🔴 Steam Leakage → Water Ingress into Bearing Housing

(Labyrinth + Carbon Ring Failure Mechanism)

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1. What the Image Really Shows (Critical Interpretation)

Your image highlights a classic but dangerous design reality:

• Steam flows through the turbine (center section)
• At shaft exits → carbon rings + labyrinth seals
• Beyond that → bearing housings (oil-filled)

👉 The red arrows clearly show:
Steam leakage path → directly toward bearing housings

This is not a defect.
This is inherent to the design philosophy.

Because:

Labyrinth seals are controlled leakage devices, not perfect seals (ScienceDirect)

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2. Why Steam Leakage is Inevitable

2.1 Labyrinth Seal Limitation

• Non-contact seal → requires clearance
• Works by pressure drop across teeth
• Always allows some leakage

➡️ “They slow leakage… they do not stop it” (לאור הנדסה בע”מ)

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2.2 Carbon Ring Behavior

• Initially tight → good sealing
• Over time:
  • Wear
  • Loss of radial tension
  • Groove formation

➡️ Leakage increases progressively

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2.3 Combined Effect

Labyrinth + carbon rings =
✔ Controlled leakage
❌ Not zero leakage

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3. The Real Root Cause Chain (Step-by-Step Failure Mechanism)

Step 1: Steam Escapes Through Shaft Seals

Causes:

• Low gland steam pressure
• Worn carbon rings
• Increased clearances
• Seal rubbing / thermal distortion

➡️ Steam bypasses sealing system (Powerplant Manual)

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Step 2: Steam Enters Bearing Housing Region

Once leakage exceeds design capacity:

• Steam migrates along shaft
• Reaches bearing housing labyrinth

➡️ OEM labyrinth cannot stop steam ingress (aesseal.com)

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Step 3: Steam Condenses → Water in Oil

Inside bearing housing:

• Temperature gradient exists
• Steam hits cooler oil/housing surfaces

➡️ Condensation occurs instantly

Result:

• Free water
• Dissolved water
• Emulsified oil

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Step 4: Continuous Water Ingress Cycle

Unlike external contamination:

❗ This is continuous internal generation

• Steam leakage persists
• Condensation continues
• Oil never stabilizes

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4. Why This Root Cause is Extremely Dangerous

4.1 It is INTERNAL (not external contamination)

• No obvious ingress point
• No operator visibility
• No leak outside

➡️ Hidden failure mechanism

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4.2 It Bypasses Conventional Filtration

• Steam → vapor phase
• Not removed by filters
• Not stopped by particle control

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4.3 It Drives Multiple Failure Modes

A. Lubrication Failure

• Reduced film strength
• Micro-pitting
• Bearing wipe

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B. Accelerated Oxidation

• Water + temperature → oxidation catalyst
• Acid number increase

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C. Varnish Formation

• Water accelerates degradation
• Soluble varnish formation
• Deposit formation in:
  • Bearings
  • Servo valves
  • Control systems

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D. Additive Depletion

• Antioxidants consumed faster
• Demulsifiers overwhelmed

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5. Key Root Causes (Detailed Breakdown)

5.1 Seal Degradation

• Carbon ring wear
• Loss of sealing force
• Surface scoring

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5.2 Labyrinth Seal Issues

• Clearance increase
• Vibration-induced damage (Cowseal)
• Thermal expansion mismatch

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5.3 Gland Steam System Problems

• Low pressure (most common)
• Blocked lines
• Incorrect valve positions (Powerplant Manual)

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5.4 Drain System Failure

• Blocked drain holes
• Poor condensate removal

➡️ Steam accumulates near seals (community.oxmaint.com)

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5.5 Pressure Differential Reversal

• Improper sealing pressure balance
• Steam forced inward instead of outward

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6. Diagnostic Indicators (Field Reality)

This is where your expertise becomes critical.

Oil Analysis Signs:

• Sudden water increase (ppm)
• Poor demulsibility
• Increasing MPC (varnish potential)
• TAN rise

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Mechanical Symptoms:

• Bearing temperature increase
• Milky oil appearance
• Foaming
• Seal oil system instability

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Advanced Insight (Khash-level):

👉 If water keeps returning after dehydration →
You are not removing water… you are ignoring steam ingress

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7. Why Many Plants Misdiagnose This

Typical wrong conclusions:

❌ “Cooling water leak”
❌ “Heat exchanger leak”
❌ “Condensation from atmosphere”

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Reality:

If your image scenario exists:

✔ Root cause is steam seal system failure

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8. Engineering Solutions (Correct Approach)

8.1 Fix the Source (Not the Symptom)

Seal System

• Replace carbon rings
• Optimize clearances
• Upgrade to brush seals (if applicable)

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Gland Steam System

• Maintain proper pressure differential
• Clean strainers
• Verify flow distribution

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8.2 Improve Bearing Isolation

• Upgrade from OEM labyrinth to:
  • Bearing isolators
  • Advanced sealing systems

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8.3 Condensate Management

• Ensure proper drainage
• Remove trapped steam

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8.4 Oil System Strategy

This is where Khash philosophy applies:

• Remove water (vacuum dehydration / sparging)
• Remove acids + varnish precursors (chemistry management)
• Restore oil equilibrium

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9. Final Technical Insight (Most Important Takeaway)

👉 This image represents one of the most critical hidden failure mechanisms in turbomachinery lubrication:

Steam turbines are designed to leak —
The question is whether that leakage is controlled or destructive.

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10. One-Line Summary

“When steam crosses the seal boundary, lubrication reliability is no longer a filtration problem — it becomes a sealing system failure.”

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