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There are different types of pumps available in the market. This article will assist you to know the main functionalities of each type of pump.
The type of pump, as well as selection, mainly depend on our requirement.The application mainly includes the type of fluid you desire to pump, the distance you desire to move the fluid, and the quantity you require to get over a particular time frame.
It is complicated to recognize accurately what kind of pump you must select. The identifying of the pump can be done with the design as well as positions. To make simpler things while seeking to choose your exact pump, and the pumps can be classified into two types which function in extremely dissimilar ways & generally summarize most of the pump designs.
Classification of pumps
Pumps are divided into two main categories: dynamic and positive displacement.
The following are some of the pumps under these two categories:
Dynamic pumps:
Positive displacement pumps:
- Diaphragm pumps
- Gear pumps
- Peristaltic pumps
- Cam pumps
- Piston pumps
What is the different between Centrifugal and Positive Displacement Pumps?
Both pump types move fluids in a specified direction, but accelerating a fluid continuously is not the same as displacing it in fixed amounts. As a result, there are important performance differences between both pump types.
When pumps are driven by an electric motor, a variable frequency (VFD) can achieve major energy savings, by reducing motor RPM when the full pump speed is not required. However, you must make sure to check compatibility: some pumps are incompatible with VFDs, while others allow speed control above a minimum RPM value.
How Do Pumps Work?
Pumps are basically simple devices that are used to move fluids by mechanical means. Pumps come in many different forms, but all share the common goal of moving fluid from one place to another. Pumps can be used for various applications based on need, including moving water, air, gasoline, and other liquids.
Pumps work by creating a vacuum which is used to push or pull liquids or gasses. Different types of pumps have different ways of working; however, what remains common is creating a difference in pressure points which creates suction. The liquid or the gas will always move from high to low pressure.
The type of pump you use will depend on the job you need it to do. For example, a small hand-held pump is typically used to inflate a tire, while a much larger pump is necessary to move water through a plumbing system. There are many different types of pumps, each with unique features and benefits.
Dynamic Pumps
There are different types of dynamic pumps, some of which will be discussed below, such as centrifugal pumps, vertical centrifugal pumps, horizontal centrifugal pumps, submersible pumps and fire hydrant systems.
Centrifugal Pumps
A centrifugal pump uses an impeller, which has curved blades that accelerate the fluid outward when rotating. Impellers are normally driven by an electric motor or combustion engine, and their movement produces suction at the pump inlet, pulling water inside.
This pump produces an enhanced force by transferring the mechanical power of the motor to the fluid throughout the rotating impeller. The fluid flow will enter the center of the impeller and flow out with its vanes. Centrifugal force thus increases the velocity of the fluid and energy like kinetic energy can be changed into force.
Centrifugal pumps are the most common type since they are suitable for handling water and relatively easy to manufacture. These pumps also tend to have a lower price, since mass production has brought down their manufacturing cost.
Based on the type of water flow they produce, centrifugal pumps can be classified into three sub-types. The flow pattern is determined by both the impeller shape and the pump’s construction.
| SUB-TYPE | DESCRIPTION | PERFORMANCE |
| Axial Flow Pump | Also known as a propeller pump, it produces water flow along the impeller shaft direction. | High flow rate Low pressure |
| Radial Flow Pump | This pump type produces flow in a direction perpendicular to the shaft (90° angle). | Low flow rate High pressure |
| Mixed Flow Pump | This pump type combines radial and axial flow, producing a conical flow pattern around the shaft. | Medium flow rate Medium pressure |
Vertical Centrifugal Pumps
Vertical centrifugal pumps are also known as cantilever pumps. These pumps use a unique shaft and maintenance design that allows the volume to fall into the pit because the bearings are on the outside of the pit. This pump model does not use a filled container to cover the shaft, but uses a throttle bushing in its place. Parts washers are a common application for this type of pump.
Horizontal centrifugal pumps
These types of pumps include at least two otherwise more impellers. These pumps are used for pumping services. Each stage is basically a manifold pump.
All phases are in a similar bunker and mounted on a similar shaft. At least eight additional phases can be installed on separate horizontal shafts. Each phase enhances the head by approximately equal amounts. A multi-stage pump can also be a single-stage pump, or else a double suction pump on the first impeller. Various pumps have been supplied and repaired for this type of centrifugal pump.
