Pump definition

A pump, or in other words, a pump, is a device or a device that is used in all kinds of mechanical or industrial work such as irrigation and causes the transfer and transfer of all types of liquids to higher heights with increased pressure or even to lower heights such as ponds or It is stored. They are also used to drain fluids from a low-pressure area to a high-pressure area; Of course, pumps will also be used in cases where the length of the pipes is very long or the hydraulic resistance is high, such as oil transmission lines. Pumps in various other industries also have different, diverse and numerous uses. Pumps are available in different sizes and sizes, for example: it includes a microscopic size pump for medical work or a pump for industrial work such as agriculture.

Uses and uses of pumps

Pumps have different applications in various industries.

Due to the variety and many types of liquids and different transfer needs, different types of pumps have been designed and manufactured. According to the applications of the pumps, there are different shapes and sizes of them. Among the most common ones, the following can be mentioned:

  • Pump for honey, thickener pump
  • Fluid transfer
  • The possibility of moving to a higher height (by increasing the head)
  • Wide application of pumps in industry
  • Wide application of pumps in vehicles and...

Also, today, pumps are used in various applications and industries, such as:

  • Sanitary pumps: used in food, pharmaceutical and biotechnology industries
  • Sewage pumps: Used inside sewage ponds and wells
  • Submersible water pumps: used in cooling devices and machining industries
  • Pumps for deep wells: with the ability to pump liquid from deep wells and also the ability to pump hot liquids
  • Measuring pumps: with the ability to adjust the flow rate and pump a certain amount of fluid with high accuracy and other types of pumps with different applications.

Classification of types of pumps

Classification of types of industrial pumps is done based on different methods.

There are different types of pumps, each of which has its own application. A lot of variety is one of the characteristics of industrial pumps. Pumps have different groups based on their function, internal structure, material, liquid they pump, installation status, price, fluid transfer method, etc.

Pumps are generally distinguished by two completely different characteristics:

  • Hydraulic characteristics or pumped fluid.
  • The type of pump with a special application intended for the pump.

Using this classification to identify the pump may be a little confusing at first for beginners and even some experienced people. Therefore, pumps can be divided into the following two categories based on the geometry and mechanism of the power transmitting member:

Dynamic pumps

These pumps continuously and continuously transfer kinetic energy to the fluid, and the way the water pump works in this type of pump is that the kinetic energy produced inside the pump is converted into pressure energy, and the fluid moves with speed and pressure. A lot passes through the outlet duct.

Features of dynamic pump

  • Using centrifugal force to increase the liquid inside the pump
  • Using a rotating propeller to create suction to pull the fluid inside
  • Fluid transmission with low viscosity and high flow rate
  • Changing the amount of flow according to the required pressure changes
  • Significant reduction in flow due to increase in fluid viscosity
  • The most famous type of dynamic pumps: centrifugal pumps

Positive displacement pumps

Another name for this category is discrete pump. The working method of the water pump in the positive displacement pump model is that the transfer of energy to the fluid is not permanent and they are constantly disconnected and connected, and in each cycle of this type of water pump, a certain amount of liquid or fluid is pumped.

Features of positive displacement pump

  • Features of positive displacement pump
  • Output to impact mode
  • High ability to withstand pressure to transfer fluids with high viscosity
  • Entering a specific volume of fluid into the chamber, applying force due to oscillating suction, and exiting the fluid in a pulse-like manner from the pump.
  • Constant flow rate with pressure changes
  • Having a powerful structure and the ability to work with fluids with high viscosity
  • In terms of efficiency: insignificant dependence of pump performance on pressure
  • The most famous type of positive displacement pumps: reciprocating pumps and circulation pumps

The road map of the world of pumps

In the figure below, a complete guide is provided regarding the classification of pumps and it can be called the road map of the world of pumps.

This figure, based on the standards that are often used for classification, provides useful explanations regarding the selection and application of pumps.

Note that these two classes are only related to the mechanics of fluid movement and are not related to the uses for which the pump is designed. This issue is important because many pumps are produced and sold for special purposes and basic issues such as pump class and type may be overlooked in the complexities of finding the best design.

Each class, in turn, can be divided into different types; For example, rotary classification will be divided into types of pumps: screw, gear, vane, etc., each of which is actually a specific type of rotary pump.

components and constituent parts

According to their type, pumps are composed of different parts, but there are common parts among all of them. These components include the following:


It is a chamber that contains the vanes, shaft and sealing system of the pump and the fluid flows in it. Usually, the pump body is of spiral type or increasing diameter type. Its material according to the environment in which the pump is used. It is variable. For example, the body of sea salt water pumps must be resistant to salt

Pump impeller

The pump impeller increases its speed by applying a lot of force to the fluid. In other words, we can say:

The hole in the center of the impeller is called the eye of the impeller, which can be one of the criteria for determining the pump capacity. Butterflies are divided into the following three types:

  1. open butterfly
  2. Butterfly half open
  3. closed butterfly


The impeller cover covers the pump blades and limits the fluid flow in the area of the pump impeller.

Pump blades

Pump vanes are parts of the impeller that guide the fluid inside the pump.


A cylindrical piece for connecting the propeller to the engine. Of course, some also call the shaft “Shaft”.

Features of pumps

Knowing the characteristics of an industrial pump is effective in choosing it correctly.

As already mentioned, a pump is a device that transfers fluid from a lower height to a higher height. In this definition, four basic concepts of pumps are included:

A pump is a device for transferring and moving fluid, so a pump is a device.
The pump is for fluids and liquids, and a compressor is often used to transfer gas.
Pumps give energy to fluid, this energy is usually expressed as pumping pressure or pump head.
Pumps transfer a volume of fluid. Usually, this volume of fluid is expressed in unit time, which is the pumping speed.

In addition to these four items, in order to know and choose the correct pump, the application of the pump should also be known. That is, what volume of fluid per unit of time with what pressure and for what purpose should be pumped by the pump? Usually, this is the first question of all those who intend to buy a pump. The answer to this question is the first opening to the wonderful world of pumps.

As mentioned above, the basic concepts of pumps are as follows:

Structure and construction of the pump
Pump selection

How pumps work

The pump receives the required mechanical energy from an external source such as an electric motor, and as soon as the fluid enters the pump chamber, the impeller or the pump vanes start rotating, and with the rotation of the vanes, kinetic energy is transferred to the passing fluid. As a result, the fluid gains more energy and is pumped at a higher speed and pressure. In general, the water pump works in such a way that it transfers energy to the fluid and increases its pressure.

Pump pressure or height (head) means that a pump in its standard conditions is able to raise the fluid up to what height under pressure.

In other words, pumps transfer fluid by creating a pressure difference on the suction side and the discharge side. A pump converts mechanical energy supplied through an external source into fluid motion energy; Therefore, by increasing the energy of the fluid, the pumps cause the fluid to rise or overcome the hydraulic resistance in the discharge pipe.

Note: the principle of operation of pumps is the reverse of the operation of hydraulic motors; That is, in hydraulic motors, fluid movement energy is converted into mechanical work, but in pumps, as mentioned above, mechanical work will increase the fluid energy.

For centrifugal water pumps, the height (head) or pressure (v) of the water is in meters (m) or feet (ft). For rotary pumps and positive displacement, the pump pressure is in bar, PSI, kilopascal. (kpa) is called.