Electromagnetic flowmeter solves problem of how to calibrate pumps

Problem
Late in 1997, KROHNE representatives from Penn Del, Inc. responded to an inquiry from Milton Roy, a subsidiary of United Technologies, with a request for level sensors. Milton Roy provides a final test of chemical metering pumps and generates certified pump performance curves. They had historically certified their metering pumps with a calibrated water tower fitted with an array of point level sensors. The sensors were interfaced with a software package and curves were created for each sensor. Those curves were “bumpy” due to the level sensor spacing and had to be “smoothed" in software. The initial thought at Milton Roy was to switch to a continuous level system to help smooth out the bumps and, hopefully, speed up the process.

On the initial meeting with Dan Ardente of Milton Roy, Penn Del personnel learned that the current calibration rig was old and the plant was going through some general upgrades and this was one of the upgrade items to address.

During the initial discussions Penn Del considered several continuous level technologies, as well as suggested that Milton Roy consider measuring the pump flow directly instead of indirectly using level. The idea was received with some concern as the industry standard has always been to use level. The capability of measuring flow rate and totals accurately from metering pumps that are oftentimes “pulsing” was questioned.

Solution
In order to answer the “capability” question, Penn Del conducted a flow seminar at the Milton Roy site and met with several of the engineers. Penn Del was able to convince the engineering staff at Milton Roy that a “flow measuring” solution was feasible. Thankfully the open-minded Milton Roy technical engineers were willing to “think out of the box” and agreed to evaluate what they considered to be an unconventional solution.

For installation evaluation, Penn Del supplied a PROFIFLUX 5090 Electromagnetic Flowmeter with an 090 converter. Milton Roy set it up on a test bench and connected some of their smaller pumps to it to examine the system capability. After some initial configuration help from KROHNE field service, Milton Roy was able to achieve accurate flow rate information and accurate recording of totals. (It should be noted that Penn Del was working with chemical metering pumps which were double diaphragm operated.) The KROHNE reps were challenged to show flow and total accuracy with the flow dampeners taken out of the monitoring system. Tests are typically run with dampeners in, but for this particular demonstration, the units were repeatedly valved “off” and back “on” quickly.

The 090 with the pulsating flow algorithm “on” could not be beaten. KROHNE was put to a tough test and passed with flying colors.

After the evaluation, Penn Del selected the set of magmeters and the one coriolis mass flowmeter that would cover the initial flow range of the pumps. They went to the very bottom of the 0.3E coriolis flowmeter to cover the angle of their smallest pump. In order to complete the system, they also supplied an integrated SCADA system that included H-View PC software and an H-Port 32 Channel Hart Multiplexer. Each of the converters were Hart Smart so the system was configured to display and record flow, total, repeated accuracy and pass/fail status. Several other operator-entered variables are also recorded and displayed including: station number; serial number; model number; rate/flow, pressure and “notes.” Critical information is exported via DDE to an Excel spreadsheet where the actual curves are generated.

Key Words: chemical industry, chemistry, EMF, MID, electromagnetic, flow, calibration, EFM
AP0024