Trucking – Pay now, or pay later

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 does not happen at all – now there may be rain and road water in places where this would normally never get to and now creates a major start up issue.  Inexperienced drivers hit bridges and trees with the new equipment and some manage to completely drop the machines off the trailer. 

 

Here the straps are being put on way too tight. 

 

Here is a unit with “tree damage” – the unit was struck by a tree inroute to the site. 

Addressing these issues cost a lot of money and most of all – time.  You will not be able to use the blower or compressor for a while now that key components must be fixed.  While most freight companies are pretty good about financial compensation, it still puts the burden on you the customer to make sure to either not take damaged freight off the truck, but at an absolute minimum make mention on the bill of lading that there is a problem with the freight.  This helps alleviate the debate with the carrier later and speeds up the damage claim.  Scheduling the pick up at our facility or even just making sure the correct truck shows up (needing a drop deck trailer when a regular one shows up makes for interesting calls) is often beset with issues.  One example had a trucker show up no fewer than 5 days late because he had other drop offs to make.  Is this worth the money that you thought you could save?

Best choice would be to let Aerzen handle the freight.  Sure, sometimes this is more expensive, but we have aligned ourselves with people that will make sure your freight gets to the job site in the great shape you expected.  The worst case had a good OEM of ours insist that his broker be used with the result that the very same blower packages were damaged twice and needed to make the trip toFloridathree times of which the last trip was with our house carrier.  This is another life lesson of pay-me-now-or-pay-me-later. 

Got a comment?  Please drop me a note.    

AerzenUSA
Ralf Weiser
rweiser@aerzenusa.com

Operating Time Versus Condition Based Oil Changes

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 oxidation values are still acceptable there is no need to change the lubricant.  Going from a time based to a condition based oil change interval is not only great for your budget, but also for the environment.  It helps stretch our precious resources too. 

Got a comment?  Please drop me a note. 

Ralf Weiser
AerzenUSA
rweiser@aerzenusa.com

Making A Shop Air Compressor Green(er)

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 time setting and a digital switch and relay type control panel.  Throughout most of its life it seemingly operated all day, and it was never shut off after business hours and the weekends.  Using an Aerzen AS200 compressor controller we were able to reduce the minimum and after-hour run time.  With a so called weekly operating schedule program it was possible to enter the daily time frames where the compressor was expected to be online.  This reduced the operating time significantly because even though our company’s compressed air system’s leakage rate is well below the industry benchmark of 10%, it would have still meant for the compressor to run multiple times overnight or the weekend.  Ideally, we could install a smaller compressor that would then be able to operate at a better overall efficiency, because it would operate at a higher RPM.  Running a bigger compressor than necessary at a low speed causes for the motor and compressor to run at lower electric and volumetric efficiency.  

The next thing we installed was an Aerzen iAir Remote Control monitoring system.  This is a system that connects to the controller via industrial cell phone technology and is connected to the central server allowing accessing and trending of the compressor operating parameters.  We found out that the compressor capacity was much larger than practical.  This led to the installation of a constant speed – constant torque variable speed drive.  We were able to reduce the speed to about ½ from max speed and were still able to maintain and never drop below nominal system pressure.  This offered a phenomenal power reduction. 

In the final step we thought that we could make use of the heat energy that comes off of the oil cooling system.  An oil flooded rotary screw compressor puts the gross majority of the heat stemming from the compression process into the lubricant.  This heat is removed by air cooled oil coolers and can present issues with the removal of this heat out of a compressor room.  Here we installed one oil cooler with fan in our production area away from the compressor room.  This allows us using the heat to help heating the production area in the winter months.  By ways of using oil system diverter valves we can also put the hot oil through another cooler that is installed on the outside wall of the building.  This makes sure we can operate in the summer without having to cool the compressor room, or to put additional heat into the building. 

Please see the link below for the quick video showing the key elements for the upgrades. 

Challenge yourself by asking how your compressed air system may be improved upon.  There is a large amount of energy potential that is currently wasted and thus pulls straight from your bottom line – the power bill often gets overlooked.  Please drop me a note in case you have comments, suggestions or questions.    

