A hydraulic seal is a sealing device that prevents fluid leakage in hydraulic cylinders, preserving system efficiency. It is typically a non-metallic ring that prevents leakage and seals openings between hydraulic cylinder components.
The main purpose of hydraulic seals is to form a barrier that keeps hydraulic fluid under pressure from escaping the cylinder. Seals ensure that the fluid stays confined within the hydraulic systems. They also enable efficient power transmission and mechanical work performance.
Hydraulic seals prevent impurities such as grit, dust, and moisture from entering the system, which could impair system functionality and lead to component failure.
This guide explains what a hydraulic seal is, the types of hydraulic seals, and the benefits of using hydraulic seals in hydraulic cylinders.
Common Types of Hydraulic Seals
There are two types of hydraulic seals: static and dynamic, depending on their application. However, both of these seals are used in hydraulic cylinders for different purposes. Static seals remain stationary, whereas dynamic seals move with the cylinder’s motion.
Depending on the static and dynamic conditions, there are different types of hydraulic seals, each suited to distinct applications. Common types of hydraulic seals include piston seals, rod seals, static seals, rotary seals, wiper seals, and wear seals.
Piston Seal
As the name implies, the piston seals are designed to seal the piston and the cylinder. They seal dynamic pressure by enabling the cylinder to extend and retract. They are responsible for preventing fluid from leaking between the two sides of the cylinder.
Rod Seal
The rod seals are also known as grand or neck seals. These seals are located between the rod and the cylinder head and are typically designed to seal between the rod and the gland. These seals prevent liquids from seeping into the area around the rod.
Static Seal
Static seals are designed to create a seal between two non-moving surfaces. These seals are commonly O-rings or gaskets made from materials such as NBR, Viton, or PTFE. Static seals prevent fluid and gas leakage between two stationary parts of machinery.
Rotary Seal
As the name implies, they seal against a dynamic rotating surface. These seals stop liquids or gases from leaking and keep the system intact. Rotary seals are frequently used in rotating machinery such as rotating joints and shafts, compressors, and pumps.
Wiper Seal
The wiper seals are also known as scraper or dust seals. These hydraulic seals keep impurities out of a hydraulic system and keep the rod surface clean. Wiper seals are typically mounted on the exterior of a hydraulic cylinder.
Wear Seal
Wear seals are commonly referred to as wear rings, backup rings, and guide rings. These enhance sealing performance by providing an additional layer of support. Backup rings are used in conjunction with hydraulic seals and are positioned on one or both sides of the main seals.
Benefits of Hydraulic Seals
Hydraulic seals offer numerous benefits to hydraulic systems, such as preventing fluid leaks and damage, maintaining pressure, and protecting the system from contaminants. They also improve performance by reducing friction and heat, enhancing safety and longevity, and minimizing maintenance costs.