Hydraulic cylinders or cylinder jacks are used commonly in a variety of lifting and pushing applications in the load and house moving industry. For expert users, cylinder jacks are very easy to configure and use. For people that have never used these jacks, configuring a system and accurately using the system seems extremely complicated. The reason is that between the 3 main manufacturers of cylinders in the US, over 10,000 cylinders, pumps and fittings are available.
A novice user does not know how all these components work, what job they do and how to configure them. The basic set up of a hydraulic cylinder entails a hydraulic hose that connects the cylinder to a hydraulic pump. The jack cannot be operated without the basic set up.
The pump takes hydraulic fluid and pushes it into the connected hydraulic hose. The oil flows through the hose into the connected hydraulic cylinder. Inside the cylinder, the oil then pushes and raises the piston out of the cylinder. This basic setup is used for a single acting hydraulic cylinder that has a single hydraulic hose that pumps the oil into the bottom of the cylinder.
In a double acting system, the cylinder and the pump have two connections for two hydraulic hoses. One hose runs from the pump into the bottom of the cylinder and one hose runs from the pump to the top of the cylinder (Both hoses connect to the side of the cylinder – top and bottom).
A single acting cylinder and a single acting pump are outfitted with one connection nipple each for one hose. With lower capacity cylinders you can push the extended piston back down and force the oil to flow back to the pump by simply pushing down on the piston with your foot. A single acting system is consequently an adequate set-up.
A double acting system is more expensive than a single acting system. Also, there are more components to connect, and if you are operating multiple cylinder jacks at the same time, too many hoses become user unfriendly. Most users stay with a single acting hydraulic cylinder set-up if at all possible.