Diaphragm pumps come with two fundamentally different drives: electric or compressed air. Both move the fluid with diaphragms, so the fluid never comes into contact with drive components. In operation, however, they differ considerably – in energy consumption, safety, control and purchase price. This comparison helps you decide.
What types of electric diaphragm pumps are there?
The term "electric diaphragm pump" covers two very different pump types:
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Small electric diaphragm pumps: An electric motor moves one or more diaphragms via an eccentric. These pumps are compact, often designed for 12 V or 24 V, and are used for water, laboratory liquids or gases.
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Electric double diaphragm pumps: They work with two diaphragms like an air-operated diaphragm pump, but are driven mechanically by a geared motor. They are intended for industrial use where no compressed air is available.
In an air-operated double diaphragm pump (AODD pump), compressed air provides the drive: an air valve alternately pressurises the back of the two diaphragms. More in our guides for diaphragm pumps.
Comparison: electric or air-operated
| Criterion |
Electric double diaphragm pump |
Air-operated diaphragm pump |
| Energy efficiency |
Higher – electricity is used directly |
Lower – compressed air is expensive to generate |
| Infrastructure |
Power supply, possibly frequency inverter |
Compressed air network or compressor |
| Explosion protection |
Explosion-proof motor required, more complex |
No electrics on the pump, ATEX versions available |
| Running against a closed valve |
Overpressure protection or pressure monitoring required |
Pump stalls and restarts when the valve opens |
| Dry running |
Depends on the model |
Can run dry without damage |
| Control |
Speed via frequency inverter, easy to automate |
Simple via air pressure or air volume |
| Purchase price |
Usually higher |
Usually lower, simple design |
| Mobility |
Cable and power connection required |
Very mobile, lightweight, rugged |
| Maintenance |
Diaphragms, valves, gearbox, motor |
Diaphragms, valves, air valve |
When is an electric diaphragm pump worthwhile?
- The pump runs continuously for many hours a day – the energy savings pay back the higher purchase price.
- There is no or insufficient compressed air at the point of use.
- The pump is to be integrated into a process control system and precisely controlled via its speed.
When is the air-operated diaphragm pump the better choice?
- In hazardous areas – without a motor and electrics, explosion protection is much simpler. See ATEX diaphragm pumps.
- For changing locations, e.g. transferring from drums and IBCs.
- For applications with frequent start/stop or operation against closed valves, such as dispensing with a nozzle.
- For abrasive, solids-laden or aggressive fluids where a simple, rugged design is required.
- When compressed air is already available and the pump does not run continuously.
Reducing air consumption
The main drawback of the AODD pump is its air consumption. It can be reduced considerably:
- Set the air pressure only as high as the application actually requires
- Size the pump correctly instead of running it permanently at its upper limit
- Use energy-optimised series, e.g. the Versamatic® Valor series
- Eliminate leaks in the compressed air network
More practical tips: 8 essential tips for improving AODD pump efficiency.
Frequently asked questions
What is the difference between an electric and a pneumatic diaphragm pump?
The electric version is driven by a motor and gearbox, the pneumatic version (AODD pump) by compressed air. Electric pumps are more energy-efficient; air-operated pumps are simpler, safer in hazardous areas and stall safely against a closed valve.
Can I run an air-operated diaphragm pump with a compressor?
Yes. The compressor must continuously deliver the required air volume at the desired pressure. You will find the air demand in the performance curve of the respective pump.
Are electric diaphragm pumps quieter?
Generally yes. With air-operated diaphragm pumps, noise mainly comes from the air exhaust; a muffler reduces it considerably.
