Pump Alignment / Pump Piping

Pump Alignment / Pump Piping Q&A

Proper positioning of the pump that is fixed on the base and correct orientation of pump piping that is pipe that connects pump to the system, are two factors that go a long way in enhancing efficiency of the centrifugal pumps in varied tasks.

Pump Alignment: Proper pump alignment relates to the position of the shaft of a centrifugal pump in relation to the driver shaft as usual to be a motor or an engine. During such alignment it is the aim to arrive at angular and therefore also at parallel alignment. While the angular alignment is responsible for dealing with the angular displacement of the pump and the driver shafts, the parallel one is employed to treat with parallel displacement of the two shafts. The right positioning also particularly eradicates oscillations and by doing this, reduces stress forces on the different parts of a pump which contributes positively towards performance and service durability of the pump. Other methods, which can be used in alignment are; the use of lasers in alignment, for example.

Pump Piping: Pump piping is therefore the process of formation of the piping system that is linked to a centrifugal pump and the installation of the piping system to the centrifugal pump. Proper design of pump piping is of great significance when it comes to influencing the character of the pump both in terms of performance and in safety. Some of the areas concerned are suction and discharge piping, pipe dimensions, pipe materials and pipe supports. The design of an effectively system of piping entail low friction head losses, nonformation of cavitation, and accommodation of expansion and contraction. The fixed valves, strainers and other accessories to be installed in the piping system are also required for good flow regulation, prevention of pump damage.

Pump alignment and pump piping are two of the critical areas in the life cycle of any pump system. Appropriate positioning is that the mechanical parts of the pump run in a co-ordinate manner, PIPEnn, systems that have been well designed and are in good condition enables flow of fluids within the pump with; out any interruption thus facilitating the internal reliability and performance of the whole mechanical systems.

1. What are different types of pumps?
Basically there are two types of pumps.
A. Centrifugal pump.
B. Positive displacement pump.
2. What are the different types of centrifugal pump?
Different types of centrifugal pump are: -
A. Single stage or
B. Multi-stage
3. What is the basic difference between single stage and multi-stage centrifugal pump?
The Single stage pump has one impeller and multi-stage pump has two or more impellers in series. The discharge of one impeller is the suction of the next one and the head developed in all the stages are totaled.
4. How many types of centrifugal pump are available based on the suction and discharge arrangement?
Based on the suction and discharge arrangement, the type of centrifugal pumps available is: -
A. End suction top discharge.
B. Top suction top discharge.
C. Side suction side discharge.
5. What are the different types of casing?
Casings are generally of two types: volute and circular. The impellers are fitted inside the casings.

