Introduction: The Symptom of the Explosion That Triggers Research
A production workshop in Ukraine experienced a malfunction of the hydraulic drive. The maintenance personnel discovered that the HYDAC 0660D005BH4HC coupling had exploded, causing the line to shut down. After disconnecting the drive, a fatigue crack was detected on the surface of the coupling, as well as the presence of an axis deviation. Temperature measurements showed that the coupling heated up to 75 °C during operation, which exceeds the permissible value of 60 °C according to the EN 13445. standard
Component Overview: Function, Location, and Operating Conditions
The HYDAC 0660D005BH4HC coupling performs the function of transmitting torque between the engine and the pump. It is located on the output shaft of the engine, which operates in the mode of continuous rotation with a frequency of 1500 rpm. Permissible load: maximum power 110 kW, maximum torque 350 Nm, maximum temperature 60 °C.
The coupling is made of high-quality steel, which ensures high strength and resistance to wear. It is used in conditions of high vibration load and partial moisture, which requires additional protection.
Signs of an explosion: what a technician sees
After stopping the equipment, the technician discovered the following signs of an explosion:
- Fatigue chip on the surface of the coupling, measured with a depth of 0.3 mm.
- The presence of an axis deviation measured with a tolerance of 0.1 mm.
- Temperature measurements showed that the coupling heated up to 75 °C.
- The explosion caused damage to other parts of the drive, including the bearings and shaft.
In addition, higher vibration levels were detected, which were measured at the level of 8.5 mm/s RMS. Vibration exceeded the permissible level of 5.0 mm/s RMS according to the ISO 10816-3. standard
Investigation of the causes of the explosion: a systematic analysis
The 5 Whys, Ishikawa and fault tree methods were used to determine the causes of the explosion. The main causes of the explosion were determined through analysis of vibration, temperature and visual data.
The causes of the explosion have been determined
The following is a correspondence between the causes of the explosion, the probability and the supporting evidence:
- Axis Deviation - probability: 45%. The measurements showed an axis deviation of 0.1 mm, which exceeds the permissible level of 0.05 mm.
- Surge - probability: 30%. The presence of a crack and a higher temperature indicate overstress.
- Fatigue Cod - probability: 25%. Vibration measurements and visual signs indicate fatigue cracking.
Expected activities
The following measures were taken to solve the explosion problem:
- Correction of axis deviation - adjustment or replacement of the shaft. Using a measuring device to measure axis deviation.
- Load reduction — perform system adjustment to reduce overvoltage.
- Replacing the coupling - using a coupling with higher strength that meets the EN 13445. standard
A quick diagnostic checklist for the technician
Below are 10 points that a technician can use on a tablet in the work area:
- Measure the deviation of the shaft axis (max. 0.05 mm).
- Measure the temperature of the coil (max. 60 °C).
- Measure the vibration level (max. 5.0 mm/s RMS).
- Check the surface for cracks.
- Check the condition of other drive components.
- Use measuring devices for accurate measurements.
- Use visual assessment to identify fatigue cracks.
- Perform vibration data analysis.
- Use diagnostic programs to detect abnormalities.
- Adjust the system to reduce the load.
Prevention strategy
In order to reduce the risk of explosion, it is recommended to:
- Perform regular axis deviation checks (6-month interval).
- Measure the temperature of the bed (interval of 3 months).
- Perform vibration data analysis (1 month interval).
- Use higher-strength cleats (corresponding EN 13445).
- Adjust the system to reduce the load.
Conclusion: UNITEC-D E-Catalog
A blowout can lead to significant costs and production downtime. The use of high-quality components, such as the HYDAC 0660D005BH4HC coupling, ensures the reliability and durability of the systems. For replacement or prevention, use the UNITEC-D E-Catalog.
Sources
- EN 13445:2009 - Steel pipelines for gas transportation.
- ISO 10816-3:2009 - Vibration of machines - Assessment of vibration of production machines.
- DSTU 3084-2019 - Standards for the production and use of industrial equipment in Ukraine.
- Additional recommendations from HYDAC: Technical conditions for couplings.
- Book "Failure Analysis of Industrial Components" — Additional methods of explosion analysis.
