Below the five different forms of cavitation. Let’s look at how to prevent each.

Vaporisation Cavitation
Try the following:

• Reduce motor speed (RPMs). Note: Slowing the pump down will reduce flow rate and head pressure.
• Install an impeller inducer
• Incorporate a booster pump into your pump system. This will take some of the stress off of your primary pump.
• If possible, reduce the temperature of your pump, liquid, and/or other components.
• Increase liquid level around the suction area.
• If possible, try to increase the diameter of the eye at the centre of your impeller.

Turbulence Cavitation
Preventative steps:

• Evaluate all components to ensure that they can take the strain of the flow rate, volume, and properties of your transported fluid. Replace components as needed.
• Ensure you are not exceeding your pump’s manufacturer performance guidelines. A pump system which is pushed too hard will inevitably fail. Such as running the pump off the end of the performance curve. It is best to increase
• Increase pump suction line size to reduce turbulence

Vane Syndrome Cavitation
Preventing vane passing or vane syndrome cavitation is relatively easy. Ensure that the free space between your impeller and its housing is 4% of your impeller’s diameter or more. Any less and cavitation will begin.

Internal Re-Circulation Cavitation
In order to prevent this type of cavitation, follow this process:

• Open up your pump’s restricted discharge valve and assess the inside for any blockages.
• Unclog the downstream filter of any debris or accumulation.
• Ensure that the check valve has been installed correctly. A common mistake during installation is for this valve to have been fitted backwards.
• Check the discharge valve and make sure that it is open and not closed.
• Assess pressure at the discharge line. If there is a problem with head pressure then it could be that the header isn’t up to the job and needs replaced, or the system is operating close to the shut-off head.

Air Aspiration Cavitation
This can be a tricky one to prevent. Even the smallest amount of air being sucked into the system could over time cause cavitation. Going over your installation with a fine tooth comb to make sure all joints and connections are sealed properly, is the best approach.
Prevent this type of cavitation by:

• Regularly checking joint rings on any suction piping to make sure they haven’t perished.
• Assess whether foaming liquid is causing an accumulation of bubbles. If so, run the system slower, or periodically empty the system of all contents, including air.
• Check all O-rings and any secondary mechanical seals.
• Ensure all piping has no cracks or signs of erosion.
• Make sure that all system materials are capable of handling the liquid you intend to transport. Viscous, abrasive, or acidic liquids can erode materials to the point where air can be sucked into the system.
• Regular checks of valves, joints, and anywhere else that may seem likely to fail at some point. As soon as anything shows signs of failure, replace.


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There are two types of cavitation that may occur in reciprocating positive displacement applications: suction and discharge. Suction cavitation occurs ahead of the suction stroke, when the pump is starved of flow, either from being in a high-vacuum or low-pressure environment. The opening of the valve is delayed by inertia, causing a lower flow rate on the suction side and resulting in expansion, pressure decrease, and the formation of bubbles close to the plunger.

Common causes of suction cavitation include:

• Clogged filters
• Pipe blockage on the suction side
• Poor piping design
• Pump running too far right on the pump curve
• Conditions not meeting NPSH (net positive suction head) requirements

Discharge cavitation occurs when the pump’s discharge pressure is too high. Under these conditions, it’s difficult for the fluid to flow out of the pump. Instead, it continues moving at high velocities inside the working chamber, forming bubbles in the process.
Common causes of discharge cavitation include:

• Clogged filters
• Pipe blockage on the discharge side
• Poor piping design

When working with pumping applications in a processing industry, cavitation should always be kept in mind; being able to recognize the warning signs and identify the root causes of cavitation in your machinery can significantly reduce the risk of long-term damages, saving both time and money.

Water pump repair dubai  has nearly a 5 years of experience assisting clients with pump issues such as cavitation. Our pump components are designed to preserve expensive parts such as crankshafts and power frames by transferring the majority of wear to less expensive, more expendable parts such valves, plungers, and packing.

Call us today to talk to our engineer.​

Cavitation is an issue that plagues many of our industrial water pump customers, and can cause very serious damage to the water pump's impeller while slowing down the overall pump flow and effectiveness. How do you avoid cavitation? First, let’s explore exactly what cavitation is, what types of cavitation exist, and then how to prevent or fix this issue.

