadian Approvals
• Composite Curing Solutions

Share your industrial and process heating requirements with the product specialists at M.S. Jacobs & Associates. Combining your process expertise with their product knowledge will produce effective solutions.

Analynk Wireless For Process Control Connectivity

Analynk Wireless is an innovative designer and supplier of wireless instrumentation for the process control industry. Their instruments and equipment have been successfully implemented in numerous applications for temperature measurements, 4-20 mA bridges, discrete inputs/outputs, pulse inputs, lighting and pump controls. Analynk's products are used in both hazardous and non-hazardous locations. Watch the short video for a animated overview of Analynk products and capabilities.

Share your wireless connectivity challenges with product specialists. Combining your process knowledge with their expertise with produce effective solutions.

Gentherm GPT Provides Turnkey Remote Power

Thermoelectric Generators, part of  a remote power system

There are many industrial operations and processes that operate outside the confines of a factory building. Some even operate outside the confines of what most consider "civilization". Sometimes, if you need electric power, you have to generate your own.

Gentherm Global Power Technologies specializes in providing equipment and complete systems to produce electric power at remote sites. Their signature product line is the thermoelectric generator, or TEG. It uses a solid state thermopile and gas fired heaters to generate DC current. The technology is especially useful at sites where gas is naturally present. As a turnkey systems provider, Gentherm GPT will design complete systems, customized and configured for each particular installation. Here is an example of a fuel gas conditioning system provided for an offshore oil rig, designed specifically to address an issue at the site.

GPT's power generation products are well suited for a wide array of applications.

• Oil, gas, product, or water pipelines
• Well sites
• Offshore platforms
• Telecommunication sites
• Well monitoring and automation
• Security and surveillance
• Navigational aids
• Communication systems

For your remote power generation projects, consider a thermoelectric generator. Contact a product specialist and share your requirements. Combining your project knowledge with their product expertise will produce an effective solution.

Advantages of Thermoelectric Generators from MSJacobs-Cali

Don't Ignore the Simple Solution for Flow Measurement

Flow indicator also permits visual
inspection of fluid
Courtesy ERDCO Engineering Corp.

For process control and commercial or industrial applications, there are numerous methods of flow measurement from which to choose. Technologies range from very simple applications of physical principles to deployment of very specialized electronics and sensors. The available range of accuracy, response, and cost is quite broad, with a general expectation that higher cost will deliver better performance and accuracy.

Making the best instrument selection for a flow measurement application should include an assessment of what the operators really need in order to safely and effectively run the process or perform the task related to the measurement of fluid flow. Installing instrumentation with capabilities far beyond what is required is almost certainly a waste of financial resources, but may also have an unexpected impact on operators. Through the generation of data that, while accurate, does not provide any actionable information about process condition, operators can be misled, similar to the occurrence of a false or nuisance alarm. Some applications call for high accuracy, some do not. Define your informational needs and select instruments that will meet those needs.

There is a large array of applications that can be satisfied with simpler, less costly measurement technology. These devices often employ turbines or vanes to produce an indication of flow rate. Incorporated into some of the instruments is a means to visually observe the flowing liquid to verify color and clarity. Simple devices sometimes are intended only to indicate the presence of fluid flow, and whether the flow rate is high or low. Configurations are available that allow insertion into lines under pressure (hot tap) through a full port ball valve. Other variants with combinations of features and capabilities abound.

The selection range is enormous, so define your minimum needs first, then search for a compatible product. Your search can be enhanced by contacting an instrumentation specialist. Combining your process expertise with their broad product knowledge will produce effective solutions.

Hayward Announces New Electric Valve Actuator Line

New HRS Series Electric Valve Actuators
Courtesy Hayward Flow Control

Hayward Flow Control issued a press release in early June announcing the introduction of its HRS Series of quarter turn electric valve actuators. The actuators complement the company's companion lines of fluid process products, including thermoplastic valves, strainers, filters, controls, bulkhead fittings and tank accessories, and corrosion resistant pumps.

The new HRS line provides practical features and benefits to users.

• Product torque range from 300 in-lb to 177,000 in-lb
• Aluminum housing with powder coat
• Double square drive socket, ISO5211 compliant mounting
• On/Off or Proportional Control  with 2-10 vdc or 4-20 ma inputs and outputs
• NEMA 4/4X/IP67 enclosure rating
• Range of available AC and DC voltages
• Integrated local control station
• Visual position indicators
• CSA Certified, UL439
• Two Year Warranty

There are numerous variants that can be configured using base models and available options. For more detail, contact a product specialist. Share your fluid process control challenges with them, combining your process knowledge with their product application expertise to produce the most effective solutions.

Electric valve actuators for process control from MSJacobs-Cali