What is a Reverse Osmosis (RO) booster pump and how does it work?

What is a Reverse Osmosis (RO) Booster pump and how does it work?

Nowadays, most of us get our tap water from municipal water treatment plants. After the water reaches our home, we use pumps to move water to different points.

As a result, pumps have become a popular household product these days. In addition to that, we use pumps for various applications.

  • One of the notable pumps is the booster pump used in reverse osmosis water systems. As RO filters are becoming popular day by day, these pumps are also replicating that.

Today, in this article, we’ll be discussing everything about RO booster pumps, how they work, and when you need those. 

So, if you’re stuck with how to use this booster pump properly, stay tuned. Let’s start.

What is a booster pump?

Let’s start at the basics. So, what is a booster pump? A booster pump is a device that we use to give a boost to air and water pressure.

In general, a booster pump consists of a constant or variable speed electric motor along with a strong impeller.

  • The function of a booster pump is similar to that of an electric fan. Electric fans are composed of a single-phase induction motor powering a set of blades.

The fans work to create circulation in the air around us. Booster pumps perform the same function.

The application of booster pumps can be broadly classified into industrial and residential or household categories.

For example, we use booster pumps to enhance the pressure of our input water supply. In this case, the impellers stay inside the water.

  • As the incoming water pressure falls, the booster pump would convert electrical energy into mechanical energy and supply it to the incoming water stream.

The supplied energy would improve the water pressure inside the pipelines, and in turn, the flow rate would improve significantly as well.

The booster pumps get frequently used in industrial systems as well. We use them not only for hydraulic systems but also for pneumatic systems as well.

The working principle is similar. As the water or air enters the pump, they would get a boost in pressure and flowrate respectively. 

Nowadays, you might find advanced electronic devices to control the speed of the booster pumps. Those are mostly for industrial purposes.

What is a RO booster pump?

  • A RO booster pump or a reverse osmosis booster pump is a category of booster pumps that we use to maintain water pressure in a RO system.

If you’re familiar with conventional reverse osmosis water filters, you already know that those employ reverse osmosis to purify our drinking water.

This reverse osmosis process requires external pressure to produce pure and freshwater. The incoming water pressure at the input of the RO chamber serves that.

  • In any case, if the water pressure becomes too low or too high, the reverse osmosis process gets disrupted. As a result, the efficiency of the system goes down.

Therefore, to serve water within a constant pressure range, we use the RO booster pumps. They will stay in between the pre-filters and the RO chamber.

The input water would enter the pre-filters. Those will remove parts of debris, clay, or sand particles from the water. After that, the water will enter the booster pump.

Inside the booster pump, the water will get sufficient pressure head. This will help the purification process inside the RO chamber.

  • In this fashion, the RO booster pumps help maintain adequate pressure head inside the tubings. This results in more purified water from the RO chamber.

This boosted pressure head serves another purpose. It will reduce the amount of rejected water going into the drain. 

So, you see, the RO booster pump helps improve the efficacy of your RO filtration system.

What are the components of a RO booster pump?

Now, let’s discuss the components of a RO booster pump. So, what stays inside a RO booster pump?

Like all other electric pumps, a RO booster pump consists of the following elements.

  • Electric motor
  • Impeller
  • Shaft
  • Shrouded plates 
  • Casing for the impeller
  • Mechanical seal
  • Bearings
  • Adaptor
  • Transformer

Now, let’s discuss how they are assembled. For the ease of discussion, we’ll divide the complete structure into two portions.

  • Motor portion
  • Impeller portion

Motor portion

A variable-speed induction motor, along with a transformer and an adaptor, forms the motor portion of the system. 

Variable speed motor works best because the flow rate of the input water goes up and down at various times of the day.

  • The transformer is generally set up to produce a voltage of 115V, 60Hz, AC for the induction motor.

The voltage and frequency level will change according to the country where you’re using the pump.

  • The induction motor takes the AC voltage produced from the transformer and translates into mechanical energy. A shaft is connected to the rotor of the motor.

As the rotor rotates, the shaft will rotate accordingly. Meanwhile, the impeller portion stays at the other end of the shaft. 

Therefore, as the shaft rotates, the impeller will rotate as well. In this fashion, the motor portion converts electrical energy to mechanical energy for the pump.

Impeller portion

The other portion of the RO booster pump is the impeller portion. This one consists of the impeller, its casings, mechanical seal and the shaft.

The impeller is formed of several circular blades placed around a cylindrical core. The other end of the shaft connects with the core.

