Products Description
1. Excessive Temperature and Frequent Temperature Changes
1.1 Prolonged Exposure to High Temperatures
Gaskets have specific temperature limits, and the maximum allowable operating temperature varies depending on the gasket material. When the operating temperature exceeds the material's limits, the gasket may harden, soften, degrade, or undergo permanent deformation. These changes reduce its elasticity and sealing capability, eventually leading to leakage.
1.2 Frequent Temperature Fluctuations
When a plate heat exchanger is frequently started, stopped, or operated under changing conditions, its gaskets repeatedly experience thermal expansion and contraction. Over time, these temperature cycles can accelerate material fatigue and alter the contact between the gaskets and plates. If temperature changes are too rapid or severe, cracks may develop in localized areas of the gasket.
1.3 Incorrect Gasket Material Selection
Different gasket materials have different temperature resistance and chemical compatibility characteristics. For example, EPDM is commonly used for hot water and many water-based applications, while NBR is often suitable for certain oil-based applications within its specified operating limits. If the selected material cannot withstand the actual operating temperature, premature gasket failure may occur even when the operating pressure remains normal. Material selection should consider the maximum and minimum operating temperatures, temperature fluctuations, and fluid characteristics.
1.4 Uneven Temperature Distribution
Uneven flow distribution or partially blocked channels may cause temperature differences across the heat exchanger plates. As a result, certain gasket areas may experience greater thermal stress and age more rapidly than others. Since localized damage may not affect all gaskets equally, inspections should focus on leakage points and the surrounding areas.
2. Excessive Operating Pressure and Pressure Fluctuations
2.1 Operating Above the Design Pressure
Plate heat exchangers and their sealing systems are designed to operate within specified pressure limits. When the actual operating pressure exceeds the allowable range, gaskets may become excessively compressed, displaced, or locally extruded. Prolonged overpressure increases the risk of seal failure and fluid leakage. Therefore, the operating pressure must remain within the limits specified on the equipment nameplate and in the technical documentation.
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2.2 Frequent Pressure Fluctuations
Frequent pump starts and stops, rapid valve operation, and changes in system load can cause pressure fluctuations. Repeated pressure changes expose gaskets to cyclic loading, potentially accelerating material fatigue and damaging the sealing surfaces. If significant pressure fluctuations occur, the pumps, valves, and control system should be inspected, and appropriate pressure-control measures should be implemented when necessary.
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2.3 Water Hammer
Water hammer occurs when the velocity of fluid in a pipeline changes suddenly, generating a pressure surge. This transient pressure can significantly exceed the normal operating pressure and place additional stress on the plates, gaskets, and connecting components. Repeated water hammer events may cause gasket displacement, localized damage, or leakage. To reduce this risk, sudden valve closure should be avoided, and the piping system should be designed and operated appropriately.
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2.4 Abnormal Differential Pressure Between the Two Sides
The hot and cold sides of a plate heat exchanger may operate at different pressures, so the design must account for the pressure on each side and the allowable differential pressure. If the actual differential pressure exceeds the equipment's limits, the plates may deform and affect gasket compression. Both sides' operating pressures should be monitored, and abnormal differential pressure, blocked channels, and improper valve operation should be investigated.
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3. Incompatibility Between the Fluid and Gasket Material
3.1 Chemical Attack
Certain acids, alkalis, solvents, and other chemicals may react with gasket materials. Chemical attack can cause swelling, softening, discoloration, cracking, or reduced mechanical strength. When selecting gaskets, their chemical compatibility should be verified based on the fluid composition, concentration, operating temperature, and exposure duration.
3.2 Swelling Caused by Oil-Based Fluids
Some rubber materials absorb incompatible oils and undergo volumetric expansion. Swollen gaskets may move out of their intended positions and interfere with the proper alignment of adjacent plates. Excessive swelling can also cause deformation, extrusion, or difficulties during disassembly.
3.3 Effects of Oxidizing Agents and Special Additives
Certain oxidizing agents, cleaning chemicals, and water-treatment additives may accelerate rubber degradation. Even if the primary process fluid is compatible with the gasket material, additional chemicals can change the operating conditions and increase the risk of damage. Before changing the fluid or adjusting the water-treatment program, the compatibility of all substances that may contact the gasket should be checked.
