When purchasing plate-and-frame heat exchangers, the problems commonly encountered are concentrated in three areas: whether the plate material matches the medium, whether the gasket can simultaneously satisfy temperature and chemical compatibility requirements, and the vague operating condition ranges on quotations. Compared with shell-and-tube solutions, the plate-and-frame structure is compact and has higher heat transfer efficiency, but gaskets and plates are more sensitive to the medium. Before selection, the medium composition, maximum operating temperature, and start-stop frequency must be clearly listed as input conditions, and material certificates and applicable operating condition tables should be requested from suppliers, avoiding ordering based solely on flow rate and heat transfer duty.
Shell-and-tube units have wide pressure and temperature resistance ranges and are suitable for high-pressure and high-temperature conditions, but under the same heat transfer duty they require more floor space and higher initial investment; brazed units have no gaskets and good sealing performance, but are difficult to disassemble and clean, and maintenance costs rise after blockage on one side. The difference of plate-and-frame heat exchangers lies in their detachable structure: plates can be pulled out for cleaning or added/removed, making them suitable for systems requiring regular maintenance, such as HVAC, district heating, and process cooling. During procurement, maintenance methods, spare parts supply, and disassembly/assembly frequency should all be included in the comparison, rather than looking only at the equipment unit price.
Gasket materials need to balance temperature resistance and chemical resistance. The three common types are nitrile, EPDM, and fluororubber, which should be matched according to the medium type and operating temperature and confirmed together with the plate material. Plate thickness and corrugation pattern affect pressure resistance and heat transfer. During procurement, suppliers can be asked to provide applicable operating condition tables to verify design temperature, design pressure, and medium compatibility. For systems with frequent start-stop cycles, attention should also be paid to gasket resilience and plate fatigue. It is recommended to specify material certificates and acceptance criteria in the technical agreement.
