Why the Performance Witness Test is Important for Centrifugal Pumps

Performance witness test is the procedure to establish the integrity of a pump and keep a record for future reference. It is necessary to ensure the pump meets industry standards and is compliant with various norms and regulations. Very often some technical snags and issues also surface during a performance witness test. 

VEMC is the leading Kirloskar Pump Distributor based out of Mumbai

In This Blog, We Explain Why A Performance Witness Test Is Important For Your Centrifugal Pump.

Verification Of Design Specifications

A performance witness test enables a user to verify first-hand the various design specifications of the pump, as promised by the supplier. The data generated during the test could be plotted on a graph to ascertain whether the pump is performing satisfactorily within the expected limits. The pump must be run long enough in order to stabilise it and test it at raised temperatures.

Detection Of Defects And Malfunctions

As any Kirloskar pump distributor will explain, testing the mechanical integrity of the pump is another important reason to carry out a performance witness test. This ensures that the pump operates satisfactorily with no defects or problems at higher temperature and vibration levels. During the test, the pump is checked for possible leaks from parts such as gaskets and seals. 

Identification Of Operational Problems

Data is plotted to identify any possible problems while running the pump. Operational issues such as misalignment, or their symptoms such as unexpected vibrations or excessive noise can be identified and corrected once the pump is put through a thorough performance witness test. Your Kirloskar pump distributor most likely will also provide pump AMC services and can be of great help in this regard.

Determination Of Energy Efficiency

A performance witness test culminates in the drafting of statistical reports which help determine the efficiency of your pump. The performance curve for instance has energy curves and efficiency curves among many others. These curve helps identify any efficiency-related issues such as overconsumption of electricity.

Documentation Of Performance

One of the most significant outputs of performance witness tests is the documentation of results. This can be of great value for future reference, especially in case of a pump breakdown, poor performance, or reduced efficiency. In other words, this acts as a medical history of sorts for your centrifugal pump!

Compliance With Industry Standards

Your centrifugal pump must comply with a number of industry standards which mostly signify optimum performance and efficiency. Some of these industry standards are:

  • Hydraulic Institute (HI) “vertical pump tests”, ANSI/HI 2.6-1994
  • ASME Power Test Codes (PTC) 8.2-1990
  • American Petroleum Institue (API) Standard 610
  • HI “Centrifugal Pump Tests” ANSI/HI 1.6-2000

If you are looking to get your centrifugal pump performance tested, get in touch with VEMC today. We are the leading Industrial Water Pumps Dealers In Mumbai and have a proven track record of excellence in AMC services. We take pride in being the most reputed Kirloskar Pump Distributor across the country. Give us a call at 022 43436655 or email us at marketing@vemc.co.in.

Five Ways to Maintain a Centrifugal Pump

 Centrifugal Pump

Maintaining your centrifugal pumps can extend the life of your pumps, reduce operation costs and minimise the chances of a sudden breakdown. With proper maintenance, you are also able to keep a record of all the problems arising in the pump which can help you zero in on future problems easily. VEMC is the leading Industrial Water Pump Dealer in Mumbai.

In This Blog, We Take You Through 5 Ways In Which You Can Ensure Comprehensive Maintenance Of Your Centrifugal Pump. 

1. Proper Lubrication

The failure of bearings is mostly caused by lubrication or the lack of it. Make sure you are lubricating the pump just enough. Over-lubrication can be as harmful to the pump as under-lubrication by creating solids on the bearings and making them run at higher temperatures.

2. Regular Inspection

Make sure you are regularly checking the pump for leaks, excessive vibrations, lubrication, and discharge pressure. Maintain a log register of your inspections and note any remarkable changes or faults. This way you can ensure proper upkeep and identify the problem instantly in case of a breakdown.

