SPOTLIGHT Temperature measurement
Improved industrial processes with better temperature devices
Jon Davison, Product Manager, Temperature and Pressure, for ABB Measurement & Analytics UK and Ireland discusses the benefits of non-invasive temperature sensing in industrial temperature applications
I
n industrial processes, temperature is a key indicator of system safety, product quality and process effi ciency, and equipping operators with the data they need to ensure their plant is running at optimum performance is more important than ever. However, temperatures should ideally be measured as widely as possible to provide the best overview of process conditions, which is not always the case. Historically, thermowells have been the
favored solution. These are metal sheaths that protect a measurement sensor against the process it is measuring. However, their installation is not simple and requires shutting down the pipeline and drilling a hole through which a probe can be inserted. The procedure also requires fl anges and fi ttings, to help maintain pipeline integrity and meet critical safety requirements. The medium being measured and the operating conditions will dictate the thermowell design – there’s no one-size-fi ts all.
A thermowell? Think again Fortunately, a thermowell may no longer be needed. Let’s see why: The behaviour of a fl ow in a pipeline is known as the “fl ow profi le”. Turbulent fl ow is the most common profi le type in industrial applications, making temperature measurement challenging. Physics models of temperature distribution demonstrate that, in contrast to a laminar fl ow regime where the
Outlet temperature of a heat exchanger in a large chemical processing facility, comparing an invasive thermowell with ABB non-invasive temperature sensor
best representative temperature would typically be in the middle of the pipeline, in a turbulent fl ow temperature would be evenly distributed with little diff erence between the centre of the pipe and its wall.
For metal pipes, the inner and outer wall temperature in such a fl ow case would have a negligible temperature diff erence because, like electricity, metals are extremely good heat conductors. The vast majority of piping in plants will be metallic. This makes non-invasive surface temperature measurement an increasingly attractive option for process measurement applications, because some 70% of installations feature turbulent fl ows. To date, the challenge has been to accurately capture temperature changes throughout a system non-invasively.
Going non-invasive Devices to measure the surface temperature of piping have been around for quite some time. So- called ‘skin temperature’ sensors that measure pipe wall temperature are readily available. These usually use either thermocouples or resistance temperature detectors (RTDs) that are mounted on the pipe surface.
8 October 2023 | Automation
Although they can be eff ective, their performance tends to be hampered by poor design, bad location on the pipe, or bad installation, greatly reducing accuracy and response times. The ABB NINVA uses a dual sensor
confi guration – one measuring the temperature of the pipe wall, the other the ambient temperature – and uses the data to calculate and output the process temperature in real time. By taking account of ambient conditions, the transmitter signifi cantly increases the accuracy and responsiveness of the surface measurement. Savings of at least 30% can be achieved by either minimising or eliminating the time and eff ort required to plan, design and install a conventional invasive temperature sensor. Installation time is also vastly reduced; the sensor can typically be installed in under an hour.
A new era of plant efficiency The numerous benefi ts off ered by non- invasive temperature sensors avoid the traditional drawbacks of conventional measurement that have previously prevented temperature from being measured more widely across process plants. By combining high performance with deployment fl exibility, non-invasive temperature sensors such as ABB’s NINVA solution provide a new era of plant effi ciency.
automationmagazine.co.uk
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50
