Heavy Duty Hydraulic Cylinders
With working pressure capabilities up to 10,000 pound-force per square inch gauge (psig) heavy duty hydraulics make the many cumbersome tasks of these mechanisms possible. Marine, mining, defense, hard milling, power generation, forge and foundry, turbines, oil and gas, injection molding, construction, demolition, automotive, material handling and aerospace equipment all utilize hydraulic cylinders in everyday operations. The cylinders convert the hydraulic energy of pressurized fluids into useable mechanical energy, generating linear force and motion. Even a relatively small hydraulic motor and pressurized fluid source can yield a very high work force with substantial gains on energy inputs. Heavy duty cylinders in particular must be made of durable materials and extremely sound construction. Stainless steel, bronze, aluminum, cast iron, nickel and chromium are common choices as they are compatible with hydraulic fluids and can withstand the wear and friction of cylinder use. Additional considerations include stroke, operating pressure, maximum working pressure, rod diameter and bore diameter.
While there are several different types of cylinders, tie rod hydraulic cylinders and welded hydraulic cylinders are the most popular models for use in heavy duty applications. Each cylinder works in relatively the same manner. Hydraulic fluid is pressurized and forced into an enclosed barrel, the main body of the cylinder, through one or more ports located at either end of the mechanism. The fluid, usually an ether, mineral, oil or water composite, engages a disc-shaped piece of metal or ceramic that blocks the cross-section of the barrel dividing it into two compartments. The disc, known as the piston, is attached to a rod that moves in and out of the cylinder through a seal located in one of the end caps. When the hydraulic fluid is forced into the cylinder below the piston the rod is extended while the inverse retracts it. This pump like action in heavy duty hydraulic cylinders is often extremely forceful. Tie rod cylinders use several steel rods attached along the outside diameter of the cylinder to ensure safe and efficient use in heavy duty applications. The high tensile strength rods bear much of the load, thereby allowing greater load to be applied without risk of damage to the unit. As this particular type of cylinder has an increased diameter due to the external attachments, it is more appropriate for relatively immobile equipment while welded hydraulic cylinders are utilized in applications that necessitate mobility and portability. Because welded cylinders are a solid piece of construction, they provide the stability and strength needed to endure heavy duty forces without the increased diameter of tie rod cylinders. It is integral to productivity and safety that the type and dimensions of heavy duty cylinders be calibrated to match the application for which they are used.