3.4 Changes in Fluid Composition
Changes in production processes, raw materials, or system contamination may cause the actual fluid composition to differ from the original design conditions. For example, an increase in fluid concentration or the introduction of new chemicals may increase the risk of gasket degradation. When premature gasket deterioration occurs, the actual fluid composition should be reviewed in addition to operating temperature and pressure.
4. Natural Aging and Material Fatigue
4.1 Loss of Elasticity During Long-Term Operation
Rubber gaskets gradually age under continuous compression and exposure to operating conditions. As their elasticity decreases, they may become less capable of recovering their original shape, resulting in insufficient sealing contact pressure. Even without visible cracks, aged gaskets may begin to leak.
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4.2 Permanent Compression Set
Gaskets are compressed during installation to establish the contact pressure required for sealing. If they remain exposed to high temperatures or excessive compression for extended periods, they may develop a permanent compression set. When operating conditions change or the equipment is shut down, the gaskets may fail to recover sufficiently. As a result, they may no longer provide reliable sealing when the equipment resumes operation.
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4.3 Oxidation and Environmental Aging
During storage, installation, and operation, gaskets may be exposed to oxygen, ozone, heat, and other environmental factors. Prolonged exposure to unsuitable conditions can cause certain rubber materials to harden, develop surface cracks, or lose mechanical strength. Proper spare-part storage, protection from direct sunlight, and avoidance of unsuitable environmental conditions can help slow material aging.
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4.4 Exceeding the Expected Service Life
The service life of a gasket depends on several factors, including its material, operating temperature, pressure, fluid characteristics, and start-stop frequency. Even under relatively stable operating conditions, gasket performance may gradually deteriorate over time. Therefore, regular inspections and planned replacement schedules should be established rather than waiting for leakage to occur.
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5. Improper Installation and Incorrect Plate-Pack Compression
5.1 Incorrect Plate-Pack Compression Dimensions
Gasketed plate heat exchangers must generally be assembled according to the compression dimensions specified by the manufacturer. If the plate pack is compressed too tightly, the gaskets may become excessively compressed, deformed, or damaged. If the plate pack is not compressed sufficiently, the gaskets may not achieve adequate contact pressure, resulting in poor sealing.
5.2 Misaligned Gaskets
Gaskets must be correctly positioned in the sealing grooves and fit properly against the plate surfaces. If a gasket is twisted, partially lifted, or displaced during installation, it may not contact the adjacent plate evenly. These installation defects can cause localized leakage and, in severe cases, allow the gasket to move under operating pressure.
5.3 Foreign Matter in the Sealing Grooves or on Plate Surfaces
Dirt, adhesive residue, metal particles, and other foreign materials left in the sealing grooves can interfere with gasket positioning and contact. Such contaminants may also create localized stress concentrations, damaging the gasket during compression. Before installation, the sealing grooves and plate surfaces should be cleaned and inspected to ensure that no debris or visible damage compromises the seal.
5.4 Improper Installation Methods
Different plate heat exchanger designs may use snap-in, glued, or other gasket-retention systems. Using unsuitable tools, adhesives, or installation procedures may damage the gasket or compromise its retention. Maintenance personnel should follow the manufacturer's installation instructions and use gaskets and auxiliary materials that are compatible with the specific equipment model.
6. Fluid Erosion, Particle Abrasion, and Channel Fouling
6.1 Erosion Caused by Excessive Flow Velocity
When the fluid velocity exceeds the design requirements, areas near the gaskets may be subjected to stronger localized fluid forces. Prolonged exposure to these conditions may accelerate surface wear, particularly near channel inlets and areas where the fluid changes direction. Operating flow rates should be controlled according to the design requirements and allowable pressure drop to prevent prolonged operation at excessive flow rates.
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6.2 Abrasion Caused by Solid Particles
If the fluid contains sand, metal fragments, or other hard particles, these particles may enter the sealing areas and cause abrasion. Particles trapped between a gasket and a plate can also disrupt the sealing contact and cause leakage. For fluids containing suspended solids, appropriate pretreatment measures, such as filtration or settling, should be considered based on the particle characteristics and equipment design.
