Page 274 - Intro Predictive Maintenance

Visual Inspection 265

Figure 12–4 Control chart warning of possible failure before it occurs.

Figure 12–5 A simple manometer to warn of
inadequate airflow.

need for maintenance and notification that a problem is building up to a point where
maintenance should be scheduled when convenient. A simple threshold indicator is
the manometer shown in Figure 12–5.

This simple device can be effective in air conditioners, computer cabinets, office
copiers, and any devices that rely on airflow. A spring-loaded block can serve the same
function in vacuum cleaners and other devices that must be moved and therefore
cannot rely on the pull/push of air against gravity. The purpose of a filter is to remove
contaminant materials so they will not clog coils, fans, electronic components, or
optics. As the filter is doing its job, the caught contaminants reduce airflow. This will
build to the point where equipment is straining to pull enough air, and temperatures
will probably begin to rise. At such a point, the filter should be changed or cleaned,
which will restore equipment to normal operating conditions. This buildup of dirt can
be easily detected by a difference in the air pressure.