Hydraulic vs. Pneumatic

Hydraulic or pneumatic? When it comes to your mechanical systems, you often have the choice of whether to opt for hydraulic systems, which are liquid-based, or pneumatic systems, which are gas-based. Which is right for you and your business? Does it really make a difference what kind of system you use?

Whether you’ll prefer a hydraulic or pneumatic machine often depends on the situation and your specific goals. Here’s what you need to know regarding hydraulic vs. pneumatic applications.

Hydraulic System Pros and Cons

Hydraulic mechanical systems are liquid-based, meaning they use water or oil to deliver power. You’ll frequently find hydraulic systems in mechanisms like car brakes and construction equipment. They can be a highly effective way to operate heavy machinery.

One of the biggest pros to the use of hydraulics in your mechanical systems is that the liquid will not be compressed in response to pressure. You’ll have seen this effect if you’ve ever seen someone belly flop into a pool. Hitting a body of water from a great height is not that different from hitting concrete. There’s not enough distance between the molecules of a liquid to give way when you hit it with pressure. With hydraulics, you get the best properties of a solid with the flow of a liquid.

One of the things that this characteristic will mean is that you can apply much more pressure when working with a hydraulic system than with a pneumatic system, and the system responds immediately, without delay. Also, if you’re using water as your liquid, it can be very cost-effective, as water — especially recycled, non-potable water — is in most cases quite plentiful.

So what are the downsides to using hydraulics, if any? There are a number of issues you have to consider when working with liquid. One is that liquid can leak. You must always be vigilant to avoid holes in your valves, improperly tightened seals or any breach in the system that could allow the liquid to leak out.

Hydraulics also create a problem if you’re working in a clean environment, such as in the pharmaceutical industry or food and beverage. If you’re working with products that can’t risk contamination, you usually can’t use hydraulics. Any leak could contaminate your product, whether you’re using water or oil.

Another issue you have to concern yourself with is corrosion. If you’re not using galvanized steel or some other non-corrosive material for your pipes, you’ll have to keep stock of how your fluid is affecting the material’s condition. If you need to use oil for your hydraulics, this issue can create more complications. Oil-based hydraulics require more energy because oil is thicker. You also need to recycle your oil or collect it after use — you can’t just let it seep out into the environment. This issue also makes leaks an even greater hazard.

Pneumatic System Pros and Cons

Pneumatic systems, on the other hand, are air- or gas-based. The idea is exactly the same, except the medium you’re using to transmit power is gas instead of liquid. You’ll find pneumatic drills in dentist’s offices and mining operations, and these systems are also popular in mechanisms like air brakes on trains, vacuum pumps and some construction equipment.

What are the benefits of using pneumatic systems? All the problems that liquids create in a hydraulic system are removed from the equation when someone is using pneumatics. There’s no liquid to leak into the environment, corrode your parts or require recycling. This difference, of course, means that pneumatic systems are usually much more environmentally friendly than hydraulic ones.

You’ll find that the designs of pneumatic systems are typically simpler and thus less expensive. Furthermore, once you have a compressed air machine, you don’t need to deal with the expense of paying for the medium to transmit your power — there’s no costly oil to buy. Finally, pneumatic systems are low-maintenance and long-lasting.

The main disadvantage to the pneumatic system is the issue of pressure. Because gas compresses quite easily, you can’t effectively apply as much pressure as you can with hydraulics, and there’s a slight delay in the system’s action. In addition, while pneumatic machines are less expensive, they use a lot more energy to operate, which can inflate costs.

Hydraulic vs. Pneumatic Machines

So which should you choose, hydraulic or pneumatic systems? In general, the bigger the project, the more likely you are to use a hydraulic machine or hydraulic systems, benefiting from their more extensive capabilities. They’re much more likely to provide the power you need to get a heavy job done. If you have a smaller project, you may not want to invest in more expensive hydraulic machinery and the liquid that makes it work. Instead, you might opt for the pneumatic approach.

Also, if you’re a green company or leaning toward greener manufacturing practices, you may want to lean toward using pneumatic machines whenever possible. While there are certainly many safeguards you can put into place to prevent leaks in your hydraulics, they do happen, and in some cases, the consequences for the environment can be extremely serious. If you’re using pneumatic machines, you never have to worry about that issue, nor about what to do with your oil or dirty water once you’re done with it.

You’ll probably find in your own manufacturing business that you’re using a combination of hydraulic and pneumatic machines depending on what the situation calls for. With a modern trend toward lean manufacturing and environmentally responsible manufacturing practices, however, many businesses are finding that unless the job requires the heavy-duty, pressure-resistant power of hydraulics, they prefer to use the cleaner, simpler mechanisms of pneumatic machines.

When you’re trying to make a decision about pneumatic vs. hydraulic systems or need help repairing one of your machines, you need repair technicians who are fully versed in the workings of both hydraulic and pneumatic systems.

For repair support for hydraulic or pneumatic machines or any kind of motorized or electronic mechanisms, contact Global Electronic Services.