What is Water Pump Cavitation?
Cavitation is the process in which rapid changes in pressure in a liquid lead to small, vapor filled cavities where the pressure is low. These cavities, or bubbles, can collapse when put into high pressure water and cause a shock wave that can damage the impeller. In simpler terms: the changes in pressure cause bubbles, and when the bubbles increase in pressure they burst and cause shockwaves inside the pump. These shockwaves wear down the impeller and the pump body (volute) over time and can cause some very serious damage which may seem surprising given the size and strength of the bubbles. How is it that bubbles bursting can wear down a metal impeller? The reason cavitation can be so damaging is that it affects the pump over a long period of time. The cavitation may not immediately affect the pump, but over a long period of time, with constant cavitation happening, even a metal impeller can become worn down by bubbles. Before we talk about how to prevent cavitation, we need to talk about the symptoms, the five different types of cavitation, and how they happen.

Symptoms of Pump Cavitation
Before you jump to the assumption that you are dealing with pump cavitation, you need to know the symptoms of it, and make sure that you can properly ensure that any issues you are having are indeed cavitation. The first thing you can easily check for is any unusual noise coming from your pump. When the bubbles burst and cause cavitation, they make a bubbling, almost cracking sound. Another noise to look out for is a rattling coming from the impeller housing, often described by many people as “marbles bouncing around inside the pump.”
This is obviously a sound you don’t want to hear, but it’s an easy way to know that your pump might have a problem like cavitation. The next thing you can check for is if the pump is experiencing any unusual vibrating or shaking. Any cavitation can cause the pump to vibrate and shake, so watch out for your water pump vibrating strangely. You also need to check that your pump has the correct flow and pressure. If either one is decreasing, you could have a cavitation problem inside your pump. The last thing to check without opening the pump up is whether or not your equipment is using more power than usual to move the impeller. If it is cavitation, the bubbles are slowing the impeller down and causing the engine or motor to have to use more power to operate the impeller.
Any more symptoms of pump cavitation require inspection of the pump’s internal parts. Check the impeller and make sure it hasn’t sustained any erosion damage. If it has, or there are small parts of the impeller broken off inside the pump, you almost certainly have a cavitation problem. You should also check your seals and bearings, as cavitation can sometimes cause them to leak or fail.

VaporizationVaporization is the most common type of cavitation, and as such is the one that most people are looking to avoid and fix. Often called inadequate NPSHa cavitation or classic cavitation, vaporization happens when the liquid inside the pump passes through the suction side of the impeller which has lower pressure, creating the bubbles. Once the liquid passes through the impeller, any bubbles will cavitate when they encounter the higher pressure, causing the shockwaves. As you already may be able to tell, this can be a very common problem, because it can happen so easily. There are, however, solutions to help prevent vaporization cavitation in your water pump.
This first thing you may want to try is to reduce the RPM (rotations per minute), also known as the motor speed. Slowing down the pump will help reduce the speed at which liquid is flowing, and will also help decrease the head pressure. Just be careful not to reduce the power of your motor too much, as doing so can prevent your pump from pumping at the rate you need it to. Another way to help prevent vaporization cavitation is to purchase an impeller inducer (if your pump is capable of utilizing an inducer). An impeller inducer is basically a smaller impeller that you attach to the front of the main impeller. It is mainly used to increase the pump suction head, or pressure, as well as to help avoid cavitation, as the bubbles that are formed don’t have the main impeller front to attach to. The only problem with this solution is that you would have to buy an impeller inducer, as opposed to changing something in your pump. There are however other ways to try and reduce or prevent vaporization cavitation from happening, such as trying to reduce the temperature of your water pump, as hotter temperatures can also cause vaporization cavitation, as the heat literally vaporizes the water into bubbles. You could also try increasing the liquid level around the suction area of your pump to try and prevent cavitation. It's also possible to increase the diameter of the eye of your impeller, meaning that you will have less surface area for cavitation to occur on the suction side of your impeller. Only do this if it will not affect the amount of liquid you need pumped and has been approved by the manufacturer.
Internal CirculationAnother type of cavitation that can happen inside your pump is called internal circulation. This type of cavitation is a little simpler than vaporization, and can be easier to fix and avoid, as long as you have good pump maintenance. Internal circulation cavitation occurs when the pump discharge port isn’t getting liquid out at the right rate, so any liquid that wasn’t discharged as a result is recirculated back through the water pump. This recirculated liquid goes back through the high- and low-pressure points, causing it to have high heat and velocity, creating the cavitation bubbles that can damage your impeller. A common cause for your pump not discharging enough liquid or discharging it too slowly is that the discharge port was left open while the pump was still running. This is something you should always avoid, as leaving the discharge port closed can cause more problems than just cavitation, which is already something you want to avoid at all costs. In order to fix or avoid internal circulation cavitation, you need to be especially watchful of your discharge port, not allowing it to close while you are running your pump and completing regular maintenance to ensure everything is moving and working well. To make sure your discharge port is functioning, open the pump’s restricted discharge valve and look for any blockage that could be causing the liquid to recirculate. If there is any blockage, remove it and make sure the discharge port is clean and open so that your pump can effectively operate.
You should also make sure that the discharge line has the appropriate pressure. If the pressure is too little or too much you may have a problem with your header. If this is the case, you may need to replace the header to make sure you have the right amount of pressure. Also make sure that the check valve is installed correctly, as a common issue when installing the check valve is that it has been installed backwards. This is as easy as removing the check valve and re-installing it correctly. Any issue with internal circulation is usually related to the discharge line, so always make sure that you are on top of its maintenance and care so that you can avoid damage to your pump and save yourself time.

