Hot
Topics
Your
Temperature Industry Monitor
Flow Research, 27 Water Street, Wakefield, Massachusetts 01880
Volume 1, Number 1 April 2000
Welcome to Hot Topics! Hot Topics is a periodic update on the temperature sensor and transmitter industry. Part of our job at Flow Research is to keep you up to date on recent developments in the temperature industry. This is the purpose of Hot Topics.
We also hope to stimulate discussion and the exchange of ideas. If you have an article you would like to submit to Hot Topics, please contact the editor, Jesse Yoder, at Flow Research. Our phone number is 781-224-7550, and our email address is info@flowresearch.com. For more information on Flow Research, check out our website at http://www.flowresearch.com/.
Flow Research recently spent a year studying the temperature sensor and transmitter markets. The results of this research are detailed in The Market for Temperature Sensors and Transmitters, a market research study that is currently available. We included both sensors and transmitters because the two markets are so closely related. In fact, they are similar in some ways and different in others. The following are some of the differences between the temperature sensor and temperature transmitter markets:
· While the temperature sensor market is highly fragmented, with several hundred suppliers competing for market share, a few top suppliers dominate the temperature transmitter market.
· Many temperature sensors are available for under $100, while most temperature transmitters range in price from $200 to $800 dollars. This makes temperature sensors much more of a commodity item than temperature transmitters, although low-cost temperature transmitters are also available for $100 or less.
· Temperature sensors can be used without temperature transmitters, if lead wire is provided, but temperature transmitters cannot function without input from a temperature sensor.
· The temperature sensor market is split almost evenly between the process and non-process industries, while the temperature transmitter market primarily services the process industries.
While there are major differences between the temperature sensor and temperature transmitter markets, there are also some important similarities:
· Just as many temperature sensor suppliers purchase temperature transmitters for resale to enhance their sensor business, many temperature transmitter suppliers purchase temperature sensors for resale to enhance their transmitter business. Some of the same companies are significant players in both markets, although this is the exception rather than the rule.
· There are internal shifts occurring within both markets based on changing technologies. Within the temperature sensor market, the major change is toward RTDs, and more specifically toward thin-film RTDs. This change is mainly occurring at the expense of thermocouples. Within the temperature transmitter market, the major change is toward programmable and smart temperature transmitters. This change is mainly occurring at the expense of analog transmitters.
· In both markets, high-end products are available for specialized needs that are priced significantly higher than other products in the market. For sensors, these products are high-end customized thermocouples and RTDs, as well as high-end infrared thermometers and scanners. The applications tend to be specialized high-temperature applications. For transmitters, these are multivariable transmitters that are designed to monitor complex processes involving multiple variables.
While the temperature market is clearly moving towards smart and high-tier transmitters, analog temperature transmitters have a huge advantage in installed base. The Flow-Ducker Research end-user survey found that more than half of the temperature transmitters currently installed are of the analog variety. This means that even though the trend is for end-users to order smarter products, many will continue to use analog transmitters. Some of these end-users will also upgrade to programmable temperature transmitters rather than smart, reflecting a tendency of some end-users to go up one level when upgrading field device products.
The output of a temperature sensor normally goes to a transmitter, a controller, a distributed control system (DCS), or a programmable logic controller (PLC). If the controller is located near the sensor, often users simply use a wire to connect the two. But what if the device that reads the temperature sensor is several hundred feet away from the sensor? In this case, many users turn to temperature transmitters.
This article looks as the advantages and disadvantages of the “direct connect” solution. When the signal does not have to travel more than 50 to 100 feet, the direct connect solution can often be used, meaning there is no need for a temperature transmitter.
There are several advantages to a direct connect solution. One advantage is simplicity. If a temperature sensor can be directly connected to a monitoring or controlling device, making this connection with a wire can often be a simple matter if the two are relatively close to each other. Secondly, cost can be and advantage. If the distance is not great, the direct connect solution can be a cost-effective one.
In process plants such as chemical, refining and food processing, where temperature sensors are often used to control the temperature of liquids or gases, temperature transmitters are more widely used than in non-process applications. Often the monitoring or controlling device is in a control room hundreds of feet from the temperature sensor. On the other hand, in non-process applications it might be only a few feet away. A thermocouple that is monitoring the temperature in an oven might be located only a few feet away from the temperature controller for the oven. In this case, a temperature transmitter is not required.
