16 Nov

A comparison of Hydraulic Power and Pneumatic Power 


As a manufacturer of high-performance hydraulic equipment, our field may not be something that everybody is familiar with. For the lay person, they’ll find that most domestic power tools are fuelled by electric, with a few pneumatics in the mix, such as nail hammers.  It’s uncommon to stumble across hydraulic tools outside of manufacturing or other heavy industrial environments. Although there are some hand held hydraulic tools in circulation, it’s quite rare and they are usually specialised.

In this post, we are going to study the differences between these two types of equipment power.

Overall, both types of tools are based on the same principle. An action is created as a result of a motor compressing a substance whether it is air or liquid. This puts them in the same category in contrast to the rigid transmission that may for example be used in a car.

In addition, what makes these tools more accommodating is the fact that the lines that they use are flexible, so therefore aren’t constrained by needing to be set on a fixed configuration. The gas and liquid can also absorb shock which can result in a longer life of a system compared to those that endure a large amount of vibration and breakages.


The following are areas in which there is a major difference between hydraulic and pneumatic:

 ·     Compression: gas is compressible and liquid isn’t. This means that the pneumatic machine will operate once air pressure drops to a certain level as it can store energy, whereas on a hydraulic system, it’s necessary to continually run a pump.

 ·     Exhaust: as air is a by-product of pneumatic systems, it is not suitable for work such as underwater machinery, whereas hydraulic systems are.

 ·     Lubrication: hydraulic fluid can be its own lubrication, whereas pneumatic air needs to be lubricated with an aerosolised oil. Lubrication is important when it comes to maintaining the longevity of moving parts.

 ·     Filtering: air compressors can capture a huge amount of particles and dust when used in a dirty environment. Hydraulic systems are more likely to produce their own impurities as they are a closed and pressurized system. Quite often anti-corrosion additives need to be added to aid hydraulic systems in protection against erosion.

 ·     Heat: this is why aircraft and other large vehicles depend on air brakes as opposed to brake fluid. Fluids can retain heat, but on the other hand hydraulic systems are less likely to need cooling but when they do they can create vapour pockets and can fail catastrophically. Brake fluid used is more likely to be used on cars when there are not multi-tons involved.

 ·     Smoothness: the incompressible nature of fluid enable hydraulic systems to be far more precise and smooth in control.

 ·     Pressure: There’s a big difference in the amount of pressure that hydraulic and pneumatics operate under. Hydraulics can be in the 1,000s of psi, whereas pneumatic tools are usually more like 90-125 psi.

These are just some of the differences and similarities between hydraulics and pneumatics.