While many people are buying a cylinder to replace an existing component, there are also cylinders that are used in the development of prototype machines or in new equipment construction. For these situations, one of the first choices will be if a double or a single acting cylinder is the best choice.
Both options can be the best choice for any given application, although there are some specific use differences. Both the single and double acting cylinder will have the same components. These will include the pump, hose and the cylinder, but the double will actually have an additional hose, creating the double action.
The Basics Of Single Acting Cylinders
With the single acting cylinder, the pump is used to create pressure and force the hydraulic fluid through the hose to the base of the cylinder. As the pressure inside the cylinder base increases through the pressure of the hydraulic fluid it causes the piston in the cylinder to lift up. This creates the pushing or lifting power of the cylinder.
When the operator of the equipment releases the pressure by disengaging the pump, the weight of the equipment will allow the piston to slide back into the cylinder and the oil, now that the pressure is released, to flow back down the hose to the pump.
The Basics Of Double Acting Cylinders
Double acting cylinders are lifted the same way that the single acting cylinder operates. However, instead of relying on pressure from the object lifted or pushed to return the cylinder, there is another hose and connector at the top of the cylinder.
When the pump is reversed, hydraulic fluid is pumped through the top hose which creates pressure on the foot of the piston at the top of the cylinder. This pushes the piston back down into the cylinder. At the same time, the pressure is released from the bottom hose, allowing the oil to flow back into the pump to allow the retraction of the piston.
Typically, with large capacity cylinders, the double acting cylinder is the most effective and the quickest. This allows for more rapid retraction of the piston and greater operator control through all movement.
Both the single and the double acting cylinders will be rated for specific load capacities. It is essential to choose a cylinder that meets and exceeds your maximum load capacity to prevent damage to the cylinder during use.
