Diaphragm Pumps








  • Air Operated Double Diaphragm Pumps (AODD):
    • Aluminium Pumps
    • Polypropylene Pumps (Plastic)
    • PVDF Pumps
    • Stainless Steel / Food Grade Pumps
    • Cast Stainless Steel Pumps
    • High Pressure Pumps
    • Electric Driven Pumps
  • Mechancial Diaphragm pumps / Electric Diaphragm Pumps:
    • Electric Driven Pumps





  • Mechancial Diaphragm pumps / Electric Diaphragm Pumps:
    • Electric / Engine Driven Pumps


What is a Diaphragm Pump:

A diaphragm pump is a positive displacement pump which operates with a flexible diaphragm, and integrated check valves. The diaphragm is moved inward & outward toward the pump body which works in conjunction with the check valves and draws in and expels the fluid out the pump casing.

There are two main styles of diaphragm pumps, namely mechanical driven diaphragm pumps and air operated diaphragm pumps. The difference between these two styles is their method of being driven, ie. with compressed air, or mechanically drive with an electric motor or engine.

These pumps are available in various sizes from ¼” to 3”.

They are also available in a range of materials that suit a range of applications. These materials are Aluminium, Cast Iron, Polypropylene, PVDF, Cast Stainless Steel, Food Grade Stainless Steel.

For applications where there is an Explosive Atmosphere, we have ATEX Certified conductive pumps.


Diaphragm Pumps have a wide variety of applications and uses in many industries including food, dairy, pharmaceutical and cosmetic industries, where Stainless Steel pumps are used for these hygienic requirements.

Air pumps are very  commonly used in the food sector as the transfer of the fluid does not disrupt the chemical properties and consistency of products such as milk, buttermilk, yogurt, cream, mustard, mayonnaise, ketchup and similar products.

Other uses of AODD pumps include transfer of petroleum products, oil and sludge removal operation, transfer of many types of chemicals, including adhesives, solvents, solvent and water based glues and adhesives, paints and inks. The diaphragm pump is the preferred option for these and other types of chemicals and are widely used as they have the ability to operate safely in a flammable environment.

Air Operated Double Diaphragm Pump (AODD):

The most common diaphragm pump is an Air Operated Double Diaphragm (AODD) pump.

The AODD is a form of positive displacement pump in which has two pump chambers, a “left” & a “right”. The left and right chambers each have their own diaphragm which interconnect with a shaft so when the one moves, the other one moves proportionality at the same time.

How the Air Operated Double Diaphragm Pump works:

Right Stroke

Compressed air is directed to the back side of diaphragm B by the air valve. The compressed air moves the diaphragm away from the centre block. The compressed air pushes the liquid column separated by elastomeric diaphragm, forcing the fluid through the fluid outlet. At the same time, the opposite diaphragm is pulled in by the shaft connected to the pressurized diaphragm. So, diaphragm A is on its suction stroke: the air behind diaphragm A is forced out to the atmosphere through the exhaust port of the pump. The movement of diaphragm B away from the centre block of the pump creates a vacuum within chamber A. The vacuum force draws in the fluid into the inlet manifold forcing the inlet valve ball off its seat. The fluid is free to move past the inlet valve ball and fill liquid chamber A.



Middle Stroke

When the pressurized diaphragm, diaphragm B, reaches the limit of its discharge stroke, the air valve redirects compressed air to the back side of diaphragm A. The pressurized air forces diaphragm A away from the centre block while, at the same time, the connected shaft pulls diaphragm B to the centre block. Diaphragm A is now on its discharge stroke. Diaphragm A forces the inlet valve ball onto its seat due to the hydraulic forces developed in the liquid chamber and manifold of the pump. These same hydraulic forces lift the discharge valve ball off its seat, while the opposite discharge valve ball is forced onto its seat, forcing the fluid to flow through the pump discharge. The movement of diaphragm B toward the centre block of the pump creates a vacuum within liquid chamber B. Atmospheric pressure forces the fluid into the inlet manifold of the pump. The inlet valve ball is forced off its seat allowing the fluid being pumped to fill the liquid chamber.


Left Stroke

At completion of the stroke, the air valve again redirects air to the back side of diaphragm B, which starts diaphragm A on its exhaust stroke. As the pump reaches its original starting point, each diaphragm has gone through one exhaust and one discharge stroke. This constitutes one complete pumping cycle. The pump may take several cycles to completely prime depending on the conditions of the application.




Mechanically Operated Diaphragm Pumps:

Mechanically operated diaphragm pumps work on a similar principal to the Air Operated Double Diaphragm pump, but instead of compressed air driving the diaphragms back & forth, they have a mechanically driven shaft which pushes & pulls the diaphragms back & forth.

These pumps are available in a single diaphragm configuration, and also a double diaphragm configuration