What is a Diaphragm Pump? How it Works and Key Components

Diaphragm pumps, also known as membrane pumps, are one of the most versatile pump types available. They are widely used in many industries, for good reason. They are robust, compact and available in wide range of materials and sizes. In addition, they are self-priming and have dry-run capability. Plus, they are suitable for wide ranging tasks, such as transferring viscous fluids moving corrosive chemicals and pumping abrasive materials. But what is a diaphragm pump, how does it work, and what are its key components?

What is a Diaphragm Pump?

Firstly, a diaphragm pump is a type of positive displacement pump that utilises anywhere between one to five flexible, oscillating diaphragms to move fluids.

These pumps have the ability to transfer most liquids and even solids-entrained slurries safely and effectively. In addition, they are suitable for a broad range of applications and environments, including food and beverage, chemicals, pharmaceuticals, explosive atmospheres and wastewater treatment.

Furthermore, standout features include their ability to run dry without damage, handle highly viscous or abrasive media and their self-stalling operation.

How Does a Diaphragm Pump Work?

The operation of a diaphragm pump relies on the movement of one or more diaphragms and the action of check valves. Here’s a simplified step-by-step breakdown of how it works:

1. Suction Stroke:
   • Firstly, the diaphragm retracts, creating a vacuum in the pump chamber.
   • This vacuum consequently causes the inlet check valve to open, allowing the fluid to flow into the chamber.
2. Discharge Stroke:
   • The diaphragm moves forward, therefore compressing the fluid in the chamber.
   • This pressure forces the inlet check valve to close and opens the outlet check valve, consequently pushing the fluid out of the pump.

This process is repeated continuously, driven by either mechanical force, pneumatic energy (compressed air), or hydraulic energy.

Key Components

To understand a diaphragm pump fully, it helps to understand the key components and their roles:

1. Diaphragm:
   • Firstly, the flexible membrane that creates the pumping action. Manufactured from a range of materials such as PTFE, natural rubber, EPDM or other elastomer materials, depending on the application.
2. Pump Chamber:
3. The cavity draws in and expels fluid during the pump’s operation.

3. Check Valves:
   • Typically located at the pump’s inlet and outlet, these valves ensure fluid flows in the correct direction, preventing backflow.
4. Drive Mechanism:
   • The method used to initiate diaphragm movement. Options include hand-actuation (via lever or handle), pneumatic drive (compressed air), mechanical drive (crankshaft, piston or cam), or hydraulic drive.
5. Inlet and Outlet Ports:
   • Usually threaded or flanged connections on the pump body that allow fluid to enter and exit the pump. These are designed to accommodate a range of pipe and hose connections and configurations.
6. Housing or Casing:
   • Finally, the pump body that incorporates the internal components, provides structural support and retains the pumped fluid.

Why Choose a Diaphragm Pump?

Diaphragm pumps are valued for their reliability and versatility. Here are some of the top reasons to consider one for your application:

• Leak-Free Design: Ideal for handling hazardous or sensitive fluids.
• Dry Self-Priming: Can operate effectively without needing external priming.
• Handles Most Fluids: Works with everything from water or solvents, to adhesive products and thick slurries.
• Wide range of sizes and materials: For variable frow rates and chemical compatibility
• Runs Dry Safely: Capable of operating without liquid for short periods without damage.
• ATEX-approved models: constructed from conductive materials

Application Examples

Due to their adaptability, diaphragm pumps are used in:

• Chemical Processing: For transferring corrosive acids, alkalis and flammable solvents
• Food: Safely pumping liquids such as vinegar, sauces, syrups and beverages
• Pharmaceuticals: Ensuring sterile handling of sensitive gels and topical treatments
• Mining: Handling slurries and dewatering operations
• Wastewater Treatment: Moving sludge, disinfection chemicals and abrasive materials

Diaphragm pumps are common across every industry, thanks to their versatility and ability to handle challenging fluids. By understanding how they work and the key components, you can hopefully make an informed decision about whether these pumps are the right choice for your application.

At Flux Pumps UK, we offer a range of high-quality ARO and Flux diaphragm pumps. Finally, if you have any questions, or need guidance to select the right pump for your needs, don’t hesitate to contact us.