Seals for hydraulic cylinders are essential parts that keep fluid from leaking and allow the hydraulic system to work properly. But with time, these seals get worn out and need to be replaced.
Under normal circumstances, the service life of standard hydraulic seals can reach thousands of hours of operation under normal conditions. Common rubber material seals, such as nitrile or fluorine rubber, have a service life of 1,000-5,000 hours. Under harsh working conditions, the service life of hydraulic seals will be significantly shorter. In contrast, some hydraulic seals made of high-performance materials, such as PTFE seals or PU seals, have a longer service life, up to thousands or tens of thousands of hours, depending on the actual usage environment.
We have 25 years of experience in the development of hydraulic seal materials. Through actual testing of the decisive influence of various material properties and the severity of working conditions on service life, the PTFE/PU sealing combination independently developed by TYS material experts has achieved more than 10,000 hours of stable operation in multiple assembly lines and field tests with ultra-low friction, high wear resistance, and wide temperature adaptability. Whether it is a high-pressure (≥20 MPa) or high-temperature (≤150 ℃) environment, TYS can provide customized sealing structures and precision matching to help users maximize service life and reduce leakage. The following will analyze the life performance under various typical working conditions in detail.
The following important variables determine the exact lifespan of hydraulic seals:
Working Environment
The particular operating conditions, such as system pressures, operating temperatures, cylinder speeds, exposure to contaminants, type of hydraulic fluid, and maintenance procedures, are arguably the most important factors that determine how long hydraulic seals last. Extremely harsh environments can shorten the lifespan of seals to just a few hundred hours, but mild-duty seals with proper maintenance can last up to 50,000 hours.
Seal Materials
Durability is impacted by a seal’s construction, internal lubricants, and elastomer grade, among other properties. Materials like fluoroelastomers or high-consistency PTFE compounds typically allow for longer seal lives than typical nitrile rubbers, but they come at a higher cost. It’s critical to carefully choose the seal material to meet operating requirements.
The following offers service life data of different materials and working conditions under conventional design conditions for your reference:
| Material | Normal working conditions <br> (≤20 MPa, ≤0.5 m/s, –20 ℃～80 ℃) |
Harsh working conditions <br> (>20 MPa, >0.5 m/ extreme temperaturesor heavy pollution) |
| NBR (nitrile rubber) |
1000-5000 h | 300-2000h |
| HNBR (Hydrogenated Nitrile Rubber) |
5000 – 8000 h | 800–5000 h |
| FKM (Viton) | 5000 – 10000 h | 1000 – 5000 |
| PU (polyurethane) | 8000 – 50000 h | 1000 – 10000 h |
| PTFE (Polytetrafluoroethylene) |
8000 – 20000 h | 2000 – 8000 h |
| Perfluoroelastomer | > 50000 h | > 5000 h |
Seal Designs
Modern seal profiles that are more complex, like double lip designs with optimized geometry and multi-stage pressure zones, increase resistance to fluid contaminants, pressure spikes, and thermal cycling, thus increasing the potential lifespan of the seal.
Replacement Intervals
Many plant managers replace seals as a preventive measure during scheduled equipment overhauls or replace regularly, such as in the case of no ultra-high frequency operation, usually replaced every 12-24 months to avoid unplanned and potentially dangerous seal failures. But thanks to developments in seal diagnostics, it is now possible to precisely estimate a seal’s life based on its actual operating history.
In conclusion, operating conditions and seal specifications have a significant impact on hydraulic cylinder seal lifespans. However, there is a chance for significantly longer, dependable high-performance seal operation by adhering to strict maintenance procedures and making use of technological advancements in materials, designs, and diagnostics.
Data on changes in influencing factors
Based on experience, the following common factors have an impact on lifespan for your reference:
Material formula: High-temperature, high-wear-resistance, corrosion-resistance, and low-friction materials such as PTFE or PU can extend the service life by about 30% compared with ordinary formula materials.
Media cleanliness: For every level of hydraulic oil medium pollution increase, the service life can be reduced by 10-30%.
Temperature range: For every temperature exceeding the recommended temperature of the material, the service life can be reduced by about 15%.
Seal structure: A multi-lip or U-shaped design can effectively increase the service life by about 10% under harsh working conditions.
If you have any questions or suggestions for how to make this expert summary of the variables that affect hydraulic seal longevity better, do let me know. If you want to know more about how to improve the service life of hydraulic seals and how to maintain the seal tips, you can click to learn. I hope it will be helpful to you.
