What is the difference between a double-acting and a single-acting hydraulic cylinder?

What is the difference between a double-acting and a single-acting hydraulic cylinder?

• A. Double-acting cylinders produce force in both directions; single-acting cylinders use an external force or spring to return.
• B. Double-acting rely on springs; single-acting use both ports.
• C. Double-acting are only for vertical orientation.
• D. Double-acting use a single rod; single-acting use two rods.

Answer: (A)

The main idea is how the cylinder is controlled in both directions. A double-acting cylinder has two fluid ports, so hydraulic pressure can be applied to either side of the piston. This lets it push out and retract under hydraulic control, giving force in both directions without relying on external forces. A single-acting cylinder uses only one pressurized side; the movement in one direction comes from the applied pressure, and the return is achieved by an external force such as a spring or gravity. So, the key difference is that double-acting provides bidirectional force via two ports, while single-acting uses one port with a return mechanism rather than pressure on both sides. The other statements mix up how the return works, and aren’t accurate descriptions of the two types.

The main idea is how the cylinder is controlled in both directions. A double-acting cylinder has two fluid ports, so hydraulic pressure can be applied to either side of the piston. This lets it push out and retract under hydraulic control, giving force in both directions without relying on external forces. A single-acting cylinder uses only one pressurized side; the movement in one direction comes from the applied pressure, and the return is achieved by an external force such as a spring or gravity. So, the key difference is that double-acting provides bidirectional force via two ports, while single-acting uses one port with a return mechanism rather than pressure on both sides. The other statements mix up how the return works, and aren’t accurate descriptions of the two types.