Table of Contents
What is Pump Alignment?
The proper alignment of the pump ensures its proper working. The different experiences represent that many pumps fail due to their misalignment. Misaligned pumps also use more energy (up to 15%) and increase utility costs.
A pump may produce big losses 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:
- Reduce energy loss that may generate due to vibration and friction
- Improve pump efficiency by saving time and eliminating maintenance
- Lower the expenses for the new parts
- Reduce inventory needs
To ensure proper alignment of your pump, you should also check and adjust the alignment in the following cases:
- Pump and driver motor installed for the first time (before grouting the floor, after grouting the floor, after plumbing, after the first time running).
- After repairing the device.
- After changing the process operating temperature.
- After some changes in the piping systems.
- 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.
Pump Alignment Methods
The alignment of the pump and driver is one of the most complex and critical works. A good alignment increases the service life and efficiency of the driver motor and pump. Following are the famous methods of pump alignment:
- Lasers-optic
- Dial Indicator
- Straight Edge and Feeler Gauges
1) Straight Edge, Feeler Gauges
This is the cheapest and easiest way of pump alignment. This method is less 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 a trial-and-error process. The use of a straight edge and feeler gauge makes it difficult for a device manufacturer to achieve alignment requirements.
2) Lasers-optic Device
This system generates a harmless, pulsing laser beam that automatically finds a relative shaft position and sends this data to the microprocessor. The benefits of the 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.
- 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.
- Reverse display method: This method uses two dial indicators. One dial indicator is installed 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 is fixed 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:
- Vertical Alignment
- Horizontal Alignment
For vertical alignment, lift the drive motor in a controlled and safe way to install the shims under the foot. This process can be done through different methods. 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 the 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 are prone to rusting and sticking. These may also affect the position of the shims.
Pump Alignment Problems
Multiple problems may be caused due to an incorrect alignment. The most common problems that may occur due to a bad alignment are given below:
- Reduce the efficiency and service of the system.
- Can cause an expansive repair or maintenance.
- Misalignment can damage or break different parts.
- Extreme vibration into your system.
- Overheating of the couplings may cause wear of the different components.
- Fatigue failure of drive shafts and pumps.
- Overloading of the driver bearings and pumps, which leads to bearing failure or reduce bearing life.
- Any misalignment can cause dangerous mechanical vibrations. Excessive pump vibration reduces the service life of the mechanical seal and bearings.
FAQ Section
What is a pump alignment?
Pump alignment primarily relies on precise measurements of the motor and pump shaft positions at multiple points.
How is pump alignment done?
Typically, a pump is anchored to its base, which is securely fastened to a stable foundation. The alignment process involves adjusting the drive motor shaft to align with the pump shaft. To achieve the desired vertical position, the motor must be carefully and safely elevated, allowing for the placement of shims under its feet in a controlled way.
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