Some of the oldest and most common machines employed not only for household uses but also in case of flood and heavy rain, water pumps are, as the name suggests, devices that move water from one point to another. How does a water pump work, and what are its applications? Read on to find out more about these devices.
Water pumps – what are they and how do they work?
Water pumps have been used for quite some time now, and primitive pumps known as shadoof have existed since about 2000 BCE. They have evolved significantly to make it easier for the user to benefit from their features and advantages.
Dewatering systems and water pumps are devices designed to control water and thus remove or drain it from different places, such as tunnels, riverbeds, construction sites, and residential buildings, by utilizing evaporation or pumping.
Given their applications, water pumps hold great importance in areas where there is heavy rain or floods are frequent. The market now offers a variety of water pumps, and we will describe a few of them later on. How does a water pump work, though?
As we’ve just said, there are different water pumps available for sale, and while the working principle is almost the same, there are some differences between certain types of water pumps. These devices are built to convert kinetic energy/rotational energy into hydrodynamic energy with the help of a motor.
A centrifugal pump, for example, features a rotating impeller through which fluid enters. The water is then expelled out through the tips of the impeller with the help of centrifugal force. Such a process increases the velocity and pressure of the water, directing it thus toward the pump’s outlet.
Then there’s the positive displacement pump that comes with an expanding cavity on its suction side and a decreasing cavity on its discharge side. This type of water pump alternatively fills the cavity and then displaces the water. What is different is that all these cycles have the same volume regardless of the pump head used or the pressure.
Therefore, the flow of a centrifugal pump varies depending on the pump head featured and its pressure. Another difference between these two types of water pumps is that when the flow of a centrifugal pump is reduced, the viscosity increases. In the case of a positive displacement pump, the viscosity increases when the flow does so.
Types of water pumps
As we have just seen, there are two general water pump classifications, including the centrifugal water pumps and the positive displacement pumps. Each type has its advantages and disadvantages.
Positive displacement pumps are appreciated for delivering superior efficiency and are suitable for applications that require the creation of high-pressure and very precise flow volumes. They are a great option for uses that involve sensitive solids or high-viscosity fluids.
Centrifugal pumps use a rotating impeller, as we’ve said above, to spin the fluid inside a housing through centrifugal force. In order for these pumps to work properly, they must remain filled with water/fluid. Almost all pumps that are employed in irrigation are centrifugal types.
They are also utilized to provide a constant pressure source for a fire protection system, for example, or to boost the pressure of a fluid that is received through intake lines. Each of these two categories includes subtypes or models that can be employed for different applications and come with specific features.
- Submersible pumps
The pumps in this category are centrifugal pumps, and, as their name suggests, are designed to be used underwater. Such an item features a pump and a waterproof electric motor that work as a single unit.
A submersible pump is designed to push the fluid to the surface instead of pulling it, which comes with various benefits. One of them is that such a pump prevents pump cavitation, which usually occurs if there is an elevation difference between the pump and the fluid surface.
Another advantage is that this type of water pump does not require priming since it is designed to be used underwater.
Submersible pumps are generally employed for applications that involve the pumping of fluids that are relatively thin, with or without solids. They are thus used in sewage services, general industrial pumping, and drainage, and can therefore be seen on residential, industrial, and commercial sites.
- End-suction pumps
These water pumps are also centrifugal pumps, and they are some of the most frequently employed devices for water pumping. The models in this category feature a single impeller, as well as a horizontal shaft.
What makes this type so common among users is its compatibility with a variety of both clean and dirty water services and different levels of solid materials. The impeller type can be altered, and thus the pump can be used for various applications.
- Multistage water pumps
If your specific needs require a pump that can keep up with high-pressure applications, then a multistage water pump is worth considering. Such pumps are equipped with two or more impellers. These impellers can be of the same type or different types, and most parts of this type of water pump are similar to the ones of a standard centrifugal pump.
The difference lies in the addition of diffusers that are used to channel the water into the impeller’s eye and a thrust balance device. These units are employed for high-pressure applications, including water delivery to high-rise buildings, fuel delivery, and high-pressure cleaning, to name a few.
Examples of multistage water pumps include submersible pumps, side channel pumps, vertical turbine pumps, and sanitary multistage pumps.
- Trash water pumps
Another centrifugal pump is the so-called trash water pump, which is employed for dewatering and usually found on sites such as mines, utility pits, and construction sites. These pumps are specifically designed to pump dirty water that contains debris, mud, stones, and abrasive materials.
- Portable pumps
If you’re interested in a pump to pump water out of your basement or boat, a portable pump is worth considering. These models are designed to help you cater to various water-pumping needs while making it easy and comfortable to transport the unit from one place to another.
A portable pump can be used not only on residential sites but anywhere you need to transfer water from one point to another. They can be used in lawn and garden irrigation as well as to increase line water pressure.
- High head pumps
These pumps are designed for uses that involve water pumping over long distances or uphill water pumping. Thanks to their heavy-duty design, they can handle large flows and be employed for high-pressure water pumping applications.
The above-mentioned models are some of the most commonly used water pumps, yet the market offers many other such units, each of them falling into a category that was specifically designed to meet certain applications.
We can thus talk about automotive, dewatering, agricultural, wastewater, industrial, saltwater, and stormwater pumps, to name some of them.
Choosing the right water pump for your needs
Given the wide variety of water pumps available for sale these days, finding the one for your needs might turn out to be a challenging and time-consuming task. Thankfully, there are some factors to consider before adding such a product to your shopping cart. Paying attention to a few aspects will help you identify the right pump for your needs faster and more easily.
The first things to consider are the size and site of the operation, as well as the distance covered. Pumps come in various models, and there are different hose lengths you can choose from depending on the distance your operation involves. Moreover, in such cases, a high head pump is recommended.
The site also counts a lot when it comes to deciding on a specific water pump. For example, if you need such a unit for residential areas, a silenced water pump is ideal. The power required by your application and the one offered by a certain model will also help you make a decision faster.
Consider the type of motor featured and the horsepower and flow rate ensured. Water pumps can further be divided based on the type of motor they feature, and, therefore, we can talk about pumps that are powered by battery, an electric motor, a solar-electric motor, wind power, water power, gas/diesel/steam motors, or human muscle power.
The materials used for the construction of a pump also require consideration. If you’re interested in water pumps that can be used underwater, a waterproof design is essential. Submersible water pumps are specifically designed to handle such applications.
Think of the type of water/fluid that needs to be pumped as certain pump models work better with thin fluids, while others are built to be employed for dirty water containing debris and abrasive materials. If this is your first water pump, you might also want to look for a model that is easy to use and comes with instructions.