ADVERTORIALS
UNDERSTANDING THE THERMAL LOOP H
eat treatment processes are a crucial component of many manufacturing processes, but precise control of temperature requires more than just heating control. This is where the thermal loop comes into play. Thermal loop solutions have become increasingly popular for achieving improved temperature control and consistent outcomes, but what exactly does the thermal loop mean? In this article, Andy Selvy, chief system designer at industrial technology company Watlow, offers his insight.
A thermal loop is a system designed to precisely control the temperature of an object, fluid or gas. It comprises a closed loop system with vital components, such
as an electrical power supply, power controller, heating element, temperature sensor and process controller. The electrical power supply furnishes the necessary energy for heating, while the power controller modulates the power output to the heating element. Subsequently, the heating element raises the material’s temperature, and the temperature sensor gauges the temperature. Ultimately, the process controller fine-tunes the power output to sustain the desired temperature for the specified duration, ensuring improved temperature control and consistent results. In some cases, a single component can play multiple roles.
For example, with high temperature coefficient of resistance (TCR) materials, it’s possible for a single component to act as both a heater and a
sensor, which cuts down on the total number of components and wires needed in the system. Altogether, these parts create a system known as a thermal loop that can maintain process temperatures automatically through time. How does it work?
A home thermostat is a simple, everyday example of closed loop temperature control. You can adjust the temperature of the range, but this must be done manually. The system does not detect temperature or adjust itself — it only provides heat. A homeowner could set a thermostat and leave it for months, never having to actively direct or control the system, but the system would maintain the same temperature range during that time. They work well for heating our homes, but certainly come with limitations with regards to temperature control.
The limitations seen with traditional thermostats provide a good parallel for understanding the challenges that industries face when it comes to process heating and thermal control. For instance, heaters are typically controlled by consistently monitoring the power being provided. If power can be controlled in a more precise manner, then heaters can be better controlled and heater life can be extended. This often requires going beyond simple “power on or off” switches and introducing advanced forms of power control. Temperature sensing needs to be done in multiple zones, not just one place. For example, a surface for creating semiconductor chips might need to be divided into several zones so that temperature uniformity can be achieved at each point — much like having a thermostat in every room of your house.
Watlow +43 6244 201 29-0
www.watlow.com
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EKA associates are proud to announce a second version of Pageant, their intrinsically safe Operator Display. Thanks to a certified impact resistant front panel, the new display can be mounted in an Ex e or Ex t enclosure without invalidating the certification of the enclosure. This allows the new BA3102 Display, which retains all of the original state of the art features, to be safely installed in the same cubicle or enclosure as other Zone 1 or 2 equipment. The original and new models simplify the design and reduce the cost of providing an Operator Display, Modbus Remote Display, or a PLC in a hazardous area. Multiple variables can be displayed simultaneously,
and eight touch buttons with tricolour LED annunciators accept operator inputs. Intrinsic safety Ex ia protection provides maximum safety and allows installation in almost any flammable gas or combustible dust atmosphere in any Zone.
Featuring a 7 inch backlit trans-reflective display which can be read in all lighting conditions, Pageant and each of its plug-in I/O modules, have separate apparatus certificates allowing installation in Zones 0, 1, 2, 20, 21 and 22. The IECEx, ATEX and UKCA certifications permit any combination of plug-in modules to be fitted to the display without the need for additional certification. Plug-in input and output modules for interfacing 4/20mA currents, switch contacts,
Instrumentation June 2024
proximity detectors and pulse sources are available.
Pageant employs industry standard CODESYS® runtime software which complies with IEC 61131. The software includes a wealth of features and function blocks and is supplied with a lifetime licence. CODESYS runtime software is an industry standard already installed in more than 1,500 different products worldwide. It is supported by extensive documentation, including video presentations, and will already be familiar to many users. The display, eight programmable touch buttons and LED annunciators are mounted behind a 4mm thick toughened
glass, or a scratch resistant polycarbonate window in the 316 stainless steel front panel. The front provides IP66 protection, is totally flat and easy to clean, making these Operator Displays ideal for petrochemical, pharmaceutical and distilling applications. Both Operator Displays are lightweight and dissipate less than 5W limiting enclosure heating.
BEKA +44 (0) 1462 438301
https://www.beka.co.uk/pageant
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