Anyone at least slightly involved in pneumatics should be aware of how important properly prepared air is important. Air preparation is a crucial for any system using devices operated by compressed air. Thanks to clean air equipment can operate for long periods of time without corrosion, damages and leakage.
On the other side ignoring, or not paying enough attention to those requirements can lead to serious damages. And serious damages in the end always leads to high economical costs.
Damage from the sky
While it might seem abstract, or at least exaggerated truth is that compressed air can be hazardous. Key word here is compressed. When air is compressed everything that is in it is also compressed.
That means dirt, dust, microscopic bits of proteins as well as water and various aerosols. All those elements when tightly packed together do create viscous, acidic liquid called condensate, which can be really deadly to pneumatic devices. It contributes a lot to creation of rust, which is at the end main cause of micro holes. Micro holes causes pressure drops in the system, which at the end causes all sort of other problems. Dropping pressure can cause other elements to malfunction and so on.
How to defend against invisible enemy?
One word – prevention. To avoid problems caused by bad and dangerous liquids in pneumatic system it it best not to let it happen at the first place. This can be achieved by using another type of devices before your pneumatic cylinders, namely filters, lubricators and regulators. Why so many devices you ask its simple – your air cylinders needs clean compressed air with a little bit of oil and of course appropriate pressure.
Filtering air for pneumatic cylinders
Air filters effectiveness is usually expressed in a unit known as micron. It represents the minimum size, in micrometers, of an object that will be captured by this filter. Everything smaller will get through. There are some industry branches that have special requirements, for example products designed for food processing factories have their own „food grade”. However most of industries do not have any special requirements and thus comply to requirements set by equipment manufacturer.
In case of pneumatic cylinders, since they cannot be considered as extremely sensitive devices, this number is about 50 micrometers.
Whats with that oil?
Most important thing to know about pneumatic cylinders is that its basically a piston inside a tube. Piston that has to move inside it. If it has to move it obviously needs lubrication. For that sole purpose it is recommended to install air lubricator before your air cylinders. There are also other devices that need lubrication, like air tools and even some valves. Lubricator simply releases so called oil mist to compressed air stream. It is generally recommended to use air lubrication before most of those devices.
Keep calm and lower your pressure
Since compressed air pressure is directly responsible for output force and speed of air cylinders it is important to pay attention to it. Too low pressure can cause cylinders not to work, or work to slow. To high pressure can cause some elements to burst or cause damage to seals. Most air cylinders can work up to pressure of 10 bar, but there are of course specific cylinders that can withstand much higher pressures. Of course while selecting cylinder it is important to perform some calculations about output force. Depending on their bore size (internal tube diameter) and pressure, cylinders can obtain different output forces. It is very important to calculate output based on some medium pressure value, so it can be easily increased any time.
At the end…
Remember air preparation is crucial and it cannot be ignored. If you want your cylinders to work long time and trouble – free always use air filter, air lubricator and air regulator.
There are many types of pneumatic cylinders, but its impossible to cover all of them here. It is also important to remember that at the end it is output force that really matters, and every pressure drop in pneumatic system will cause your cylinders to move slower and obtain smaller forces.