How does a Diaphragm Pump work?


Diaphragm Pumps are one of the most popular pumps available on the market. Here at TS Pumps, we supply a range of Diaphragm Pumps from one of the leading manufacturers around the world, Tapflo. They are renowned for their innovative Pump technology and fewer parts in Diaphragm Pumps that many others on the market. Take a look below at our Diaphragm Pump guide for an overview of the range we supply and answer some frequently asked questions.

How does a Diaphragm Pump work?

What is a Diaphragm Pump?

A Diaphragm Pump is a Positive Displacement Pump that transfers fluid via diaphragms working together to push the liquid through the system within the pump.

The Diaphragm Pumps that we supply are driven by compressed air, also referred to as Air Operated Double Diaphragm Pumps or AODDs.

View the full range of Air Operated Diaphragm Pumps.

An Air Diaphragm Pump works by using the following operation:

  1. Compressed air drives the diaphragms within the pump casing to simultaneously work in order to positively displace the product
  2. The diaphragms then work together to trap fluid
  3. As the air drives the diaphragms, this then pushes the trapped fluid into the discharge pipe, transferring the fluid out of the pump.

This is achieved by one diaphragm creating suction to draw in the fluid and trap it, whilst the fluid trapped by the other diaphragm pushes the fluid, in the other half of the pump, out.

What materials are available for a Diaphragm Pump?

Metal – Available in Aluminium, Cast Iron or Stainless Steel AISI 316, a Metal AOD Pump is perfect for handling fluids that are viscous, chemically aggressive or contain coarse solids.

HDPE & PTFE – Available in solid block polyethylene and solid block PTFE. The Diaphragm Pump housing is machined from solid block plastic to ensure that the design is strong enough to withstand mechanical force and aggressive chemicals without creating weak points for leakage.

Our Metal and HDPE & PTFE ranges of Diaphragm Pump are also available as ATEX rated upon request, you can view both pumps in the ranges linked above.

Sanitary – Our Sanitary Diaphragm Pump range is designed specifically for industries that require the highest level of hygiene: beverage, cosmetic, food & pharmaceutical industries. ATEX, EHEDG, USP VI and FDA approved.

If you’re looking for more information on TS Pumps’ range of Sanitary Pumps, not just Air Pumps, check out our Sanitary Pump Guide.

Plastic Diaphragm Pump

What are the benefits of Air Operated Diaphragm Pumps?


  1. Air operated diaphragm pumps means that compressed air fully drives your Diaphragm Pump and there is no need for an electrical connection.
  2.  They are easily maintained. Our range of Air Operated Diaphragm Pumps is made from 70% less parts than the industry standard. This makes maintenance easy and straightforward, without the need for expensive service costs or for specialist Diaphragm Pump training.
  3.  AOD Pumps have an air distribution system that doesn’t require lubrication, which reduces pollution into the environment.  – Keen on helping the environment and saving money on compressed air? Check out our Low Energy Diaphragm Pump
  4. The Diaphragm Pump is an enormously versatile pump with 3 different installation points, an industry list that’s double the size, and a list of applications longer than the long-life span of the next Diaphragm Pump you buy from us! For a full list, carry on reading!
  5. A no-nut diaphragm face ensures the long life of the diaphragms and the pump itself. A no-nut face is achieved by joining the layers of the diaphragm together through chemical bonding. By removing the nut from the diaphragm, this reduces a leakage point and protects your pump.
  6.  Our Diaphragm Pumps can Self Prime up to 5m – see the installation section below for more information.
  7.  Air Operated Diaphragm Pumps can also occasionally dry run without causing damage, however, we must highlight the importance of the fact that this does not mean that the pump should be left to dry run indefinitely. It will cause damage to the pump if you leave it dry running for long periods of time.


