Nagle Pumps, Inc.         March 2000                              Volume 1, Issue 2     PERSPECTIVE A National And International  Newsletter Inside This Issue  1 Introduction              When And Who              Should Stock Those               Spare Parts?  2 Standards for Pump              Impeller Balancing     3 What's Cooking?     4 The K.I.S. Principle             From The Mail Box       NAGLE PUMPS, INC.  1249 Center Avenue Chicago Heights, IL  60411   U.S.A. Tel.  708-754-2940 x219 FAX:  708-754-2944 E-Mail:  service-parts@naglepumps.com

Introduction By  Wayne E. Lovison - NPI News issues will be generated as material becomes available.  If you have a good story or some- thing for our readers, send it to me and I will get it into  publication. The Field Service Newsletter is  for entertainment but it should  also contain interesting facts  that need to be addressed. The Rules:  The article cannot name drop or be too specific about anyone or product.  It must be  discretionary reading but enough information to make the point.   When And Who Should Stock Those Spare Parts? By  Wayne E. Lovison - NPI The (OEM) Original Equipment Manufacturers will stock as many parts based on their yearly usage and/or turnover, but no one can stock every part in every alloy.  It isn't cost effective. No one knows when they will  have a premature failure or  a failure from normal wear...  but having no spare parts is  risky. No one wants to spend money for spare parts that can be used  elsewhere but lets consider the following:

1.  Is this equipment in a      process?  Consider how much       money is lost for each hour       the equipment is down. 2.  Is this installation subject to      OSHA regulations?  You may      be subject to penalty or fines. 3.  Is this equipment in a critical      installation? Consider a      backup or standby installed       spare - buy yourself some time. Note:   Many of the above             situations are encountered             each day and some occur             with devastating results. Planners and Storekeepers can prevent this problem.  Research your system criteria  and stock those long lead parts. The inevitable premature outage will occur - trust me! Using Non-OEM Parts Original Equipment Manufacturers (OEM) are seeing more premature failures because the replacement parts used during the repair were non-OEM components. Be careful!  This type of cost  savings has its shortcomings  and will eventually make a full circle back to the person who purchased those parts and may require accountability. To save a dollar expediting a part,  only to have it fail prematurely, will result in additional cost.  Reverse  engineering a part will produce a  similar item  but it "may not" have  the original tolerances and materials of construction, thereby causing  an unwanted premature failure.

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Miss another opportunity? Contact our Sales Engineers at sales@naglenumps.com for  the latest product news.   STANDARDS FOR PUMP IMPELLER BALANCING By Wayne E. Lovison - NPI  All impellers should be balanced in accordance to standard ISO 1940 titled: "The Quality of  Rotating, Rigid Bodies."  This standard establishes a classification of balance quality. For machinery such as pump  impellers, fans and flywheels a grade G6.3 is specified.  REPAIR SHOPS: Take notice you will not be able to repair rotating equipment much longer without having provisions for impeller and shaft balancing. CUSTOMERS: Balancing does take a  certain amount of expertise and proper equipment.  For best results contact  professionals that are  readily available in your area.

SHAFT STRAIGHTNESS  AND TOLERANCES  By Wayne E. Lovison - NPI Installing a new shaft and bearings into a bad bearing bore will only result in a premature failure. Things To Check Out - a.  Check the shaft thrust and      radial bearing tolerances      and seal fits. b.  Check the thrust and      radial bearing bore fits. c.  Check shaft straightness. Do Not - a.  Change shaft material. b.  Weld repair a shaft more      than once. Material      stress and/or metal       fatigue is a concern. c.  Forget if recently rebuilt -       to lubricate the unit. d.  Use nominal bearing       tolerances for repairs.       Call the OEM.  Because a shaft is straight between its machined centers doesn't mean it  will be straight once  you've installed the  preheated bearings. A preheated bearing installed  onto an ambient shaft (a shaft  at room temperature), will in  most cases be preheated to  about 225º F. This preheating will cause the bearing to expand enough to get it over the shaft  bearing diameter in most cases.

Remember as the bearing  cools it will shrink to the  shaft. This in turn will apply a predetermined internal bearing load. Note:  Preheated bearings will quickly heat sink (the heat will  be drawn off from the bearing into the ambient shaft.) This sudden heat displacement  into an ambient shaft, will (in  most cases) cause a shaft to  relieve or bend. Manufacturers try to remove as much tooling stress as possible but some will always be present  and the possibility of its relieving  is always a consideration. All cantilevered shafts should be  checked for shaft run out after the bearings have been installed.  If a bent shaft is not straightened and  later installed with an impeller, the  equipment may suffer from higher  levels of vibration.  This will lead to a premature failure when under load.  As a guideline NPI recommends that your total indicated run-out  (TIR) not exceed 0.003”.  Refer to the sketch below for details. Click on the picture to get  full size details. Any questions?  Contact the  factory @ service-parts@nagle pumps.com

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Shaft Tolerances  (cont’d) Caution do not use nominal  bearing clearance selections out of a bearing book.  This is not permitted.  Loss of  bearing clearances or their  tolerances produces two  types of bearing conditions -  1.   Skidding  - occurs from        lack of load. 2.  Preload - occurs from       excessive load. Fit selection variances of 0.0005” or more could adversely affect the unit's performance and overall bearing life.   WHAT'S COOKING?  By Wayne E. Lovison - NPI This story occurs in the upper  Mid-West where impending doom will result if the equipment isn't up and running within 48 hours – Sound Familiar? Any attempt to resolve the  problem over the phone was not  an option. Someone had to be  on-site with new parts ASAP. Two of us drove to the site with  the new bearings, seals and  gaskets.  We also needed to  make a determination as to the  cause-of-failure. The situation was pretty grim.  This unit supplied all the water  needs to the entire plant and if it wasn't up and running within  36 hours 3500 people would be  out of work - until it was.

