If you are a regular user of hydraulic equipment, you must already be aware of the costs associated with cylinder repair form a significant component of your overall operating costs. Hydraulic cylinders are quite standard, almost as much as pumps or motors combined! Studies have indicated that almost 25% of mechanical equipment failure occurs due to a failure of design. If we were to extend this fact to hydraulic equipment, we could conclude that almost 25% percent of hydraulic cylinders are not adequately designed to suit the application they are operating in. Although this doesn’t imply that the cylinder will not perform the tasks, but its shelf life will undoubtedly be shorter than its well-designed counterpart.
If you are operating a hydraulic cylinder that is not lasting as it should, you may have to find a solution for one or more of the following issues.
Bending of Rods
A bent rod is a common problem that occurs with hydraulic cylinders. Usually, the bending of cylinder rods can be caused due to inadequate rod diameter, lack of material strength, faulty cylinder mounting arrangement, or a combination of all three factors. It is imperative to note that once the rod starts bending, the rod seal experiences a deforming pressure. This can lead to leaks and ultimately premature failure of the seal. If you want to check the permitted rod loading for a cylinder in your existing application, use the Euler formula to do so.
The finish of the Rod
You may be surprised to know, but the finish of your cylinder rod has a significant impact on the shelf-life of the rod seal. If the surface is very smooth, the seal life will be reduced as it doesn’t have adequate lubrication. On the contrary, with a rough surface, the contamination ingression becomes high. This can cause severe leakage past the rod seal. From the perspective of increasing the cylinder’s service life, one needs to regard the cylinder rod’s surface as a lubricated, wear-surface and make sure to maintain it accordingly. In some applications, many hydraulic cylinder users consider using an alternative rod surface treatment which has an ability to convert superior mechanical properties to conventional hard-chrome plating, like using nickel-chrome plating or High-Velocity Oxygen Fuel (HVOF) metal spraying, which helps to increase the service life of the rod and its seals. You can also consider installing a shroud or bellows to preserve the rod surface and its seals from the damage caused due to impact and contaminants. All these can help to extend the life of your hydraulic cylinder.
Another common issue with hydraulic cylinders is the ballooning of the cylinder tube. This problem is a result of insufficient wall thickness or material strength needed for the cylinder’s operating pressure. You will notice that in due course, once the tube balloons, the correct tolerance level between the piston seal and tube wall is affected. This results in high-pressure fluid bypassing the seal. This high-velocity fluid has the capacity to erode the seal and decrease its life expectancy. This can cause premature failure of the piston seal.
Inadequate Surface Area
Your hydraulic cylinder’s bearing (wear) band surface area is more important than you can imagine. For starters, if the surface area of these bands in the gland and on the piston are inadequate to support the side thrust transferred to the cylinder, the rod and piston seals experience high pressure. This can cause deformation of the seal and result in premature failure.
To summarize, not all hydraulic cylinders have the same standard issues and what you may need to do for prolonging your cylinder life may be different from what others need to do. It is imperative to regard that in some conditions, design modifications may be required to break the vicious circle of failure and repair. If you want to know more about the possible costly mistakes with your hydraulic equipment, speak to our associates at Go Hydraulics, Canada’s trustworthy and reliable hydraulic cylinder repair and service provider.