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Arguably, every component in a hydraulic cylinder is critical for reliability and performance, but the often overlooked hydraulic cylinder seals are the unsung heroes. Why? If hydraulic cylinders didn’t have seals, they wouldn’t work. Let’s investigate how seals work and look at the different types of seals so you’re better informed when you next choose a cylinder for your machinery.
There can be a number of seals inside a cylinder, each performing a different function. They keep the cylinder working efficiently, protect the internal components and perform other tasks. We make seals out of different materials to achieve different functions, all dependent on the machinery you use.
Static seals, as the name suggests, are fixed in place. It’s important to remember there’s a lot going on inside a cylinder while it’s in use. Static seals handle components that don’t have relative movement.
The most common example of a static seal is where the piston meets the rod. The seal sits within the piston, and the rod passes through it. During operation, the pressure of the rod working with the seal prevents the hydraulic fluid from escaping.
Dynamic seals are used in areas of the cylinder with relative movement, which is where both components move. Piston seals, for example, are one of the most important seals in the cylinder because they prevent oil from flowing past the piston, which creates the power.
Rod seals have an important dual function. They prevent oil loss during operation and lubricate the piston rod, which prevents corrosion. Heavy-duty culinders may also have a buffer seal further inside the cylinder past the rod seal. The buffer seal smooths out the increased load and acts as a barrier to contamination.
The other protective seals you can find in a cylinder include wiper seals and guide rings. Wiper seals, as the name suggests, clean the piston rod as it retracts. As the rod is coated with oil, dust and other contaminants can stick to it and enter the cylinder, so it’s important to keep the rod clean.
Guide rings help all the working parts to remain in the correct position during operation and prevent abrasion, which prolongs the working lifespan of the cylinder and helps to reduce the chances of cylinder drift.
We can manufacture seals out of different materials for different applications, such as environmental factors, high pressures and extreme temperatures. In specialised applications, we have to use other materials for seals where machinery is working with chemicals or where there is a risk of fire.
Examples of materials for seals
There are many considerations when choosing the right seals for your machinery. The primary considerations are efficiency and durability. You need your machines to work well without constant maintenance to keep them at peak performance. Usually, we can evaluate what seals you need in your cylinders by looking at operating pressures. You’ll blow seals if you put cylinders into machinery needing cylinder performance at higher pressures.
Here’s how the standard Motus range works:
View our range of Hydraulic Cylinder Parts
Setting the right expectations helps you choose the right seal for your cylinders. In turn, you’ll ensure you get the best performance out of your machinery.
If you need help choosing seals, talk to our team for expert advice.
