Two-Wire Cable Cuts Magmeter Costs

Yamatake America’s MagneW Two-Wire Plus magmeter costs four or five times less to install than four-wire magmeters.

Jordan Easson, process control engineer at Valero Energy Corp.’s McKee Refinery, near Sunray, Texas, installed 15 MagneWs earlier this year at the discharge of its water wells, which supply its steam generators and cooling equipment. These wells used to be proven manually because they’re so remote, from 0.125 mi to 2.5 mi away from the refinery, but the local groundwater conservation district recently required McKee to improve its metering and provide steady flow data to help the district with aquifer management. He says McKee used to avoid  costly magmeters, but MagneW’s ability to use loop power cuts installation costs enough to make them a workable option.

Easson adds that McKee’s well pipes only emerge from the ground for limited straight runs, while the flows transition between multiple diameter pipes as they move from the upstream discharge pipes to their downstream check valves. “This is a terrible place to measure flow, but our Yamatake flowmeters did it,” says Easson. “We also added parameters to eliminate data spikes and detect empty pipes, which further reduced headaches.”

Brent Fowler, design engineering manager at Osmose Inc., Grifin, Ga., uses 12 MagneWs to help switching among the two to four chemicals it combines to make batches of wood preservatives. “We also recently went to a thicker, more viscous chemical, but we found we could no longer use the paddle-wheel or turbine flowmeters we used before,” says Fowler. “Both our old and new flowmeters check pulses per gallon and totalize them to determine gallons measured. However, the viscosity change affected the pulses and caused some accuracy issues. The MagneWs resolved this and have been completely accurate.”

Doug Hammell, process engineer, and Bruce Valentine, instrumentation engineer, both at Cytec Industries Inc., Willow Island, W.V., say they use nine MagneWs to control water flows to 11 scrubber systems, which remove mineral acids and organics from its process-vent emissions. The bulk chemical manufacturer previously used local-display flowmeters, but switched because its environmental permits now require it to monitor the scrubbers’ flows, transmit signals every five minutes and store the results in a database.

“Because the two-wire flowmeters combine signal and power, they’re a lot cheaper to install and are just as accurate as four-wire flowmeters,” says Hammell. “We used to have some reliability problems with our previous flowmeters, so when they failed, we installed Yamatake’s MagneWs, and we’ve had no problems with them. We’re also looking at using Yamatake’s flowmeters in the organic-fluid applications in our batch process.”

Donny Dunlow, instrumentation mechanic at International Paper’s mill in Franklin, W.V., reports his facility uses 30 to 40 MagneWs to manage water, whitewater from bleach and chemical flows in the bleaching section of its two-part filtering area. 

“We used four-wire devices before, but they needed 110 V runs for power in addition to the 4-20mA loop,” says Dunlow. “Yamatake’s two-wire feature means we have one cable for 24 V dc power and our 4-20mA communications, and this cuts our installation costs for labor and time in half. We also save a lot on conduit because we now have one run instead of four. Because we’re taking back the same signals as before, we found that the two-wire also ran at the same speed as a four-wire over a one week period.”