Page 84 - ENGINEERING REVIEW NOVEMBER 2022_Neat

ENGINEERING
REVIEW TECH INNOVATION

have the task of keeping the hydraulic
oil in circulation and thus significantly
influence the mode of operation of the
machines. Changes in the gap can lead
to pressure loss or a pump failure. The
behavior of the gap is therefore measured
on the test rig in order to optimize the
design of the pump.
So far, gap measurements inside the
pumps were not possible because of
the extreme requirements. The sensors The eddyNCDT 3060 eddy current measuring system
used deliver precise results even when shows its strengths also when analyzing the gaps in axial
exposed to high rotational speeds, high piston pumps where sensors monitor the gasket gaps in
pressures and temperatures above very limited space exposed to high rotational speeds and
100°C. Furthermore, the pumps are harsh ambient conditions.
extremely compact, which significantly
limits the space available for integration For this reason, non-contact eddy high service costs.
of sensors. Thanks to the extremely current displacement sensors of the To date, bearing gaps were measured
small sensor designs and their high eddyNCDT 3060 series are used. Decisive during standstill based on a tactile
pressure and temperature stability, factors for the measurement task are principle. Inductive sensors based on
the eddyNCDT inductive miniature good repeatability and high temperature eddy currents from Micro-Epsilon acquire
sensors are ideal for this application. The stability. These sensors have a robust, the measurement values during plant
eddyNCDT 3060 eddy current measuring compact design. The plant is operated operation, thereby enabling reliable, cost-
system is therefore used on the test rig outdoors where splash oil and water is saving real-time analysis. The sensors
for evaluating the pumps. As a result, present. can be used in the test bench and in high
micrometer gap measurements can be volume applications. Serial use is ideal
achieved from which ultimately analyses Measuring the bearing gap in wind as the sensor technology can already be
can be made in order to optimize the turbines aligned and precisely adjusted during
efficiency of axial piston pumps. Wind turbines typically have two main installation and initial operation.
bearings in which the rotor shaft runs.

Monitoring oil gaps in hydrostatic Due to safety and cost reasons, wind High robustness for industrial
bearings turbines require 24/7 monitoring. environments
Monitoring the oil gap in hydrostatic Monitoring the bearing gap between In contrast to conventional inductive
bearings is also a task for the eddyNCDT the bearing surface and the drive shaft sensors, displacement sensors based
3060 measuring system. Hydrostatic is one of the primary objectives. An oil on eddy currents from Micro-Epsilon
bearings are used in large plant and film in the lubricating gap prevents direct stand out due to their high accuracy,
machinery such as stone mills and contact between the bearing surface and frequency response and temperature
telescopic installations. Monitoring the the shaft. Improved sliding properties stability. The sensors are suitable for use
gap size in these bearings is a critical of the bearing increase the turbine’s at ambient temperatures of up to 200°C.
factor, as any disturbances in the effectiveness while prolonging its service Furthermore, the sensor and the controller
hydraulics can cause pressure drops, life. The sliding properties mainly depend are actively temperature-compensated
which in extreme cases, can cause the on the width of the bearing gap. Based on at the factory while providing reliable
gap to close, resulting in damage to the the size of the bearing gap, conclusions measurement results even with
bearings and ultimately system failure. can be drawn about the wear. This is fluctuating temperatures. The sensors
In order to be able to retrofit older plants, because when the gap width is reduced, are insensitive to dirt, pressure and oil
the measuring system used which is less oil covers the bearing surface and the which is why they provide highly accurate
fixed on the bearing shoe must be easy to component wear increases. This would results in ambient pressure up to 20 bar.
install. Due to the long service life and the lead to high temperatures, rapid wear and
worldwide use of these plants, the sensor to bearing damage. In the worst case, the For more information,
should be easy to replace. plant comes to a standstill which results in Website: www.micro-epsilon.com

80 | NOVEMBER 2022