alignment - rotating equipment
DESCRIPTION
Rotating equipment alignmentTRANSCRIPT
Shaft Alignment
Type of misalignment Shaft alignment is the process to align two or more shafts with each other to within a tolerated margin.
Parallel or Lateral misalignment
Shaft in Alignment
Combined Angular and
Lateral misalignment Angular misalignment
Types
•Parallel or Lateral misalignment•Angular misalignment•Combined Angular and Lateral misalignment
Disadvantages of Misaligned shafts
• Forces are generated• Vibration, noise, bearing damage, shaft damage,
coupling damage and Looseness.• Shaft to fracture and break.
Shaft Aligning Techniques
• Conventional method
• Dial Test Indicator (DTI)
• LASER Equipment
• By using computer
Preliminary alignment procedure Clean the machine base, bolts. Remove rust burrs etc. Check coupling & shaft run-out Check bearing clearance (especially for old machines) Check strain of pipes, cables & conduits Rough alignment Check DBSE Check soft foot Check dial gauges before taking readings Check indicator sag Verify accuracy of readings Use correct bolt tightening procedure Don’t lift the machine more than necessary Put the stem of dial gauge perpendicular to the surface Use jack bolts Use stainless steel shims
Run-out check
Max. allowable run-out;
0 – 1800 rpm = 125 µm (5 mils)1800 – 3600 rpm = 75 µm (3 mils)3600 + rpm = 50 µm (2 mils)
(unless otherwise not given by vendor)
Rough alignment
Within 0,5 mm (20 mils)
Angled soft foot
Parallel soft foot
Soft Foot
Soft Foot correction
Shell DEP and API 686;
min shim height 3 mm at beginning of alignment
Hold Down bolts tightening
Soft Foot checking
Shell DEP max 0.03 mm (API 686 max 0.05 mm (2 mils))
What is Sag?
Shell DEP ≤ 0.02 mm/ meter
Sag check
Perpendicular to the coupling surface.
Fixing of Dial gauges
Rim and Face Method
VERTICAL; V TIR = 180ᴼ - SAG - 0ᴼ, Face FVₒ = TIR, Rim RVₒ = TIR/2, VO = RVₒ - (VA x C x (C1/C)), VA = FVₒ/ C2Shim MNf = VA x (B + C) - RVₒ, Shim MFf = VA x (A + B + C) - RVₒ
HORIZONTAL;H TIR = 90ᴼ - 270ᴼ, Face FHₒ = TIR, Rim RHₒ = TIR/2, HO = RHₒ - (HA x C x (C1/C)), HA = FHₒ/ C2Move MNf = HA x (B + C) - RHₒ, Move MFf = HA x (A + B + C) - RHₒ
Alignment TolerancesShell DEP
Parallel =
All speeds and coupling spacer lengths ≤ 250 mm; 0.05 mm
All speeds and coupling spacer lengths > 250 mm; 0.02 mm per 100 mm of spacer length
Angular =
0.05 mm (based on a diameter of 150 mm)
Piping AlignmentShell DEP
Off-set = 0.3 mm/ of 100 mm flange diameter and max 1.5 mm
Angularity =
For flange dia. < 300 mm; max 0.2 mm
For flange dia. 300 to 600 mm; max 0.3 mm
For flange dia. > 600 mm; max 0.5 mm
Gap = Gasket spacing and ± 1.5 mm