Aerzen USA

Ralf Weiser

rweiser@aerzenusa.com

Top 5 Questions To Ask When Sizing A Blower System With A Vacuum Pump

In order to properly size a blower system with a vacuum pump, there are five main requirements to consider:

How fast the customer would like to get to a base pressure in their vacuum chamber?

After they load the chamber, they then have to evacuate it down to certain pressure. This must be accomplished within a given time because, time is money, especially in manufacturing environment.

How to handle the gas load when we get to the base pressure?.

In most cases the roughing system is big enough to handle the gas-load, however this needs to be confirmed.

          Examples of applications:

          Vacuum furnace

          Vacuum coating – may have a flow of reactive gases

          Making computer chips to solar panels

 How deep a vacuum do they need to get to – what is the base pressure?

What is the rate of in-leakage going to be?

Do we have to overcome out-gassing from the chamber or the product?

The biggest problem that comes up time and again is how far away from the process the pumps are going to be located. In high vacuum applications the pressure drops are very significant. We have to evaluate the line size and diameter as well as if it is possible to get the pumps closer to the chamber to spend less money on the vacuum.

Another key area for sizing the blowers is a matter of modeling the thermodynamics of compression and making sure we avoid a thermal overload situation in the blowers. Rough vacuum systems are the most vulnerable to overheating in the range around 10 torr. Often times we are sizing blower systems for people who already have a primary vacuum pump selected. Sometimes we are selecting the correct size for maximum efficiency and type of pump with respect to process considerations such as condensable vapors or sensitivity to having oil molecules contaminating the product.

Solutions range from various oil sealed types of vacuum pumps to completely dry or liquid ring systems.

To learn more about proper blower sizing visit our website – www.aerzenusa.com or send me an email with your application question.

 

Bruce Impey
Vacuum Technology Specialist
bimpey@aerzenusa.com

Lowering start-up power draw with across the line start - PD blower

The most common motor start is what is commonly known as “across the line” (direct) motor start.  Power companies like when consumers do this as the resulting power draw (Amperage) spike is typically assessed with so called power demand charges on top of the regular power consumption charge in cents/kWh.  In any application where the blower or compressor must start against header pressure this starting method carries the greatest penalty as the motor must overcome the rotating equipment’s moment of inertia and the system pressure.  The graph below illustrates the power draw and the time it takes to bring the blower / compressor on line.  An Aerzen Aeromat automatic start-up unloading valve may be the answer to your problem. 

The line C shows the power draw needed with an unloaded machine.  Line A depicts the start up curve with full header pressure at time of start up.  Line B represents the power draw with an automatic start up unloading valve.  It is almost as good as the unloaded start up.  Major spikes upon start- up are avoided. 

Please find below the device that achieves this without any external auxiliary power.  The Aeromat valve is produced by Aerzen and its operation is as follows: 

 

The unloading valve is a normally open device. Thus when the blower is started, the discharge air of the blower is diverted from the process piping (due to the closed check valve) through the unloading valve and out the vent opening (2). As the air flows through the valve a small amount of air travels up the spindle (5) to pressurize the top of the diaphragm (6). Ultimately the force resulting from the pressure on the diaphragm overcomes the spring force and the valve (7) closes, diverting the blower airflow back to the process piping. Normal closing time is 30-35 seconds, which is adjustable with the spindle (8).  The Aeromat does not need any sort of external electrical or pneumatic auxiliary power.  In some cases a solenoid valve (9) is installed allowing customers to take the blower or compressor off line while not having to shut it down completely. 

 

Saving energy cost will become increasingly important.  Please check out the following video explaining the Aeromat’s functionality. 

Please drop me a note in case you have comments, suggestions or questions.    

Ralf Weiser
Technical Manager
Aerzen USA
rweiser@aerzenusa.com

Of Pipework And Other Surprises During Blower And Compressor Start-up

Day of start-up is always an exciting time as all the long hard work of engineers and construction folks can finally show off what they have worked on for typically a long time.  Most focus is placed on equipment, infrastructure, controls and plant processes.  One item that is often underestimated in air and gas moving equipment is the pipe-work that connects primary air movers and the process.  Materials of construction, alignment, thermal growth allowance and most of all cleanliness continue to be one of the most unique challenges start-up engineers continue to encounter. 