3. Control The Pump’s Operating Conditions

While the pump is working, a number of parameters like temperature, pressure and vibrations need to be kept under check. Usually, a pump will exhibit a rise in temperature while operating but watch out for overheating to prevent damage to parts. Likewise, determine the optimum flow range of your pump (represented by parameters like BEP, POR and AOR). As much as possible, make sure that your pump doesn’t operate beyond this acceptable range. 

4. Proper Alignment

Misalignment of your centrifugal pump can cause a number of problems like greater wear and tear, leakage, excessive vibration, noise, higher maintenance costs, lower energy efficiency, and even early failure. These issues can be avoided by ensuring the proper alignment of your pump.   For this, station your pump on a solid foundation which is at least thrice the mass of your pumping system. Affix the pump with cement grout or epoxy to eliminate any movement and misalignment during operations. 

Besides, monitor the shaft alignment of your pump regularly as well, to avoid any disproportionate stress and strain. In case the pump is functioning at a higher temperature, the likelihood of thermal expansion will demand greater attention to pump alignment.

5. Regular Maintenance

All said and done, regular maintenance of your centrifugal pumps is absolutely indispensable. While this may seem like an annoying overhead on your operations costs, it actually helps save you from a sudden breakdown which may cause longer downtime and serious business losses. Setting up a comprehensive preventative maintenance regime along the lines suggested by your dealer can contribute to longer pump life, better efficiency and reduced downtime. As the top Industrial Water Pump Dealer in Mumbai, VEMC provides AMC services and can also help you maintain your pumps better.

VEMC is the leading industrial water pump dealer in Mumbai. We pride ourselves in electromechanical engineering products like pumps, compressors and control panels. If you are looking to buy an Industrial Pump in Mumbai, get in touch with us by calling 022 43436655 or emailing us at marketing@vemc.co.in.

How to Install Mechanical Seal in an End Suction Centrifugal Pump

End Suction Centrifugal Pump

Centrifugal pumps have a rotating shaft that sticks out from the back of the pump casing through a seal chamber or stuffing box. The mechanical seal is needed to prevent fluid from leaking into the atmosphere along this shaft. Failure of these mechanical seals can have serious implications for the pump’s safety and reliability. It is therefore very important to install the seal properly.

How a Mechanical Seal Works in an End Suction Centrifugal Pump

A mechanical seal needs two smooth and flat seal faces in contact, one that is rotating with the shaft and another that is stationary with the casing. The faces are sealed to their holders using secondary seals. These are flexible so that they’re placed in contact and move to compensate for any misalignments or wear and tear. The faces however need lubrication to function at their best.

Steps for Installing a Mechanical Seal in Centrifugal Pumps

Here are 7 simple steps to follow when you are installing or replacing a mechanical seal in end suction centrifugal pumps:

1. Make sure the power is off

Make sure you cut the power so that the motor is not in motion. It’s even better to be doubly sure by cutting the main supply so that the motor may not start up while you’re working on it. 

2. Isolate the fluid from the pump

Next up, shut both inlet and outlet isolation valves and drain the pump casing by removing the drain plug.

3. Dismantle the pump

Use a wrench to unscrew the bolts holding the housing of the pump in place. Detach the pump carefully and keep the bolts safe for reassembly later.

4. Identify the stuffing box arrangement

If the pump is of the back pull-out design, remove the spacer element in the coupling, remove the casing bolts and pull the pump away from the casing. You can then access the seal without having to disconnect the casing from the piping. 

In case the pump is not a ‘back pull-out design, you’ll have to completely disconnect the pump after you disconnect the coupling between the pump and shaft. If the pump is a close-coupled design, you’ll have to remove the entire pump.

5. Remove the impeller

Dismantle the impeller of the pump. You can find the seal located on the shaft behind the impeller. Detach the shaft by holding it in place using a wrench and then rotate the impeller to unscrew it.

6. Detach the old seal

After removing the impeller, you can access both the rotary and stationary seal parts. The parts are usually held in place with screws all along the shaft. Remove the screw and pull away the rotary seal parts, and then remove the stationary part of the seal.

