In liquid-liquid heat exchange duty on the secondary side of district heating or in chemical process applications, design and selection engineers often need to determine the material and gasket combination for a plate-and-frame heat exchanger within limited installation space. Both the plates and gaskets of the BR-160 plate-and-frame heat exchanger must be confirmed item by item according to the media conditions. The following provides technical interpretation of common on-site questions.
Q: If only flow rate and temperature are provided at the procurement stage, can the plate material be determined directly?
A: Not sufficiently. The medium name and concentration directly determine the direction of plate material selection. During procurement, the supplier should be required to record the medium name and concentration, and then technical personnel should verify and determine the material. If the material grade is too low, the plates may suffer early perforation in chloride-containing or acidic media, and the cost of subsequent replacement will be higher than a one-time verification at the selection stage. For operating conditions with large concentration fluctuations, verification should be based on the higher concentration that may occur during operation.
Q: How should gaskets and plates be matched simultaneously?
A: The gasket material must take into account both 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. If the plates are selected in a higher grade to meet corrosion resistance requirements, but the gaskets are configured for ambient-temperature conditions, the sealing area will still become a weak point. During selection, the medium, operating temperature, plate material, and gasket material should be listed in the same verification table to avoid mismatching caused by item-by-item confirmation.
Q: On what parameters should the number of plates and pass arrangement be calculated?
A: Before selection, the medium name, inlet and outlet temperatures, flow rate, and allowable pressure drop should be provided so that the number of plates and pass arrangement can be calculated. Allowable pressure drop is often overlooked, but it affects the number of passes and the inter-plate flow velocity, and thus affects heat transfer performance and pump power consumption. Design and selection engineers can submit the above parameters together with the material and gasket confirmation results for calculation, forming a complete basis for selection.
