Air-Operated Double-Diaphragm – AODD pumps

AODD pumps is a variety of positive displacement pump which contains of two pumping compartments that are alternately filled and discharged by the movement of flexible diaphragms. Compressed air is interchangeably sent to, and vented from, air compartments on the differing sides of the diaphragms to generate the propelling action.

AODD pumps are usually used for transmitting applications and can manage a wide variety of inputs that includes sludge’s, slurries, rough and shear delicate solutions. Even though they are robust, dependable and easy to maintain they can be loud, prone to frosting, and are restricted to low pressure applications.

How AODD Pumps Work?

LEFT STROKE

The air valve leads pressurized air to the posterior side of diaphragm A. The compressed air is applied straight to the fluid column divided by elastomeric diaphragms. The diaphragm acts as a parting membrane between the compressed air and fluid, balancing the weight and eliminating mechanical stress from the diaphragm. 

The compressed air moves the diaphragm away from the middle block of the pump. The opposite diaphragm is dragged in by the shaft attached to the pressurized diaphragm. Diaphragm B is on its suction thump; air behind the diaphragm has been forced out to the ether through the exhaust port of the pump.

The movement of diaphragm B toward the middle block of the pump creates a vacuum within compartment B. Atmospheric pressure forces liquid into the inlet multiple times forcing the inlet valve ball off its position. Fluid is free to transfer past the inlet valve ball and fill the fluid Compartment.

MID STROKE

When the pressurised diaphragm pump, diaphragm A, reaches the limit of its release stroke, the air valve transmits pressurised air to the posterior side of diaphragm B. The pressurised air forces diaphragm B away from the middle block while pulling diaphragm A to the middle block.

Diaphragm B is now on its ejection stroke. Diaphragm B forces the inlet valve ball onto its position due to the hydraulic forces developed in the fluid chamber and manifold of the AODD pump. These same hydraulic forces lift the release valve ball off its position, while the opposite discharge valve ball is forced onto its seat, forcing liquid to flow through the pump ejection. 

The movement of diaphragm A near the middle block of the pump generates a vacuum within fluid chamber A. Atmospheric pressure forces liquid into the inlet manifold of the AODD pump. The inlet valve ball is then forced off its position letting the liquid being pumped to fill the fluid compartment.

RIGHT STROKE

At close of the stroke, the air valve again transmits air to the back side of diaphragm A, which starts diaphragm B on its exhaust stroke. As the AODD pump reaches its original initial point, each diaphragm has gone through one exhaust and one ejection stroke.

This establishes one complete pumping cycle and the pump may take numerous cycles to totally prime depending on the conditions of the application.

Antlia Engineering Works is one of the leading manufacturers of AODD pumps in India, Middle-East, Australia, Africa  and produce pumps that robust, reliable, easy to maintain, and comparatively low cost. They tend to be all-purpose mainstay devices and are usually used for transmitting applications in a wide range of industries.