7. Replace the seal

Now place the replacement seal parts along the shaft. Push the stationary part into the casing using a new o-ring or gasket material. 
For any guidance on your centrifugal pumps, including all your sealing needs, feel free to speak to our experts at 022 43436655 or email us at marketing@vemc.co.in. We at VEMC are authorised Kirloskar dealer based in Mumbai and deal in a range of Kirloskar centrifugal pumps including multistage centrifugal pumps, (also called horizontal multistage pumps).

How to Calculate Total Dynamic Head for an Industrial Pump

TDH for an Industrial Pump

The total Dynamic Head in an industrial pump refers to the total pressure when water is flowing in a particular system. It has two parts: the vertical rise and friction loss. In this blog, we explain to you the complete calculation of the TDH. So let’s get started.

Broadly, the TDH of a pump can be calculated by following these steps:

  1. Calculate the value of the vertical rise 
  2. Find out the friction losses in the system as the water passes through the pipe and other components
  3. Add both these values to arrive at the TDH.
  • How to calculate the vertical rise:

As the name suggests, this parameter seeks to calculate the distance up to which the liquid has to rise from its starting point in the system below to the endpoint. If the liquid level at the bottom goes down, the vertical rise will naturally increase. Likewise, in case the level of liquid rises at the bottom, it has to rise over a shorter distance to reach the endpoint, and hence the vertical rise will decrease. With the increase of the value of vertical rise, the TDH also increases.

  • How to calculate friction loss:

To find out the friction loss, it is necessary to calculate the desired flow. The greater the flow going through your pipes more will be the loss due to friction. Friction loss also depends on the type of pipe in use, its vertical and horizontal length, and its schedule. You must also factor in the elbows, valves, connectors, or other components that come in contact with the liquid, and hence contribute to the friction loss. 

  • The result: Total Dynamic Head calculation:

As stated earlier, TDH is simply the summation of vertical rise and friction loss. To arrive at the TDH value, first ensure both are in the same units of length, say feet. For instance, if the vertical rise in the worst-case scenario is 25 feet, and the friction loss of the system is 6 feet, the TDH value would be 31 feet.

  • Alternative scenario:

Always considers the worst-case scenario in case of vertical rise to ensure you have sufficient amount of TDH. For instance, in the above case, if the water level never goes below 5 feet, the vertical rise will always be 20 feet and hence the TDH value will only be 26 feet.

Other Considerations When Calculating Total Dynamic Head

A few other factors also have an impact on the Total Dynamic Head. These include viscosity, specific gravity, and temperature. The specific gravity of a liquid can slightly alter the friction losses. Likewise, viscosity can significantly increase friction losses. 
For any information on centrifugal pumps, multistage centrifugal pumps, horizontal multistage pumps, or vertical pumps, feel free to call us at 022 43436655 or email us at marketing@vemc.co.in. VEMC is the authorised Kirloskar dealer that deals in the entire range of pumps suited for various operations. VMC is an ISO 9001:2015 certified company with a rich industry experience of 72 years.

What is pump cavitation? How to get rid of it

What is pump cavitation?

Cavitation is one of the most common issues in centrifugal pumps. Often this surfaces as strange noise, vibration and reduced performance of the pump. Prevention of cavitation is necessary as this may otherwise impact the lifespan of the pump. But before talking about the ways to prevent it, let’s understand what cavitation really is.

What is cavitation?

Cavitation is simply the accumulation of bubbles around the pump impeller. Bubbles are formed in liquids of any viscosity and when these burst inside the pump, high energy shock waves are created inside the pump. This is analogous to the ripples created in a pond when you throw a stone into it. However, with the enormous number of bubbles exploding inside the liquid, cavitation can cause serious erosion of pump components over time.

How does pump cavitation occur?

When the pressure quickly drops below the vapour pressure, bubbles or voids are formed inside the liquid. When the same bubbles experience high pressure, they collapse and create small shockwaves in the process. These shockwaves create tiny holes in the pump components over a period of time. This is called “pitting”.

