Pump Care Manual - CH Spencer

1 Pump care ManualA collection of centrifugal pump maintenance articlesTABLE OF Need A Good Pipe Flanges to Pump Face and Flat Face Flanges (Mating Combinations)..10 Pump Driven Air Out of Your Pockets in Suction for Air in Centrifugal of Proper Suction Pipe Throttling Can Shorten the Life of Your Accelerates Erosion When Pumping Liquids Containing at Pump Suction Opening Can Cause Trouble Unless Precautions Are Taken .. 18 Use a Thermometer to Measure Bearing Stuffing Box You Increasing Your Stuffing Box Packing Problems?..23 Stuffing Box Box Cooling for High Temperature SealsPart I - The Basic II - III - IV - Trouble Level Oilers - Operation and Bearing - Handling, Replacement and Maintenance Mounted Vibration Maintenance Records Pay Offers A Complete Line of often problems with pump and motorbearings, shaft breakage and difficulty inaligning units stem from the improperinstallation of the pumping foundations, bent or twistedbaseplates, and excessive pipe strain canall work together to make an otherwisesimple installation an operational andmaintenance headache for the life of are some tips on how you canprevent these things from causingincreased downtime and higher thanexpected maintenance NEED A GOOD FOUNDATIONThe importance of a good foundationcannot be overemphasized.

2 Thefoundation must be heavy enough toprovide rigid support for the pump, motorand base combination and to resist thenormal forces encountered when the unitis in concrete foundation firmly attached to awell designed floor system would be themost satisfactory arrangement. When siteconditions make it necessary to supportthe pump on a metal structure, thestructural members should be selectedand designed to provide adequatestiffness and mass to support the unit anddampen any vibration that may bepresent. Unsupported wood floors andthin concrete pads should be INSTALLATIONRe-alignment of the pump and driver isrequired prior to final grouting of thebaseplate. Even though the unit mayhave been aligned at the factory prior toshipment, components tend to shift intransit, during handling, or because ofuneven foundation surfaces. Factoryalignments cannot be depended uponduring or after the baseplate installed on thefoundation you need to adjust thebaseplate as necessary to level it andprovide a flat surface for the pump anddriver to rest.

3 In some installations thereare strict baseplate flatness guidelineswhich need to be adhered to. A good ruleof thumb is to level the base to per foot in all directions. Othertypes of installations may require the baseto be level to within .002 per foot. This isusually done to avoid problems later witha condition known as soft foot and toassure that oil lubricated bearings receiveequal and adequate lubrication. It isusually necessary to remove the pumpand motor from the base to attain thislevel of baseplate is leveled using shims orwedges at various locations around thebase close to where the anchor bolts arelocated. Some bases may be equippedwith leveling screws which make this5(cont'd)process somewhat easier. The wedges,shims or leveling screws are alternatelyadjusted as necessary to bring the baseto within the specified limit. Once donethe components are re-installed on this point, before grouting the unit, it isimportant to check the pump and motorfor Soft Foot and to check the RoughAlignment of the components.

4 If thesechecks are not made now and the unit isgrouted in place, any changes that needto be made later become much moredifficult and expensive. Taking a fewminutes at this point to check and correctany problems that exist may save manyhours of work 1 BASEPLATE GROUTINGOnce the baseplate is properly installed, itmust be grouted. Grout is a concretematerial or multi-part epoxy compoundthat is used to fill the cast iron orfabricated steel baseplate so that whenhardened, the baseplate and foundationbecome a unit. We recommend the useof a non-shrink grout for this grout is mixed to a water-likeconsistency, and when poured should bepuddled to insure that it flows evenlythroughout the under portion of the6(cont'd)baseplate, completely filling the base. It isrecommended that the cementatiousgrout be allowed to cure for at least 48hours. Refer to the epoxy groutmanufacturer's instructions for the propermixing and application of that to your equipment instructionmanual for further 2 INITIAL ALIGNMENTThe proper alignment of your pump anddriver is important to assure trouble-freemechanical operation.

5 Noisy operation,vibration, reduced bearing life, shaft andcoupling failures and wasted energy mayresult from faulty alignment. Beforeproceeding, you must know the thermalrise estimates of your equipment. Referto the pump and driver manuals for most common methods of measuringmisalignment are:Straight Edge and Feeler Gauges Thisis the easiest and least expensive methodof doing alignment but is also the leastaccurate. Used primarily for very smallpump/motor combinations where there isnot enough room to use more accurate,but larger alignment systems. Thestraight edge is laid across the flanges ofthe coupling hub and the feeler gaugesare used between the faces of thecoupling hubs. Shim changes areestimated and the alignment is attainedthrough a process of Trial & Error .Usually you cannot attain the equipmentmanufacturer's alignment specificationsthrough the use of a Straight Edge andFeeler Indicators Used either singly or inpairs, as with the Reverse IndicatorMethod, the actual misalignment ismeasured by the indicator and through afew arithmetical calculations shimchanges are Somewhat more complicated toset up but can be more accurate ifproperly used.

