Flowmeter developed for wind turbine’s grease supply
Although China leads the world in the amount of power generated from wind, Denmark has the highest generation rate per capita by a long way. In 2015, the country was generating over 2 megawatt hours of wind energy per person, well ahead of China’s 0.26. This relatively high generation rate has resulted in a local industry which produces large numbers of wind turbines for the rest of the world. One of the fundamental requirements of ensuring reliable and efficient wind turbine operation is to keep the heavily loaded main bearings fully lubricated in all operating conditions.
Titan Enterprises were approached to supply a small flowmeter to monitor the grease being supplied into a wind turbine main bearing mechanism. For simplicity, the grease mechanism is mechanically driven from the blade rotation and therefore the flow rate is potentially very low if the blades are barely rotating.
The grease flow is crucial and an alarm must be tripped and the rotation stopped should the grease flow be insufficient. In addition, if the lubricant supply line becomes blocked the flowmeter has to be able to withstand pressure that could potentially rise to several hundred bar. An extra requirement for the required flow measurement device was for a low power system, as the backup system is battery powered.
Drawing upon its proven OG2 flowmeter that fulfilled the low flow measurement specifications on lubricating viscous fluids, Titan Enterprises redesigned this meter to operate at 700 Bar in a small body and fitted a miniature reed switch detector to keep the power requirements to a minimum.
Fully IP67 / NEMA 4 compliant, the OG2-700 flowmeter is optimised for measuring the flow of viscous fluids and liquids at pressures of up to 700 bar and temperatures up to 150°C. With a standard flow range from 0.03 to 4.0 litres / minute on 30Cstk oil the OG2-700 can routinely achieve accuracy of 0.5% and repeatability of 0.1%.
At the heart of the OG2-700 flowmeter are a pair of toothed oval gears, one of which contains chemically resistant magnets. The gears rotate freely on robust bearings, with rotation detected through the chamber wall by a Hall effect detector or a reed switch giving approximately 1100 pulses per litre passed. The output is an NPN pulse or a voltage free contact closure either of which is readily interfaced with most electronic display or recording devices.
