Common faults of plate heat exchanger and treatment methods

I. Sealing Leakage

Fault Phenomenon

Fault Causes

• Gasket - related Issues: The gasket ages, deforms, or gets damaged, losing its elasticity and sealing performance. Improper selection of the gasket material makes it unable to adapt to the temperature, pressure, and chemical properties of the working medium. Incorrect installation of the gasket, such as misaligned installation position, incomplete embedding in the sealing groove, or uneven tightening force of the fastening bolts, etc.
• Plate Sheet - related Issues: The sealing groove of the plate sheet is worn or deformed, causing poor adhesion with the gasket. Cracks or holes in the plate sheet lead to medium leakage.
• Abnormal Operating Parameters: During operation, the temperature and pressure fluctuate suddenly and excessively, exceeding the bearing capacity of the gasket and plate sheet, resulting in seal failure.

Treatment Methods

• Inspect and Replace the Gasket: Regularly check the condition of the gasket, and replace the aged or damaged gasket in a timely manner. Select the appropriate gasket material according to the characteristics of the working medium. Install the gasket strictly in accordance with the installation specifications to ensure its correct position, and evenly tighten the fastening bolts to the specified torque.
• Repair or Replace the Plate Sheets: For plate sheets with slightly worn sealing grooves, methods such as grinding and patch welding can be used for repair. If the plate sheets are severely worn, cracked, or have holes, new plate sheets need to be replaced.
• Stabilize Operating Parameters: Optimize the process flow, set a reasonable temperature and pressure control range, install monitoring equipment to continuously monitor the operating parameters, and adjust them in a timely manner once abnormalities occur to avoid drastic parameter fluctuations.

II. Decrease in Heat Transfer Efficiency

Fault Phenomenon

Fault Causes

• Scaling on Plate Sheets: The working medium contains impurities, suspended solids, calcium and magnesium ions, etc., which deposit on the surface of the plate sheets to form dirt, such as scale, rust scale, oil scale, etc. Dirt has poor thermal conductivity, which hinders heat transfer and leads to a decrease in heat transfer efficiency.
• Insufficient Medium Flow: Reasons such as pipeline blockage, incomplete opening of valves, and pump failures cause the flow of hot and cold media to be lower than the designed value, reducing the contact area and time between the medium and the plate sheets, and affecting heat exchange.
• Deformation of Plate Sheets: Long - term exposure to uneven pressure, temperature changes, or a decline in the performance of the plate sheet material leads to the deformation of the plate sheets, damaging the flow channel structure between the plate sheets, making the medium flow uneven and reducing the heat transfer efficiency.

Treatment Methods

• Clean the Plate Sheets: Select an appropriate cleaning method according to the type of dirt, such as chemical cleaning (using acid, alkali, and other cleaning agents to dissolve the dirt) and mechanical cleaning (using high - pressure water jets, brushes, etc. to remove the dirt). Regularly clean and maintain the plate heat exchanger, and formulate a reasonable cleaning cycle to prevent excessive accumulation of dirt.
• Inspect and Unclog the Pipelines: Check whether the pipelines are blocked and clean the impurities inside the pipelines. Ensure that the valves are in the correct open - close state, repair or replace the faulty pump to ensure that the medium flow meets the design requirements.
• Repair or Replace the Deformed Plate Sheets: For slightly deformed plate sheets, they can be repaired using correction tools. If the plate sheets are severely deformed, new plate sheets need to be replaced, and pay attention to the arrangement sequence and direction of the plate sheets during installation to ensure the smooth flow of the channels.

III. Excessive Pressure Drop

Fault Phenomenon

Fault Causes

• Excessive Medium Flow Velocity: During actual operation, the medium flow is too large, resulting in an excessive flow velocity, increasing the resistance of the medium flowing between the plate sheets and causing the pressure drop to increase.
• Flow Channel Blockage: The flow channels between the plate sheets are blocked by impurities and dirt, hindering the flow of the medium, causing a local increase in flow velocity and an increase in pressure loss. Fragments of aged and damaged gaskets entering the flow channels can also cause blockages.
• Incorrect Arrangement of Plate Sheets: During the installation process, the arrangement sequence of the plate sheets is wrong, changing the original flow channel structure, making the flow path of the medium unsmooth and increasing the flow resistance.

Treatment Methods

• Adjust the Medium Flow: According to the design parameters of the equipment and the actual working conditions, reasonably adjust the medium flow, reduce the flow velocity, and restore the pressure drop to the normal range. Flow adjustment can be achieved by adjusting the valve opening, replacing a suitable pump, etc.
• Clean the Flow Channels: Disassemble the plate heat exchanger, check the blockage of the flow channels, and remove impurities, dirt, and gasket fragments. Strengthen the filtration of the medium and install a filter at the pipeline inlet to prevent impurities from entering the equipment.
• Re - arrange the Plate Sheets: Re - check and adjust the arrangement sequence of the plate sheets according to the equipment installation instructions to ensure the correct flow channel structure. Carefully check the plate sheet markings during installation to avoid errors.

IV. Abnormal Vibration and Noise

Fault Phenomenon

Fault Causes

• Unstable Foundation: The installation foundation of the equipment is uneven, or the anchor bolts are loose, causing the equipment to vibrate during operation. Insufficient stiffness of the foundation makes it unable to effectively absorb the vibration energy generated during the operation of the equipment.
• Uneven Medium Flow: Large fluctuations in medium flow, gas - liquid two - phase flow in the pipeline, and other situations make the medium flow unevenly between the plate sheets, generating impact forces and causing equipment vibration and noise. Rough surfaces or defects of the plate sheets also affect the stability of medium flow.
• Loose Components: Components such as the clamping bolts of the heat exchanger and the flange bolts of the connecting pipelines are loose, generating vibrations and noises during the operation of the equipment. Aging of the gaskets and loss of elasticity, which cannot effectively buffer the forces between the plate sheets, may also lead to increased vibration.

Treatment Methods

• Reinforce the Foundation: Re - check the installation foundation of the equipment, repair the uneven foundation, and tighten the anchor bolts. If necessary, increase the stiffness of the foundation, such as pouring concrete to reinforce the foundation.
• Optimize Medium Flow: Stabilize the medium flow and avoid large fluctuations. Install an exhaust device in the pipeline system to remove the gas in the pipeline and prevent the generation of gas - liquid two - phase flow. Polish and grind the surface of the plate sheets to repair surface defects and ensure smooth medium flow.
• Tighten Components: Regularly check the connecting bolts of each component of the equipment, and tighten them in a timely manner if looseness is found. Replace aged gaskets that have lost their elasticity to ensure the sealing and buffering effect between the plate sheets.