6. Define the working mechanism of centrifugal pump?
A centrifugal pump is arguably the most uncomplicated object of use in any process plant. The basic function to transform the input energy from the prime mover which is an electric motor or turbine into kinetic energy and then to pressure energy of the fluid that is being bore.The energy changes occur by virtue of two main parts of the pump, the impeller and the volute or diffuser. The impeller is rotating part that converts drivers energy into the kinetic energy. The volute or diffuser is the stationary part that converts the kinetic energy into pressure energy.
7. How the kinetic energy created by centrifugal force is converted to pressure energy?
Rotational energy is kinetic force energy; it’s the energy that manifests by virtue of the centrifugal force. The energy supplied to the liquid is proportional to the velocity which is at the edge or the tip of the vane of the impeller. With either an increase in impeller revolutions per minute, or impeller diameter, the velocity at the vane tip is higher and therefore the quantity of energy transferred to the liquid is higher. This kinetic energy of the liquid coming out of the impeller is utilised by the establishment of resistance to the flow. The first resistance is created by the pump volute (casing) that catches the liquid and slows it down. In the discharge nozzle, the liquid further decelerates and its velocity is converted to pressure according to Bernoulli’s principle. Therefore, the head (pressure in terms of height of the liquid) developed is approximately equal to the velocity energy at the periphery of the impeller expressed by the following formula as: -
H = v2/ 2g
Where,
H = Total head developed in feet.
V = Velocity at periphery of impeller in ft/sec.
G = Acceleration due to gravity-32.2ft/sec2
Formula for calculating peripheral velocity:
V = NX D
229
Where,
V = Peripheral velocity in impeller in ft/sec.
N = The impeller rpm (revolution per minute)
D = Impeller diameter in inches.
One fact that must always be remembered: A pump does not create pressure, it only provides flow. Pressure is a just an indication of the amount of resistance to flow.
8. What do you mean by cavitation in pump?
A pump is designed to handle liquid, not vapor. The satisfactory operation of pump requires that vaporization of the liquid does not occur at any condition of operation. This is so desired because when a liquid vaporizes its volume increases very much. For example, 1 ft3 of water at room temperature becomes 1700 ft3 of vapor at the same temperature. The vaporization begins when vapor pressure of the liquid at the operating temperature equals the external system pressure, which in an open system is always equal to atmospheric pressure. Any decrease in external pressure or rise in operating temperature can induce vaporization. The vapor pressure occurs right at the impeller inlet where a sharp pressure drop occurs. The impeller rapidly builds up the pressure, which collapses vapors bubbles causing cavitation and damage the pump internals. This is avoided by maintaining sufficient NPSH. (Cavitation implies cavities or holes in the fluid we are pumping. These holes can also be described as bubbles, so cavitation is really about the formation of bubbles and their collapse. Bubbles form whenever liquid boils. It can be avoided by providing sufficient NPSH.)

Alignment pump and motor

To align a pump and motor, you will need the following tools:

• Dial indicator
• Straight edge
• Feeler gauges
• Alignment shims

Procedure:

1. Place the pump and motor on a level surface.
2. Connect the pump and motor with a coupling.
3. Mount the dial indicator on the motor shaft.
4. Position the dial indicator tip so that it is contacting the coupling face.
5. Zero the dial indicator.
6. Rotate the pump shaft by hand.
7. Observe the dial indicator reading.
8. If, once more, at the instant when all the bolts that secure the motor are released, it becomes possible only to obtain a number other than zero at the dial indicator, it should be shifted in such a way that the reading at the dial indicator will be equal to zero.
9. Check the motor mounting bolts and if sighted then tighten the bolts up.
10. Perform 4-9 on the other part of the coupling as well.
11. But where coupling is well aligned one may be in a position to have to use feeler gauges to measure the space between the two halves of the coupling. The sources of the gap should be between 0. 005 and 0. 010 inches.
12. If the gap to be provided between the compressor cover and compressor shell is larger or smaller, then the alignment shims had to be made to the gap dimensions.
13. Once the gap is correct, tighten the coupling bolts.

Tips:

• To begin alignment of the pump and motor, make sure that both are flat on the floor.
• The proper way to align the pump and motor shafts is to employ a straightedge to the two sets of shafts.
• Mount a suitable dial indicator that should be sensitive to at least 0. 001 inches or less.
• One should be extra cautious not tighten the coupling bolts to an extent that may strain a lot.

If you are not comfortable in aligning a pump and motor, it will be advisable to seek assistance from the technician.

Safety precautions:

• Wear safety glasses whenever you are in the vicinity of operating machinery.
• Accidentally never place your hand in the process of the machinery as it is in rotation.
• It is also important that the pump and motor be off and locked out at the start of the process.

Steps for Proper Pump-Pipe Alignment

To properly align a pump and its piping, you can follow these steps:

1. In preparation: The pump and piping. Ensure that there are no restrictions and that the pump and all the piping are clean, free from debris, and adequately supported.
2. Roughly align the pump and piping. This can be done by eye or using a straightedge.
3. Precise accuracy and repeatable alignment should be obtained by adjusting the alignment with controlled coarse and fine adjustments with a dial indicator. Place the dial indicator on the shaft of the pump and align it in such away that it will be touching the piping. Manually rotate the pump shaft and take the reading of the dial indicator. If we get a reading other than zero, then move the pump or piping in the system in a way so as to get a zero reading.
4. Tighten the pump and piping connections. Once the pump and piping are aligned, tighten all of the connections.