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The motor used to power a centrifugal pump needs to be able to produce enough torque to start the pump and bring it to an optimal operating speed. If a motor lacks enough torque to operate a pump, the pump may not start or may only operate at a reduced speed. The centrifugal pump suppliers at pump repair in dubai will guide you through the pump motor selection process.

A pump’s torque-speed curve is used to determine the appropriate motor to match with it. A pump’s torque-speed curve is produced by plotting the percentage of full load torque (FLT) vertically against the percentage of full load speed (FLS) plotted horizontally. 

The torque-speed curve is similar for all centrifugal pumps due to simple math: the pump torque varies as the square of its speed. However, when the pump is at rest—0% full load speed—the full load torque is never also 0%. Starting a rotating pump requires the motor to overcome the pump inertia and static friction.
To overcome pump inertia and static friction, approximately 20% of full load torque is required. As the pump’s speed increases, the required torque gradually declines. For example, at about 15% full load speed the required torque typically is around 5% or 10% full load torque. As shown below, the pump torque-speed curve follows the square law:
Like pumps, motors produce a torque-speed curve of their own. By overlaying the torque-speed curve of a pump and a motor, one can verify that the motor is producing enough accelerating torque to drive the pump to full speed.

Torque and Motor Selection for Centrifugal PumpsA motor’s horsepower (HP) is used as a baseline measure of its capabilities in the field. HP is a combination of torque and speed (RPM), with 1 HP equal to 550 foot pounds per second, or 33,000 foot pounds per minute. A motor’s torque can be calculated using its horsepower using this formula, which is derived from an expression of HP as a function of torque:
T = (5,250 x HP) / N
Where T = Torque and N = RPM.
When a pump needs a new motor, three values will drive the motor selection process:

• Torque at Zero Flow (shut-off)
• Torque at Rated Flow
• Torque and Maximum Flow

Torque at zero flow is especially important for pumps with axial flow (or propeller) designs. The torque-speed curve of such pumps is such that the highest HP, and therefore the highest torque, is required at zero flow. An axial-flow pump must be paired with a motor with adequate HP to get the pump moving.

The Importance of Pump Inertia in Motor Selection
Another important factor in motor selection is the pump’s inertia value at the motor shaft. Inertia is a measure of an object’s resistance to movement change. The higher the pump inertia, the longer the motor will take to start the pump and bring it to full load speed.

This is significant because motors draw current to bring pumps up to speed. The longer a motor takes to overcome a pump’s inertia, the more heat it will generate. A motor must be sized to handle the pump’s inertia to avoid damaging the motor’s windings.
Inertia is based on one of two approaches:

• Radius of gyration (WR2 expressed in units of lb.ft2, or MK2 expressed in units of kg.M2)
• Diameter of gyration, used in many European countries (GD2 expressed in units of M2)

How Does a Gearbox Influence Inertia?
If a motor directly drives the pump, the values of the pump and pump-motor coupling inertias are the same regardless of pump speed.  If the pump is driven by a gearbox and motor, however, the gearbox can have a major impact on inertia values. In this application inertia can be expressed as:

Pump & Coupling Inertia Totals x (Gearbox Ratio)2
A gearbox’s effect on inertia can be understood by analogy to a bicycle. When a bicycle is ridden at high speeds, the rider may change to a higher gear ratio (one greater than 1.0) to go faster. Such a ratio also requires the rider to put in more effort. Likewise, if a gearbox shifts to a higher gear ratio, the motor will have a higher load. The same logic applies if the gearbox is reducing the motor speed to drive the pump slower. When the gearbox ratio is less than 1.0, it will reduce the load requirements on the motor.