Submersible Pumps
These pumps are also known as stormwater, sewage and septic pumps. Applications for these pumps include primarily building services, domestic, industrial, commercial, rural, municipal and stormwater recycling applications.
The Submersible pumps are suitable for transferring stormwater, groundwater, sewage, blackwater, greywater, rainwater, trade waste, chemicals, bore water and food. These plumbing applications mainly include different impellers such as closed type pumps, convection pumps, vortex pumps, multistage pumps, single channel pumps, cutting pumps or grinder pumps. For different applications, a wide range of options are available, including high flow, low flow, low head or high head.
Fire hydrant system
Fire hydrant pump systems are also known as fire hydrant booster, fire pump and fire pump. These are high pressure pumps designed to increase the firefighting capacity of a building by increasing the force within the hydrant service, as the mains are not sufficient. Applications for this system include mainly irrigation and water distribution.
Positive displacement pumps
Positive displacement pumps move a fixed amount of fluid at regular intervals. They are built with internal cavities that fill up at the suction side, to be discharged with higher pressure at the outlet. Based on how fluid is displaced, positive displacement pumps can be reciprocating or rotary.
There are different types of volumetric pumps, some of which will be discussed below, such as diaphragm pumps, gear pumps, peristaltic pumps, lobe pumps, and piston pumps.
SUB-TYPE | DESCRIPTION | EXAMPLES |
Reciprocating Pump | Flow is established inside a cavity that expands and contracts, such as a piston. Water moves into the cavity during expansion, and is forced out during contraction, while the flow direction is controlled by using check valves. | Bladder |
Rotary Pump | This pump type uses a rotor that traps water in cavities, releasing it at the outlet. These cavities can be the spaces between gear teeth or screw threads, among other configurations. Some designs use more than one shaft, but the principle is the same: the rotor shape is designed to capture “pockets” of water and displace them in the intended direction. | Gear |
Diaphragm Pumps
Diaphragm pumps are also known as AOD pumps (Air Operated Diaphragm), pneumatic and AODD pumps. Applications for these pumps include mainly in continuous applications such as general plant, industrial and mining. AOD pumps are particularly suitable where power is not available and are otherwise used in unstable and combustible areas. These pumps are also used for transferring chemicals, industrial wastewater, food manufacturing, underground coal mines, etc.
Gear Pumps
These pumps are a rotating positive displacement pump, which means they produce a steady amount of fluid with each revolution. These pumps move the fluid by entering machinery inside and outside the network for a non-exciting pumping action. These pumps are capable of pumping at high forces and can efficiently pump highly concentrated fluids.
Gear pumps do not contain any valves that cause losses such as friction and high impeller speeds. Therefore, the pumps are suitable for handling thick fluids such as fuels and grease. These pumps are not suitable for driving solids and harsh liquids.
Peristaltic pumps
Peristaltic pumps are also known as tube pumps and peristaltic dosing pumps. It is a volumetric pump and the applications of these pumps are mainly related to processing in the chemical, food and water treatment industries. It provides a steady flow for measuring and mixing and is also capable of pumping various liquids such as toothpaste and various chemicals.
Lobe Pumps
Lobe pumps are also called rotor pumps and these pumps have different characteristics such as excellent efficiency, rust resistance, sanitary quality, reliability etc. These pumps can handle highly concentrated fluids and solids without harming them. These pumps may work with gear pumps, except for the vanes that do not touch each other. In addition, these pumps have superior pumping chamber compared to gear pumps that allow them to move slurry. These are made of stainless steel and are very polished.
Piston Pumps
Piston pump is a positive displacement pump, also known as a plunger pump, in which a high pressure seal responds through a piston. These pumps are often used for water irrigation, scenarios requiring high, reliable pressure and delivery systems for conveying chocolate, pastry, paint, etc.
Conclusion
Pumps have multiple applications, and they are widely used in residential, commercial, and industrial buildings. As a result, a wide variety of pump designs has been developed. However, variety can also lead to confusion, and using the wrong pump for an application can cause energy waste or even equipment damage.
To ensure that all your building systems use the correct pump types, the best recommendation is to work with qualified MEP engineers. They can also help you integrate VFDs and other control features during the design phase, saving thousands of dollars in power bills over time.