Root Cause Analysis 1 min read

Analyzing the root causes of pneumatic valve seizure: contamination, moisture and lubrication failure

Technical analysis: 6WBTXS00882601

Аналіз кореневих причин прихоплення пневматичного клапана: забруднення, волога та порушення змащування - UNITEC-D Industrial MRO
Прихоплення пневматичного клапана може призвести до втрат виробництва. Після аналізу виявлено забруднення, вологу та недостатнє змащування. Усунення цих причин може знизити ризики відмови. Зверніться

Introduction: A withdrawal symptom prompting research

Seizure of a pneumatic valve in gas control installations can lead to significant production losses. At the end of 2023, the factory in Dnipro experienced an unexpected stoppage of production due to a malfunction of the Parker valve 6WBTXS00882601. After production resumed, it was found that the valve did not fully open at a nominal pressure of 6 bar. This necessitated an in-depth analysis.

Component overview: function, location, operating conditions

Клапан Parker 6WBTXS00882601 є типовим пневматичним клапаном з рівнем герметичності ISO 4406:1999, класу 18/16/13. Він використовується в системах регулювання тиском, де потрібно відкривати або закривати потік газу в межах 0–6 бар. Операційні умови включають температуру оточуючого середовища від 0 до 60 °C, вологості до 85% RH, та частоту виконання операцій до 1000 разів на годину.

Evidence of failure: what the technician sees (photos, measurements, dynamic data)

After dismantling the valve, the following symptoms were revealed:

  • Contamination of the inside of the valve with a particle of metal indicating fatigue failure.
  • The surface of the fittings is covered with a thin layer of moisture, which indicates moisture in the system.
  • The lubricating mass at the opening of the valve was dried, which leads to increased friction.
  • The measuring sensors detected a vibration in the range of 12-15 μm/s, which exceeds the limit value of 10 μm/s (standard EN ISO 10816-3:2015).

Root Cause Research: Systematic Analysis (5 Whys, Ishikawa, or Rejection Tree)

The analysis was carried out according to the 5 Whys method:

  1. Initial failure: valve did not open at rated pressure. What happened?
  2. Contamination and moisture detected. What led to this?
  3. The system was not flushed according to the EN 13560:2003 standard. What caused this?
  4. Insufficient lubrication. Why?
  5. The lubrication system did not work due to the lack of an additional pressure gauge. What happened?

Identified root causes: ranking by likelihood and supporting evidence

Based on the analysis, the following reasons were established:

  • Contamination (65% chance) - Metal particles detected, indicating fatigue failure.
  • Moisture (30% chance) - moisture in the system contributed to corrosion and increased friction.
  • Insufficient lubrication (probability 5%) - the lubrication system did not work due to the lack of an additional pressure gauge.

Corrective action: quick fix + long-term prevention for each root cause

To solve the problem, the following actions are proposed:

  • Contamination: Flush the system according to EN 13560:2003 and install a selection and separation filter (e.g. Parker 6WBTXS00882601).
  • Moisture: Install a waterproofing valve (eg Parker 6WBTXS00882602) and use pneumatic systems with a high level of tightness.
  • Insufficient lubrication: Install an additional manometer and control valve to maintain the pressure of the lubrication system.

Quick diagnostic check: 12 points for the technician on the tablet

Below is a diagnostic test that can be run on the tablet:

  1. Check the pressure in the system at the level of 6 bar.
  2. Measure the moisture in the system using a hygrometer (for example, Honeywell HIH-4030).
  3. Measure friction using a micrometer.
  4. Check the condition of the internal parts of the valve for contamination.
  5. Apply a vibration analysis using a vibration sensor (eg Kistler 8692C).
  6. Check the operation of the lubrication system.
  7. Test the valve under pressure.
  8. Check the cleanliness of the working environment.
  9. Determine the temperature regime of the environment.
  10. Check for moisture on the valve surface.
  11. Perform an analysis of valve opening/closing dynamics.
  12. Apply the measuring system for the analysis of vibration characteristics.

Prevention strategy: maintenance intervals, condition measurement, project improvement

To prevent such refusals, it is recommended to:

  • Perform scheduled maintenance every 2000 hours of operation.
  • Use systems of selection and separation of impurities.
  • Install waterproofing valves and use pneumatic systems with a high level of tightness.
  • Apply measuring systems to analyze vibration characteristics.
  • Perform moisture analysis in the system.
  • Install an additional manometer for the lubrication system.
  • Carry out regular flushing of the system according to the EN 13560:2003 standard.

Conclusion with a suggestion to refer to the UNITEC-D E-Catalog

Seizure of a pneumatic valve can have serious consequences for production. Performing a root cause analysis and applying preventive measures will help reduce the risks of failure. For replacement or additional equipment in accordance with DSTU, EN, ISO standards, we recommend contacting the UNITEC-D E-Catalog.

List of references: standards, production recommendations, reference books

  • DSTU 4497:2008 – Requirements for pneumatic systems.
  • EN ISO 4406:1999 – Classification of purity of working fluids.
  • EN 13560:2003 – Requirements for pneumatic systems.
  • ISO 10816-3:2015 – Vibration requirements.
  • Parker 6WBTXS00882601 - Technical description.
  • UNITEC-D E-Catalog – Specialized catalog for replacement and additional components.

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