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The Hydraulic Cylinder

Hydraulics and, by extension, hydraulic cylinders have been a part of civilization since records dating back to Mesopotamia and Egypt. While these were rudimentary in form, they laid the foundation that 16th century mathematician Blaise Pascal would use to study fluids and compression. Once that was exposed, Joseph Bramah would finally create his “hydrostatic machine” 140 years later. Over the course of time, this early design would be refined time and time again until today’s various cylinder designs.

At its root, hydraulic cylinders work by using the simple fact that when force is applied at one point, this will transmit to another point. Current cylinders use fluid to generate linear movement in this fashion. This technology, though relatively simple, is in use today by vast numbers of machines and equipment, making it possible for our current society to continue thriving.

As far as machinery is concerned, hydraulics can be found everywhere. From workout machines at the local gym to cranes used to construct skyscrapers, there is virtually nothing these machines can’t handle. Even so, there are certain specifications they can be broken into to determine what designs are best for each project.

Cylinder Design
The modern design is relatively simple with only four parts total. These, of course, vary from type to type but otherwise follow a basic set up. First, there is a reservoir used to hold the fluid while still allowing space for contaminants to settle and the liquid to release moisture and air. The second part, the pump, transforms the mechanical energy into hydraulic. It does this through the movement of the fluid. Third are the valves. Though varying in number in types, they all are used to stop, start and otherwise direct the fluid. Finally, actuators convert the hydraulic energy back into mechanical through the use of the cylinder.

Plunger Cylinders
Also dubbed Ram cylinders, these are always upright. The reason for this is because once the fluid is removed, the cylinder automatically returns to its start position due to the weight being exerted on it. Most of the cylinders at car service centers are of this design, however, elevators, both personnel and freight, use it as well.

Telescoping Cylinders
Because they can have up to six stages, they are also referred to as multistage hydraulic cylinders. Telescoping cylinders are special designs for projects with far less area while keeping the stroke long. For instance, forklifts and cranes can’t have huge cylinders sticking off their sides but yet still need an immense amount of power and reach. They can also be structured around equal lift on both sides and slowing higher speeds.

Cable Cylinders
Like the telescoping cylinders, cables are available for limited spaces. Producing moderate force through long strokes, these cylinders are attached to cable lines in a way that allows for equal force applied in both directions. They are mainly used as a means to haul heavy items across distances. Warehouses, for example, may have a few installed in their cargo bay for easy loading and unloading.

Diaphragm Cylinders
Of the various types, this style is the means by which the conversion of pressure to force is frictionless. This happens because the seal between the piston and cylinder is kept because of a rolling action instead of the typical sliding. This means they have absolutely no leak, making them perfect for harsh environments and intense jobs. Their durability makes them ideal for jobs in industries such as the aerospace, automotive and medical.

To say these little devices are important is a vast understatement to the otherwise superior numbers it shows in all areas of work. By giving us a means of increased strength, durability and stamina, we are able to ship supplies, process water and otherwise push forward in our medical and scientific advances. Even though designs are ever changing as inventors try to continually improve upon its design, the hydraulic cylinder will always remain constant and dependable.