Flow and Level Measurement
Instrumentation technology has witnessed dramatic developments in past few decades. Numerous techniques have been researched and developed using various physical phenomena to fulfill demand of flow and level measurement of thousands of industrial process control applications and these advancements will continue to go on. However, stipulating a flow or level meter that can consistently perform satisfying all anticipated process conditions is still a complex and challenging task.
Instrumentation technology has witnessed dramatic developments in past few decades. Numerous techniques have been researched and developed using various physical phenomena to fulfill demand of flow and level measurement of thousands of industrial process control applications and these advancements will continue to go on. However, stipulating a flow or level meter that can consistently perform satisfying all anticipated process conditions is still a complex and challenging task. Almost all the conventional flow and level meters used complex mechanical designs with multiple moving parts. Involvement of mechanical design naturally comes with wear-and-tear and thus additional maintenance cost. Automatically users prefer to avoid such mechanical and electromechanical instruments and opt for more robust electronic devices which have minimum or no moving parts. The base theory behind latest technology existed even back in a decade or two. But advancement in electronics, materials and manufacturing methods has improved the sustainability of products in rigorous environment and pre-integration of assemblies has made its installation easier. This is the main reason of growing popularity of latest flow meters such as Coriolis, ultrasonic and Vortex.
Ultrasonic technology has widened its application area and is being used even in gas custody transfers. Ultrasonic along with radar and sonic profiling gauges mark their utility in level measurement. These techniques offer a splendid three-dimension view of solid level in the tank. In case of gas measurement applications, the thermal dispersion meters perform extremely well in specified range of application. Invention of fiber optics has certainly taken the metering technology to a new level. Underwater oil and gas applications make us of fiber optic probes for flow measurement. Guided wave radar is yet another technology gaining popularity which minimizes mechanical moving parts. Float is the only free moving part along the waveguide probe. In spite of all these modern devices, differential pressure transmitters still dominate the market of flow and level measurement instruments. This is because familiarity and dependency of users and technicians on differential pressure transmitters overcome other difficulties like complex installation and over power consumption. Users, at times, even compromise on accuracy and repeatability of operation over familiarity and trouble free operation.
The purchase cost and installation cost is another key factor of choosing a particular instrument. Selection between mechanical and electronic devices has a tough competition. At times, simplicity and cost effectiveness of a mechanical instrument wins the race with complex and costly electronic circuitry. For example, purely mechanical devices are serving in minor but important safety applications like tank overflow prevention, pump protection etc. Here, a mechanical switch or a ballcock and a magnetic level indicator ensure the expected performance. Therefore, a balance between selection of conventional mechanical devices and modern electronic ones in appropriate places is crucial.
In coming years, materials will improve which will offer better chemical compatibility; signal processing techniques will improve resulting in availability of more information for processing; digital interfaces will replace analog and provide more precise readings and compact design. More real-time signaling, lesser power consumption and wireless sensor interface will indeed contribute to increase cost effectiveness and performance of flow and level measurement instruments. However, the design complexity tends to increase while trying to incorporate the most advanced technology.
Quality improvement of existing flow and level measurement techniques is persistent. Several suppliers coming up with numerous methods of measurement result in continuous evolution in this area. Ultimately the end user is getting benefitted with variety of options to select from available range of measurement techniques. Despite of having the most advanced measurement instruments and constant evolutions in its technique the flow and level measurement is still a complex and subtle job as there is always a scope to improve quality, reliability and attain perfection.