For more info contact water pump repair dubai or call us at +971 4 252 2966

Submersible pumps of all types can provide decades of reliable performance if you can maintain them correctly and watch for wear and tear. Use these useful tips to watch for any changes and to schedule appropriate services for your submersible pumps, whether used for your own property or for an industrial application.

Maintaining regular inspections
Submersible pumps will quite often go substantial periods of time without being seen, however, there are a few easy maintenance checks you can do to ensure optimal performance and longevity. The first is to monitor the output of the pump to ensure everything is running as usual. From the surface, be sure to check for water leaks, assess the condition of electrical wiring and arrange valves and seals to be changed on time according to the manufacturer’s or supplier’s directions. It’s a good idea to book in annual maintenance inspections at a minimum from your local pump service team, who will provide you with a record of each service and what has been checked.

Symptoms to look out for in submersible pumpsKeep an eye out for these signs of failure or lesser performance on a regular basis, and you’ll be better equipped to address pump problems before they become unmanageable.

• Decreased output
  If the pump isn’t working at all, check the circuit breaker to see if it has tripped. Possible causes for a decrease in output can include a low water table or liquid supply, an obstruction of sand or grit, a restricted impeller or general wear and tear.
• Irregular water flow
  If the water is sputtering at the surface then you may potentially have a problem with cracked water pipes, or your submersible pump may have a broken check valve. If you’re having trouble identifying the problem you can call MTP’s mobile service team to assess the issue.
• Excessive noise
  If you can hear noise from your electric motor, stop using it and book a water pump service as soon as possible. If you hear noise from the pump itself this may be due to insufficient liquid levels (if the pump is pumping air for part of the time), or there may be a component that is blocked or failing.
• Overheating
  Overheating of a submersible water pump can sometimes indicate that there is insufficient water in the well to keep it cool, or that the pump is failing. If the electric motor is overheating, it’s important to have this checked to avoid more costly repairs or replacement.
• Cloudy water or clogging
  If the liquid you’re pumping is unusually clogged or cloudy you may have a problem with sediment or silt in the system. Possible solutions can include digging a deeper well for water pumps, or flushing the pump to clear any blockages.
• Particularly high electricity bills

Submersible pumps usually do not run at all times, and if this is occurring it may be a sign that either your float switch or pump is failing. Higher electricity usage could also indicate insufficient impeller clearance or a blockage in the system.

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Water pressure is the factor that can make or break a satisfying shower, give you the power to suds up your dishwater or give you a quick rinse of your soapy hands. For municipal water supply, the water pressure is mainly controlled by the city or township, although there are a few internal plumbing issues that can decrease pressure. When you have a well for your home’s water supply, the technology of your pressure tank will give you the pressure through your pipes.


Your well, water pump and pressure tank work together to get the water from the water table to your home. The well pump pulls or pushes — depending on the type of pump — the water from the well, sending it to the pressure tank, which holds the water under pressure until something in your plumbing system is turned on. The pressure tank creates pressure with a portion of its tank filled with compressed air.


When a water valve is opened within your home’s plumbing, the tank pushes out the water through the piping and then only fills up again when the pressure in the tank falls below a specific pressure rating. By having the pressure tank hold a significant amount of water, there is less wear and tear on the well pump because it doesn’t have to cycle on and off as often. Since well pumps are a bit more work to repair and replace, the pressure tank, specifically the right size of pressure tank, is an important component to a well water system.

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How Water Pressure Tanks Work
Once the water is in the pressure tank, how does it know when to get more? By the hard-working pressure switch. When the tank pushes out enough water to trigger the pressure switch, it then allows more water in from the well pump. The tank is refilled to its maximum capacity, measured by the pressure gauge on the tank, and then it shuts off again. The pressure switches are set to a 20-psi range of the starting and stopping pressures. So if a pressure switch is set for 40 to 60 psi, when enough water is drained from the tank to reduce pressure to 40 psi, the pressure tank will turn on to collect water from the well through the water pump and turn off when the pressure in the tank reaches 60 psi.


