Why are hydraulic systems used in machinery such as bulldozers and backhoes, while pneumatic systems are .?
Why are hydraulic systems used in machinery such as bulldozers and backhoes, while pneumatic systems are used for things like opening and closing bus doors?
Please provide a lot of detail, and examples!
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You get the detail.
The reason is that hydraulics provide *lots* more power than pneumatics. You need power to move heavy machinery around, but not much to operate a bus door or even a jackhammer.
Liquid is more dense than air; therefore it is easier to generate more “power” with hydraulic. This results in smaller systems to give you the equiv. power. It is also more reliable, as well as more forgiving.
Air is compressible whereas oil is not. If a back hoe or shovel on an excavator was driven by compressed air, then as you tried to make them do “work”, they would compress the air in the cylinders.
You would have virtually no control over the positioning or movement.
Hydraulics are much more controllable for position and as the oil is not compressible, the actuators will stay in position.