I will start with cleanliness. Ideally, you should attempt for the construction crew to install the pipes in a clean state.  Sometimes that may not be possible and the welding and cutting process is typically a dirty process to begin with.  Cigarette butts, rags, welding beads and rods and so much more can be found on the inside of new construction pipe-work.  The largest object that has held my progress on site up was a red Sawsall tool box that obstructed the flow to a waste water treatment system.  If you have the opportunity at all make sure to open the pipe at a location where it is safe to exhaust all of this debris into the atmosphere and then run the equipment and literally blow the pipe clean.  Make sure to do this safely and abide by the local and plant safety codes. 

Then there are pipes on the blower or compressor inlet that cannot be cleaned as the air will be moving toward the machine.  Here it is imperative to make absolutely sure that the pipes are clean prior to start up.  Ideally, such installations should have an inlet start-up strainer installed right upstream of the blower / compressor inlet flange. 

Here a installation crew was not so lucky and forgot a 5/8” bolt in the ducted inlet to the GM150S Aerzen blower – the bolt went through the blower upon start up.  Amazingly the blower kept working even though the blower lobes sustained severe damage. 

Often pipe expansion joints either do not exist, or they exist but they have been abused as pipe installation tools and for correcting misalignment.  Neither is a good situation to find during your inspection process.  Pipe strain is the leading cause of rotating equipment failure as it exerts stress on the housings that may let the rotors hit the housing.  Also, the pipe strain may worsen once the machine is up and running due to additional stress from thermal growth.  Expansion joints are meant to compensate for thermal growth and to separate structural borne noise from the equipment to the pipes.  They are not pipe assembly and misalignment correcting aids. 

One last piece of important safety advice is to always walk the pipe-work from the primary air / gas mover to where the medium enters the designated process.  This helped me safe a crew of two pipe installers at a cement factory that had been working on connecting an elbow to the open 6” pipe.  Had I not inspected the pipe one last time before start-up, they would have been blasted with hot high pressure air. 

Please do yourself a favor and inspect pipework on the inside and as a minimum installed start-up strainers if at all possible.  Before switching a machine on make sure to walk the pipe down to the final exhaust point – it may save a life. 

Please drop me a note in case you have comments, suggestions or questions.    

Aerzen USA
Ralf Weiser
rweiser@aerzenusa.com 

Air filter maintenance: Impact on efficiency and machinery health

In the ideal world would we not all want to eliminate air filters altogether?  If it was not for the fact that foreign material would be detrimental to air moving rotating equipment and the process that receives the air this would even be a possibility.  Now that we must live with the filter elements, let us look what not maintaining it properly can mean to you. 

In the realm of positive displacement machines most filters do not require cleaning before they reach a pressure loss of approximately 20 inches of water column (“H20).  That is true for Aerzen filters as well.  That is quite a bit restriction for a filter element.  Let us put this in perspective:  If you have a house that has an air conditioning system than you also have these neat “furnace” and “AC” filters.  Most of them will collapse when they are subjected to more than 2”H20 restriction and your air flow really drops because the centrifugal fan cannot handle the restriction.

  

A positive displacement blower or screw compressor can easily deal with this inlet restriction and it will not affect the total air flow of the machine much as the rotor lobes positively trap the air within the housing and the rotor lobes. 

While this is great news for the process that is supplied with this consistent amount of air, it still makes the blower or compressor work harder.  Any amount of increase in inlet restriction will impact how the machine will operate.  The restriction typically causes for the machine to run hotter than normal and thus would also cause for more Amperage draw from the motor that must overcome the additional pressure differential.  Do not get me wrong here, we are only talking about a couple of Amps – but one Ampere difference on even a small motor can add up to thousands of dollars when you operate it 24/7/365.

The opposite side of the spectrum of how I have observed folks deal with filter maintenance is when they choose a coarser filter or take it out completely – yes, it is the year 2011 and yet folks still practice this.  The practice renders a longer filter service interval and thus less maintenance cost – in theory.  In really dusty conditions some maintenance managers must deal with weekly and in really bad conditions daily filter cleaning or changes.  This is a significant cost factor that is deducted straight from the company’s bottom line.  It is therefore understandable that solutions are sought to reduce the maintenance.  Since positive displacement machines have a reputation for being rugged, OEM filters are sometimes replaced with much coarser elements and in some cases are completely removed.  The filter maintenance goes down and the process may even be able to deal with the extra amount of foreign matter that now goes straight through the machine.  What happens to the inside of the air mover though?  The bigger issue can be erosion stemming from long term operation with fines going through the machine.  Especially affected are the rotor sealing strip at the outer rotor diameter that seals against the main housing.  This allows more hot air to re-circulate within the machine making it run hotter and less efficient. 

