Condition Monitoring/Predictive Maintenance

Plant air is a known energy sink and you may not think of a shop air compressor as an area that can be made more sustainable.  At Aerzen’s LEED certified facility in Coatesville we initially were not able to improve upon old concepts at first either.  During the course of the last three years we were able to make significant changes to reduce its environmental impact. Adding an electronic controller, variable speed drive, remote monitoring and recycling waste heat did a fantastic job reducing the carbon foot print of the compressed air system.  They are simple ideas that you can implement in one way shape or form.  Your bottom line may be affected by this more than you think. 

This is a view into the sound enclosure of the Aerzen compressor package.

One improvement that anyone can make right from the time to look for a new compressor system is to choose a continuous duty rotary screw compressor over a conventional piston compressor.  The reason is that you have to quite oversize a piston compressor since they typically are not intended to be run continuously.  Also, the piston compressor usually requires a higher discharge pressure to make the best use of the two-point pressure control and / or a bigger air tank.  Both of the measures contribute to less run time per hour for the piston compressor and yet this uses more energy than a rotary screw compressor that can continuously operate at a lower pressure. 

The 15 year old oil flooded single stage Aerzen rotary screw compressor VMXa0937R had initially been designed for a simple 2 point load-unload compressed air system with a single speed belt drive and a 25 horsepower motor.  It was set up with a long minimum run

The majority of all operating manuals provide the equipment user with a time based plan when to change the machine’s oil.  This interval is typically designed to protect the oil and subsequently the machine from breaking down prematurely in most if not all operating conditions.  So far so good.  This comes with a price tag as the machine needs to be properly shut down and locked / tagged out.  Besides of the obvious cost for the lubricant you also incur labor and potential production down time cost.  For most of the smaller machines requiring less than a gallon of oil for each change it may not make sense to go with a condition based lubricant change.  Experts fix what needs fixing and this applies here also.  For larger quantities it may make much more sense to go with an oil condition based oil change schedule. 

First ponder what constitutes a “larger machine” for you.  Prioritize by amount of oil and how crucial the machine is to your plant.  Then pick an oil analysis company or diagnostic tool that will provide you with a fast oil analysis result.  Best are systems that provide an online access with e-mail notification when there are samples that need attention.  If the lubricant is still ok, why would you change it?  This helps saving time, labor and oil and thus you can do your part to help conserve resources. 

Here are test requirements that the analysis should bring to the table: 

• Viscosity at 40C
• Viscosity at 100C
• Oxidation
• Water content
• ISO cleanliness grade
• Particle count

One company that offers such a service is ALS Stavely at www.alsstavelylabs.com .  Important to any analysis is that there be at least twice a year samples taken.  Quarterly and for really crucial pieces of equipment perhaps even monthly trending may be warranted.  Assuming viscosity, cleanliness, water and

Shipping damage is the top number one issue followed by scheduling and only then cost.  It is amazing how much freight gets damaged per year.  This is particularly true for new blower packages that are shipped via LTL (Less than truckload) and so called common carrier.  Although deemed the most cost effective – expediting and broker companies managed to push the cost down - it is the most difficult way to get machinery to a job site undamaged. Because freight must be consolidated in the carrier’s main hubs the equipment must be moved often.  The mostly heavy and odd shaped freight with uneven weight distribution is moved with fork trucks that are significantly undersized.  Making things worse is the fact that logistics is a business model where people make Cents on a Dollar and thus the time freight spends in non value adding moving around within terminals is kept to an absolute minimum causing fork lift drivers to drive fast and furious.  Freight gets shoved around, stacked (when it should not be) and dropped rapidly (giving drop-shipment a different meaning).  The result is that sound enclosures, castings, instrumentation etc gets damaged significantly before it even makes it to the final destination. 

Here is a brand new unit that was literally “drop shipped” – it fell off the lift truck during the off loading process at the job site. 

FTL (Full truck load) shipments do not fare much better.  Here the truckers often get completely carried away by putting the tie down straps way too tight on the sound enclosure roofs resulting in dented and crushed panels.  Some leave with promising that they will tarp the freight when they get the next best change.  You guessed right, this more often than not