Evaluating Cylinder Replacements and Application-Specific Designs

Hydraulic and pneumatic cylinders are critical components in many industrial systems, and even small deviations in design or performance can impact reliability, safety, and equipment uptime. As machines evolve and operating demands increase, teams are often required to re-evaluate existing cylinder designs or identify suitable replacements that meet current requirements.

When designing a cylinder, it is important to consider how much force will be on the piston rod as the cylinder is extending. If too much compressive force is applied to the piston rod in extend, it will cause it to bend and buckle. Consider a coffee stirrer. When placed between two fingers and pushed on, it very easily bends. Now consider a drinking straw. While it might be longer, it also has a larger diameter, thus when placed between two fingers and pushed on with the same amount of force it does not bend as easily. In the same way piston rods will bend when the force to rod diameter ratio becomes too large. Several factors contribute to the force, and associated cylinder pressure, when this bending will begin to occur. These factors include bore size, rod diameter, mounting style, length of stroke and extra plain rod extension, and even rod material.

Hydraulic and pneumatic cylinders are designed to deliver years of dependable performance—but when a failure happens, it can halt production, reduce efficiency, and create costly downtime. Understanding the most common cylinder issues and how to troubleshoot them is essential for keeping your equipment running smoothly.

In the fast-paced and high-risk oil and gas industry, having reliable, durable equipment is critical to operational success. At the center of many vital systems lies a key component: the Hydraulic Cylinder. Whether it’s land-based drilling, offshore platforms, or refinery systems, hydraulic cylinders provide the power and control needed to operate safely and efficiently.

Cushions much like the ones on your couch right now are designed to take the impact force that comes from the piston moving quickly and abruptly stop when coming in contact with the Head or Cap. While this can happen occasionally without major damage to the cylinder, over time this impact loading can cause the tie rods to fail due to fatigue loading, or can cause excess compression loading to the piston, head or cap. This causes distortion of these parts which will ultimately lead to cylinder failure.

Piston sealing is critical to proper cylinder function.  Piston seals keep fluid from bypassing the piston which would otherwise reduce the pressure differential across the piston and in turn reduce the available force for the cylinder to perform work.