How to perform Pump Alignment? | Methods of Pump Alignment

The proper alignment of the pump ensures its proper working. The different experiences represent that the many pumps fail due to their misalignment. Misaligned pumps also use more energy (up to 15%) and increase the utility costs.  In this article, we are going to deeply the pump alignment.

What is Pump Alignment?

Alignment is mainly based on accurately measuring the position of the pump and driver motor shafts at two or more points. Different equipment such as laser alignment tools, dial indicators, vernier calipers, and feeler gauges can be used to measure alignment.

The pump shaft installs in three-dimensional space. Therefore, the shaft can misalign in any direction. 

There are four specific misalignment conditions traditionally referred to as Horizontal angularity, Horizontal alignment, Vertical Angularity, and Vertical alignment. These conditions refer in the coupling position, and as long as there are misalignments, harmful mechanical vibrations can occur.  

A pump may produce big loses when the shaft misalignment exerts a reaction force on the shaft, even if the flexible coupling is not damaged immediately.

The good alignment of the pump has the following advantages:

  1. Reduce energy loss that may generate due to vibration and friction
  2. Improve pump efficiency by saving time and eliminating maintenance
  3. Lower the expenses for the new parts
  4. Reduce inventory needs

To ensure proper alignment of your pump, you should also check and adjust alignment in the following cases:

  1. Pump and driver motor installed for the first time (before grouting the floor, after grouting floor, after plumbing, after first time running).
  2. After repairing the device.
  3. After changing the process operating temperature.
  4. After some changes in the piping systems.
  5. After pump maintenance and service.

How are Pump and Motor Secured?

The pump and motor must have minimum vibration to maintain a good alignment. Therefore, you must install your pump system on a solid foundation.

As you can observe in your industry, maximum pumps are usually secured directly onto the machined baseplate and the rest of the hardware is aligned and assembled to it. This assembly is placed on a concrete base and fixed with cement or epoxy grouting. With proper construction, the dampening effect of the foundation mass helps to reduce overall vibration.

Generally, the foundation mass should be 5 times more than the mass of the piston pump pumping system and 3 times more than the mass of the centrifugal pump.

Read Also: Working of AODD Pump

Pump Alignment Methods

The alignment of the pump and driver is one of the most complex and critical work. A good alignment increases the service life and efficiency of the driver motor and pump.  There are multiple methods of the alignment and the most famous methods are given below:

  • Lasers-optic
  • Dial Indicator
  • Straight Edge and Feeler Gauges

1) Straight Edge, Feeler Gauges

This is a most cheap and easy way of pump alignment. This method is the least accurate than other alignment methods. It is mainly employed for very small pump and motor combinations that are more accurate but do not have enough room to use a larger alignment method.

In this method, a feeler gauge inserts between the coupling hub faces and a straight edge gauge inserts through the coupling hub flange. Calculate the wedge variability and make adjustments by trial-and-error process. The use of a straight edge and feeler gauge makes it difficult for device manufacturer to achieve alignment requirements.

2) Lasers-optic Device

This system generates a harmless, pulsing laser beam that automatically finds relative shaft position and sends this date to the microprocessor. The benefits of latest laser optical alignment equipment far outweigh any potential upfront cost benefits of more traditional methods.

3) Dial Indicator Alignment method

The dial indicator method has two types.

  1. Single reading method: This method contains a single dial indicator to calculate the face and rim readings. After getting these readings, you can calculate the variations in shim for the motor feet to find a perfect alignment.
  2. Reverse display method: This method uses two dial indicators. One dial indicator installs on the pump shaft to take the motor shaft reading and the second indicator installs on the motor shaft to take the pump shaft reading. After these readings, mathematically calculate the shim variations and align the system accordingly.

Although the dial gauge method is superior than the ” straight edge and feeler gauge method “.

It has the following disadvantages.

  • Sink indicator mount
  • Hold/jump on the dial hand
  • Rounding loss at low resolution
  • Read error
  • Play a role in the mechanical connection

How to Align the Pump Shaft?

In normal cases, the pump fixes to its base and fixed to a solid foundation. Next, perform an alignment to align the pump shaft with the drive motor shaft. The pump shaft alignment can be done through two methods:

  1. Vertical Alignment
  2. Horizontal Alignment

For vertical alignment, lift the drive motor in a controlled and safe way so that the shims can install under the foot. This process can be done through different methos. Usually, all legs of a motor have an integral jackscrew with a vertical screw. These can allow reasonable height changes but tend to rust and stick. You may use different hydraulic jacks, or wedges. You can also use hoists or cranes but they are difficult to perform properly.

In case of horizontal alignment of the pump, a hammer uses a hammer (hollow, rigid, or soft face) to push the motor into its mounting location. For this process, you need suitable access because it doesn’t provide sufficient control, and can cause damage. Some types of motors connected to the pumps have horizontal jackscrews that allow fine adjustment but is prone to rusting and sticking. These may also affect the shims position.

 Misalignment Problems

There are multiple problems that may cause due to an incorrect alignment. The most common problems that may occur due to a bad alignment are given below:

  1. Reduce the efficiency and service of the system.
  2. Can cause of an expansive repair or maintenance.
  3. Misalignment can damage or break different parts.
  4. Extreme vibration into your system.
  5. Overheating of the couplings which may cause wear of the different components.
  6. Fatigue failure of drive shafts and pumps.
  7. Overloading of the driver bearings and pumps, which lead to bearing failure or reduce bearing life.
  8. Any misalignment can cause dangerous mechanical vibrations. Excessive pump vibration reduces the service life of the mechanical seal and bearings.

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