In MIDAS the fluid sample tube is positioned inside a solenoidal
coil. Here the magnetic field is at its greatest and most consistent across its axis. Sensitivity
and repeatability for the measurement is assured. It is this unique feature which provides MIDAS with its
ability to monitor ferrous wear debris in the many systems where Fe levels are below about 10 milligrams per litre (10 PPM),
where other magnetic debris analysers struggle or fail to provide reliable indexing. Such low levels are to be
expected in very many systems. Electrostatic screening between sample and coil is employed
to reduce baseline zero reading for clean water, oil or alcohol samples. Otherwise a very significant reading
due to permittivity differences in the base oil results.
MIDAS was conceived, developed and manufactured by Manor Technology as an simple to use on-site debris monitor.
To this end no digital communications are incorporated. We at MTML feel that this would very much compromise
its straight out of the box ease of use. Data may be entered directly to a portable PC,
Palmtop or handheld which contains other user data for trending purposes.
It is widely recognised that very high standards of cleanliness are demanded for successful trending of total
particle counts. An apparently clean sampling point or bottle may overwhelm true contamination
readings, should a little dust be present. Whilst sampling oil systems for ferrous debris readings should not be
taken without due care, general cleanliness of equipment can be somewhat relaxed compared with optical counting. This helps to reduce costs of
sampling procedures for the ferrous debris monitoring.
Ferrous wear debris monitoring can provide many of the advantages of total particle counts, whether by filter
blockage or optical methods but avoiding their higher associated costs. It also has a place in pre sampling
routine oil samples. Oil companies may provide 'free' analysis of such samples. But the majority of samples will
show no problem. With MIDAS only high wear debris content samples may be sent away. The same applies to
pre-screening of samples before applying ferrographic techniques. Whilst providing more insight into detailed
problems these are notoriously time consuming and demand relatively high skill levels in use.
Wear debris analysis is perhaps as well established as oil analysis
itself, as a tool in predictive / proactive maintenance. Oil analysis may indicate
when lubricant problems such as water in oil or additive depletion may
be likely to cause problems. Monitoring the trend of wear debris will
readily show the transition from a normal benign wear regime to the
onset of abnormal wear (if adequately sensitive). Investigation at this early stage can save more
extensive damage and allow cheaper repair and reduce production loss.
A degree of flexibility as to when to schedule the maintenance operation
may yet be retained, if the wear is detected reliably at an early
stage. This is a key factor in the use of MIDAS. It is very easy to use, and
readings are operator independent. It has the sensitivity only
previously available from a spectrometer but responds only to only to
metallic iron, not chemically combined forms such as rust or other corrosion products which will often mislead as
to wear condition. Also results are effectively instantaneous and locally available, immediately and on-site.