When choosing an inline viscometer, it’s important to understand the differences between off-line and in-line measurements. Off-line measurements, often performed with bench-top viscometers, involve testing samples under controlled conditions such as temperature, shear history, and shear rate. In contrast, inline viscometers measure viscosity continuously within the process stream, directly under operating conditions. Laboratory measurements tend to prioritise scientific accuracy, whereas inline control focuses on generating stable, repeatable signals for consistent operation.
This means there's a lot to think about when it comes to choosing the right viscometer. The right instrument for inline measurement should be optimised for use in the process and deliver a reliable, repeatable signal you can trust, whilst providing many years of trouble-free operation. All with minimal maintenance and downtime.
Below we've compiled a list of the key features to look for in a process viscometer:
1. Performance
Look for a viscometer that offers high measurement accuracy and reproducibility to ensure precise and reliable viscosity readings. Consider the viscometer's repeatability, resolution, and sensitivity to variations in viscosity and make sure this aligns with your requirements.
2. Viscosity Range
Evaluate the viscometer's capability to measure viscosity across a wide range, even down to zero. Often this can reveal a lot about the stability of the measurement. Consider whether the instrument can handle both low and high viscosity fluids to meet your specific application needs.
3. Installation and Maintenance
Assess the ease of installation and ongoing maintenance requirements. Look for a viscometer that can be easily integrated into your existing system or process without costly site alterations. Consider factors such as sensor size, mounting options, and accessibility for cleaning and maintenance.
4. Temperature and Pressure Sensitivity
Evaluate the viscometer's ability to provide stable, repeatable measurements under varying temperature and pressure conditions. Nothing effects viscosity more than temperature, so it's essential to choose a viscometer that can track this relationship reliably, even at extreme levels.
5. Reliability and Durability
Is the instrument reliable and durable? Consider factors such as the construction, quality of materials, and the manufacturer's reputation for producing robust and long-lasting instruments.
6. Calibration and Validation
Look for instruments that offer traceable calibration methods, as well as validation procedures that ensure reliable and repeatable measurements. Ask the manufacturer to provide evidence of this procedure if required.
7. Cost of ownership
Consider the overall cost and lifetime of the viscometer. A lower entry price often does not mean lower cost of ownership, particularly if costly site alterations are required to accommodate the installation. Factoring in the cost of deployment, expected length of service, maintenance, and process downtime costs (if instruments need to be taken offline), are all critical components in the TCO calculation.