Here are some additional tips for proper pump-pipe alignment:

• This is because if the two are to be aligned, both the pump and piping must originally be in level.
• Such an indicator should be, at the very least, of high sensitivity. 001 inches or less.
• For example do not make the pump and piping connections any tighter than the necessary tightness.
• But if you are not certain of how to align a pump and piping you have to consult a professional technician.

Safety precautions:

• One of the safety measures that should always be taken is putting on of safety glasses each time there is the use of any equipment.
• What does not make sense and can lead to severe action is putting ones’ hand into the rotating machinery part for one’s hand will be chopped off.
• To this end the power switch should be switched off and locked before approaching the pump to avoid endangering the lives of the workers and other people in the surrounding area.

Here are some of the benefits of proper pump-pipe alignment:

• Reduces vibration and noise
• Extends the life of the pump and piping
• Improves pump performance
• Reduces energy consumption
• Prevents leaks and other problems

By following the steps above, you can ensure that your pump and piping are properly aligned, which will lead to a number of benefits.

Pump Installation Alignment Method and Piping installation Details

Pump laying and alignment of pumps are very sensitive factorities which determine effectiveness of centrifugal pump in the system. In order to avoid problems such as vibrations and lack of alignment, as well as wear, it is crucial to install the pipes as well as their connections correctly. Here are the key methods and details for pump installation, alignment, and piping:

Pump Installation:

Foundation: Ensure that the pump is fixed on stable and level base because the vibration may affect the pump. It should also be in a position to support loads and preassure which is exerted by the pump in question.

Alignment: There is always a misalignment between the pump and the driver which in the majority of the cases is an electrical motor or an IC engine. Parallel and angular alignment should be done accurately and this can satisfactorily be achieved with laser alignment.

Baseplate: These are to be generally mounted on a base plate and the plate should be sufficiently large and constructed to bear the loads from the equipment and contribute towards avoiding misalignment.

Coupling: For the diagnostic of each type of pump couplings, if a coupling connects the pump to the driver, then the coupling must be in the right position and should also be elastic to accommodate the expansion of both parts by heat expansion.

Piping: The pump is connected to the piping system by an appropriate flanges gasket and fasteners in order to meet the rigors demanded for the system in an appropriate manner so as to avoid possible leakage. Inlet and outlet pipe sizes and pipe arteries must conform to several specifications envisaged by the pump maker.

Alignment Methods:

Straightedge Method: This basic method involves using a straightedge and feeler gauges to check parallel and angular alignment. It provides a rough estimate and is often used as an initial check.

Rim and Face Method: Involves checking the alignment by measuring the gap between the driver and pump couplings using dial indicators. This method provides more precise alignment.

Laser Alignment: Laser alignment systems are very precise and give instant results on alignment set-up. They are commonly used for critical applications.

Piping Installation Details:

Suction Piping: This should be done until every suction piping will have been progressively designed so that cavitations cannot occur. It should also be sized such that it does not have high frictional loses and should be provided with a strainer to avoid getting debris in the pump.

Discharge Piping: The process piping in the program should also be arranged in a way that it can be able to handle the flow rates and the pressures that are required. It should also possess suitable control and isolation valves some of which included the gate valves, check valves among others.

Supports: Pipe should be restrained to reduce the load on the pump and pipe connection and this can be done by use of pipe supports. Support structure spacing and support structure anchoring are essential to getting the correct structure.

Flexible Couplings: Certain of the flexible couplings can be employed to connect the pump to the piping which helps in minimizing vibration transmission and stress of the pump and the driver.

Expansion Joints: Thermal expansion and contraction maybe regulated and managed specially in system where there are high variant in temperature using expansion joints that does not impose stress on pumps and the piping.

Alignment Flanges: It is intended for the alignment of shafts of the pump and of the motor, using one of the alignment flanges. This make it possible to make small correction along the horizontal and vertical axis.