6 The laser especially lendsitself to aligning shafts that are separatedby more than a few inches. Since themachines have the capability ofcalculating the shim changes required,once the operator becomes familiar withthe set-up he or she can do the alignmentof a pump / motor combination fairlyquickly and accurately. The primarydrawback of the Laser is its cost and, insome cases, its size, although continuousadvances in technology are making themachines both smaller and (cont'd)Angular With a non-spacer coupling,measure the space or gap between thehubs from top-to-bottom and fromside-to-side using a feeler gauge. Themeasurements obtained should be verynearly the same. If they are not, shim ormove the motor as necessary to satisfythe tolerance stated in your instructionmanual for angular alignment. Withspacer type couplings, a dial indicatorshould be used to obtain these the indicator base on the drivercoupling hub so that the indicator readson the face of the pump hub. Rotate bothshafts and read the indicator at 4 points,90 apart.

7 The readings obtained will tellyou how far out of alignment yourequipment is from side-to-side as well asfrom top-to-bottom. Add or remove shimsfrom under the driver to correct thealignment. The amount of shimadjustment needed depends on theamount of misalignment present anddistance from the point of measurement tolocation of the Using a straight edge rest theedge on top of the coupling hub and at90 to the top. The amount ofmisalignment is shown by the gap presentbetween the straight edge and the a spacer type coupling mount a dialindicator on the pump coupling hub sothat the indicator reads on the motorcoupling hub. Rotate both shafts andread the indicator at 4 points, 90 readings obtained will tell you how farout of alignment your equipment is fromside-to-side as well as top-to-bottom(elevation). Correct the top-to-bottomalignment first by shimming the driver asneeded one half the amount shown on theindicator. Correct the side-to-sidealignment by moving the driver asneeded, again, by one half the amountshown on the indicator.

8 Recheck thetop-to-bottom (elevation) to make surethat it did not change during the sure to allow for the thermal riseestimates of both pump and 38 ALIGN PIPE FLANGES TO PUMP FLANGESN ever run pipe to the pump - always runpipe from the pump to a point several feetaway where the final pipe connection canbe made. This will help to minimizeexcessive pipe strain on the pumpnozzles. The piping must beindependently supported with anadequately designed pipe hanger systemthat will not allow the pump to carry theweight of the pipes or the liquid in system should also be designed toaccommodate whatever thermalexpansion or contraction is the piping has been made up, thealignment must be rechecked. Bycomparing this check with the initialalignment figures, the installer candetermine the amount of pipe strain whichhas been put on the pump nozzles. Thepiping should be adjusted if there is anysignificant change in the 49 RAISED FACE AND FLAT FACE FLANGES(MATING COMBINATIONS) pumps of cast iron construction arefurnished with 125 or 250 lb.

9 Flat face( ) flanges. Since industry normallyuses fabricated steel piping, the pumpsare often connected to 150 or 300 " raised face ( ) steel can occur with this flange matingcombination. The pump flange tends topivot around the edge of the raised faceas the flange bolts are tightened. Thiscan cause the pump flange to breakallowing leakage at the joint (Fig. 5).A similar problem can be encounteredwhen a bronze pump with flanges isconnected to steel flange (Fig. 6).Since the materials are not of equalstrength, the bronze flange may distort,resulting in avoid problems when attaching bronzeor cast iron pump flanges to pipe flanges, the following stepsshould be taken (refer to Fig. 7):1. Machine off the raised face on thesteel pipe Use a full face the pump is steel or stainless steel flanges, no problem arises sincematerials of equal strength are beingconnected. Many customers, however,specify flanges on steel pumps formating to companion flanges. Thisarrangement is technically and practicallynot purpose of an flange is toconcentrate more pressure on a smallergasket area and thereby increase thepressure containment capability of thejoint.

10 To create this higher gasket load, itis only necessary to have one-half of theflanged joint supplied with a raised face -not both. The following illustrations show4" steel and mating flangecombinations and the gasket loadingincurred in each the force (F) from the flangebolts to be 10,000 lbs. and constant ineach combination, the gasket stress is:P (Stress)Bolt Force (F)Gasket Area=P (Fig. 8)10,000 sq. psi ==P (Fig. 9) =P (Fig. 10) =10,000 sq. in .630 psi=It can be readily seen that the smallergasket, used with a raised face flange,increases the pressure containmentcapability of a flanged joint. However, itcan also be noted that there is nodifference in pressure capability to and to addition to being technicallyunnecessary to have a to combination, the advantages are:1. The elimination of the extra cost The elimination of the extradelivery time required for anon-standard (cont'd)11 PUMP START-UPAll of the factors that contribute tosuccessful pump operation must bechecked carefully before starting a new orrebuilt pump.