Lots of wear can be seen on the tips of this rotor set. 

There are ways to minimize filter maintenance cost and also not jeopardize machinery health and efficiency.  Ducting the air intake to areas with less contaminant load is just one method.  Another successful practice is installing a cyclone type pre-filter that removes most large particulate before it enters the main filter element.  Even increasing the size of the filter can help extend the service life and thus reduce the manpower needed to maintain and check on the filter. 

Please drop me a note in case you have comments, suggestions or questions.    

Ralf Weiser
Technical Manager
Aerzen USA
rweiser@aerzenusa.com

PD Blower "Free" Oil Analysis - There Is Usually A Good Reason For It

Oil analysis and vibration analysis make a great tag team when it comes to assessing rotating equipment condition.  Even if oil analysis trending is carried out by itself it still can be a powerful tools assessing whether or not there may be trouble coming down the pike – rolling element bearings, gears and other key components leave key evidence of them failing behind in the lubricant.  Depending on your plant size and usage of lubricant, quite a few lubricant suppliers also offer free oil analysis.  While that seems great at the first glance, there are quite a few wrinkles that can lead straight to catastrophes that the analysis was supposed to help prevent.  I will review a few issues and elaborate on what an analysis report should cover in the course of this blog. 

For one, the report is only as good as the one who reads it can understand and interpret it.  Most reports that I have come across in my career have a line with CYA-ish terminology in them, e.g. “Action: Resample next service interval to further monitor”.  How are you supposed to make any heads or tails of it on your own?  The advice tends to be too broad to be useful.  Two more big issues can arise if you do not know what all the different tests that are out there and which one you should apply for which machine.  The greatest print out will not do you any good if it is the wrong test or you really do not know what the readings mean. One of the most often overlooked issue id the task of sampling the oil.  Location, time and sampling cleanliness have a huge impact on analysis accuracy.   Is the sample taken from a sump or a centralized pressurized lube oil system?  Is the sample bottle and sampling port clean?  Are you taking the sample with the machine down and not having operated in quite some time allowing for sediment to settle in the sump?  Are you taking it from a running machine up or down stream of the filter (if any), oil pump, sump?

Then there is the lubricant.  Only when you know what you put into the machine in the first place (and you let the analysis crew know what it is) will the report be meaningful.  Finally, there is the issue with knowing what kinds of parts reside on the inside of the machine you got the report for.  Your analysis accuracy goes way down, if you do not know what kind of bearings, cage materials, how many bearings there are, what kind of gears may be contained in the machine, etc.  What other parts are in the machine?  Are there lip seals, labyrinth seals, or other parts that may come in contact with one another?  All of these components leave traces of themselves behind that can be invaluable in the condition monitoring process. 

I bet that most people who offered the free oil analysis to you did not tell you about all these potential issues.  There is a method to this madness.  First identify how critical the machine is for the operation of your plant.  For those machines do yourself and management a favor and get either the manufacturer or an oil analysis lab, e.g. Stavely involved.  Most reputable OEM’s offer a good condition monitoring program.  For machines that you feel like you can make use of the free oil analysis, make sure that the following criteria and information is included in the report:

• Oil make, quality and quantity
• Viscosity @40C is Cst and @100C in Cst
• Viscosity index or VI change
• Spectrochemical analysis in ppm
• Wear element concentration (particle couont) as per ISO 4406
• Water concentration in %
• Additives listing
• TAN index (for some applications the TBN index)
• Oxidation index

Next best thing is to contact the equipment manufacturer and obtain their expert opinion where, when and how the sampling should take place.  While you are at it please ask them too what their best lubricant and test recommendation is.  Ask them for a list of bearings, gears and any other wear and tear items within the machine.  Please call our product support group, if you need any Aerzen blower, compressor, hybrid or vacuum booster information. 