Type and position of available centrifugal pumps, and details of piping system affect flow efficiency in relation to working life of the pumps and frequency of maintenance. Manufacturers’ specifications such as those dealing with the installation and alignment of the pump should be followed as should industry best practices.

pump alignment calculation

There are two main methods for calculating pump alignment: the rim and face method and the reverse dial indicator method.

Rim and face method:

In this method, distances from the middle of the cylinder of the pump shaft to the extreme circumference of the coupling bore and the coupling face are taken. The alignment of the pump shaft with that of the coupling and other components is considered to be correct when the distances measured from the center line of the pump shaft to the rim and face as well as the face of the coupling are also the same.

Reverse dial indicator method:

In this method, the dial indicator displacement is taken while revolved the pump shaft. It is when the dial indicator reading has been equal to zero at four positions that the pump is regarded to have aligned.

Calculation:

The following formulas can be used to calculate the pump alignment:

Rim and face method:

Vertical misalignment = (Rim measurement - Face measurement) / 2

Horizontal misalignment = (Rim measurement + Face measurement) / 2

Reverse dial indicator method:

Vertical misalignment = (1/2) * (Dial indicator reading at Top - Dial indicator reading at Bottom)

Horizontal misalignment = (1/2) * (Dial indicator reading at Left - Dial indicator reading at Right)

Once the pump alignment has been calculated the pump is fine tuned into the required alignment. This can be achieved by reshaping the pump base or by repositioning of the motor.

Example:

The following is an example of how to calculate the pump alignment using the rim and face method:

Rim measurement = 0.005 inches

Face measurement = 0.010 inches

Vertical misalignment = (0.005 inches - 0.010 inches) / 2 = -0.0025 inches

Horizontal misalignment = (0.005 inches + 0.010 inches) / 2 = 0.0075 inches

In this example the pump shaft is offset in the vertical direction by -0. 0025 inches vertically and absent tenon joints horizontally. 0075 inches. Alignment of the pump can be corrected by shifting adjust the pump or alternatively it can be performed through adjusting the position of the motor.

The following are some simple formulas that can be used in determining alignment of a pump; More complex formulas may be required for certain applications. It is always best to consult with a qualified technician when aligning a pump.

pump alignment standard

Pump alignment standards refer to the general and recommended practices of aligning the centrifugal pumps with their drivers and in most cases are either electric motors or engines. The correct pump alignment is crucial to its performance and durability and also plays a pivotal role in obviating the problems like arising vibrations, premature wearing and knocking more frequently resulting in frequent service calls. Despite the fact that, there are several alignment standards and procedures, among the international standard procedures, one of the best known is the ISO 1940 standard on balancing and vibration of mechanical rigid rotors.

Here are some key alignment standards and guidelines that are commonly referenced in the industry:

ISO 1940: ISO 1940 is an international standard that focuses on the balance quality of rotors including the ISO pump rotors. From it, one can determine the degree of unbalance and it has standard prescriptions for the amounts of unbalance allowable. The appropriate sharing of loads is very important when it comes to prevention of vibration and probably the destruction of the pump and the driver.

Centrifugal Pumps: API 610: The American Petroleum Institute (API) has issued the API 610 standard for a centrifugal pump used in the petrochemical and oil industries. It also covers alignments for and specifications on centrifugal pumps in the above applications.

ANSI/HI 9. 6. 4: The Hydraulic Institute (HI) releases the ANSI/HI 9. 6. 4 A Pump Installation : VSP 68 : 4 – A: A standard for alignment of vertical shaft pumps. This standard gives detailed instructions on how the vertical pumps should be aligned as they have challenges that different from the horizontal ones.

AGMA 423. 06: The AGMA, the American Gear Manufacturers Association has a standard known as the AGMA 423. 06/MACH the standard that deals with the selection and installation of flexible couplings commonly applied in various kinds of equipments inclusive of pumps. In this case, it is important to ensure that the couplings are aligned correctly to reduce on vibration as well as any form of shaft misalignment.