  • As a result, if the shaft rotates, the impeller will rotate. Two shrouded plates cover the impeller on both sides. Therefore, as the impeller turns, it will create a rotation tangential to the blades.

The impeller is submerged in water. Now, there is a casing that covers the impeller. The casing has two openings. Through the input or suction opening, water enters into the impeller.

  • On the other hand, water, with high-pressure head and flow rate, goes out through the output nozzle.

As high pressure gets induced at the impeller end of the shaft, a mechanical seal ensures tight and proper joint. 

  • Bearings will also be used to ensure proper fitting of the pump. So, you see, the impeller, casing, seal, and bearings construct the impeller portion of a RO booster pump.

How does the RO booster pump work?

Now, that you know the construction of a conventional RO booster pump, let’s focus on its working mechanism.

  • The adaptor connects the transformer to the power line. The AC voltage gets an operational voltage level. Then, it gets fed into the armature or stator of the induction motor.
  • This voltage at the stator will induce circular motion to the rotor. As the rotor connects to the shaft, the shaft will rotate as well. In turn, the impeller will rotate.
  • Now, input supply water enters into the impeller casing through the suction end. Then, the rotating motion of the impeller creates circular motion in the water as well.
  • As a result, the water gets dispersed radially from the impeller and gets out through the output nozzle with high pressure and an adequate flow rate.
  • The mechanical seal makes sure the impeller is tightly attached to the shaft. 

In this fashion, water from the pre-filters will get into the impeller casing. Then, inside the impeller, hydraulic energy will transfer into the input water.

  • The water will leave with a high enough pressure head. Now, the water will proceed towards the reverse osmosis membrane where it will get purified.

So, you see, this is how a RO booster pump works to boost input water pressure at the reverse osmosis chamber.

When do you need a RO booster pump?

Now comes the most important topic. When do you need to install a RO booster pump? 

  • Firstly, we’ve mentioned earlier, the RO booster pumps are specially designed to work with the conventional reverse osmosis water filtration systems.

Moreover, we also explained that the reverse osmosis membrane requires sufficient water pressure to purify the water. 

Therefore, if the water pressure is too low, the RO membrane will not work properly, and you won’t get enough water from your faucet.

  • For example, in most households, the water pressure stays above 40 PSI. Meanwhile, the RO chamber requires the incoming water pressure to remain within 40-100 PSI.

Now, during the day time, all of us use water more or less. But, the usage drops during the night. As a result, water pressure at your home also changes at various times of the day.

  • If the water pressure falls below 40 PSI, the RO membrane won’t perform well. As a result, more and more water will become RO reject water and go to the drain. 

This will drastically lower the efficiency of your RO system. That’s why you need the RO booster pump. 

As you have a booster pump installed in between the pre-filters and the RO membrane, it will give a sufficient boost to the water entering the RO chamber.

Therefore, the incoming water pressure will rise and the efficiency of the RO membrane will increase accordingly. 

So, if your input water pressure goes below 40 PSI, you need to install a RO booster pump immediately. 

How and where should you install the RO booster pump?

Now, let’s see how you should install the RO booster pump into your RO filter system. As we’ve already mentioned, you will require a booster pump only if your input water pressure is low.

The pressure is necessary for the RO membrane to function properly. Therefore, the booster pump should stay at any point before the reverse osmosis membrane.

Therefore, you can set up the booster pump in between the reverse osmosis membrane and the pre-filters. Again, you can also install it before the pre-filters as well.

In most conventional RO filters, the RO membrane is set up automatically with the pre-filters. Therefore, it would be easier for you to install it before the pre-filters.

  • So, water from the cold water supply should enter into the suction end of the booster pump. On the other hand, the output nozzle will connect with the filter assembly.

Therefore, water will enter from the cold water supply into the pump and then, leave it with adequate pressure, and enter into the pre-filter. 

  • So, this is how you should set up your RO booster pump. One thing you should note, the pre-filters won’t significantly reduce the water pressure at the RO membrane.

Concluding remarks

Throughout this article, we discussed everything you need to know about a very common household product, a RO booster pump.

As RO water filters are getting more and more popular, you need to get an overview of all the other devices that increase the efficiency of the RO system.

  • In this post, we showed you what are the components of a RO booster pump, how it works, and, most importantly, how you should install it with your RO system.

So, what do you think? Do you find this article helpful? Or, do you still have some questions left? If so, feel free to leave those in the comment section.

  • Also, don’t forget to check out our blog page to get more informative articles like this. Cheers!!!

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