On the other hand, there are several disadvantages to a direct connect solution. One is that when the sensor signal is not converted to a 4-20 mA or digital output form, it is more susceptible to being degraded or corrupted during the transmission process. This can happen as a result of the distance involved, since temperature sensor signals are weak to begin with. It can also happen due to interference from other signals in the area of the wires doing the transmitting. Hence, using a transmitter is a safeguard against signal corruption and degradation.
Secondly, the cost of the connecting wire can be substantial both in material and labor costs. If the sensor is a thermocouple, the transmitting wire must match the type or the thermocouple. This might not be an issue if the thermocouple is located only five or ten feet from the monitor or controller. But if the signal has to travel any distance, the cost of the wire and the labor cost can be significant. In this case, these costs must be weighed against the cost of a temperature transmitter. Since some temperature transmitters are available for less than $100, and other good-quality analog temperature transmitters can be purchased for several hundred dollars, temperature transmitters can be an attractive option. In larger process plants that use digital field devices and temperature values are critical, end-users may also decide on a “smart” or even a fieldbus transmitter.
by Jesse Yoder
When I was in California recently, I heard that one county is conducting a "thermometer exchange" program. They are exchanging mercury thermometers for newer, digital ones,
at no charge. Have any of you thermometer suppliers out there heard of this?
The reason is for the exchange program is due to the pollution problems with mercury, presumably from old, discarded mercury thermometers. When thermometers are thrown out, they are likely to break. And when they break, the mercury leaches out into the environment.
After hearing about the thermometer exchange program, I decided to look into the history of the mercury thermometer. Could any other liquid do the job of mercury? Other liquids that had been tried for the purpose of measuring temperature are water and alcohol. In fact, colored alcohol is used today. In his book Science of Measurement (Dover Publications, New York: 1988), Herbert Klein discusses the advantages and disadvantages of using alcohol in comparison to water in thermometers. According to Klein, the use of alcohol in thermometers has these advantages:
1. It has a coefficient of expansion eight times that of water. This means that a temperature increase will cause alcohol a volume increase that is eight times as great as that of water.
2. Alcohol has a lower specific heat than water. As a result, to bring about a rise in temperature of alcohol, less heat is required than is required to bring about the same rise in temperature of water.
Disadvantages are:
3. Alcohol boils at a lower temperature than water, so it cannot be used to measure temperatures from 90 to 100 degrees C unless special steps are taken.
4. Like water, alcohol tends to cling to the walls of the tube its in. Supposedly it can also "crawl" to higher levels than the temperature justifies, due to capillary effects. This makes it less useful in a thermometer. This is where mercury is superior.
Daniel Fahrenheit invented the mercury thermometer in 1714. Klein goes on to say that, when Fahrenheit was inventing the mercury thermometer, he considered alcohol and water, but was dissatisfied with both of them. The mercury-in-glass thermometer that Fahrenheit invented in 1714 served as the prototype for the ones we still have today.
On February 23, 2000, Siemens Energy & Automation (Alpharetta, GA) completed its acquisition of Moore Products, which now operates under the name Moore Process Automation Solutions. Siemens Energy & Automation is a wholly owned subsidiary of Siemens AG of Germany. Moore Products was founded in 1940, has 1,200 employees worldwide, and had revenues of $168 million in 1998. Moore’s website address is http://www.moore-solutions.com/,
It will be interesting to see how Siemens and Moore integrate their temperature transmitter businesses. Siemens is in the process of introducing a new temperature transmitter, while Moore has an established line of temperature transmitters, the XTC Series.
Our new temperature study is now available, and it’s selling like hotcakes! The study is called The Market for Temperature Sensors and Transmitters in the Americas. It represents a year of research by Flow Research and Ducker Research. Besides market size and market share information for both temperature sensors and transmitters, the study includes the results of a temperature end-user survey. It also includes a product and technology analysis, strategies for success, and 54 company profiles.
More detailed information on the study, including the list of figures and tables, is available on the Flow Research website at http://www.flowresearch.com/. Or, call Jesse Yoder at Flow Research at (781) 224-7550 (jesse@flowresearch.com). While the sensor and transmitter components are available individually, almost everyone so far is buying the complete study.
Hot Topics is published by Flow Research, 27 Water Street, Wakefield, MA 01880.
(781) 224-7550; Fax: (781) 224-7552 Copyright Ó 2000 by Flow Research
Editor: Jesse Yoder Research Assistant: Adele Coppola