Most of the domestic shell and tube graphite heat exchangers use phenolic graphite profiled tubes, which are made of artificial graphite powder and phenolic resin in a certain proportion, mixed and extruded. They are dense and hollow, and do not require resin impregnation or surface machining, but the tank itself must be completely cured, smooth and clean, free of cracks, sand holes, etc.
When installing the heat exchanger, if the pressure test and surface inspection of the single tube are not strict, the heat exchange tubes of the graphite heat exchanger that do not meet the above requirements may be misused. The heat exchange tubes are fixed on the tubesheet in the form of bonding, forming the constraint of the tube bundle on the tubesheet.
During production and use, the tubesheet will inevitably deform under the pressure of the medium. The reasons are as follows:
One is longitudinal stretching or compression in different directions between connecting equipment;
Second, the uneven deformation of various parts of the heat exchanger leads to the bending of the tube sheet, which causes the bending of the heat exchanger tube. At this time, the tube closer to the edge bends more.
However, if the defective graphite profiled tube is arranged in the area with large stress deformation, the graphite heat exchanger is easy to break and cause leakage.
