Why Do Your Heat Exchanger Gaskets Keep Failing? Five Common Failures Explained

1. Improper Heat Exchanger Gasket Selection

Typical Symptoms

Chemical Corrosion: Honeycomb-like pits appear on the gasket surface (common in acidic media)

Swelling and Deformation: Non-metallic gaskets expand by more than 20% after absorbing the media

High-Temperature Carbonization: Rubber gaskets harden and crack in temperatures exceeding 150°C

Solutions

For Acidic and Alkaline Media: PTFE-coated graphite gaskets (pH resistant 0-14) are preferred

For High-Temperature Oils: Metal-Grooved Gaskets (maximum temperature resistance 800°C)

For Solvent Media: Perfluoroelastomer (FFKM) Gaskets

2. Installation Process Defects

Common Errors

Uneven Preload: Bolt Torque Deviation >15%

Improper Surface Treatment: Flange Roughness Ra >6.3μm

Excessive Compression: Non-metallic Gasket Compression Ratio >50%

Comparison of Technical Standards

Correct Installation Procedure

Clean flange surfaces (use special degreaser)

Use a torque wrench (tighten in a crisscross pattern)

Retighten 24 hours after pre-tightening

3. Operating Condition Fluctuation

Destructive Operating Conditions

Temperature Swing: Temperature Ramp Rate >100°C/min

Pressure Pulsation: Amplitude >10% of design pressure

Mechanical Vibration: Frequency >50Hz and Amplitude >0.2mm

Case Study

Steam purging in a refinery heat exchanger resulted in:

Gaskets subjected to 30 thermal cycles per day

Compression rebound rate dropped from 45% to 18% after 3 months

Eventually, stress relaxation leaks occurred

Countermeasures

Install a buffer device (e.g., pulse dampener)

Use a spiral wound gasket (allowing 0.3mm radial displacement)

Set an operating condition alarm threshold (temperature ramp rate ≤50°C/min)

4. Aging Failure (15%)

Material Performance Degradation Curve

Preventive Maintenance Recommendations

Rubber gaskets: Mandatory replacement every 3 years

Graphite gaskets: Annual compression set test

Metal gaskets: Hardness test every 5 years

5. Design Defects

Typical Design Errors

Insufficient pressure ratio: Calculated value <40 MPa (metal gasket requirement)

Poor flange stiffness: Bolt center diameter / flange thickness > 8

Inappropriate gasket width: Use gaskets <10 mm wide for NPS10 flanges

Improvement Solutions

Calculate bolt loads using ASME PCC-1

Optimize flange structure using finite element analysis

Select gasket size according to EN 1591