In the Internet age nothing beats free advice – I love it myself and make use of it as much as possible.  Think twice before starting to rely on free oil analysis for critical machines though.  

Please drop me a note in case you have comments, suggestions or questions.    

Aerzen USA
Ralf Weiser
Technical Manager
rweiser@aerzenusa.com

Preventive Maintenance or Precision Maintenance?

Have you ever pondered the term of "preventative" maintenance?  Well, I have often done so and must admit that I had to laugh when I pictured how this was supposed to actually work in a plant setting.  It conjured up visions of maintenance people getting a "call" from the machine controls in question and telling them to come in soon as one of the bearing will fail next Sunday night at 4:05am.  While we are closer than ever in diagnosing machinery problems and averting the worst from happening, we are not able to be able to exactly "predicting" when the usable time of a piece of equipment will come to an end.  Precision maintenance is when you identify, prioritize and implement a condition monitoring philosophy that is trending based and is designed provide a review process for any process and incident occurrence.    

Trending is the key to success with precision maintenance.  At Aerzen USA we make good use of state of the art condition monitoring devices that fit any budget.  From low cost vibration sensor based switches to full blown online monitoring systems ranging from IFM Efector's VKS, Octavis and Multiplex devices we have the trending system that will fit anyone's budget. 

 

Any of the devices will at least alarm the user of trouble and also at the same time provide the output of external trending.  The more sophisticated Octavis and Multiplex units have their own built-in internal trending software, which is set up at the factory using our own expert information.  It can eliminate any blowers and compressors from any existing regular vibration analysis routes as the units are constantly monitoring the equipment in real time and are set up with their own alarm and shut down levels.  Customers with real critical pieces of equipment might even choose the Ethernet based connection that allows customer SCADA or DCS integration. 

In any system that you choose, make sure that you do not implement without prior planning session as well as planning to review your results.  Also, keep in mind that results are only as good as the accuracy of the information that goes into the monitoring equipment.  Then always focus on trending and only fix what needs fixing.  That is what I call Precision Maintenance.  One reading alone may not mean anything; or would you only consult one doctor before you undergo open heart surgery because of a single high blood pressure reading? 

Please drop me a note in case you have suggestions or questions.   

Aerzen USA
Ralf Weiser
rweiser@aerzenusa.com

Lubrication mix-up

Is it not amazing how many different lubricants there are in a industrial or even a municipal waste water treatment plant?  At the outset the problem is not all that challenging.  Lubrication or maintenance managers usually start by compiling a complete list of machines and the lubricants they need as per their respective operation manuals.  So far, so good.  Than it starts to get complicated, because maintenance techs, operations people or lubrication crews need to do the actual work and more often than we realize they need to make their own mental notes to remind themselves which machines takes what lubricant.  Sometimes people use permanent markers or other devices and leave themselves scribble notes directly on the machines themselves.  How many times has that caused any machinery trouble at your plant? 

There are many solutions that can help avert such issues.  One effective one comes from the Lean Manufacturing program called 5S in which - among other important aspects - lets you sort and mark all items you need to do your job with.  This is perfect for lubricants.  Visual signals such as color coding bins, drums and cans and using the same colors on markings on the actual equipment will make anyone's life a lot easier and also help you reach the maximum service life of your equipment. 

Kick it up a notch with making a list of the lubricant, where it goes, how often it needs to be changed and checked and how much you need on a label of suitable size and then laminate it.  Post it next or on the machines and voila, you are on the way to using best practices in the industry.  Track your success though as most managers tend to overlook when things are going well. 

Aerzen USA offers a built-in benefit when it ships products to their final destinations.  All standard air and neutral gas machines are shipped with a Polyalphaolefin oil from one of the premium brands in North America.  It is fully synthetic and there is only one brand and a total of one standard viscosity class for each blower and compressor.  The end user does not have to scramble for oil at start up, but the lubrication expert on site has some time to place the machine on his lube oil chart and can even take time to color code it and place a laminated sign on it. 

Does this help you make your working life easier?  As always, I am looking for your feedback. 

Ralf Weiser
Aerzen USA Technical Manager
rweiser@aerzenusa.com