Handbook Of Shaft Alignment Episode 2 Part 8 doc

FIGURE 16.4 Compressor case. FIGURE 16.5 Thermal image of compressor case. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C016 Final Proof page 480 6.10.2006 12:03am 480 Shaft Alignment Handbook, Third Edition instruments scan the object for the infrared radiation and amplify the converted electrical signals from a supercooled photodetector onto a cathode ray tube (CRT), where a photo- graphic image of the object can be recorded. Figure 16.4 shows a three-stage centrifugal compressor case and Figure 16.5 illustrates the temperature profile when the compressor is running under full load. The white areas show where the infrared radiation (heat) is the greatest. The hottest areas in the image are approximately 1358F. Figure 16.6 shows an axial flow compressor with rigid supports at the inlet end and flexible supports at the discharge end. Figure 16.7 illustrates the thermal profile of the discharge end with the compressor running under load (note the hot spot at the one o’clock position). Figure 16.8 shows a closer view of the flexible support leg. The lifting eye is at the left side of the photograph and the flex leg is the black portion just to the right of the lifting eye. The photograph clearly shows that the support leg stays at ambient temper- atures and does not expand thermally (as originally thought when the machinery was installed). Although movement of rotating machinery casings does not occur solely from temperature changes in the supporting structures and the casings themselves, infrared thermographic studies can assist in understanding the nature of the thermal expansion that is taking place. 16.7 INSIDE MICROMETER–TOOLING BALL–ANGLE MEASUREMENT DEVICES Another technique that falls into the category of movement of a machine case centerline with respect to its baseplate is performed using tooling balls as reference points and measuring the distance between the tooling balls with inside micrometers or with an inside micrometer and an inclinometer (angle measuring device). FIGURE 16.6 Axial flow compressors. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C016 Final Proof page 481 6.10.2006 12:03am Measuring and Compensating for Off-Line 481 Tooling balls can be purchased from a tool and die supplier or they can be handmade. Figure 16.9 shows a fabricated tooling ball and Figure 16.10 shows how it was made. Figure 16.11 shows the basic setup of the tooling balls on the baseplate and machine cases. Figure 16.12 through Figure 16.14 show the measurements taken by employing this technique. A traditional inside micrometer could be used for these measurements but environmental problems could occur. When capturing the running or hot measurements, any heat radiating from a machine case or even your hands could (and will) increase the temperature of the micrometer itself, changing its length. It is not uncommon to measure distances of 20 to 40 in. from tooling ball to tooling ball. If you are taking a 30 in. measurement and the carbon steel inside micrometer goes from 608F to 1208F, the micrometer length will change by 0.013 in. (13 mils). Not consistently accurate enough when you are trying to measure +1 mil in positional change. Figure 16.15 and Figure 16.16 show a custom made set fabricated from invar to considerably reduce the inside micrometer thermal expansion error. Tooling balls or similar reference point devices are rigidly attached to the foundation and to the inboard and outboard ends of each machine case as near as possible to the centerline of rotation as shown in Figure 16.17 through Figure 16.19. Distances between the tooling balls (and angles if desired) are captured for each tooling ball when the machinery is at rest and then measured again when the equipment is running and has stabilized thermally. Three tooling balls can be set up in a triangular pattern as shown in Figure 16.20 at each bearing on each machine in the drive train. A more accurate method is to set up four tooling balls in a four-sided ‘‘pyramid’’ arrangement at each bearing on each machine in the drive train as illustrated in Figure 16.21. These measurements can then be triangulated mathematically into vertical and lateral components (using the triangular arrangement) or into vertical, lateral, and axial component distances (using the four-sided pyramid arrangement). By comparing the coordinates of the tooling ball mounted on each end of all the machine cases from OL2R (or from R2OL) FIGURE 16.7 Thermal image of compressor end casing. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C016 Final Proof page 482 6.10.2006 12:03am 482 Shaft Alignment Handbook, Third Edition positional changes can be determined. Figure 16.22 shows the mathematics for a triangular tooling ball arrangement and Figure 16.23 for a pyramid arrangement. Key considerations for capturing good readings: . Remember that you will probably be dealing with oblique triangular arrangements not right angle triangles (i.e., watch your math). . Important to have stable positions for the tooling balls. FIGURE 16.8 Thermal image of the support leg. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C016 Final Proof page 483 6.10.2006 12:03am Measuring and Compensating for Off-Line 483 . The tooling ball on the machine case should be located as close as possible to the centerline of rotation since we are trying to determine where the shafts are going (if the bearing moves, the shaft is sure to move with it). . Recommend that concave tips be used at both ends of the inside micrometer to consist- ently seat on the round tooling balls when taking measurements. . Keep the inside micrometer away from heat sources to prevent the mike from thermally expanding. FIGURE 16.9 Tooling ball fabricated from 0.5 in. steel ball and 1.5 in. Â1.5 in. Â0.25 in. steel plate with the ball welded to the plate. Standard tooling ball Round steel ball from ball bearing 1.5" 3 1.5" 3 1/4" carbon steel plate “Vee” out a cone with a drill bit in the center Apply a bead of epoxy Tooling balls can be purchased from machine tool suppliers or can be homemade as shown below. If standard tooling balls are used, holes must be drilled in the machine case and baseplate or foundation for installation. The homemade design can be attached to machine case and baseplate or foundation with epoxy or dental cement and then removed when the survey is complete. FIGURE 16.10 How to construct a tooling ball. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C016 Final Proof page 484 6.10.2006 12:03am 484 Shaft Alignment Handbook, Third Edition . During measurements have a reference standard length comparator to insure the micro- meter itself is not thermally expanding or contracting. . Triangular tooling ball arrangements assume that there will be motion in the horizontal and vertical planes only which may not necessarily be the only directional change that is occurring (namely axial). . For best accuracy, use the pyramid arrangement with four tooling balls. . Have two or more people to take measurements and compare notes to insure the readings are identical (or at least close). . Capture a set of readings from OL2R conditions and another set of readings from R2OL conditions to determine if there is a consistent pattern of movement. Advantages: . Relatively inexpensive . Somewhat easy to set up Tooling ball arrangements are placed at both ends of both machines. The tooling balls attached to the machinery case should be as close to the centerline of rotation as possible. FIGURE 16.11 Basic tooling ball setup on the machinery. FIGURE 16.12 Measuring between two tooling balls with inside micrometer. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C016 Final Proof page 485 6.10.2006 12:03am Measuring and Compensating for Off-Line 485 Disadvantages: . Mathematics somewhat tedious particularly on four-sided pyramid arrangements. . Caution must be taken during running measurements since one end of the inside micro- meter is frequently near a rotating shaft. . If one or more tooling balls disengage from their positions (i.e., it worked out of its hole or the epoxy gave away), you will probably have to start over. FIGURE 16.13 Measuring a distance with the Acculign invar rods. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C016 Final Proof page 486 6.10.2006 12:03am 486 Shaft Alignment Handbook, Third Edition Figure 16.24 shows the results of an OL2R survey conducted on a motor-fluid drive-boiler feed water pump using the inside micrometer-tooling ball method. A pyramid tooling ball arrangement was used on this drive system. Notice the amount of movement in not only the up and down and side-to-side directions but also the axial amount of movement. Figure 16.25 FIGURE 16.14 Measuring the angle with the Acculign inclinometer. FIGURE 16.15 Acculign kit. (Courtesy of Acculign, Austin, TX, www.acculign.com. With permission.) Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C016 Final Proof page 487 6.10.2006 12:03am Measuring and Compensating for Off-Line 487 FIGURE 16.16 Acculign micrometer in calibration fixture. (Courtesy of Acculign, Austin, TX, www. acculign.com. With permission.) Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C016 Final Proof page 488 6.10.2006 12:03am 488 Shaft Alignment Handbook, Third Edition shows the desired off-line shaft position alignment models for the side and top views for the motor-fluid drive-boiler feed water pump shown in Figure 16.24. 16.8 VERTICAL, LATERAL, AND AXIAL OL2R MOVEMENT Before we go any farther into these methods, it would be prudent to closely examine the OL2R data observed on the motor-fluid drive-boiler feed water pump drive system in Figure 16.24. Pay particular attention to the amount of movement that was observed in the axial direction. As you can see, there was more movement of each machine case axially than there was in the vertical or lateral (side-to-side) directions. On the motor, the outboard end moved 19 mils FIGURE 16.17 Tooling ball setup to measure outboard bearing on motor. FIGURE 16.18 Tooling ball setup to measure inboard bearings on motor and hydraulic clutch. