Pump | Definition, Types, Applications [A Brief Guide]

What is a pump?

A pump is a mechanical device which is used to move fluid (sometimes also slurry) from one place to another.

One of the examples of a pump is the water pump which is used in our houses to carry water from the ground to the tank on the top of house.

Types of pumps

Pumps can be broadly classified into two types

1. Positive displacement pumps
2. Rotodynamic pumps

Now we will discuss each of the above-mentioned type of pump in details.

Positive displacement pumps

To move fluid from one place to another a positive displacement pump traps fluid and then forces it to the discharge pipe.

Below is an animated image to understand positive displacement pumps.

Safety considerations with positive displacement pumps

A positive displacement pump must not be operated against closed valves, because it does not have a shutoff head like a rotodynamic pump.

Providing a safety valve is must in positive displacement pumps.

Types of positive displacement pump

Following are the two main types of positive displacement pumps.

1. Rotary positive displacement pumps

• Rotary vane pump
• Screw pump
• Gear pump

2. Reciprocating positive displacement pumps

• Radial piston pumps
• Piston pumps
• Diaphragm pumps
• Plunger pumps

Rotodynamic pumps

A rotodynamic pump uses impellers to impart kinetic energy to the fluid. With the help of the centrifugal force the fluid is forced to the discharge pipe.

Generally, the pumps which we use in our homes (which has an impeller) are most popular example of rotodynamic pump.

Below is an animated image to understand Rotodynamic pumps.

Types of rotodynamic pumps

Rotodynamic pumps can be classified into following three types.

1. Radial flow rotodynamic pump

2. Axial flow rotodynamic pump

3. Mixed flow rotodynamic pump

Applications of pumps

Below are some most popular applications of pumps.

• Pumping water from the wells
• Aquarium and pond filtering
• Water cooling and fuel injection in automobiles
• Pumping oil or gas and operating cooling towers in energy industry
• They also have their uses in waste water recycling, pulp and paper, chemical industry etc.

Also read:

What are different types of fluid flows?

What is capillary effect?

Image source:

Positive displacement pump: By The original uploader was Xlory at French Wikipedia. – Transferred from fr.wikipedia to Commons by WikedKentaur using CommonsHelper., CC BY-SA 1.0, https://commons.wikimedia.org/w/index.php?curid=9596789 [Date: 08-12-2018]

Rotodynamic pump: By EagleX – Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=12753938 [Date: 08-12-2018]