Pump unit alignment with the Vibro-Laser
VIBRO-LASER «EXPERT CONFIGURATION»
Any equipment should always be checked and tested in real conditions: everything always works well on the stands! I got a VIBRO-LASER «Expert configuration» (this configuration includes geometry alignment functions) and simple equipment that needs to be centered — wilo centrifugal pumps. The equipment was fairly new, but according to the results of vibration diagnostics, which must be performed before and after work on the rotor equipment, there were indications that these units were misaligned. The maintenance department was not able to do the alignment well enough to ensure long and trouble-free operation, so we decided to do the alignment together.
Any equipment should always be checked and tested in real conditions: everything always works well on the stands!
I must remind you, that before you start work (by order or authorization), it is necessary to ensure full compliance with safety requirements and to study the installation instructions first. Immediately before alignment it is necessary to check the tightness of the fastening elements of the structure (ideally using a torque wrench) and the "soft foot". And Ii necessary, also check the tensioning of the piping.
LACK OF REPEATABILITY
During discussion with colleagues, I found out that they had encountered a problem, namely lack of repeatability. Inspection of the elastic coupling revealed quite large backlashes. As one option, it is possible to remove the backlash by wrapping both halves of the coupling halves with duct tape. A hex key of the required size can be inserted between the coupling halves to ensure the required coupling spacing (DBSE).
If the repeatability of the alignment results is hindered by increased vibration, such as that transmitted through the piping, and is difficult to eliminate, the software allows you to disable the inclinometers and perform a clockwise alignment using a bubble level.
ALIGNMENT ALGORITHM
There is no point in describing the theory of alignment, quoting the VIBRO-LASER manual or the installation instructions for the pump unit, but I will describe the alignment algorithm in briefly: First eliminate the misalignment in the vertical direction, then make the displacement in the horizontal direction.
It is often the case that horizontal and vertical displacements are not possible. The motor is higher than the pump or the hole in the foot is against a bolt, i.e. the desire arises to move the pump. For such a decision it is necessary to weigh all the risks so that the alignment work does not turn into reassembly and repair of the pump unit: a piping without a soft insert can significantly move the pump sideways, a rigid piping will not ensure vertical displacement of the pump. And most importantly, by this actions the pump can be broken: the casing will crack, the pump legs will break off, etc. In practice, in this case it is better to use a low-cost option: to grind the bolts according to the thread diameter (the breaking torque will not be reduced), to bore the hole or to reduce the height of the motor feet, possibly to move the subframe or other element of the pump frame.
After all necessary movements have been made, the alignment must be checked at least twice and the results must be reported.