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C016 Final Proof page 489 6.10.2006 12:03am Measuring and Compensating for Off-Line 489 [...]... te ce rfa su X Y FIGURE 16 .21 Pyramid tooling ball setup Z Piotrowski / Shaft Alignment Handbook, Third Edition DK4 322 _C016 Final Proof page 4 92 6.10 .20 06 12: 03am 4 92 Shaft Alignment Handbook, Third Edition Far center or near center Inside tooling ball More basic equations for oblique triangles (the law of cosines) E d k d 2 = e 2 + f 2 −2ef cos D f cos D = (e 2 + f 2 −d 2 )/2ef G D F j = f * cos G e... micrometer−tooling ball OL2R method mathematics Deltanearlateral ial Nearaxial Y Z Far end math Farlateral=((farbaselft2basert ^2) +(farcenter2baselft ^2) −(farcenter2basert ^2) )/ (2* farbaselft2basert) Farbasevertical=SQR((farcenter2baselft ^2) −(farlateral ^2) ) Farbaselateral=((farbaselft2basert ^2) +(farbaselft2axial ^2) −(farbasert2axial ^2) )/ (2* farbaselft2basert) Farbaseaxial=SQR((farbaselft2axial ^2) −(farbaselateral ^2) ) Deltafarlateral=farlateral−farbaselateral... Piotrowski / Shaft Alignment Handbook, Third Edition DK4 322 _C016 Final Proof page 507 6.10 .20 06 12: 03am 507 Measuring and Compensating for Off-Line Crosshair when viewing through scope barrel Optical micrometer Optical scale target 2 4 6 8 1 2 4 6 8 2 2 4 6 83 10 10 5 0 0 5 10 10 Instrument lens Plate glass with near perfect parallel sides Optical scale target 30 2 4 6 8 1 2 4 6 8 2 2 4 6 83 10 5 40... Farvertical=farbasevertical*sinG Near end math Nearlateral=((nearbaselft2basert ^2) +(nearcenter2baselft ^2) −(nearcenter2basert ^2) )/ (2* nearbaselft2basert) Nearbasevertical=SQR((nearcenter2baselft ^2) −(nearlateral ^2) ) Nearbaselateral=((nearbaselft2basert ^2) +(nearbaselft2axial ^2) −(nearbasert2axial ^2) )/ (2* nearbaselft2basert) Nearbaseaxial=SQR((nearbaselft2axial ^2) −(nearbaselateral ^2) ) Deltanearlateral=nearlateral−nearbaselateral... 25 00 hp • 3600 rpm 5 .8 mils north Fluid drive 35.7 mils up 87 .7 mils east 4.3 mils south 494 FIGURE 16 .24 Observed movement on a motor-fluid drive-boiler feed water pump drive system from OL2R conditions 19.1 mils west 1 .8 mils up Motor Piotrowski / Shaft Alignment Handbook, Third Edition DK4 322 _C016 Final Proof page 494 6.10 .20 06 12: 03am Shaft Alignment Handbook, Third Edition Piotrowski / Shaft Alignment. .. transit (Courtesy of Brunson Instrument Co., Kansas City, MO With permission.) Piotrowski / Shaft Alignment Handbook, Third Edition DK4 322 _C016 Final Proof page 505 6.10 .20 06 12: 03am 505 Measuring and Compensating for Off-Line 0.060 in Gap between marks for sights from 50 to 130 ft 0.004 in Gap between marks for sights up to about 7 ft 4 6 8 1 2 4 6 8 2 2 4 6 8 3 Optical scale target 2 0.010 in Gap between... Nearvertical=nearbasevertical*sinG FIGURE 16 .22 Triangular tooling ball mathematics Piotrowski / Shaft Alignment Handbook, Third Edition DK4 322 _C016 Final Proof page 493 6.10 .20 06 12: 03am 493 Measuring and Compensating for Off-Line Y Farcenter farcenter Deltafarlateral asev ertic ial lft r2ax l se ente ltaxia ba Farc enter2de r2 te Farc en rc Fa Fa rb Farbaser as t2axial Fa ea rax xia ial sert l t2ba aself Farb Farb X X... / Shaft Alignment Handbook, Third Edition DK4 322 _C016 Final Proof page 495 6.10 .20 06 12: 03am 495 Measuring and Compensating for Off-Line Desired off-line side view looking north Motor Up Fluid drive Pump Projected centerline of rotation of the fluid drive shaft Projected centerline of rotation of the pump shaft With respect to the fluid drive shaft centerline, the far east bolt set of the motor should... Projected centerline of rotation of the pump shaft Projected centerline of rotation of the fluid drive shaft Actual centerline of rotation of the pump shaft With respect to the fluid drive shaft centerline, the far east bolt set of the motor should be set 1 mil to the north of the projected centerline of With respect to the pump shaft With respect to the fluid drive rotation of the fluid drive shaft centerline,... is the shaft expanding Notice that the machine cases (and probably the shafts) are moving toward each other from OL2R Piotrowski / Shaft Alignment Handbook, Third Edition DK4 322 _C016 Final Proof page 496 6.10 .20 06 12: 03am 496 Shaft Alignment Handbook, Third Edition Bolt pinching case to pedestal here Bolt sleeved here to allow sliding 10 20 mils gap between washer and casing Pedestal Key at 9 08 orientation . rods. Piotrowski / Shaft Alignment Handbook, Third Edition DK4 322 _C016 Final Proof page 486 6.10 .20 06 12: 03am 486 Shaft Alignment Handbook, Third Edition Figure 16 .24 shows the results of an OL2R survey. Alignment Handbook, Third Edition DK4 322 _C016 Final Proof page 488 6.10 .20 06 12: 03am 488 Shaft Alignment Handbook, Third Edition shows the desired off-line shaft position alignment models for the side. end * * FIGURE 16 .22 Triangular tooling ball mathematics. Piotrowski / Shaft Alignment Handbook, Third Edition DK4 322 _C016 Final Proof page 4 92 6.10 .20 06 12: 03am 4 92 Shaft Alignment Handbook, Third