New Wireless Position Monitor Boosts Safety at Harcros

Sept. 30, 2009
Emerson's Network of Fisher Wireless Position Monitors Helps Harcros Chemicals Monitor Valves Previously Unconnected to the Plant's Control System

Touting successful beta tests at customer Harcros Chemicals in Kansas City, Kansas, Emerson Process Management announced expansion of its Smart Wireless solutions family with formal release of the Fisher 4320 wireless position monitor at a Monday press conference during Emerson Global Users Exchange 2009 in Orlando, Fla.

Emerson Process Management's network of Fisher wireless position monitors helps Harcros Chemicals monitor valves previously unconnected to the plant's control system. The Fisher 4320 position monitors are components of Emerson's Smart Wireless family, and they change project economics since they represent only 10% to 20% of the installed cost of a wired solution. The wireless monitor installs and commissions quickly, providing users with a cost-effective way to access the information.

"Most process plants have situations similar to Harcros Chemicals," related Emerson's Terry Buzbee, president of Fisher. "They might have hundreds or even thousands of valves that are not connected to the control system because of high wiring costs. These valves therefore provide no feedback on their actual positions, even though incorrectly positioned valves represent a significant cause of safety-related incidents. Unfortunately, users typically have not been able to access the position data that is valuable to the performance and safety of their plant."

Harcros uses manual valves for sampling, directing, injection and extraction processes at the chemical production facility. Many of the valves are in remote, hard-to-reach locations too costly to access with wires. "Monitoring them was a difficult process, requiring operators to enter hazardous areas or climb ladders to check the valves' state or position," added Buzbee. "Searching for an easier, safer way to monitor valve performance, the managers at the Harcros site installed the new Fisher 4320 wireless position monitors."

"Wireless valve position monitoring enabled us to reduce inadvertent emissions and bad batches, as well as avoid the high costs of rework, clean-up and lost material." Lloyd Hale of Harcros Chemicals discussed the use of wireless position monitors to report the status of previously uninstrumented valves.Before handing the presentation off to Lloyd Hale, director of manufacturing at Harcros, Buzbee explained that the Fisher wireless position monitors can be integrated easily with an Emerson Smart Wireless Gateway and AMS wireless configurators to form a Smart Wireless network communicating with the site's existing DeltaV digital automation system. The self-organizing wireless network passes signals along to the gateway, bypassing obstructions as needed. Frequent performance updates occur without any involvement by the user. With redundant communication paths, wireless networks provide better reliability than direct, line-of-sight communication between individual devices and a receiver.

Reporting on the Harcros tests, Hale explained that the Harcros facility has documented numerous benefits from the wireless instrument applications, and total savings were far beyond the direct cost reductions of a "no wires" installation. "This was about eliminating mistakes and increasing safety," Hale said. "Wireless valve position monitoring enabled us to reduce inadvertent emissions and bad batches, as well as avoid the high costs of rework, clean-up and lost material. Eliminating these costs―up to $25,000 per incident, not including fines―is a good thing for our plant."

Hale explained that the new Fisher 4320 wireless communicating position monitor can be used to monitor the position of any valve anywhere in the plant. The easy-to-install wireless instrument provides frequent, wireless updates about the valve's position while reducing the time and risk associated with visual inspections. "At Harcros, worker safety is a primary concern, not only because of the location of the valves, but also because of the toxic chemicals the valves contain and control," stated Hale. "The facility uses propylene oxide and ethylene oxide for its processing operations, and exposure to either one can irritate a person's eyes, skin or respiratory tract. Leaks involving toxic chemicals can also result in expensive fines."

Hale explained that sample and drain valves, for example, are opened and purged before and after each batch. Some product could be released or leaked during this process, and a new batch begins every eight to 16 hours. "Adding twenty-two wireless position monitors to these isolated, manual valves enabled Harcros personnel to identify inadvertent emissions before they could result in costly fines or production delays," reported Hale. "Downtime, rework, clean-up and disposal can cost the facility up to $25,000 per incident. The wireless monitor units helped us avoid three ‘product release' incidents, saving at least $75,000, not including fines."

"Besides applying the Fisher wireless position monitors to more of our manual valves, we are considering Emerson Smart Wireless technology for tank-level management, rail-car monitoring and a host of temperature, pressure and flow applications at our Kansas City site," concluded Hale.

Beyond its wireless advantages, the 4320 monitor is the first and only linkage-less device to provide accurate position feedback. The 4320 monitor uses industry-standard WirelessHART communications.

The Fisher wireless device monitors equipment such as valves, regulators, louvers, displacement and float level sensors, and relief valves in standard and hazardous area locations. With its patented, non-contacting rotary and linear monitoring, the 4320 is adaptable to almost application for which a percent of span is desired.