Air-operated pumps represent a versatile and reliable technical solution for fluid transfer in a wide range of industrial applications. Due to the absence of electrical components, they offer high safety standards, making them particularly suitable for use in explosive environments (ATEX). The most common configurations, such as air-operated double diaphragm (AODD) pumps and piston pumps, are well-suited to handling challenging fluids, including viscous, abrasive liquids or those containing suspended solids. Their modular design and ease of maintenance facilitate integration into complex systems, ensuring operational continuity even under extreme working conditions.

AODD Pumps: Operating Principles

Diaphragm pumps, also referred to as AODD (Air Operated Double Diaphragm) pumps, fall into the category of reciprocating positive displacement pumps. Their operating principle is based on the use of a flexible diaphragm, which enables fluid transfer through cyclic variation of the internal volume of the pumping chambers.

The air-operated diaphragm pump is arguably the most versatile pump available. Designed to be constructed from a variety of materials, it offers excellent chemical compatibility, making it suitable for transferring a wide range of industrial fluids, including medium-viscosity liquids, abrasive or corrosive fluids, and those containing suspended solids.

AODD Pump Operating Cycle

As illustrated in the figure below, the pump operates through the vacuum and pressure generated by the reciprocating linear motion of two diaphragms (A), mechanically connected by a metal shaft, inside two sealed chambers (B).

During diaphragm movement, the pump simultaneously draws liquid in through the suction port (C) and discharges it through the outlet port (D), thereby creating a continuous transfer cycle.

The diaphragms are actuated by compressed air, which is automatically and alternately introduced and vented from the air chambers (E).

The pump continues its cycle as long as a sufficient supply of compressed air is maintained. Operation ceases naturally when the downstream pressure (backpressure) equals or exceeds the air supply pressure—such as when a ball valve is closed—or when the pneumatic supply is shut off.

The selection of an air-operated pump for industrial applications must be based on a thorough analysis of fluid dynamic parameters and environmental conditions. PCHEM solutions, engineered with a focus on modularity and mechanical robustness, deliver high operational performance in critical applications.