How does a diaphragm pump work and what is it used for?

What is a diaphragm pump?

A diaphragm pump, also known as a membrane pump, is a type of positive displacement pump widely used in various industries due to its versatility and efficient pumping operation. In general, diaphragm pumps are used for fluid transfer and lower pressure spray applications that require a smooth and consistent flow. This makes them great options for food and beverage manufacturing, water treatment and transfer, chemical processing, paint transfer, and more.

There are two main types of diaphragm pumps, each with its own advantages and disadvantages: air-operated diaphragm pumps and electric diaphragm pumps. Choosing the right diaphragm pump depends on a variety of considerations, such as the fluid being pumped, flow rate requirements, pressure capabilities, and environmental conditions.

Types of diaphragm pumps

What is an air-operated diaphragm pump?

Air operated diaphragm pumps (also known as pneumatic pumps or AODD pumps) are powered by compressed air, which can make them ideal for remote or hazardous locations where operating with electricity is not always an option. Since pneumatic pumps do not need electricity to operate, they are less likely to generate sparks, which could be a concern in some hazardous environments. The biggest downside to air operated diaphragm pumps is the amount of energy they use, which can be very costly over the life of the pump.

What is an electric diaphragm pump?

Electric diaphragm pumps (or EODD pumps) use electricity as the power source to create a reciprocating action that moves fluid. It combines the reliability and fluid compatibility of a standard air operated diaphragm pump with the convenience and energy efficiency of an electric power source. Since they are powered by an electric motor, energy consumption can be reduced by up to 5x compared to air operated diaphragm pumps. Electric diaphragm pumps are also easy to install and operate without the need for specialised training, while offering precise control over flow rate and pressure.

How does a diaphragm pump work?

A diaphragm pump (both air and electric operated) relies on diaphragms which are flexible membranes that swing back and forth to move fluid through the pump and out to the discharge point. The difference between the two types of diaphragm pumps is how this movement takes place. While air-operated diaphragm pumps use air pressure to shift the diaphragm from one side to the other, electric diaphragm pumps accomplish this with its electric motor.

Diaphragm pump uses and applications

As discussed, diaphragm pumps are common choices for numerous applications due to their ability to handle many different types of fluids. Some of the most common industries include:

• Automotive: paint transfer and waste disposal
• Ceramics: slip/slurry transfer and wastewater transfer
• Chemical processing: material transfer, acid transfer, and chemical pumping
• Food and beverage: food and beverage processing and ingredient transfer
• Printing, packaging, pulp and paper: ink/glue/solvent/adhesive transfer
• Water and wastewater: water treatment/transfer and wastewater management
• Paint manufacturing: Mixing, loading, unloading and transferring of acrylics, solvents, resins, pigments and additives between different stages of production

Choosing the right diaphragm pump

When it comes to choosing the right diaphragm pump, there are a few considerations to keep in mind depending on your specific needs.

1. Type of fluid: The first step is to determine the type of fluid you need to pump. Is it abrasive, corrosive, viscous, or contain any solid particles? For thicker fluids, a diaphragm pump with a larger port may be required.

2. Flow rate and pressure requirements: Determine the flow rate and discharge pressure required for your pumping application. Electric diaphragm pumps have precise control in these areas, which is needed for fluid handling that requires consistency.

3. Power source: Your available power source could decide the type of diaphragm pump you can use. If access to a reliable electricity source is a concern, air operated diaphragm pumps might be the better option. Otherwise electric diaphragm pumps are ideal, especially for indoor environments where noise levels are a common issue, since electric pumps offer much quieter operation.

4. Maintenance and costs: Air operated diaphragm pumps typically have higher maintenance costs due to the number of moving parts, but can have a lower initial purchase price compared to electric diaphragm pumps. However, since electric diaphragm pumps require less energy, the total cost of ownership is considerably lower over the pump life. In fact, Graco offers an electric diaphragm pump that can reduce energy usage and costs by up to 80% of a traditional air operated diaphragm pump.