Cleaning of plate heat exchangers and methods for installing plates

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Common materials for the plates of plate heat exchangers include 304, 316L, titanium, and SMO254; the thickness of these plates is generally 0.5–0.8 mm, resulting in excellent heat transfer performance. However, the channels between the plates of plate heat exchangers can also become blocked by scale or foreign substances formed due to excessive impurities in the fluid, which affects the proper operation of the heat exchange equipment. At this point, the heat exchanger plates need to be removed one by one for cleaning. 1. Disassembly, cleaning methods, and precautions: (1) Before disassembly, measure the dimensions inside the two clamping plates of the heat exchanger unit and record them for use during reassembly. (2) Disassemble the flanges of the plate heat exchanger and move it to an open area; open the drain port to release the remaining water inside the heat exchanger. (3) After the water has been drained, place the plate heat exchanger in a horizontal position (with the flanged side facing down), then evenly loosen the bolts on the clamping plates of the exchanger. Be sure to loosen them symmetrically and with even force, to prevent the plates from shifting or deforming due to uneven pressure on either side. (4) After all the bolts are loosened, remove the clamping plate on top first, then take out the plates one by one for cleaning. Be sure to pay attention to the position of the plates and gaskets. (5) Cleaning method: It can be cleaned manually or mechanically; it is recommended to choose an appropriate cleaning agent based on the degree of dirt present in order to remove the contaminants from the plates and gaskets, thereby preventing slippage or misalignment during assembly and ensuring good sealing performance. When cleaning by hand, be sure to use a soft brush dipped in cleaning solution. Be careful not to damage the plates and gaskets. 2. Sequence of plate installation and precautions: (1) When installing the plates, be careful not to place them randomly or step on them, as the thickness of these plates is generally no more than 1 mm – they are quite thin. If they become deformed, it will affect their sealing performance and lead to leaks in the heat exchanger. (2) Clean the gasket groove. The plates all have gasket grooves; if the particles or impurities in these grooves are not cleaned properly, the gaskets will not be able to fit fully into the sealing grooves, resulting in leaks. (3) Installation sequence of the plates. Taking a one-way flow as an example, the plates themselves are identical; only by making proper distinctions can the cold and hot media be separated. They are generally divided into A/B plates, with each plate being installed by rotating it 180°. (4) Assemble the cleaned plates and gaskets in the order they were removed, and clamp the clamping plate to the dimensions previously recorded. After tightening, conduct a test at 1.25 to 1.3 times the operating pressure to ensure that there are no leaks in the heat exchange equipment.