Pneumatic pumps use compressed air as their driving energy. They need no electric motor on the pump, are rugged, easy to control and can be used in hazardous areas. In industry, air-operated pumps are therefore found wherever compressed air is already available – from chemicals and paint shops to wastewater treatment.
How does a pneumatic pump work?
The basic principle of all air-driven pumps: the energy stored in compressed air is converted into a mechanical movement that displaces or accelerates the fluid. Depending on the design, this is done via
- a diaphragm deflected by air pressure,
- a piston in an air cylinder, or
- an air motor driving an impeller or spindle.
After doing its work, the air is released to atmosphere through a muffler. You simply control the flow rate via air pressure and air volume.
Types of pneumatic pumps
| Type |
Working principle |
Typical application |
| Air-operated double diaphragm pump (AODD) |
Two diaphragms are alternately pressurised with air; ball valves control the flow |
Chemicals, paints, slurries, wastewater, food, viscous fluids |
| Pneumatic piston pump |
Air piston drives a pumping piston, often with pressure ratio |
Greases, sealants, airless spraying |
| Air-driven drum pump |
Air motor drives an impeller or spindle in a suction tube |
Emptying drums and IBCs |
| Jet pump (venturi) |
An air jet creates a vacuum and entrains the fluid |
Suction, simple transfer tasks |
The pneumatic diaphragm pump – the all-rounder
The air-operated diaphragm pump – also called air-operated double diaphragm pump or AODD pump – is the most widely used pneumatic pump. It works like this:
- The air valve directs compressed air behind diaphragm A. The diaphragm pushes the fluid out of chamber A into the discharge line.
- Diaphragm B is connected to diaphragm A by a shaft and is pulled back at the same time. A vacuum forms in chamber B and fluid is drawn in.
- At the end of the stroke the air valve switches over – the process repeats in mirror image.
More in our guides for diaphragm pumps.
Advantages of air-operated pumps
-
No electric motor on the pump – ideal for hazardous areas (ATEX diaphragm pumps)
-
Can run dry and are self-priming
-
Can run against a closed line, the pump simply stalls
-
Infinitely variable via air pressure
-
Tolerant of solids and abrasive fluids
-
Easy maintenance – diaphragms and valves can be changed on site
What should you look out for?
Pneumatic pumps need clean, dry compressed air in sufficient quantity. A filter regulator upstream of the pump protects the air valve and limits the pressure. How to set up the air supply correctly is explained in Air supply for diaphragm pumps. Whether an electric drive would make more sense is covered in Electric or air-operated diaphragm pump?
Versamatic® pump systems
Our shop offers exclusively Versamatic® air-operated diaphragm pumps in sizes from 1/4" to 3":
Frequently asked questions
How much air does a pneumatic diaphragm pump need?
Air demand depends on pump size, flow rate and back pressure. Small pumps need little air, 2" and 3" pumps require a powerful compressed air network. The exact values are shown in the performance curve of each pump.
Can a pneumatic pump transfer fuel?
In principle yes – air-operated diaphragm pumps are often used for flammable liquids. Suitable, resistant materials are required and, in hazardous areas, an ATEX-certified conductive version with earthing.
How high is the discharge pressure of an air pump?
With a diaphragm pump, the maximum discharge pressure is roughly equal to the supplied air pressure. Versions with a pressure ratio are available for higher pressures.