We quickly figured out that the  pump had been operated in reverse which took out the thrust bearings. No way! They replied, "we  checked rotation prior to start up." We were then told that the plant  electrical wiring was match  marked to the motor leads so  when we were ready to start up  the repaired pump everything  would be re-connected just as  it was during their initial start up.  This unit was large, weighing  several tons.  Overhead cranes  and cherry pickers were the only  thing one could use to breakdown this large unit. By now we had stripped the unit  down to the shaft and bearing  assembly.  Now we were ready  to remove the bearings.  We  also needed to inspect both the thrust and radial shaft and bore fits. Plant maintenance was more than ready to help us get this unit  repaired.  We asked for an induction heater – but they had none.  We asked if they had a hot oil bath to preheat the bearings -  Yes - they had that. About 15 hours into the tear down and inspection - preparations were now underway for reassemble. One thing I forgot to point out is  that concrete gets awful hard after 15 hours of standing on it. The bearings were given to plant maintenance to preheat while we  set about preparing all the parts for reassembly.

After another couple hours we  were ready to put it back together.  By the way these bearings (both thrust and radial) must have cost about $5500.00 and were hand carried by us from Chicago. I was worried about the distance from the hot oil bath to the shaft assembly area.  If we were too far away (the bearings) could cool  down before we got them on the  shaft? I hadn't seen the hot oil bath but since maintenance said they knew what to do I wasn't about to  question them at this point. Maintenance rolled out a cart  and on the cart were the preheated bearings.  We must have been preoccupied doing  something else because before we knew it they had all three OB  thrust bearings installed. We came over to check out their  progress only to find some stringy substance hanging out of the bearings.  What the heck was this stuff?    Whatever it was -  it was baked on. We discovered that they had taken the bearings to the kitchen where  they have a deep fryer.  What's  worse - is that they cook their  food in it. Oh brother! I just knew it was going to be one  of those days!

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What's Cooking?  cont'd The fibrous material hanging  out of the bearing was  someone's spaghetti from  lunch.  The bearings were contaminated and we had no other spares.  What a mess.  We spent  the next three hours flushing the thrust bearings with a  cleaning agent.  Even though we removed  the majority of solids the  bearings should have been  scrapped out and replaced  with new ones. After about an hour we were  waiting to see who was going to accept responsibility.  We  had made it perfectly clear  that the bearings were  contaminated and that they should be changed out. I don't know who finally gave the green light, or the authorization to proceed, but I got the impression from overheard conversations  going around - that the contaminates are biodegradable and they may not adversely affect the bearing life.  Wow! The green light was given by one of the plant officials who said they wouldn't hold us to any warranty provisions because of the contamination. 30 hours into the job the pump  was installed and wired up. We  told them not to connect the  motor coupling so we could  check motor rotation.

Bingo!  It was reverse rotation.  We had them swap out the two of the three electrical leads to  correct motor rotation. You know that was over twelve  years ago and the bugger is still  working fine.  What can you say!   The K.I.S. Principle By Wayne E. Lovison - NPI A long time ago a good friend of mine told me that when inspecting a field problem – keep it simple. The majority of us look for things out of the ordinary when the  answer is right there in front of us. If this is new equipment, and it  was factory tested, then it has  to be one of the following that  is influencing the equipments performance. Ask simple questions - such as: 1.  What is the pump discharge       pressure?  2.  Does the system back       pressure meet the pumps      design conditions? 3.  Could I have a suction problem?       Is it starvation? Look for tramp      material.  Was the equipment      supplied with a suction strainer? 4.  Do I have the correct rotation?       Do I have the  correct motor      voltage?  5.  What is my operating speed?  6.  Do I have - High Amps or       Low Amps?

7.  Did I check all mounting      hardware? 8.  Could I have pipe strain? Might      I have Coupling Misalignment? 9.  Did you recap the plant       system operating procedures?      I have seen operations vary      from operator to operator.       If a recent repair I'd ask -      a. Did they use OEM materials?      b. Did they establish the OEM           shaft and bore tolerances?      c. Was shaft straightness          checked?      d. Was the impeller balanced?            Mail Box  E-Mail: service-parts@naglepumps.com Valuable references and additional  training is available from one or more  of the sources listed below: 1.  The Hydraulic Institute Standard’s 2.  The Pump Handbook; published      by McGraw-Hill, coauthors -      Mr. Igor J. Karassik       Mr. William C. Krutzsch       Mr. Warren H. Fraser       Mr. Joseph .P. Messina  3.  PUMPS & SYSTEMS      Titled: The Pump Handbook      Series 1999 Edition Volumes 1-5      by Randall Publishing 4.  Cameron Hydraulic Data Handbook 5.  The McNally Institute For Pumps       And Mechanical Seals,       written by Mr. William J. McNally      WEB: www.mcnallyinstitute.com