Both thermal and Coriolis technologies were introduced about the same time, in the mid-1970s. But the worldwide Coriolis meter market has grown to approach $2 billion, while the thermal flowmeter market is valued at less than 15 percent of that. Why the difference?
Here are some important differences between Coriolis and Thermal flowmeters:
- Coriolis flowmeters are widely used for liquids as well as gases, while thermal flowmeters are used almost exclusively for gases.
- Coriolis flowmeters are used for custody transfer applications, while Thermal flowmeters have yet to be approved for custody transfer.
- Coriolis flowmeters are used to measure petroleum liquids, unlike thermal meters. With oil prices at over $80 per barrel, this is a high-value measurement that requires high accuracy.
- Coriolis flowmeters are more accurate on the whole than thermal meters. Accuracy is especially important for custody transfer applications.
- Coriolis flowmeters cost more than thermal flowmeters, driving up the total revenues for this technology. Some of the new 14-inch Coriolis meters cost in the range of $75,000.
Frontiers of research
What can a thermal flowmeter supplier do to increase their visibility and performance when compared to Coriolis meters?
Develop more accurate meters. While some Thermal flowmeters have achieved accuracies in the range of one percent, this is not sufficient for many process applications.
Find a way to more effectively handle liquid flow measurement. This may be prevented by the technology, but it is worth looking at.
Try to find a way to accurately measure crude oil and petroleum liquids. Again, this may be prevented by the technology, but it would help Thermal flowmeters take advantage of the fast-growing energy markets.
Work to obtain custody transfer approvals, especially for custody transfer of natural gas. This would mean having the suppliers work together with end-users to draft a standard. Of course, in order to do this, thermal flowmeters would have to be developed to meet current custody transfer standards.
As you can see, developing thermal flowmeters that can handle all of these requirements is no easy task. But as I’ll share in my next post, Sierra Instruments has been up to the challenge, having become a leader in accurate thermal flowmeter technology.
Fascinating history
The history of thermal flowmeters is fascinating. Thermal flowmeters were born on the West Coast of the United States —the result of independent development by first two, then three separate companies. One company was Fluid Components International (www.fluidcomponents.com), which began by developing thermal flow switches that were used in the oil patch. The switches detected the movement of oil in oil well pipes, but they didn’t evolve into actual flowmeters until 1981.
The second strain of early development in the flowmeter marketplace was a result of the collaboration of John Olin, Ph.D., and Jerry Kurz, Ph.D. Both Olin and Kurz worked for Thermo Systems Inc. (TSI) in Minnesota from 1968 until the early 1970s. They used hot-wire anemometers in their research on air velocity profile and turbulence. The anemometers consisted of a heated, thin-film element. While these anemometers worked well for research purposes, they were too light for industrial environments.
While Olin and Kurz were doing research using anemometers, they were more interested in developing measurement products for industrial environments. This would require a more rugged device than an anemometer. They approached TSI about developing industrial products, but TSI wasn’t interested. As a result, Olin and Kurz decided to start their own company, incorporating Sierra Instruments (www.sierrainstruments.com) in Minnesota in 1973. In 1975, they moved the company to California , packing the business up into two trucks, driving it across the Continental Divide to set up shop in Monterey .
In 1977, Sierra Instruments was making both air sampling products and thermal flowmeters. That year, Jerry Kurz decided to become independent and formed Kurz Instruments (www.kurzinstruments.com). Sierra kept the air sampling products, while Kurz Instruments kept the thermal flowmeters. However, Sierra got back into the flowmeter market in 1983.
In the early 1980s, Sierra, Kurz, and Fluid Components were the only companies manufacturing thermal flowmeters. However, over time, more thermal flowmeter manufacturers arrived in the area of Monterey . These include Eldridge Products, Fox Thermal Instruments, and Sage Metering Inc. Eventually, some of the larger flowmeter companies entered the market, including Endress+Hauser and ABB. Magnetrol, a manufacturer of level and flow switches, also entered the thermal flowmeter market.