Maintenance Tips for Plate Heat Exchangers
Maintaining plate heat exchangers (PHEs) is crucial for ensuring their efficiency, longevity, and reliability. Here are some detailed maintenance tips based on the provided search results:
1. Regular Cleaning
- Clean-In-Place (CIP): Most PHEs can be cleaned without disassembly using a CIP system. This involves circulating cleaning solutions through the heat exchanger to remove fouling and scaling.
- Manual Cleaning: If CIP is not possible, manually clean the plates by opening the plate pack. Use appropriate cleaning agents and a soft brush to avoid damaging the plates and gaskets. Avoid using wire brushes or metal pads.
2. Inspection and Replacement
- Visual Inspection: Regularly inspect the plates and gaskets for signs of wear, corrosion, or damage. Look for any signs of leakage or contamination.
- Gasket Replacement: Check the gaskets for wear and tear. Replace them as needed to maintain a proper seal and prevent fluid mixing. For clip-on gaskets, simply remove and replace. For glued gaskets, clean the sealing surface thoroughly before applying the new gasket.
3. Pre-Teardown Procedures
- Valving Off: Isolate the heat exchanger from the system by closing the valves and draining the fluids.
- Disconnection: Disconnect the pipes and verify the plate pack arrangement.
- Leak/Contamination Tests: Perform primary leak and contamination tests to identify any issues before disassembly.
4. Teardown and Reassembly
- Disassembly: Loosen the tie-bolts and carefully disassemble the unit. Remove the gaskets if possible and clean the plates.
- Reassembly: Reassemble the unit to the previous, exact configuration. Ensure optimal tightening of the plate pack for maximum reliability and performance.
5. Pressure Testing
- Hydrostatic Testing: Conduct hydrostatic leakage tests to confirm the internal and external sealing function of the heat exchanger. Test one media side at a time with the other side open to ambient pressure.
6. Lubrication and Tightening
- Lubrication: Keep the tightening bolts clean and well-lubricated. Use EP (extreme pressure) grease for the threads and suspension wheels.
- Tightening: Ensure the plate pack dimension is within the manufacturer’s specified tolerance. Overtightening can damage the plates, while under-tightening can cause leaks.
7. Monitoring and Record Keeping
- Condition Monitoring: Regularly monitor the inlet and outlet temperatures, mass flow rates, and pressure changes across the heat exchanger.
- Record Keeping: Maintain records of maintenance activities, including the make and model number, maintenance performed, spare parts inventory, and plate pack dimensions.
8. Preventive Measures
- Upstream Filters: Use filters and strainers to remove particulate fouling and protect the heat exchanger.
- Standby Units: Keep standby units clean and dry. Flush with fresh water and drain completely if taken out of service.
- Environmental Protection: Protect heat exchangers from water splash, UV rays, and ozone generated from electrical sources.