Mechanical Basics

What is Diaphragm Pump?

Diaphragm Pump is also called Diaphragm Vacuum Pump, is a type of pump that is used to increase the velocity of the fluid to complete an action. Till now, we saw centrifugal pumps, reciprocating pumps, etc., but the diaphragm pump is quite different from all of them even though it is a positive displacement type, it purely works on the diaphragm, and air. Apart from this, there will be no pistons and motor for its functioning.

Diaphragm Pump Working Principle

Additionally, the diaphragm pump is also called as Membrane Pump. As air is capable to compress anything, it can even be used to run a pump in Industrial Applications. It is sensitive in construction but heavy in on-duty. As like other compressors, or pumps, it does not consist any electrical components inside it but it require an external source to supply high pressurized Air.

What is a Pump?

The Pump is a device that is used to transfer the fluid from the lower heads to the higher heads by adding energy to the fluid. So, to achieve this aim there are different sources; it means, the pump can add pressure to the fluid with the help of Rotary motion or reciprocating motion by the piston. But when it comes to the diaphragm pump, the source that helps the fluid to achieve high pressure is Pneumatic or Air.

Diaphragm Pump Working Principle:

The pump that works with the help of air is called the Pneumatic or vacuum Pump. In the diaphragm pump, the diaphragm will create a vacuum on one of the sides for sucking the fluid and the air in the next step will increase the pressure of the fluid with the help of the diaphragm. By this process, the required aim can be achieved.

Diaphragm Pump Parts:

The Diaphragm Pump consists of parts that help to work, they are as follow:

Diaphragm Pump Working Principle

    1. Airside (separated by a Santoprene Diaphragm)Air Distribution System.
    2. Teflon Diaphragm.
    3. Inner Diaphragm or Santoprene Diaphragm.
    4. Teflon balls or Valve balls.
    5. Valve Seat.
    6. Outlet Manifold or Fluid Outlet.
    7. Liquid Side separated by Teflon Diaphragm
    8. Santoprene Diaphragm
    9. Inlet Manifold or Suction Manifold.

Diaphragm Pump Working Specifications:

The Diaphragm Pump will account for a few Working Specifications for its operations, so they are as follows

    • Working Pressure or Input Pressure: The pressure input depends upon the capacity of the pump, there are two types of capacities, they are 1-inch capacity diaphragm pump and 2-inch capacity diaphragm pump. So, the working pressure or Input pressure required for working of 1-inch pump is 1.5 bars to 2 bars and it will be high if we choose a 2-inch pump.

    • Maximum Pressure: The maximum pressure that a 1-inch capacity pump can bear is 6 bars and it will be more than 6 bars for a 2-inch capacity pump.
    • Maximum height or head that the pump can deliver: This is very important while selecting the type of diaphragm pump because every pump is selected according to the height or head that it can deliver the fluid. So, a 1-Inch Pneumatic Diaphragm pump can transfer the fluid up to 7 meters to 10 meters maximum. When it comes to 2-inch, it may be more than 7 meters to 10 meters.

How A Diaphragm Pump Works?

The pump will achieve its aim on both sides, it means the discharge of the fluid is done by the sides of the diaphragms. The pneumatic pump consists of 4 diaphragms; two on each side which means one set on each side. One of the sides is fixed with White-coloured or Teflon material diaphragm and another was Green-coloured (or some other colour) or Santoprene material diaphragm.

Diaphragm Pump Working Principle

    • Both sides will consist of two sections; one was air side and another was fluid side.
    • The air enters into the pump from the air side and pushes one of the diaphragms located in the Pitot valve; when the air pushes the first diaphragm, the vacuum is created in the other side of the second diaphragm that results in sucking of the fluid into the pump.
    • When the first diaphragm reaches its maximum limit then the air will start pushing the second diaphragm that is already filled with fluid on its other side. Due to this, the fluid will be pumped to the higher heads on the second diaphragm fluid side with the help of White or Teflon Diaphragm. This process is called the Discharge process.


Diaphragm Pump Working Principle

    • As one of the two sides of the second diaphragm Discharges the fluid, the first diaphragm will suck the fluid due to the vacuum created by the backward movement of the Diaphragms. This process is called the Suction Process. According to this alternate working process, the pump will deliver a linear fluid flow.

This is how a Pneumatic Diaphragm Pump works on both sides.

Advantages of Diaphragm Pump:

Here are a few advantages of the diaphragm pump.

    • As this pump does not consist of any Electric components then no short circuits will take place.
    • It is easy in construction.
    • High performance with good efficiency.
    • It is easy to overhaul or repair.
    • It just requires compressed air to work and no need for electric connections.

Applications of Diaphragm Pump:

    • These types of pumps are mainly used in highly sensitive and fire restricted places.
    • It is used in Printing and Packing Industries where the electrical pumps are very dangerous to use.
    • This type of pump is used in low head discharging places.


Diaphragm Vacuum Pump purely works on the air and there will no electricity requirement. The construction is simple and the working process is not less than other pumps. This type of pump is constructed or invented to use for industrial purposes where there are flammable substances are stored or manufactures.

This type of pump is more secure to use, with no risk involved. This will never lead to short circuits and accidents.

2 thoughts on “Diaphragm Pump Working Principle-Specifications and Advantages”
  1. Sivaranjanreddy Vennapusa says:

    Hi Rudra
    Thank you so much for sharing all this wonderful info with the how-it works!!!! It is so appreciated!!!” “You always have good knowledge in your blog. So much of Information is there and easy to read!
    Good Luck..

    1. Thank you Sivaranjanreddy vennapusa

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