Combining pervasive sensing with specialty software running on a PC allows a plant to obtain data, analyze it to find equipment problems, trace root causes, and inform maintenance personnel—all without involving the main control system. This is often referred to as computing at the edge, and that’s exactly what Saltigo, a chemical plant in Germany, accomplished with its steam trap wireless monitoring system.
Emerson’s Ralph Keuper wrote a magazine article in IIoT For Engineers titled Pervasive sensing solves Saltigo steam problems. Ralph shows how Saltigo, in Leverkusen and Dormagen, Germany, determined defective steam traps were causing loss of steam and inefficient heat transfer, and therefore wasting energy. If they could identify failed steam traps as early as possible, they would save a considerable amount of energy. But finding them was a problem:
Identifying failed steam traps was very difficult using various manual inspection techniques, so the plant knew it needed a new and better method. They already had several Emerson WirelessHART pressure, flow, temperature and vibration transmitters installed in the plants, so Saltigo asked Emerson Process to do a site survey to assess where they would need to place antennas and gateways to accommodate wireless steam trap monitors.
Acting on the Emerson study, Rosemount 708 wireless steam trap monitoring transmitters and three Gateways were installed, one in each of three plant areas. The Gateways connect to the transmitters through the WirelessHART mesh network, and the Gateways connect to the control system via hard wiring. Ralph reports that Emerson helped with the installation:
Installation by Emerson personnel and Saltigo technicians consisted of mounting each transmitter on a pipe, manifold or relief valve. No cutting or entry into the piping was required as the acoustic transmitters are non-contact instruments and are easy to clamp on the outside of the steam pipe in front of the steam trap.
Installation took about 10 minutes for each transmitter. Once the team mounted each transmitter, they installed the battery, powered up the transmitter, and entered the Network ID and Join Key. In about five minutes, the transmitter had joined the WirelessHART mesh network, was recognized by the Gateway, and was transmitting data.
The team also installed Emerson’s SteamLogic software on a PC. The gateways connect to the PC via an Ethernet cable. The SteamLogic software analyzes real-time data from the steam trap monitors. The Rosemount 708s measure the ultrasonic acoustic behavior and temperature of steam traps, and the software uses this data to identify existing and potential problems.
Ralph reports excellent results:
The Rosemount 708s and Emerson SteamLogic software were installed in September 2014. The system immediately found several failed steam traps, all of which were repaired or replaced. The three plant areas immediately began to see substantial reductions in energy costs. Failed traps were no longer venting valuable steam, resulting in lower energy consumption to produce steam. Saltigo also reduced the number of process shutdowns because of steam trap failures, and eliminated the need for maintenance technicians to make regular rounds, resulting in further substantial savings.
Saltigo also recognized trap failures could be predicted early before they caused leaks. Predicting these early signs of trouble allowed Saltigo to improve its preventive maintenance program by replacing or repairing traps before they caused negative effects on production. Saltigo’s experience with the Emerson steam trap monitoring system was so good, they ordered more Rosemount 708s for the remainder of the steam traps in the plant.