On the surface, hydraulic and pneumatic hoses are quite similar to one another, as both are utilized in systems that transmit flow under pressure to generate mechanical force. Both hose types have broad applications across multiple industries, with distinct advantages for different machinery types.
The two hose types, however, are not interchangeable. Hydraulic hoses are better suited for some situations, while pneumatic hoses are more appropriate for others. In the following post, we’ll discuss the key differences between these two types of fluid conveyance systems, helping you to select the correct hose for your specific needs.
How Each System Works
As mentioned above, both hydraulic and pneumatic machinery utilize pressure changes to generate mechanical power. Pneumatic systems make use of pressurized air or other gasses, while hydraulic ones require an incompressible liquid of some type (usually oil). The hoses themselves are designed to transfer the fluid from one part of the machinery to the next, meaning they must be able to withstand the pressure themselves to prevent any leaks from occurring.
Hydraulic systems require an incompressible fluid, while pneumatic ones specifically depend on a medium that can be compressed under pressure. Pneumatic systems take advantage of this compression to generate force. On the other hand, hydraulic systems achieve mechanical strength through their ability to apply great pressure to their mediums without causing a comparative reduction in volume.
Material Composition
While the basic principles by which they operate may be similar, hydraulic and pneumatic hoses are used to perform very different tasks in construction, manufacturing, and other industries. The incompressible fluids used in hydraulic systems can generate a much greater level of force than their gas-powered counterparts. This often means that the hoses are placed under a much greater strain for large-scale jobs, such as in cranes and loaders. Pneumatic hoses, however, are often necessary for machinery that requires speed and repetitive motion. As a result, pneumatic hoses and hydraulic hoses can differ a great deal in material composition.
When it comes to pneumatic hoses, flexibility is key. That’s why they are often constructed from high-quality rubber. Hydraulic hoses may also be made from rubber; however, they must be of a type that can withstand the use of the oil medium without becoming weakened or damaged. In manufacturing, nitrile is often used. Hoses used in hydraulic systems must be reinforced with braided wire to prevent them from wearing out due to the excessive strain they are subjected to. The outer layer of the hose is also constructed from a durable material such as Teflon.
Pressure Ratings
The hoses used in fluid conveyance systems are subjected to incredible amounts of pressure as they perform their daily tasks. This is part of the reason certain hoses must be so heavily reinforced, as mentioned above. Different hoses will have different pressure ratings, and owners should ensure they are aware of their specific system’s requirements.
Although the gas used in pneumatic systems is highly pressurized, it does not generate the incredible amount of force required by some hydraulic machinery. As a result, pneumatic hoses frequently have much lower pressure ratings. Generally, they top out at around 300 PSI, although most will be rated lower than that.
Hydraulic hoses, which are built for power rather than speed, can have incredibly high pressure ratings, sometimes as high as 8,000 to 10,000 PSI. Regardless of which system you have, it’s important to ensure the hoses you are using have the correct pressure ratings in order to prevent potential damage to your machinery.
Application Suitability
Selecting the correct hose for your needs is also a matter of choosing the correct hose for the specific application. What will the hose be used for? Hydraulic and pneumatic machines rarely have interchangeable hoses, so make this determination first.
Next, you’ll have to determine a few other details about the hose and its application. Is it a supply hose or a return hose (these may have different pressure ratings)? Is flexibility important? Will the hose be subjected to extreme conditions, such as high temperatures or a corrosive environment?
The hose you choose will also need to fit your machinery. The fittings at either end must be able to connect to the machine you are using, or the hose will not be able to create the proper seal necessary to transfer fluids without leaking. It must have the correct length and be able to withstand the medium the machinery is utilizing. As mentioned above, not every hose is made from a material that will not degrade when in contact with hydraulic oil.
Maintenance Requirements
Pneumatic and hydraulic hoses also have differing maintenance requirements, largely because their respective fluid mediums act on the hoses in unique ways. The previous section mentioned how hydraulic oil has a tendency to degrade rubber—although, choosing a hose made from the proper materials can lessen this problem—it is also capable of leaking out of the hoses and causing damage to the machinery itself.
Pneumatic hoses, on the other hand, are not subject to degradation from the medium within them (since it’s usually only air). A leak in the hose, while still a major problem, isn’t likely to do any additional harm to the surrounding machinery. As a result, hydraulic hoses tend to have greater maintenance requirements than pneumatic ones.
Choosing the Right Hose
Regardless of whether you need a hose for a hydraulic or pneumatic system, the most important detail is to select one that meets all the specifications of your particular machinery. A hose that is improperly rated, too small, too large, or just poorly made will likely damage your equipment and cause your maintenance costs to increase.
Selecting the correct hose for your specific application is a matter of doing your homework. You’ll need to learn as much as you can about your specific machine, which includes reading any included technical specs. It may be necessary to have customized parts, including hoses, made by a company like Aberdeen Dynamics, which specializes in high-quality fluid conveyance systems.
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