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23 March 2023

How Submersible Pumps Work

The Pros and Cons of Submersible Pumps

We often refer to submersible pumps as electric submersible pumps. Submersible pumps move water from one location to another. They operate while fully submerged in water and other fluids. The basic components of submersible pumps are the impeller, diffuser, motor, & mechanical seals.

Let us Unpack How Submersible Pumps Function?

Your submersible pump converts electrical energy into mechanical energy. The mechanical energy then moves the fluid from one location to another.

The motor drives the impeller. This causes a suction action to draw water through the intake port. It then forces water through the impeller and out of the discharge port. Pumps repeat this process until it achieves the desired flow rate and pressure.

The motor is at the bottom of the pump. They are hermetically sealed & also close coupled to the body of the pump.

The diffuser is a stationary component surrounding the impeller. It helps increase the pressure of the pumped fluids.

Mechanical seals help prevent leaks & maintain the integrity of the pump’s watertight seal.

Submersible Pumps Have Many Advantages

  • One of the major advantages of submersible pumps is that they don’t need priming since they are submerged.
  • Submersible pumps are best known for their efficiency. This is because they can push water to the surface instead of pulling the water from below. This action saves energy when the water pressure pushes the water into the pump.
  • The selection of material the pumps handle is versatile. Although most are good for moving liquids, they can also handle solid material.
  • Submersible pumps run quietly, which makes them ideal for residential and commercial applications.
  • Some submersible pumps are compact, which makes them ideal for tight spaces. They are the perfect choice for wells, boreholes, and small basement spaces.
  • However, mining submersible pumps are quite large. Some go up to as much as 2m!
  • Submersible pumps are robust and designed for submerging in water for long periods.
  • They are more hardy than other types of pumps.
  • Fully submerged submersible pumps don’t cavitate. This is a problem that could occur with other pump types.

Cavitation is a phenomenon in which the static pressure of a liquid reduces to below the liquid’s vapour pressure, leading to the formation of small vapour-filled cavities in the liquid. When subjected to higher pressure, these cavities, called “bubbles” or “voids”, collapse and can generate shock waves that may damage machinery.

Submersible Pump Disadvantages

Submersible pumps are prone to a few disadvantages. Two of these pertain to the seals.

1. Long-term exposure to liquids could lead to corrosion of the seals. The water will seep into the motor. When this occurs, it cripples the mechanism until repaired. Because submersibles handle corrosive liquids, the seals are especially vulnerable. To avoid corrosion, they make pumps from corrosion-resistant materials, adding to costs. More so than other pump types.

2. The seal is often awkward and problematic for repairs to take place because of the location. Accessibility is especially difficult in deep well applications. The pumps are often left to run for extended periods without regular maintenance. This leads to breakdowns.

3. The initial outlay of cost is often more expensive than other pumps. For smaller projects, this could prove impractical.

4. Submersible pumps need more regular maintenance than other pump types. This ensures they continue functioning at their best. Seals need regular checking and replacing. The motor needs checking for wear and tear. The intake port requires regular cleaning.

5. Replacing a submersible pump is an expensive exercise. This is often because it needs removal from its location in the water.

6. The flow rates of submersible pumps are slow. They design them for low to medium flow. This makes the submersible pumps unsuitable for certain applications. We use single stage pumps for most home and light industrial applications. Examples are aquarium filters, sewage pumping, and sump pumps for drainage. We use multiple stage pumps for underground functions, like wells.

7. When not completely submerged, the motor will overheat.

Typical Applications of Submersible Pumps

One would typically find submersible pumps in drainage, sewerage, and irrigation systems. You would also find submersible pumps in deep well pumping. They are the preferred choice over other pumps in certain applications.

We best know submersible pumps for their reliability. They operate under harsh conditions. Manufacturers make submersible pumps from robust materials. They protect them from corrosion with a coat of epoxy.

We find submersible pumps in wastewater applications.

We use submersible pumps in grit and wastewater industries. We find them in pump and lift stations as they boast a compact design. They are cost-effective to install. More so than other pumping systems.

Wastewater applications need submersible pumps. These include grinder pumps for the transportation of solid materials without obstructions.

We use submersible pumps for removing accumulated water (sump pumping)

We use submersible pumps for the removal of accumulated water in low-lying areas. For example, we use them to remove water from tailing ponds in mining. They are also used to remove flood water from building basements.

We use submersible pumps for well applications

We use submersible pumps for wells and borehole applications. These pumps lift water to the ground surface. Oil and gas industries use ESP (electric submersible pumps) pumps.

The ESP submersible pumps used in the mines differ from those used in gas and oil wells. The pumps used in mines deal with challenging conditions because of the high acid content and suspended solids found in mine water.

Get to Know More About Submersible Pumps & Call AQS Today!

Find out everything about the advantages and disadvantages of submersible pumps. Let our team of professionals assist.

We tell you everything you need to know about the wide range of ratings for pumping speed and energy. Contact us and get the information you need about how submersible pumps work. Do you have the right type of pump for your application? We are here to tailor the right pump to suit your specific needs.

Do you still have questions? Give our AQS Liquid Transfer team a call on +27 12 548 7204 or fill out our enquiry form, our friendly team will get back to you with first-hand expertise on how to select a borehole pump for your needs.

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