Since the advent of technology, people have invented a device known as a “Pump” to elevate, transport, or compress fluids. We now use this invention for various purposes, making life easier in our modern world.
The pump is a mechanical device that is purposely designed to transport fluid by mechanical action. In its work, it converts electrical energy into hydraulic energy. This is why it is said to be a hydraulic device that lifts fluids from low to high levels and from low to high pressure areas.
Well, in this reading, we’ll explore what a pump is, its applications, functions, components, specifications, classification, types, and how it works. We’ll also explore the advantages and disadvantages of all kinds of pumps.
Let’s begin!
Related: What is a Piston Pump? its application, diagram, and how it works
What is a Pump?
A pump is a mechanical device that moves or transports fluids (liquids or gases). A pump works by mechanical action, converting electrical energy into hydraulic energy. You can also think of it as a device that uses energy to elevate, move, or compress fluids.
The earliest produce pumps were used for raising water, such as the Persian and Roman waterwheels. Just as mentioned earlier, pumps operate by some mechanism (typically reciprocating or rotary). It consumes energy to perform mechanical work (moving of fluid).
Many energy sources can power this system. This includes manual operation, electricity, wind power, engines, etc. Pumps are available in many sizes, from the microscopic type used for medical applications to large industrial types.
In the third century BC, Archimedes described the first pump. This is why it is known as the Archimedes screw pump.
I have reached a final opinion regarding the definition of a pump. A pump is a machine or mechanical equipment that is designed to lift liquid from a low level to a high level. It can flow liquid from a low-pressure area to a high-pressure area. The pump also serves as a booster in a piping network system.
If a pump casing contains only one revolving impeller, it is called a single-stage pump. But if a casing contains two or more revolving impellers, it is known as a double- or multi-stage pump.
Note that a pump produces liquid movement or flow; it does not generate pressure. The flow is necessary for the development of pressure to is produced. The pressure is a function of resistance to fluid flow in the system.
Related: What is a Submersible Pump? its application, and how it works
Applications of Pumps
The use of pumps today in our society is vast. In earlier times, applications included using windmills or watermills to pump water. Today, engineers specifically design pumps for irrigation, gasoline supply, water supply, and refrigeration (commonly referred to as a compressor).
It is also used for air conditioning systems, chemical movement, sewage movement, flood control, etc.
In biology, there are different types of chemical and biomechanical pumps that have evolved. Sometimes, researchers use biomimicry to develop new types of mechanical pumps.
Because of the various applications of pumps, they have different shapes and sizes: from enormous to very small, from handling gas to handling liquid, from high pressure to low pressure, and finally from high volume to low volume.
Note: generally, the function of a pump is to pump more liquid or gas. Well, a liquid pump can’t simply draw air; their working mechanism is different. We will explain this in the section below.
Below are the applications and functions of a mechanical pump.
- Pumping water from wells,
- Aquarium filtering, pond filtering, and aeration
- Car industry for water-cooling and fuel injection
- Used for pumping oil and natural gas in the energy industry
- Additionally, it is used for operating cooling towers and other components of heating, ventilation, and air conditioning systems.
- In the medical industry, pumps are used for biochemical processes in developing and manufacturing medicine.
- It also serves as an artificial replacement for body parts, specifically the penile prosthesis and artificial heart.
Components and Diagram of Pumps
Since pumps are categorized into two: dynamic pumps and positive displacement pumps. Below are the major components of the two types of pumps.
The major parts of dynamic or centrifugal pumps are the impeller, casing, delivery pipe, and suction pipe. Positive displacement pumps come in various types, each with distinct parts.
For example, a diaphragm positive displacement pump part includes two diaphragms, a transfer valve, balls, or a check valve. Furthermore, the gear types of this pump have different parts compared to diaphragms.
Diagram
Related: What is Screw Pump? Its Application, Diagram, And How It Works
Classifications of Pumps
Pumps can be classified in many ways, depending on their applications and materials. The liquid’s transport and its space orientation can also be used to classify the pump.