Manufacturer Guidelines: Furthermore, manufacturers of pumps have given a detailed guideline for the alignment of their products in their literature on installation and operation of the pumps. It is important to follow these guidelines in order to guarantee that the pump runs the way is predicted.

Alignment standards were found to include facets of alignment for example parallel and angular. It is done to guarantee that the pump and driver shaft will run literally in line, therefore avoiding such problems as bearing wear, leakages of seals and damages coming from vibration. Moreover, laser alignment tools are in most cases applied in order to align gears constantly and meet these standards.

To keep the reliability and capacity of pump systems, the proper guidelines of alignment standards and the recommendations of the manufacturer are to be followed while aligning the pumps. Aging many times affects the equipment and hence proper alignment can help in avoiding this situations hence making the equipment to last long and also can help in cutting costs which are used in maintaining the system more often.

pump alignment procedure

Alignment of the pump is very significant and is very useful in the running of centrifugal pumps. Here, then, is a step-by-step process for coupling a pump to its driver — for example, an electric motor or internal-combustion engine. The present procedure presumes that the reader is familiar with fundamental alignment aids and appliances, including straightedges, feeler gauges, and dial indicators. Certain other alignment techniques such as laser alignments may also be incorporated in the alignment process.

Pump Alignment Procedure:

Prepare the Work Area:

• This involves seeing to it that the working environment is clean, well-lit, hygienic and free from any form of hazards.
• Secure the pump and driver so that it cannot be started unintentionally.

Check Foundation and Baseplate:

• Verify that the pump and driver are securely mounted on a stable and level foundation or baseplate.

Initial Rough Alignment:

• Perform a visual check to ensure that the pump and driver shafts are approximately parallel and at the same elevation.
• Use a straightedge or laser alignment tool to make a rough initial assessment.

Check Soft Foot:

• Verify that there are no soft foot conditions, which can introduce misalignment. Soft foot refers to uneven contact between the baseplate and the equipment.

Angular Alignment:

• Check and adjust the angular alignment. This is the angle between the pump and driver shafts.
• Use a precision straightedge to measure the angular misalignment.

Parallel Alignment:

• Check and adjust the parallel alignment. This involves ensuring that the pump and driver shafts are parallel.
• Use feeler gauges or dial indicators to measure the parallel misalignment.

Adjustment:

• Make adjustments to the driver (motor or engine) mounting bolts to achieve proper angular and parallel alignment.
• Utilize shims, wedges, or adjustment screws to move the driver as needed.

Repeat Measurements:

• Recheck the alignment several times after adjustments to ensure that the alignment is within acceptable tolerances.

Final Verification:

• Confirm that the pump and driver are aligned correctly in both angular and parallel directions.
• Perform a final check using a dial indicator.

Tighten Fasteners:

• Tighten all of the mounting bolts to ensure that all the readings are up to the manufacturers recommended values as you tighten all the bolts on the mounting.

Check Coupling Alignment:

• Should the coupling be used to connect the pump and the driver then it has to be fit with the minimum allowable axial and angular offsets.

Reconnect Power:

• Reconnect the pump and driver to the power source and start the equipment.
• Monitor for unusual vibration or noise, which may indicate misalignment or other issues.

Documentation:

• It is also important to take records of the measurements of alignment, adjustments that have been made as well as the final results of the alignment.

In the long run, the fact that this pump and the driver are aligned in the right manner eliminates problems such as vibration, badly aligned shafts, and other problems that are associated with the early wearing out of the pumping systems. If possible the advice from this manufacturer and comparison with other manufacturers and systems should be taken in regard to precision of alignment.

Pump alignment methods

There are several methods for aligning pumps, each with its own advantages and disadvantages. The most common methods include:

• Rim and face method: This entails determination of the distance from the centre of the pump shaft to face of the circumferences of the coupling. In as much as the distance of the pump shaft centre line to the coupling rim is equivalent to the distance of the pump shaft centre line to the coupling face, then the pump is deemed to be in-aligned.
• Reverse dial indicator method: This method involves use of a dial indicator to measure the amount of ‘back and forth’ movement of the shaft of the pump when the shaft is being rotated. If no reading is indicated with the dial indicator at any of the four positions then the pump is said to be in an aligned condition.
• Laser alignment: This one employs the use of laser beam in order to establish the position of the shaft of the pump to that of motor shaft. It is reckoned that the pump is aligned whenever the laser beam seems to project on to the target on the motor shaft.

