Gasket blowout and breakage are relatively common types of failure during the operation of plate heat exchangers. The main causes can generally be attributed to three categories: gasket quality, heat exchanger assembly and maintenance, and operating conditions.
The specific causes are as follows:
Gasket Quality-Related Defects
The gasket material must be selected according to the characteristics of the operating medium, including its corrosiveness and temperature, as well as the required pressure rating.
For example, using a standard NBR (nitrile rubber) gasket under high-temperature or highly corrosive operating conditions can accelerate material aging and embrittlement, eventually causing the gasket to crack or break.
Incomplete vulcanization, internal air bubbles or impurities, or excessive dimensional deviations in the sealing lips can result in uneven load distribution.
Under pressure, localized stress concentrations may develop, eventually causing the gasket to crack or break.
When a gasket is used beyond its recommended service life, the rubber material may become hardened and develop cracks.
As the gasket loses its elasticity and sealing capability, it may no longer accommodate the repeated thermal expansion and contraction of the heat exchanger, eventually resulting in gasket blowout or breakage.
Improper Heat Exchanger Assembly and Maintenance
If the clamping bolts are tightened in the wrong sequence or with inconsistent torque, the gasket may be excessively compressed in some areas while remaining insufficiently compressed in others.
Areas that are not properly compressed are more likely to be forced out of the sealing groove under operating pressure.
Excessive Clamping Force
Excessive clamping force can directly crush or damage the sealing lips of the gasket.
This damages the rubber material and may eventually cause the gasket to crack or break after a period of operation.
If scale, welding slag, process residues, or other foreign matter remains in the sealing groove, the gasket may not fit completely into the groove.
This can create excessive localized stress after assembly and eventually cause the gasket to crack or be forced out during operation.
Uneven or excessive clamping force can affect the sealing performance of the gasket and increase the risk of localized gasket damage.
Heat exchanger plates may warp or deform due to thermal stress or impact from foreign objects.
In addition, burrs or scratches along the edges of the sealing groove can disturb the load distribution on the gasket and cause localized cracking or failure.
Abnormal Operating Conditions
Frequent system start-ups and shutdowns, as well as sudden increases or decreases in fluid temperature or pressure, can cause the plates and gaskets to repeatedly expand and contract.
This creates alternating stress between the gasket and the sealing groove. Over time, repeated stress can lead to fatigue cracking and gasket failure.
Fluid Impact or Cavitation
If the fluid velocity is too high, or if gas-liquid two-phase flow occurs inside the heat exchanger, high-velocity fluid or bubbles may repeatedly impact the gasket sealing surface.
This can cause localized wear and tearing, eventually forcing the gasket out of the sealing groove.
If the operating medium contains strong acids, strong alkalis, or other corrosive substances, or if it reacts chemically with the gasket material, the gasket may swell, soften, and lose mechanical strength.
As a result, the gasket may eventually crack and fail.
To make production inspections and quality control easier, we have compiled this Plate Heat Exchanger Gasket Failure Troubleshooting and Preventive Measures Comparison Table.
It can be used as a practical reference for routine production inspections, equipment maintenance, and quality management, helping operators identify potential gasket problems and take preventive action in a timely manner.