Air operated diaphragm pumps usually do well with a Pulsation dampener fitted to the top of the pump to help minimise the vibrations caused from the air driven operation. This allows there to be a constant level of flow to suit your applications pumping requirements. The Pulsation Dampeners TS Pumps supply can also be ATEX rated upon request for potentially harmful chemical applications.

No nut Diaphragm face

What industries and applications can a Diaphragm Pump be used for?

Chemical Industry – Acids, shear sensitive liquids, alcohol, solvents.

Hygienic Applications – Food products, cleaning liquid for CIP, cosmetic products such as toothpaste and perfume.

Water Treatment – Transferring sludges, chemical reagents, dosing for pH-control.

Surface Conditioning – Transferring chemicals from tanks and containers, handling waste products.

Mechanical Industry – Oils, lubricants, cooling liquids.

Pulp and Paper Industry – Titanium oxide, bleaching products, glue

Paint, Print and Varnish Industry – Ink, varnish, adhesives, solvents, blending & recirculation of ink, water- and solvent-based paints.

The vast range of Accessories that we can supply with a Diaphragm Pump also widen the application range.


The inlet and outlet ports on your Diaphragm Pump can be turned to fit whatever pipe installation is required, making them highly versatile. Below we have listed the various installations available when using a Diaphragm Pump.

Submersible Diaphragm Pump


Flooded is the ideal installation solution to completely empty a container or where the fluid being transferred is particularly thick. This is because the piping system has a positive suction head.


Diaphragm Pumps can be submerged within the fluid being pumped and work to push the liquid out. The Diaphragm Pump will need an air exhaust from the container in order to expel air to the atmosphere and allow the pump to “breathe”.

Self Priming

An AOD can be installed above the fluid that you are transferring due to a suction lift of up to 8 meters from a wetted pipe (this is 5m if the suction pipe is empty). The suction capability will depend on the pump size that you purchase.

How to maintain your Diaphragm Pump

Our supply of Diaphragm Pumps are made from 70% less parts than other AODDs on the market, which means easy disassembly and makes maintaining your Diaphragm Pump straight forward!

4 easy tips for ensuring that your AOD pump runs smoothly:

  1. Check the seals, nuts & bolts regularly for general wear and tear
  2. Tighten the main nuts and bolts of your pump once a month
  3. Ensure your airline remains free from contamination
  4. Do not dry run your pump indefinitely

If you’re having any issues with your pump, let us know what problem you’re having and we’ll use our expert pump knowledge to advise on the best course of action! Call us on 01928 333 400 or drop us an email to [email protected]

You should be regularly checking your pump as maintenance is a key priority and takes no time at all when purchasing one of the Diaphragm Pumps from our range. We also recommend a complete inspection of your Diaphragm Pump once a year (at a minimum).


Are Diaphragm Pumps cost efficient?

It is well known that Air Operated Diaphragm Pumps are not the cheapest pump to run due to the cost of compressed air, yet with running costs typically surpassing the original price of the pump itself, they’re still an enormously popular pump. In these instances, an enormous saviour is swapping your current Air Operated Diaphragm Pump for LEAP technology. The Low Energy Air Pump can start at the lowest starting pressure known for a pump on the market, meaning investing in LEAP could save your company up to 70% in energy costs! LEAP is a revolutionary technology, designed to provide low flow rates for high-pressure applications.

LEAP can be retrofitted to any Tapflo, Dellmeco or Almatec Diaphragm Pump, and is available in plastic, metal and sanitary.

Low Energy Air Pump


What is the maximum viscosity that a Diaphragm Pump can handle?

Air Pumps can handle up to 15,000 cPs, although if the pump is operated using fluids at the maximum viscosity, the flow rate is around 20% of the nominal flow on water. If the product being pumped is more than 2,000 cPs, we recommend installing your Air Pump in a Flooded installation (as mentioned above) to aid the pump with the flow rate.

Think a Diaphragm Pump could solve all of your problems? Get in touch with us today. We aim to quote within 24 hours and we’d be happy to come up with any solution to a problem you’re having!

Contact us today!