We also classify pumps based on the principle of adding energy to the fluid. This approach has made all types of pumps fall into two main categories: dynamic (centrifugal) pumps and positive displacement pumps. We will further explain this.
Furthermore, the method of imparting energy to the fluid determines the classification of the pump. The basic methods include volumetric displacement, the addition of kinetic energy, and the use of electromagnetic force.
Mechanical displacement or the use of another fluid are both ways to move fluids. High-speed rotation of the fluid can add kinetic energy to it. Another method involves supplying an impulse to guide the direction of flow.
Classification using electromagnetic force requires the pumped fluid to be a good electrical conductor. Pumps used to transport or pressurize gases are known as compressors, blowers, or fans.
In addition, pumps whose displacement is performed mechanically are called positive displacement pumps. Finally, kinetic pumps impart kinetic energy to the fluid through a rapidly rotating impeller.
Pump Specifications
Since pumps serve different purposes, there should be different expectations in horsepower, volumetric flow rate, and outlet pressure in meters (or feet) of the head. Another aspect to consider is the inlet suction, measured in feet (or meters) of the head.
This head can be simplified as the number of feet or meters the pump can raise or lower the column at atmospheric pressure.
Engineers use a quantity termed the specific speed from an initial design perspective. Engineers use this term to determine the most suitable pump type for a specific combination of flow rate and head.
A pump imparts power into a fluid to increase its energy per unit volume. So, the power relationship is between the conversion of the mechanical energy of the pump mechanism and the fluid elements within the pump.
In general, this is governed by a series of simultaneous differential equations known as the Navier-Stokes equation. The simpler Bernoulli’s equation only applies to the fluid’s different energies.
Types of Pumps
Below are the various types of pumps, based on their classifications: These include dynamic pumps and positive displacement pumps.
Dynamic Pumps
Dynamic pump types include centrifugal, vertical centrifugal, horizontal centrifugal, submersible, and fire hydrant systems. Let’s dive into their explanation.
Centrifugal Pump:
These types of pumps are common all over the world. Their operation is simple, well-documented, and thoroughly tested. Centrifugal pumps are strong, efficient, and can be fairly cheap and easy to make.
In operation, the fluid pressure increases from the inlet of the pump to its outlet. The change experienced in the pressure will drive the liquid throughout the system.
An electrical motor in this pump transmits mechanical power to the liquid through the revolving impeller. The flow of liquid enters the center of the impeller and then exits along with its blades.
These pumps are important because their power increases fluid velocity and can change kinetic energy to force.
Vertical Centrifugal Pump
These types of pumps are also called cantilever pumps. They use an exclusive shaft and are designed to cause the volume to fall within the pit, as the bearings are external to it. A vertical centrifugal pump does not use a filling container to cover the shaft. However, it uses throttle bushing.
Horizontal Centrifugal Pump
The horizontal centrifugal types of pumps use a minimum of two or more impellers. Due to its effectiveness, it finds widespread use in pumping services, with each stage essentially functioning as a separate pump. All these stages are in the same housing and mounted on a similar shaft.
You can mount a minimum of eight stages on a single horizontal shaft, but you can also mount additional stages. In every stage, the heat increases by an equal amount. Multi-stage pumps can also have a single or double suction on the first impeller.
Submersible Pump
These types of pumps are also called stormwater, sewage, and septic pumps. The applications of submersible pumps include building services, domestic, industrial, and commercial . Submersible pumps are also useful in rural, municipal, and rainwater recycling applications.
These types of pumps are suitable for shifting stormwater, sewage, subsoil water, black water, greywater, and rainwater. Trade waste, chemicals, bore water, and foodstuffs.
There are various types of impellers available, including closed, vortex, contra-block, multi-stage, single-channel, cutter, or grinder pumps. We can make multiple selections for either high flow, low flow, low head, or even high head, depending on the applications.
