Temperature control @ plants

By Staff Report December 2, 2024 2:49 pm IST

Any process of change in nature involves temperature change, be it water ice vapour or a metal plate turning into a vehicle. Manufacturing is the transition of raw material to a finished good via processing. All the steps require temperature and a measured temperature for the desired quality. Thus, the measuring instruments have to be selected aptly.

Day in and day out, the entire manufacturing process of any good happens either by cooling the raw material, heating it or vaporising it. This transition requires precise temperature calibration, which is where the measurement devices are used. They are just as important in any industry as other tools.

Temperature control is crucial in various industries, such as oil refineries, cement, pharmaceuticals, and HVAC systems. Inadequate temperature control can lead to off-spec products, heavy production losses, and waste. In the cement industry, kiln temperature is important for the final product, while maintaining the temperature in pharmaceuticals is important. Inadequate temperature control can result in monetary loss and product waste in manufacturing facilities or processes. 

Amit Gupta, Head of Manufacturing and Pharma and Food Safety Professional, says, “Temperature monitoring and control are critical to the manufacturing process as effective temperature management greatly influences quality, safety and operational efficiency throughout the manufacturing process. Generally, temperature monitoring and control stands out as a PRP/oPRP (Prerequisite Program/ Operational Prerequisite Program) or even CCP (Critical Control Point) control in various organisations depending upon the process type.”

Altered temperature conditions during the production process can significantly affect the physical attributes of a product, including its appearance and texture. These changes may lead to a deterioration of the organoleptic profile, such as developing off-tastes like bitterness or an unpleasant aftertaste. Additionally, temperature variations can impact the storage and shelf life of the product, reducing its stability. Process efficiency values, such as sigma levels (cp, cpk), may deviate, further affecting the product’s quality. Furthermore, products may experience deterioration during intermittent or prolonged storage, such as compacting and caking in powders or separation and phase reversal in liquids.

High-precision industries like pharmaceuticals and aerospace rely on system redundancy to overcome single-element failures; sometimes, TMR or triple modular redundancy is used to compromise any failure. However, apart from all these precautions, the most important aspect is selecting the right sensing element, for example, a four-wire RTD for accurate readings rather than a three-wire RTD for normal systems.

Integration

Shahid Ahmed Kazmi, Consultant, shares that integrating temperature measurement into a manufacturing system involves a three-tier process. The first step involves the appropriate element and ensuring the whole process philosophy is considered. The second step consists of implementing and installing the selected equipment according to the prescribed standards and following them with reliability and accuracy. The third step involves integrated systems that must effectively handle loop equilibrium, as overloaded systems may delay response time, and selecting an inappropriate controller can impede the entire control function. While engineering for any parameter. When engineering any parameter, these three steps must be followed to achieve a reliable control strategy.

Temperature Measurement standards

The temperature measurement in various industries needs a universally accepted standard because selecting the right type of temperature element involves considering loop configuration, integrated systems, cost constraints, and plant control philosophy due to various factors. Some industries require precision with RTD or thermistors, while general temperature measurement uses thermocouples based on their ranges and process requirements.

Calibration and traceability

Calibration is the process of comparing a measurement’s accuracy against test equipment. It ensures the instrument works within its tolerable range and corrects errors. To ensure the reliability of equipment, it is periodically calibrated using a more precise test equipment master calibrator, which must have a traceable connection to the primary standard. Standards like NIST, ISO/IEC 17025, or regional standards must be followed to ensure accurate and precise measurements and test equipment. 

Non-contact temperature measurement

Change is the only constant in the world, and noncontact temperature measurement technologies make it easier to compare devices and points; accuracy depends on the instruments used. Non-contact types are safe to use at high temperatures and ensure the safety of the personnel not exposed to these temperature levels. They are also used in normal processes with lower temperatures due to convenience. 

Prashant Sinha, Marketing Head, WIKA India, shares, “Non-contact technologies like infrared sensors and thermal imaging are revolutionising the monitoring and control of temperature for manufacturers. Technologies improve safety by allowing individuals to measure temperatures in hazardous or hard-to-reach areas without direct exposure, minimising risks due to high heat, dangerous substances, or confined spaces.”

Non-contact measurement systems offer fast, precise temperature data, allowing manufacturers to detect thermal anomalies early. This reduces energy losses and optimises system performance, improving energy efficiency and sustainability initiatives and reducing operational costs.

A comprehensive range of non-contact temperature measuring solutions, from infrared sensors to precision and thermal imaging systems, is now available in the industry, and the field is constantly evolving. Where direct measurement at proximity may pose risks due to exposure to extreme temperatures or hazardous conditions, infrared and thermal imaging technologies take over temperature measurement tasks and improve operators’ safety. 

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Amit Gupta, Head of Manufacturing and Pharma and Food Safety Professional

Temperature monitoring and control are critical to manufacturing, as effective temperature management greatly influences quality, safety, and operational efficiency.

Prashant Sinha, Marketing Head, WIKA India

Inadequate temperature control equipment can compromise product quality, leading to defective equipment, unplanned downtime, costly repairs, and process inefficiencies. Investing in high-quality temperature measurement solutions is important to address these challenges.  

Shahid Ahmed Kazmi, Consultant

To integrate temperature measurement into manufacturing processes, a three-tier process is necessary: selecting the appropriate element, implementing and installing selected equipment according to prescribed standards, and engineering integrated systems that effectively handle loop equilibrium.