How to prevent pump cavitation

1. You can prevent pump cavitation most effectively by increasing the pressure upstream from the pump’s impeller. This pressure is called Net Positive Suction Head (NPSH). NPSH can be increased in the following ways:

  • By increasing the water level of the upstream reservoir
  • By adding an inducer to the pump inlet
  • By reducing the flow losses upstream
  • By operating the pump at lower flow rates

2. Even the smallest amount of air going into the pump can cause cavitation. Check and make sure all the joints and connections are sealed perfectly well. Check all the O-rings and any other mechanical seals regularly. Cavitation can also be caused by the bubbles created by a foaming liquid. In such a case, run the pump slower and remove all the contents periodically, including air.

3. Use a booster pump to reduce the pressure on your primary pump. Increase the liquid level around the suction area and if possible, reduce the temperature of the pump, liquid or other components.

Types of cavitation

Let’s try to understand two of the most common types of cavitation, that is, suction cavitation and discharge cavitation.

1. Suction cavitation

Also known as classical cavitation, this happens when the pump is under low pressure or high vacuum conditions. Pressure is dropped instantly when the liquid being pumped enters the eye of a centrifugal pump. Bubbles or cavities are formed near the eye of the impeller which gradually move to areas of higher pressure.

2. Discharge cavitation

This happens when a pump discharge pressure is extremely high or the flow is restricted and cannot leave the pump. This results in majority of the pump fluid getting circulated within the pump. The bursting of bubbles creates intense shockwaves, resulting in premature wear and tear of the impeller.

VEMC is a Kirloskar authorised dealer and deals in swimming pool pumps, submersible sewage pumps, vertical turbine pumps etc. We also offer AMC services for pumps and resolve technical issues. Avail our services by giving us a call on 022 43436655 or email us at marketing@vemc.co.in.

Unveiling the Taloja APOEM

Unveiling the Taloja APOEM

VEMC is thrilled to announce that the Taloja APOEM (Applied Pump Original Equipment Manufacturer) pump testing facility is all set to begin manufacturing and testing the pumps in accordance with industry standards.

Let’s take a look at what is in store:

The APOEM testing unit consists of pump assembling, alignment, and dismantling units. The components of the pump are put together during the pump assembly process. And during the alignment procedure, the pump components are brought into an alignment. It is during the dismantling procedure that the components of the pump are separated.

At the pump testing platform, the pumps must be tested after complete assembly in order to evaluate their performance properly. VEMC performs pump testing on a state-of-the-art testbed that was specially designed to meet the requirements of the pump OEM market.

The Lathe machine is used to rotate a pump to perform various operations such as turning, facing, knurling, grooving, and other movements.

Further, the vertical dynamic balancing machine helps to do the impeller balancing and trimming tasks according to the reading. It balances the unbalanced impeller and grinds the unbalanced part.

At the pump paint booth, the pumps are painted in the standard colours of red or blue using the spray painting method. After they have dried, the DFT of the paint is checked as a part of the final inspection.

The newly painted pumps are then packaged in a corrugated box, loaded in a lorry, and prepared to be sent to the customer.

We have planned each activity meticulously. We’ve also established Standard Operating Procedures as the guidelines to be followed while carrying out each task, in order to ensure optimal performance and safety.

VEMC is ISO 9001:2015 certified and a pioneer in the field of electromechanical engineering products, allied equipment, and services. We are a well-established industry leader and have been authorized Kirloskar pump dealers since 1950.

Today, we are excited to offer you an extensive range of state-of-the-art products and services. These include physical pump inspection, assembly, witness testing, performance assurance, and more. With decades of industry experience, we guarantee you superior services with shorter delivery times post dispatch.

We continue to provide you with top-quality products and services and hope to strengthen the trust you built in us.

How Does a Dewatering Centrifugal Pump Work?

