Most people think that air does not exhibit or have the same properties as fluid, but hydraulics and pneumatics work using the same principle. The primary difference is in the execution; a hydraulic actuator usually has higher power density and produce more force using a small package. The downside is that hydraulic fluid is hard to move and generates a significant amount of friction in the process.
A pneumatic system takes advantage of the inherent compressibility and low-friction characteristics of air. A large volume of air can also be transferred relatively quickly by factoring in the compressibility criteria of air.
How does pneumatics work?
For a pneumatic system to produce mechanical movement, the system makes use of a network of parts including a compressor, air tank, tubing, transition lines, open access to the atmosphere and other passive components. Pressurized air coming from the compressor gets transferred through a series of tubes. Valves control air flow, and the corresponding pneumatic cylinders transform compressed air energy into mechanical energy. In addition to pressurised air, a pneumatic system also uses inert gas if the system is self-contained. Pneumatics manufacturers like SMC supply the demand for pneumatic systems used in various industrial applications.
Advantages of using pneumatics
Both hydraulics and pneumatics use fluid as a power source. Hydraulics do have advantages over pneumatics but for other particular applications, pneumatics is more suitable. Air used in a pneumatic system is dried to remove any traces of moisture which can damage the internal parts of the system. An air-based system has a simpler design and also more economical to assemble. Additional advantages of pneumatics include:
- Cheaper equipment cost
- Able to sustain overload pressure conditions
- Long life cycle and minimal maintenance required
- Suitable when the application requires greater transmission distance
Despite the notable benefits of using pneumatics, there are also disadvantages to consider which can pose a considerable challenge in choosing pneumatics over hydraulic systems.
Disadvantages of using pneumatics
One primary drawback of pneumatics is that it is not suitable for high-pressure applications. This means that in general, if the application is highly industrial in nature, it is best to use hydraulics instead. Another pitfall of pneumatics is the sensitivity to vibrations and shock. The hissing sound of the instrument also makes pneumatic assemblies loud and noisy.
Controlling the function and speed of pneumatic systems can also be more challenging compared with hydraulics or electrical equipment. If the application requires the actuator to operate at a certain speed, there is a need to increase the capacity of the equipment so that it can perform at desired levels.
Pneumatic systems should also remain dry because moisture getting into the system will cause it to malfunction or freeze. If there are tubes and hoses connected to the system, these can become safety hazards especially when nozzles are left open. Apart from sensitivity to vibrations and moisture, pneumatic systems are also affected by changes in operating temperatures. If these factors can be mitigated, pneumatic systems perform well and are useful in many types of applications.