Fire Hydrant Pump Systems
Other names for fire hydrant pump systems include hydrant boosters, fire pumps, and fire water pumps. These types of pumps are high-force water pumps with the purpose of enhancing firefighting capabilities in buildings by boosting water pressure in hydrant systems.
The applications of this pump system include irrigation as well as water transfer.
Positive Displacement Pumps
There are also five types of positive displacement pumps, which include diaphragm, gear, peristaltic, lobe, and piston pumps. Let’s see their explanations!
Diaphragm Pump
These types of pump systems are known as AOD, that is, air-operated diaphragms, pneumatic, and AODD pumps. These pumps are mainly used in continuous applications such as general plants, industrial and mining, etc.
Particularly in unstable and combustible regions or where power is unavailable, they find use. Diaphragm pumps are also utilized for food manufacturing, underground coal mines, chemical transferring, etc.
This pump operates by driving two diaphragms with condensed air. A transfer valve creates the suction of air, which subsequently directs the air alternately toward the two diaphragms. Every diaphragm has a set of ball valves or check valves.
Gear Pumps
A gear pump is a kind of rotating positive displacement pump. That is, they force a stable amount of liquid for every revolution taken. These types of pumps move liquid with machinery coming inside and outside the mesh to make a non-exciting pumping act.
They are able to pump at higher forces and surpass pumping high-thickness fluid efficiently.
Gear pumps don’t have any valve to cause losses like friction and high impeller velocities. This is why it is capable of handling thicker liquids, such as fuel and greased oils. However, their proficiency in driving solids and harsh liquids is limited.
Peristaltic Pumps
Tube pumps are another name for peristaltic pumps. They are a kind of positive displacement pump used in the processing of chemical, food, and water treatment industries. The pump types are capable of providing stable flow for measuring and blending.
They are also capable of pumping various liquids, like toothpaste and all kinds of chemicals.
Lobe Pumps
Lobe pumps offer different characteristics such as reliability, rust resistance, excellent high efficiency, hygienic qualities, etc. These types of pumps can handle thick fluids and solids without destroying them.
Although their work is much related to gear pumps, it is only for the lobes that do not come into contact with each other.
Additionally, these pumps boast superior pumping rooms compared to gear pumps, enabling them to efficiently move slurries. They are made with stainless steel that is extremely polished.
Piston Pump
This is the final positive displacement pump. These pumps are frequently used in water irrigation, an event requiring high, reliable pressure and high delivery systems for transferring chocolate, pastry, paint, etc.
How Does a pump work?
The basic aspect of how pumps work is by using mechanical forces to push material or substances. Either physical lifting or the force of compression accomplishes this. A pump works by creating a vacuum that allows ambient air pressure to force the liquid and they create areas of low pressure.
Centrifugal force in a centrifugal pump accelerates the water to the outside of the impeller. This creates a low pressure at the center of the impeller. While in a reciprocating pump, the upstroke of the plunger or piston creates a vacuum.
In a gear pump or lobe pump, the teeth or lobe mesh come apart to create the vacuum. This is to say, the difference in pressure creates suction; for instance, a liquid under higher pressure will move to an area of lower pressure.
According to the explanation, pumps change the energy flow from mechanical to fluid. This principle made it useful in operations that require high hydraulic force. They can be seen in heavy-duty equipment that require low suction and high discharge pressure.
This is because the force at the suction part of the pump allows the liquid to be picked up from a certain depth. The expulsion side of the pump with high force drives the liquid to pick up until it reaches the required height.
Advantages and Disadvantages of Pumps
Advantages:
- Simple Construction
- Minimum Wear
- Less frictional losses
- No Drive which is why leakage is eliminated
- Low noise and smooth operation
Disadvantages:
- High Cost
- Produce cavitation
- Corrosion
- Can’t work at high speed
- High initial setup cost