Principle of operation of pneumatic diaphragm pump

A pneumatic diaphragm pump is a device that uses compressed air to move fluid. This type of pump is widely used in the chemical, oil, food, pharmaceutical and other industries, as it allows pumping high viscosity liquids, abrasive and corrosive liquids, as well as media containing solid particles. The principle of operation of a pneumatic diaphragm pump is based on the compression and expansion of the diaphragms, which create a vacuum to capture and eject the liquid.

Pneumatic diaphragm pump design

The pneumatic diaphragm pump has a simple but effective design consisting of:

• Body divided into two chambers (pneumatic and hydraulic);
• Two membranes connected by a common rod system;
• Air valve controlling the flow of compressed air;
• Inlet and outlet valves that regulate the flow of working fluid.

The pump casing is usually made of chemically resistant materials such as polypropylene, stainless steel or aluminium. The diaphragms are made of materials resistant to aggressive media such as Teflon or nitrile, making the pumps suitable for use with aggressive and abrasive substances.

The principle of operation

The basic principle of operation of a pneumatic diaphragm pump is based on the movement of compressed air between the chambers and the creation of a cyclic movement of the diaphragms. Let's take a closer look at the process:

• Compressed air supply: Compressed air enters one of the pneumatic chambers, which leads to displacement of the membrane towards the hydraulic chamber. The membranes move synchronously because they are connected by a common rod.
• Fluid entrainment: When one diaphragm compresses the hydraulic chamber, the other diaphragm creates a vacuum in the opposite chamber, allowing fluid to enter the pump through the inlet valve.
• Fluid Ejection: A membrane compressing the chamber forces fluid through the outlet valve, creating a steady flow of fluid.
• Transition of air to another chamber: The air valve switches the flow of compressed air to the opposite side, and the cycle repeats itself, ensuring continuous fluid movement.

Advantages and disadvantages of pneumatic diaphragm pumps

Advantages:

• Versatility: can pump liquids with high and low viscosity, including abrasive and aggressive liquids.
• Self-priming: the pumps are able to work without filling, which is especially important when moving environments with high requirements for cleanliness.
• Safety: due to the absence of an electric motor, the pumps are safe for use in explosive areas.
• Simplicity of design and maintenance, lack of complex mechanisms, which reduces operating costs.

Disadvantages:

• Noise during operation, as the pumps use compressed air, which may require additional noise reduction devices.
• High air consumption, which can increase operating costs under conditions of constant use.
• Pressure Limitation: These pumps typically operate within low to medium pressures, making them unsuitable for processes requiring high pressures.

Application of pneumatic diaphragm pumps

Pneumatic diaphragm pumps are used in a variety of industries:

• Chemical industry: for pumping aggressive acids and alkalis.
• Oil industry: for moving fuel, oils and other hydrocarbon liquids.
• Food industry: for pumping food products such as juices, sauces and viscous mixtures.
• Pharmaceuticals: for working with pharmaceutical viscous liquids that require careful handling.

For a detailed guide and selection of a pneumatic diaphragm pump, please visit.