A major food manufacturer in the United States drives innovation in all areas of its business, while maintaining the highest quality standards in products, services and relationships. “We are always looking to improve energy use,” said one of the project engineers who provides project and maintenance services in the utility area of this plant. “This is a large plant with multiple product lines which are run as individual business units from a cost perspective. We want to know the energy use for each business unit over time, and compare them. In that way, we can make continuous improvements to the areas that need it the most.”
Steam traps were identified as one culprit of energy loss. When a steam trap fails open, steam is not completely consumed and is blown directly into the condensate return system, where it may be lost to the atmosphere in an ‘open system.’ It also can raise the pressure in the condensate system, inhibiting the discharge of other traps, causing system-wide inefficiencies. If it fails closed, the system will flood, causing a loss of heat transfer and subsequent loss of production. Steam trap failures also increase the potential for water-hammer that may lead to equipment damage and downtime.
In an effort to prevent steam trap failures, a preventative maintenance (PM) schedule was developed. With close to 100 traps in the plant, PM could only be performed once per year. It takes the maintenance crew at least one hour per unit to check the steam traps, when done properly, so maintenance labour on the traps was 100 hours annually.
“When I heard about the acoustic transmitter from Emerson, I wanted to try it out,” the customer said. “We were looking for automatic, on-line monitoring of steam trap performance and real-time alerts to minimise preventative PM requirements and minimise energy losses. This new innovation from Emerson seemed like a good fit, and we were glad to test it.”
The solution
A self-organising, wireless network with wireless 3051S DP flowmeters had already been installed to monitor compressed air flow to the various business units in the plant, to understand the electrical energy use. Adding the non-intrusive wireless acoustic measurement device was easy, and saved a lot of money in installation cost. “Wireless greatly reduces installation cost,” said the customer, “and we use those savings to purchase more instrumentation to extend utility monitoring in our plant.”
For steam trap monitoring, nine 708 Rosemount Wireless Acoustic Transmitters (with integrated sensors that mount externally) were installed on steam lines throughout the plant and integrated into the existing Smart Wireless Gateway, which communicates to a plant host. The steam traps range from thermostatic (TT) to float and thermostatic (FT) to simple bucket traps, and the acoustic transmitters work equally well on all of them. One application is even a steam driven pump, where the acoustics of the pump are being monitored to give early indication of problems. The network was easy to expand, and the new transmitters just strengthened the mesh. They have a lot of concrete between the transmitters and the gateway, and high EMF, but the wireless communications are strong and reliable.
The 708 transmitter, with an industryleading combination of temperature measurement and acoustic ‘listening’, gives unparalleled visibility into steam trap states. “Manual monitoring of temperature did not give us enough information to conclusively target a steam trap for replacement,” the project engineer continued. “But when we installed the wireless acoustic transmitter, we could tell immediately which steam trap was stuck. It was quickly fixed, and a trend of the new trap showed normal acoustics and temperature.”
It turned out that 22 percent of the plant’s traps needed to be replaced during its last PM check. By installing wireless acoustic transmitters, the plant will now prevent steam loss and energy wastage through early detection of steam trap failure. “Not only will this minimise energy loss, but it will free up maintenance personnel to focus their time on other things that need to be fixed, to improve our productivity,” concluded the customer.
For more information contact Rob Smith, Emerson Automation Solutions, +27 (0)11 451 3700, [email protected], www.emersonprocess.com/mea
| Tel: | +27 11 451 3700 |
| Fax: | +27 451 3800 |
| Email: | [email protected] |
| www: | www.emerson.com |
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