Custom Vs. Off-The-Shelf Hydraulic Cylinders

An essential component of hydraulic systems is the hydraulic cylinder. They supply the quick physical displacement and fluid replenishment required by hydraulic lines, lifts, and presses to preserve their strength and force when coupled with a pressurizing engine.

What Is A Hydraulic Cylinder and Its Basic Components?

A hydraulic cylinder is a basic mechanical actuator, or motor, that pushes in a single direction with a stroke to produce linear force. From these modest origins, cylinders have been used in countless applications, becoming so commonplace in automobiles, construction equipment, generators, and industrial gear.

Even though there are many different kinds of hydraulic cylinders, they all have the same basic components and parts including:

A Barrel

The hydraulic cylinder barrel is a seamless cylinder that is intended to keep the component’s internal pressure contained. Although designs differ from type to type, a typical cylinder barrel is internally honed to obtain the proper diameter and has a surface finish of 4 to 16 µm. At the base end of the barrel of single-action cylinders are welded openings. Because double-acting cylinders have ports on both ends, pressure may be applied alternately to the barrel’s two sides, which are separated by the piston.

A Base/Cap

The pressure chamber at each end of the cylinder is sealed off by the cylinder base or cap. Some cylinders employ an O-ring to keep the cap and barrel apart, while others have a welded base. The base of a tandem cylinder provides access to the piston shaft of the cylinder to which it is linked.

A Cylinder Head 

The end through which the piston rod extends and force is applied is known as the hydraulic cylinder head. A spring ring, a screw connection, or rarely welding can be used to secure the head to the barrel. The head’s interior is grooved to make room for glands, a rod wiper, and piston rod seals. The wiper eliminates excess hydraulic fluid from the piston shaft following the outward stroke, and the glands stop oil from escaping outside the cylinder.

A piston

The barrel is divided into two pressure chambers by the piston’s rounded surface. The size of these might vary according to the design and pressure requirements. Special guide rings and piston seals are used to create a seal, separating the hydraulic fluid and pressure in each chamber. When one of the two chambers experiences a pressure differential, piston movement is initiated.

A Shaft or Piston Rod

Attached to the piston surface, the piston rod or shaft extends through the cylinder head. Non-differential cylinders feature two piston rods, one at the head and one at the base, whereas the majority of hydraulic cylinders only have one. High tolerances are required for piston rods, which are typically composed of cold-rolled or stainless steel with strong chrome plating.

Hydraulic seals

A range of seals are used in cylinders to preserve the component’s integrity under pressure. The most crucial are the rod and piston seals, which keep the pressure chamber clear of impurities and stop friction from building up. Cylinders that operate at high pressures or extremely hot or low temperatures require specialized seals. Materials consist of polyurethane, Viton (a fluorocarbon compound), and nitrile rubber.

These are the primary elements. In addition, hydraulic cylinders have eye brackets, cushions, ball valves, pivot pins, removable mountings, and a variety of ports for the entry and exit of hydraulic fluid. There are several varieties of cylinders since each component is made to perform a particular function related to its intended use.

Customized vs. Off-the-shelf Hydraulic Cylinders

There are two main alternatives available to the designer when creating a new hydraulic system from the ground up to get the necessary cylinders. Engineers have the option of commissioning custom cylinders from a specialized manufacturer or buying cylinders as “Off-the-Shelf” pre-machined pieces from a specialty OEM merchant.

Which kind best suits your goals and designs? This is our guide to the benefits and drawbacks of each choice.

Off-the-shelf cylinders

Mass-produced, variable-size catalog components designed to work with any hydraulic system are known as off-the-shelf hydraulic cylinders. In an off-the-shelf cylinder construction, the hydraulic machinery is developed around a pre-made cylinder. It is also possible to install off-the-shelf cylinders as replacement parts on hydraulic systems that are already in situ.

For hydraulic engineers, off-the-shelf cylinders have two significant benefits:

1) Generally speaking, they are far less expensive to install than creating a custom unit and

2) Are considerably simpler to find, especially when you need them quickly.

Additionally, certain hydraulic designs are available as standard components. If the hydraulics are being utilized for a (relatively) low-stress application, they are suitable for use as a straightforward, reasonably priced hydraulic construction.

However, employing off-the-shelf hydraulic gear has certain serious disadvantages.

The hydraulic piston’s efficiency and optimization will never match that of a cylinder designed for the diameter measurements, fluid type, and volume that you’ll be employing.

Maintaining a competing machine with a subpar cylinder hacked into it may likewise cost more. A ‘cramped’ or jagged tank interior and misaligned fittings will put greater physical strain on the stock cylinder than a well-sized and machined one. An over-engineered installation might readily result from awkwardly fitting cylinders.

It might also be problematic to modify pre-built systems to accommodate a new hydraulic cylinder. Seals, connections, mountings, and material requirements for liquid and open environments can all cause compatibility, safety, and space problems. These off-the-shelf issues are most noticeable for hydraulics utilized in systems of extraordinary scale (either extremely large or very tiny) and in harsh environments (e.g., underwater or permanently outside).Customized Cylinders

When professional quality, accuracy, and low-maintenance fixtures and fittings are needed, bespoke hydraulic cylinders are utilized. They may be made from a variety of materials and in any desired size or form. Custom units frequently pay for themselves over time by offering better performance and requiring less maintenance, even if the original cost to design and construct each cylinder may be more.

For devices that are subjected to high degrees of physical stress and operate in highly hot, cold, or pressurized settings, engineers typically use specially made cylinders. Custom cylinders are ideal for hydraulic devices with varied and acting strokes, as well as those that must be operated for extended periods of time without supervision.

A unique hydraulic cylinder design can also incorporate valve manifolds, integrated functions, electrical devices, and unconventional connecting positions. Although some factory cylinders come with these, it might be challenging to choose the best one for your system and intended use.

It’s also crucial to remember that standard cylinders cannot satisfy your hydraulic equipment’ safety and insurance requirements. That danger is eliminated with bespoke cylinders. You may always choose the precise materials and specifications required with a bespoke design.

Final Thoughts

The purpose, stress level, and environment in which your hydraulic machine will operate should ultimately determine the kind of cylinder you select. The insurance, safety, and maintenance schedule requirements that will be connected to the hydraulic machine you are building must also be properly taken into account when selecting a hydraulic cylinder.