A dewatering centrifugal pump works much like a regular centrifugal pump, but with one distinctive difference. This type of pump is built with a special feature that allows the fluid passing through it to be controlled and maintained in its movement. Let’s explore what this means and how a dewatering centrifugal pump does this.

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What is a dewatering pump used for?

A dewatering centrifugal pump, just as the name suggests, is primarily used to remove water from a particular place and transfer it to another location. A dewatering pump finds several uses across industries including construction, mining, mills, and municipal operations. Any place that needs to be kept dry and clean, such as roads and worksites, will benefit from having a dewatering pump to work with. During the monsoon season especially, a dewatering pump comes in extremely handy thanks to its effective flood control, inland wastewater management, and prompt drainage functions.

How does a dewatering pump work?

A dewatering centrifugal pump actually functions as any other pump does. Just like a centrifugal pump, the dewatering pump makes use of an impeller that has a blade to start and keep up the movement of the water. The fluid goes into a smaller part of the impeller called the impeller eye. The flow of the water is then collected from here and directed to the diffuser, which is a discharge nozzle that is shaped like a cone. This is when the velocity of the water is decreased and the energy of the water flow is changed to pressure energy.

After the above process, the water is then removed from the pump at an angle of 7 to 10 degrees for optimal efficiency. This is the stage of dewatering. To help this process along, usually, an electric motor is used. However, some pumps may use different types of motors.

Special features of a dewatering pump include a robust and compact design, light weight for portability, high fluid capacity, and high abrasion resistance to enable the most efficient handling of muddy water and slurry.

Dewatering centrifugal pumps are also easy to operate and because they are usually installed above the source of water and a ground level site, they are also quite easy to access.

Today, there are dewatering centrifugal pumps available in the market that offer extremely high performance, durability and are very reliable. Many top brands are also providing quality maintenance services. Make sure to select one that offers hassle-free servicing of parts. This will minimize the possibility of downtime and ensure that your dewatering centrifugal pump continues to function at peak efficiency levels.

For more information on industrial pumps, motors, and other equipment, feel free to contact us at +91 98199 07445. We would be glad to assist you in finding the best match for you based on your requirements. VEMC is an authorized dealer of Kirloskar dewatering pumps and provides end-to-end project management services to its clients. We are ISO 9001:2015 certified and a pioneer in the field of electromechanical engineering products, allied equipment, and services. For inquiries, contact us at marketing@vemc.co.in.

What does it mean if your pump is self-priming?

In several applications that require liquid to be pumped, the pump must be kept above the level of liquid. This lets air into the line, which can often create issues like overheating and pump failure. To avoid this from happening, a self-priming pump is used to empty out the air before moving the fluids. 

A self-priming pump is like other centrifugal pumps but is built with an outer casing that contains the fluid being pumped. The rotation of the impeller in this casing creates an area with low pressure at the impeller’s eye. This causes the fluid, along with the air, to get pushed up into the pump through the line of suction. Through its motion, the self-priming pump causes the air to separate from the fluid and get released from the casing. When all of the air has escaped, the pump allows the fluid to flow. Thus, a self-priming pump essentially removes any air pockets from the fluid to ensure smooth delivery by the pump. 

The main difference between a self-priming pump and a regular centrifugal pump is that there is no need to physically prime the former type, as its extra in-built mechanism is designed to do just that.

Practical uses

A self-priming pump can be used for anything that requires a standard centrifugal pump. This can include pumping water, sewage waste or other industrial applications. 

It is important to choose the right kind of pump for the task at hand, as well as the correct sized pump that matches the flow and head. Then, a net positive suction head (NPSH) calculation must be conducted to make sure there is adequate atmospheric pressure to sustain the required flow. Lastly, the speed of the pump must be high enough to be able to prime itself. The size of its line of suction too must be selected carefully.

Advantages of a self-priming pump

Because self-priming pumps are installed above the fluid source, the infrastructure needed to set them up is relatively less. They are easy to access due to their ground-level location. Maintenance and repair too, are simpler to conduct on a self-priming pump than on a regular centrifugal pump.

