The Uses of Pneumatics vs Hydraulics: A Complete Guide

The market for hydraulic pumps alone amounts to over 10 billion dollars globally. That doesn’t account for hydraulic cylinders, pneumatic system parts, maintenance of these parts, etc.

So it’s needless to say that both hydraulic and pneumatic systems are huge parts of getting industries powered and working to complete necessary jobs. They transfer power from the machine into a real-life application.

The specifics of how each of these systems works along with the applications of each power system are different.

In this article, we’re going into the details of hydraulics and pneumatics. We will also look at the similarities and differences of pneumatics vs hydraulics.

Let’s get started!

What are Pneumatics?

Pneumatics are confined (isolated) pressurized systems that create and transfer mechanical power with pressurized air/gas.

How do Pneumatic Systems Work?

Pneumatic systems create energy and do work using the power of compressed gas. In most cases, pneumatic systems used compressed air, but any type of compressed gas can be used.

When air is compressed, usually using an air compressor, the pressure of the system increases. This increased pressure can then be translated into mechanical work to:

  • Power machinery
  • Process materials
  • Move machinery components
  • Etc

A pneumatic system usually is comprised of air compressors that compress the air/gas along with valves to control the flow of that air. Pneumatic cylinders, motors, and rotary actuators are powered by those valves/the compressed air.

Advantages of Pneumatics

Pneumatic power systems are durable and highly reliable. They’re strong and long-lasting, especially because they don’t require liquid, fuel, or chemicals to function.

The lack of those chemicals, fuels, and liquids also make them economical, environmentally friendly, and safer than other power systems like hydraulic systems. There’s no risk of:

  • Dangerous leaks
  • Fire
  • Explosion due to chemicals/liquids

Also, and the air/gas can release into the environment without the need for disposal or processing.

Compressed air is also highly customizable for each application. This makes pneumatic systems versatile. These systems are also less affected by temperature, particles, pressure, or other environmental changes.

Disadvantages of Pneumatics

As with all machinery, pneumatics do have disadvantages.

One of the biggest is the power limitations. Pneumatics cannot power huge or heavy loads, and usually maxes out at a pressure of 100 psi.

In order to work, the air also must be compressed, which requires a separate part (an air compressor). Compressing air takes time, as well, so power/movement isn’t instantaneous like it is for other types of power systems. This can also lead to uneven/jumpy power and movement speeds.

An advantage to pneumatics is you can release the air into the atmosphere with no processing. A disadvantage is that the air/gas must go through processing before use. This is time-consuming and somewhat costly.

If it’s not processed, particles and impurities can destroy the mechanical parts of your machinery.

Lastly, pneumatic systems are loud.

Examples of Pneumatics in the Real World

Pneumatics have a number of applications in industry such as:

  • Atomizers
  • Rock drills
  • Truck/bus brakes
  • Dirt tampers
  • Nail guns
  • Pavement breakers

Other real-world examples of pneumatic systems include our own lungs, dentist drills, dentist chairs, tire pressure gauges, automatic doors, and vacuum cleaners.

What are Hydraulics?

If you recognize the prefix “hydr-“, you might know that it means “water” or “liquid”. Knowing that, it makes sense that hydraulic systems are confined (isolated) pressurized systems that create and transfer mechanical power using moving liquid.

How do Hydraulic Systems Work?

Unlike air/gas, liquid cannot be compressed. Hydraulic systems use “hydraulic liquid” to generate power and do mechanical work. They usually use liquids like mineral oil, water, ethylene glycol, and other types of synthetic liquid materials.

Here’s a basic explanation of how these systems work: hydraulic liquid is contained in a hydraulic cylinder. This has slight pressure/force exerted on it via a pump usually by pushing the liquid against the force of gravity.

This pushes the liquid to move in a certain direction and moves valves, pistons, gears, and other mechanical parts in order to do work or exert power on the desired part of the machinery/system.

Advantages of Hydraulics

Hydraulic systems are much more powerful than pneumatic systems. While pneumatics max out at 100 psi, hydraulic systems can generate around 1,000 to 5,000 psi. Some systems can get up to 10,000 or more psi.

Also unlike pneumatics, hydraulic power is instantaneous with no delay. This provides even and constant power and force.

Hydraulics also have generally low operating costs, run efficiently, and has an excellent cost-to-power ratio.

Disadvantages of Hydraulics

While hydraulics do have low operating costs, the initial investment and start-up costs are substantial and generally higher than pneumatic systems.

Hydraulic systems have the added concern of leaks and liquid maintenance. If a pneumatic system has a leak, it could affect efficiency, but it won’t be harmful or messy.

If a hydraulic system has a leak, this results in a huge mess to clean up and severely reduces your operating power. Certain liquids are dangerous if leaked, as well, leading to fires, explosions, and a huge potential for injury.

Examples of Hydraulics in the Real World

Hydraulic systems generate huge amounts of power, which means they’re used to power things like airplanes, vehicles, lifting heavy equipment, car brakes, forklifts, the Jaws of Life, etc.

Other real-world examples include our own blood flow, gas pumps, rollercoasters, elevators, factory power, and dishwashers.

Pneumatics vs Hydraulics: Wrapping Up

Hydraulics and pneumatics are both power systems that utilize pressure to perform mechanical work and create force. The main difference between pneumatics vs hydraulics is the medium that’s used to create/transfer this power.

Hopefully this guide helped you understand how each of these systems works and how they’re applied in real life. If you’d like to learn more about hydraulics, pneumatics, or both, check out the rest of our site.

Start by learning about hydraulic hoses with this article.

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