Introduction
Hydraulic cylinders play a critical role in automated production systems. Contamination, misalignment, or pressure peaks can cause a seal to explode, resulting in unscheduled equipment downtime, reduced productivity, and increased repair costs. This article examines the SKF 21315 E seal explosion case, performs an explosion cause analysis, and suggests a practical recovery and prevention strategy.
Overview of the component
The SKF 21315 E seal is a critical element of a hydraulic cylinder that ensures the tightness of the working environment. This component operates under high pressure conditions, typically up to 250 bar, at an ambient temperature of 0 to 80 °C. The maximum operating speed is up to 1.5 m/s. The seal is installed in the cylinder body and performs the function of preventing liquid leakage and contamination.
Evidence of the explosion
The following symptoms were detected during the examination:
- Peeling and wear of the rubber part of the seal;
- The presence of metal particles in the working environment;
- Increase in flow rate of hydraulic fluid;
- Vibration of the cylinder during operation;
- Temperature increase from 50 to 75 °C.
Vibration measurements showed a value of up to 7.5 mm/sec, which exceeds the permissible limit of 4.5 mm/sec according to the ISO 10816-3:2009 standard.
Investigation of the causes of the explosion
The 5 Why method and the cause and effect diagram were used to analyze the causes of the explosion. Here are the basic steps:
- Explosion causes: Seal explodes.
- Why? The seal cannot withstand pressure.
- Why? There are pressure peaks.
- Why? Pollution in the working environment.
- Why? Incorrect system cleanup before startup.
A vibration analysis was also performed, indicating a possible deviation from the center.
Causes of the explosion
1. Contamination of the working environment
The contamination was caused by improper cleaning of the system before start-up. Contamination leads to rapid wear of the seal, which reduces its service life. According to data from ISO 4406:1999, the level of cleanliness of the working environment should be at least 16/13/10.
2. Deviation from the center
Deviation from the center occurred due to incorrect installation of the cylinder or wear of the hinges. A vibration of up to 7.5 mm/sec indicates a deviation from the center, which increases the load on the seal.
3. Pressure peaks
Pressure peaks of up to 300 bar occurred due to improper adjustment of the pressure regulators. This leads to an excessive load on the seal, which reduces its strength.
Medical measures
1. Immediate decision
- Replace the SKF 21315 E seal;
- Clean the working environment by filtering;
- Check and correct deviations from the center;
- Install appropriate pressure regulators.
2. Long-term prevention
- Install a pressure monitoring system;
- Apply liquid filters in accordance with ISO 4406:1999;
- Implement a regular check of the deviation from the center;
- Maintain the system using scheduled maintenance.
Quick diagnostic checklist
- Measure the pressure in the system;
- Check the condition of the seal;
- Make vibration measurements;
- Check the cleanliness of the working environment;
- Determine the deviation from the center;
- Check pressure regulators;
- Clean the filters;
- Apply a monitoring system.
Prevention strategy
To prevent the seal from exploding, the following measures must be taken:
- Establish regular maintenance with an interval of 1000 hours;
- Use the pressure and vibration monitoring system;
- Apply liquid filters in accordance with ISO 4406:1999;
- Ensure proper cleaning of the system before start-up;
- Use hinges with high strength.
Conclusion
SKF 21315 E seal explosion can be caused by contamination, misalignment or pressure peaks. For effective restoration and prevention, it is worth using specialized components that meet DSTU, EN and ISO standards. All required components can be found in the UNITEC-D E-Catalog.
List of references
- ISO 10816-3:2009 — Vibration measurement on the machine;
- ISO 4406:1999 — Cleanliness of the working environment;
- DSTU 3045-95 — Requirements for hydraulic systems;
- EN 13151-2:2013 — Requirements for hydraulic systems;
- SKF Technical Manual - Additional recommendations.
