How do air operated diaphragm pumps work?

Air-operate double diaphragm pumps are a well-established positive displacement pump technology. They are used for a broad spectrum of applications from chemical maintenance in swimming pools, to slurry transfer in the manufacture of dog food. With few moving parts, a key benefit of AODD technology is that the diaphragm is the only moving part that makes contact with the media.

How AODD technology works?

AODD pumps require a compressed air supply to drive them. Adjacent liquid chambers are alternately filled and emptied by fluid that is drawn through a common inlet and discharged through a single outlet. The diaphragm for each chamber is connected by a single shaft allowing them to move in unison. An air valve directs pressurised air to the back of one of the diaphragms, which begins a suction stroke for the adjacent diaphragm. This works to create a vacuum and atmospheric pressure forces liquid from one diaphragm to the other past the inlet ball valve.

Once one of the diaphragms reaches the limit of its discharge stroke, the air valve redirects pressurised air to the back of the adjacent diaphragm. Hydraulic forces developed inside of the diaphragm forces the inlet ball onto its seat, and the discharge ball off its seat. This condition allows fluid to flow through the pump discharge. This same process occurs in the opposite chamber, constituting a full cycle. The pump runs continuously until the air supply is interrupted, or discharge pressure rises to become equal that of the inlet pressure.

The benefits of peristaltic technology

• No air supply needed
• No valves to clog and wear
• One-minute maintenance
• Easy to clean

If a compressed air supply is not installed at a site, they can be very expensive to install and many air supply systems are inefficient with at least 30% air leakage, so energy costs for an air operated diaphragm pumps are high.

Watson-Marlow Fluid Technology pumps are easy to install, simple to operate and inexpensive to maintain. Fluid in a peristaltic pump passes through an abrasive-resistant tube or hose. There are no ancillaries needed for installation or running and changing a hose or tube can be done in minutes, without special tools or skilled labour and with the pump remaining in-situ.