How a Diaphragm Pump Works

A diaphragm pump is a pneumatic hydraulic pump that operates through the movement of two opposing membranes.

Main components include:

  • The central body: the ends are the opposing air chambers connected by the pneumatic distributor. Through it, the intake and discharge of compressed air occur;

  • The pneumatic distributor is the component that ensures a continuous air exchange in the two opposing chambers, maintaining a nearly 1:1 ratio between the volume of fluid and air. It consists of a movable bushing connected to the shaft that manages the opening and closing of the air passages from one chamber to the other of the spool, all enclosed in a fixed cylindrical body for loading and unloading from the central body. The FLUIMAC distributor allows double diaphragm pumps to be operated with compressed air between 2 bar and 8 bar; It is possible to improve the performance of the diaphragm pump by acting on the number and arrangement of circulation channels and on friction between parts:
    - they must ensure a complete load of one chamber and simultaneously the complete discharge of the other, avoiding stall situations where the forces between one membrane and the other balance out,
    - if the friction is too high, there is not enough smoothness between the concentric parts, requiring an increase in air pressure and its consumption, making the diaphragm pump start at too “high” pressures.

  • The diaphragms are the elastic elements and main components of the diaphragm pump that allow fluid movement. They are made of rubbers that change their properties depending on the environment of use. On one side, they come into contact with the compressed air and on the other with the working fluid. The two diaphragms, being perfectly opposed, perform opposite work during the work cycle: when one inflates, allowing the pumping of the fluid, the other deflates, creating a vacuum in the fluid chamber, thus allowing the suction of the latter. They are designed so that their shape does not interfere with the distributor and to decrease flexural stress or increase thrust force.
    From them derives the name double diaphragm pump.

  • The pump bodies are the fluid passage chambers of the double diaphragm pneumatic pump. They contain a non-return ball valve in suction and one in discharge that open and close oppositely based on the fluid load or discharge phase. The valves, composed of ball, seat, and cage, are perfectly concentric to the diameter of the suction and discharge channels of the pump body to avoid fluid leakage and ensure the fluid's passage through the inner diameter. The ball rests completely on the inner circumference to prevent reverse fluid motion, and the cage restricts it to only vertical movement, not transverse. Based on the displacement of the diaphragm pump body, different flow rates can be developed, whereas based on the constituent material (PP, PVDF, POMc, AISI, aluminum, etc.), chemically different liquids are processed;

  • The collectors are the fluid passage channels of the double diaphragm pump. We have a suction collector and a discharge collector. They connect the two opposing working chambers. Based on their diameter, different flow rates can be pumped; they are made of the same materials as the pump bodies depending on the type of liquid pumped.

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