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6.3 Scale and Deposits Affecting Sealing
During long-term operation, scale, sludge, and other deposits may accumulate on the plate surfaces and around the sealing grooves. These deposits can prevent the gaskets from fitting correctly and result in uneven compression. If the deposits are not completely removed during cleaning, leakage may occur after reassembly. Therefore, the sealing grooves and surrounding areas should be inspected carefully during maintenance.
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6.4 Abnormal Operating Conditions Caused by Channel Blockage
Blocked channels can alter fluid distribution and cause abnormal local flow velocities, temperatures, and pressure differences. These changes may indirectly increase the operating loads on the gaskets and plates. If the pressure drop continues to increase or heat transfer performance deteriorates noticeably, the channels should be inspected for blockage and cleaned when necessary.
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7. Improper Maintenance and Incorrect Cleaning Procedures
7.1 Using Incompatible Cleaning Agents
Cleaning agents should be selected according to the type of deposits, plate material, and gasket material. Certain strong acids, strong alkalis, and organic solvents may damage specific rubber compounds. Incompatible cleaning chemicals can cause swelling, hardening, or cracking. Before cleaning, the chemical compatibility of the cleaning agent should be verified.
7.2 Improper Cleaning Temperature or Chemical Concentration
Even when a cleaning agent is suitable, an excessively high cleaning temperature or a concentration above the recommended level may accelerate gasket degradation. Excessively long soaking times can also increase the risk of chemical damage. The specified cleaning temperature, concentration, and duration should be followed carefully, and chemical concentrations should not be increased arbitrarily to speed up cleaning.
7.3 Gasket Damage During Disassembly and Reassembly
Using sharp tools to remove plates or old gaskets may scratch the sealing grooves or damage the plate surfaces. During reinstallation, stretching, twisting, or pinching the gaskets can also compromise their sealing performance. Maintenance personnel should use appropriate tools, handle the components carefully, and inspect the gaskets and plates for damage before reassembly.
7.4 Neglecting Regular Inspections and Preventive Maintenance
Without regular inspections, early signs of gasket deterioration, such as hardening, cracking, displacement, or minor leakage, may go unnoticed. By the time leakage becomes obvious, the damage may have become more extensive and may disrupt normal equipment operation. Establishing a routine inspection schedule, recording operating parameters, and assessing gasket condition can help identify problems early and reduce unexpected downtime.
8. Gasket Quality Problems and Improper Spare-Part Storage
8.1 Poor Gasket Material Quality
The material formulation, manufacturing process, and quality control procedures directly affect a gasket's resistance to temperature, pressure, and chemical exposure. If material quality is inconsistent, the gasket may develop hardening, cracking, or loss of elasticity prematurely. When purchasing gaskets, buyers should select products that meet the equipment requirements and verify the material specifications, operating suitability, and relevant quality documentation.
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8.2 Incorrect Gasket Specifications for the Equipment
Different plate heat exchanger models may have different plate structures, sealing groove dimensions, and gasket profiles. If the replacement gasket does not match the original design, it may not fit correctly or provide uniform sealing, even if its material quality is satisfactory. Replacement parts should be selected according to the equipment model, plate model, and manufacturer's specifications rather than by appearance alone.
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8.3 Improper Storage Conditions for Spare Gaskets
Gaskets can deteriorate even before installation. Prolonged exposure to direct sunlight, high temperatures, excessive moisture, ozone, or incompatible chemicals may reduce the performance of certain rubber materials. Spare gaskets should be stored in a cool, dry, and well-ventilated environment, away from direct sunlight, in accordance with the manufacturer's recommendations. Inventory rotation and storage-life management are also important.
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8.4 Using Expired or Long-Stored Spare Gaskets
An unused gasket does not necessarily retain its original performance indefinitely. Excessive storage time or unsuitable storage conditions may cause reduced elasticity, surface cracking, or other signs of aging. Before installation, check the production batch, storage records, and physical condition of the gasket. Any gasket showing abnormal deterioration should be replaced rather than installed.
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Summary: How to Reduce Gasket Failure in Plate Heat Exchangers
Gasket failure in plate heat exchangers is rarely caused by a single factor. It usually results from a combination of temperature, pressure, chemical compatibility, material aging, installation quality, and maintenance practices. To reduce the risk of sealing failure, manufacturers and operators should establish appropriate procedures for equipment selection, installation, operating control, and routine maintenance.
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