Hydraulic cylinders are a crucial part of hydraulic systems. With a pressurising engine, they provide the rapid physical displacement and replacement of fluid that hydraulic lines, lifts, and presses need to maintain their strength and force.
When it comes to designing and engineering a new hydraulic system from scratch, there are two major options that the designer can pick from to source the cylinders needed. Cylinders can either be purchased as 'Off-the-Shelf', pre-machined units from a specialist OEM retailer, or the engineer can commission bespoke, custom cylinders from a specialist manufacturer.
Which type is better for your designs and aims? Here's our guide to the advantages and disadvantages of either option.
Off-the-Shelf hydraulic cylinders are mass-produced, variable-size catalogue parts intended to fit into any hydraulic system. In an Off-the-Shelf cylinder build, a pre-made cylinder is selected before the hydraulic machinery is designed around it. Off-the-Shelf cylinders can also be retrofitted and installed on existing hydraulic systems as replacement parts.
Off-the-Shelf cylinders offer two great advantages to hydraulic engineers:
1) They typically cost much less at the point of installation than producing a bespoke unit and;
2) Are much easier to source, particularly at short notice.
Some hydraulic designs also come ready-made for stock parts, as well. They're good enough to be used as a simple, cost-effective hydraulic build, particularly if the hydraulics are being used for a (relatively) low-stress task.
However, there are some significant drawbacks to using Off-the-Shelf hydraulic machinery.
The optimisation and efficiency of the hydraulic piston will never be as good as with a cylinder built for the diameter measurements and the type and volume of fluid that you're going to be using.
A sub-optimal cylinder hacked into a clashing machine may also incur higher maintenance costs. The stock cylinder will suffer more physical stress from misaligned fittings and a 'cramped' or jagged tank interior than a perfectly measured and machined one. Awkwardly fitted cylinders can easily end up in an over-engineered mounting.
Modifying pre-built systems to take a new hydraulic cylinder can also cause headaches. Compatibility, safety, and space issues can arise with seals, connectors, mountings, and material requirements for liquid and open environments. These Off-the-Shelf problems are particularly pronounced on hydraulics used in extreme conditions (such as underwater or permanently outdoors) and in systems of unusual size (either very large or very small).
Bespoke hydraulic cylinders are used in circumstances where professional quality, precision, and low-maintenance fixtures and fittings are required. They can be created to any specified shape or size, in a wide range of materials. While the initial cost to design and build each cylinder may be higher, bespoke units often pay for themselves over time by providing greater performance, and incurring lower maintenance costs.
Engineers tend to pick custom-designed cylinders for machines used under high levels of physical stress, in environments that are extremely hot, cold, or pressurised. Actuating and variable stroke hydraulic machines work best with bespoke cylinders, as do machines that need to be left running unsupervised for long periods.
Valve manifolds, integrated functions and electronic devices, and unusual connector locations can also be built into a custom cylinder design. While some stock cylinders offer these, it can be difficult to find the right one to fit your system and intended purpose.
It's also important to note that stock cylinders may not meet the safety and insurance requirements for your hydraulic machines. Bespoke cylinders eliminate that risk. With a custom design, you can select exactly the right materials and measurements needed every time.
Picking The Right Cylinder
Ultimately, the type of cylinder you choose should be based on the purpose, stress level, sophistication, and environment that your hydraulic machine will be working in. You also need to carefully consider the insurance, safety, and maintenance schedule criteria that will be attached to the hydraulic machine that you're designing. To find out more, please call 01299 896953 and speak with one of our technical sales team.
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