Self-priming pumps can handle a variety of liquids as well as slurries and suspended solids. They are also ideal for frequent pumping operations, as the steps involving pump priming at the start are eliminated. As well, they use less power and time to run than other centrifugal pumps. Self-priming pumps are also safer to operate, as hoists or cranes are not required for their use.

Limitations of a self-priming pump

Self-priming pumps have a limited suction lift. There are limitations in the NPSH and fluid temperature and can cause a loss of friction in the line of suction.

For more information on industrial pumps, motors, and other equipment, contact VEMC on +91 98199 07445. We would be glad to provide customized support for your requirements. We are well-established industrial water pumps dealers in Mumbai who deliver end-to-end project management services to our clients. VEMC is ISO 9001:2015 certified and a pioneer in the field of electromechanical engineering products, allied equipment, and services. 

The Importance of Reading a Centrifugal Pump Curve

A centrifugal pump is used to transport fluids by converting rotational kinetic energy into hydrodynamic energy. It finds common applications across the food and beverage, dairy, and pharmaceutical processing industries. Reading a pump performance curve is important when choosing the pump that best fits your requirements.

A pump performance curve predicts the performance of a pump in terms of its flow and pressure head and being able to read it is imperative to a pump’s performance in the long term. Also, when selecting a centrifugal pump for a new application, you need to consider its composite curve so that its performance matches the one that is most suitable for the system. Generally, a composite curve consists of pump performance and horsepower curves, as well as the required NPSH (Net Positive Suction Head).

A centrifugal pump passes energy onto the fluid and possesses certain flow and head qualities. The pump needs to overcome a necessary level of pressure, and this is what determines where the performance point should be on the curve, and how much flow will be produced. The value of the pressure is inversely proportional to that of the flow. As pressure increases, flow decreases. This shifts the performance point to the left of the pump curve. Conversely, as pressure decreases, flow increases, and the point shifts to the right of the pump curve.

As a rule of thumb, when analyzing a pump curve for a new requirement, it is best to stay as close to the BEP (Best Efficiency Point) as possible. This is the operating point on the performance curve that shows the highest efficiency point for the pump’s impeller diameter. 

There are 8 main pieces of information that you will need to be able to identify on a centrifugal pump curve. They are as follows:

1. Title Box

This contains the pump model, size, speed, and other characteristics of the pump. 

2. Flow

The horizontal axis of the pump curve indicates the flow, so identify the amount needed from the pump.

3. Head

The vertical axis on the pump stands for the head. 

4. Impeller Trim

In some cases, performance points cannot be met with the maximum impeller size alone. This is why centrifugal pumps accommodate trimmed impellers. On the pump curve, the impeller diameters are to the left and the performance for each trim is represented as a bold line across it.

5. Horsepower

The horsepower is displayed as a dotted line across the pump curve.


Net Positive Suction Head Required (NPSHR) is the minimum amount of pressure on the suction side of the pump to overcome losses in pump entrance. (This is not to be confused with Net Positive Suction Head Available or NPSHA.)

7. Efficiency

On the pump curve, the efficiency is the ratio of energy delivered by the pump to the energy supplied to the pump. The higher the efficiency, the less energy required to operate for a specific performance point. Pump efficiency numbers of 60-80% are normal.

8. Minimum Flow

A centrifugal pump needs a minimum flow moving through the pump to dissipate the heat that is generated. On the left side of the curve, the minimum flow is indicated by a vertical bold line. Operating to the left of the minimum flow line is detrimental to the shelf life of the pump and is not advisable.

For more information on industrial pumps, motors, and other equipment, contact us on +919819907445. As leading industrial water pumps dealers in Mumbai, we would be happy to assist you in finding the best match based on your requirements. VEMC is ISO 9001:2015 certified and a pioneer in the field of electromechanical engineering products, allied equipment, and services.