Other pump alignment methods include:

• Straight edge method: In this method, simple straight edge is utilized to measure relative parallel distances of any two parallel surfaces here pump shaft and motor shaft. It is reported to happen in the lateral plane of the pump where the straight edge is perpendicular to both of the shafts.
• Feeler gauge method: Also this method requires the use of feeler gauge to establish the amount of space between the two rods, that is the pump shaft and the motor shaft. This gap is then quantified to see where it falls in relation to the manufacture’s specifications and if it falls there then it is said to be in conformity with the pump specifications.

Consequently, the optimum way of designing a pump may well be context sensitive in so far as the way it can be optimized is concerned and the means at the disposal for achieving this objective. Thus, among the techniques enumerated above, laser alignment technique can be regarded as the most time-saving one and rather effective and accurate yet expensive. The rim and face method is comprehensive all round method which is relatively easy to implement. The reverse dial indicator method is one of the most suitable procedures to use in making alignments when the use of the laser alignment is not possible.

Nevertheless, it is worthy the reminder that the pump alignment should be done by a professional technician. Improper alignment can lead to a number of problems, including:Some of the negative consequences of improper alignment are that:

• Reduced pump performance
• Increased energy consumption
• Increased wear and tear on the pump
• Vibration and noise
• Leaks and other problems

By following the proper alignment procedures, you can ensure that your pump is operating at its best and that it will last for many years to come.

pump alignment types

There are two main types of pump alignment:

• Static alignment: This type of alignment is conducted when the pump is off and thus it is recommended to carry out when the pump is stationary. The static alignment refers to the alignment process of pump shaft and the motor shaft to enable them to lie in the same plane in a parallel manner.
• Dynamic alignment: Like in simple alignment, this type of alignment is done when the pump is in operation. Dynamic alignment is the process of lining up the two shafts of the pump and the motor so as to counter for the bending of the pump shaft when it is loaded.

Static alignment is the most common type of pump alignment and normally done with the help of dial indicator or laser alignment tool. Dynamic alignment differs from static alignment and has to be done with the help of a special equipment.

In addition to the two general categorisations of pump alignment that are illustrated above, there are other types of alignment that may be used with pump: The most common methods include:There are following common practices:

• Rim and face method: This method involves determination of the following distance of the shaft of the pump, distance between the centre line of the pump shaft and the rim and face of the coupling. It was believed that the pump center alignment was good when the measurement between the center of the shaft and the exterior rim of the coupling and the face of the same rim was equal.
• Reverse dial indicator method: In this method the movement is rotational and is imposed or given to the pump shaft and the deviation from the dial gauge readings is computed. Pump is said to be aligned when for the four positions the dial indicator reading will be ‘0’.
• Laser alignment: This one uses a laser beam to set the levels of deviation of the pump shaft to the motor shaft. Alignment of the pump is said to occur when the laser beam focuses exactly on the target seen on the motor shaft.

There is also the fact that the decision-making concerning the choice of the best methods of alignment of a pump also depends on the application procedure, and the resources available. In general laser alignment is very accurate and time efficient; however it is also the most expensive of all the techniques. The Grout, Mallett and face and rim method is very adaptable and is regarded to be easy to perform. The reverse dial indicator is thus suggested for uses where laser alignment is out of the question.

Subsequently the authors wish to note that alignment of pumps should be done by a professional. Improper alignment can lead to a number of problems, including:If the spine is not aligned correctly the following consequences may occur:

• Reduced pump performance
• Increased energy consumption
• Increased wear and tear on the pump
• Vibration and noise
• Leaks and other problems

Following the right alignment procedures will see you enjoy the use of your pump for many years to come, when in the right condition.