Having the correct size of pressure tank for your house is important to the long life of your water pump and pressure tank. Most manufacturers provide a handy chart to size the right tank for your home, but getting a new pressure tank is one of those installations that’s best left to a professional who will know just the right tank for your home and ensure everything is connected properly.

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For more info contact water pump service dubai or call us at +971 4 252 2966

Take a bit of time to check the health of your well pump and all the parts that get that water from the ground to your house. You’ll likely be saving yourself some unnecessary repairs and replacements when you notice elements that aren’t working their best or issues that could become a major expense.

Here are some of the more common pressure tank issues homeowners run into that you can easily fix yourself, along with some insights to help you understand more complicated problems that you’ll need the extended knowledge of a plumber for.

Pressure Switch Maintenance
The pressure switch located near the bottom of your pressure tank requires periodic maintenance and is the most common culprit of problems with pumping your well water. Troubleshooting your well water problems is best started with the pressure switch
.
As with anything in your home that has power running through it, you should turn off the breaker in your electrical box to the pressure tank and well pump before working on it. It could be set up as one large breaker of 30 amps or more or a double circuit breaker with two lower amperages in tandem on the panelboard. The pressure tank and well pump should be wired on the same breaker, so if you find a label for “well” or “water pump,” that should be the power shut-off for the pressure tank, too.

Once you’re sure the power is off to the pressure tank — you can test with a non-contact voltage tester --follow these steps to perform basic maintenance on your pressure switch:

• Take the plastic or metal cover off the pressure switch — there may be a couple of screws to remove.
• If your pump was not operating at all, move apart the switch relay contacts and check to see if there is any pitting or burning on the contacts. Deep pitting and noticeable damage from burning will likely require that the whole pressure switch be replaced. Otherwise, clean the contacts with a fine-grit emery cloth or sandpaper until you have revealed the shiny metal on all contacts — there are usually eight: four contacts with contact points on each side.
• Locate the pressure adjustment nut, which should be located in front of the compartment where the switch relay contacts are situated. Using a wrench, adjust the nut according to the manufacturer’s instructions, which are usually printed on the inside of the switch cover.

This is a great maintenance task to do on a bi-annual basis, especially if your pressure pump is in a high-humidity area like the basement. If you were trying to get your water supply back to your house with the pressure switch maintenance and it didn’t seem to do the trick, you may need a new pressure switch.
Pressure Switch ReplacementSwitches are available in three different pressure ranges: 40 to 60 psi, 30 to 50 psi and 20 to 40 psi. Your pressure tank was designed to work properly with only one of these ranges, so be sure to check which range is right for your tank. You can usually find this information printed on the inside of the switch cover.

Here are the step-by-step directions to replace your pressure switch:

• Turn off the power to the pressure tank as described above.
• Label each of the wires that are coming out of the switch relay and remove them from the faulty switch.
• Close off the valve that goes from the pressure tank to the plumbing of your house.
• Drain all the water out of the tank.
• Remove the old switch and the pressure gauge. A new gauge will only be about $10 and is easily replaced when you’re already changing the pressure switch to ensure that neither one will be a problem in the near future.
• Wrap the pipe threads with Teflon tape and install the new pressure switch and pressure gauge.
• Connect the wiring to the new switch in the same order as you removed them and secure the switch cover.
• Turn the power to the tank back on.

If neither of these quick fixes got your system running again, you may have an issue with your pressure tank or water pump. A tank or pump failure can be caused by a number of factors: age, low-quality components, running without water, constant cycling or a clogged intake valve. Water pumps and pressure tanks don’t need much in the way of maintenance, but they do need the right environment to reach their life expectancy.

Even the most seasoned do-it-yourselfer backs off from water pump replacement or pressure tank issues. A submersible pump needs to be pulled up a long way from your well, and once it’s up, you may not be too sure what you’re going to do with it. Someone trained in water pump technology will be able to make a repair or recognize the time has come for a replacement. Even above-ground jet pumps contain a number of components that aren’t easy to troubleshoot without training and experience.

For more info contact water pump service dubai or call us at +971 4252 2966