Hydraulic Cylinders: How Do They Work? Although hydraulic cylinders are so incredibly simple, equipped with just a steel rod, an iron tube and a few other pieces holding everything together, they are remarkably powerful. They provide the workhorse brawn of our nation’s industrial works and are what makes it possible to rapidly move earth and other materials around us. In this post we look at how the hydraulic cylinder works. It’s a basic lore that area x pounds per square inch (PSI) = Force. For example, if you put 1 pound of pressure onto a 1 inch object, you will have 1 pound of pressure. If you put 1 pound of pressure on 2 inches, you will have two pounds PSI and so on and so forth. This means that the size of the piston is closely related to the power of pushing or lifting available. Inside the cylinder, the fluid will push against the piston. The diameter of the piston is known as the bore. When it comes to powerful lifting, it’s the larger bore cylinders that can perform the best and will be employed by the larger applications that we see in use. Inside the piston is the hydraulic fluid. It needs to be contained by a seal. If the seal is in anyway defective, it won’t be able to perform to its utmost capacity. Although you may not see any oil or fluid on the outside, the damaged piston seal will make it possible for the oil to bypass the piston. This will not result in ultimate pressure, and so the lifting will not reach the level of effectiveness that it should. The shaft or rod of the cylinder is what travels through the head of the cylinder. It attaches the piston to the fitting at the end. The strength of the piston in combination with the diameter of it will be what determines whether it will bend. Pistons take a lot of stress and it will need to be strong enough to cope with the ‘side load’ that it will get from being extended. When it comes to the total distance of travel between a fully retracted length and a fully extended length, this is known as the stroke. The head or gland of the cylinder is the part through which the piston rod travels. Inside the gland, the piston rod seal has a weakness for leaking as it’s exposed to the elements ad it also collects debris. The cap or butt of the cylinder is located at the base. In some cases, it does not require a seal as it is welded to the cylinder tube. Hydraulic cylinders are wonderful inventions, and without them our world would not be what it is. For more on hydraulic systems, follow our blog regularly.