Hello: even the plate heat exchanger will have problems in the course of one year's use. It needs maintenance, especially its seal, to see if it is loose. This paper will introduce the matters needing attention in the maintenance of plate heat exchanger. Plate heat exchanger is an important part of heat exchange technology for process industrial equipment. The elastic gasket (see table 1) for sealing between plate-type heat sinks is a kind of wearing parts, and it is also a part that is easy to age under natural conditions. Its service life has an important influence on the service life of plate heat exchanger. If these seals are hardened by heat and lose their original elasticity, the heat exchanger will not work normally. The following factors have an important influence on the service life of the elastic gasket: ■ The working mode of the heat exchanger (continuous or discontinuous) ■ The corrosiveness of the heat dissipation medium and cleaning agent used ■ The maximum working temperature ■ The maximum working pressure ■ The stress of the elastic gasket is large due to excessive pressure and uneven pressure ■ The softening of the natural aging elastic gasket is related to pressure and temperature. When the gasket loses its elasticity, the heat exchanger will leak. In order to solve the dripping phenomenon caused by gasket aging, some products are allowed to adjust the sealing performance of heat exchangers, that is, re-tighten the bolts of combined plate heat exchangers and adjust the pressing force of elastic gaskets between heat exchangers to solve the dripping problem. On the nameplate of the heat exchanger with this function, the allowable maximum and minimum stresses are usually given. For new heat exchanger plates, the minimum allowable stress should be used for connection and fixation. According to the number of heat exchanger fins in each group, the fastening force of the heat exchanger can be adjusted once or more. When tightening each time, the nut can be screwed in 3mm, and attention should always be paid to adjusting the stress of the fin during tightening. Moreover, only the heat exchanger without working pressure can be adjusted at room temperature to prevent dripping. For plate heat exchangers whose stress adjustment range is not given on the nameplate, the stress value is generally given in the part drawing. When tightening this plate heat exchanger, the tightening torque should not be lower than the value specified in the drawing, because it is related to the assembly quality and deformation of the plate heat exchanger. When the tightening torque reaches the specified value, the elastic gasket can be replaced in a planned way. For plate heat exchangers used in important production equipment and corrosive media, it is recommended to have a set of spare seals. When the warehouse temperature is 65438 08℃, the seal of plate heat exchanger can be kept in transparent plastic packaging for about 3 years. In principle, the fixing of seals can be divided into two categories: adhesive fixing and non-adhesive fixing. The shape of the gasket should be consistent with the shape of the seal of the plate heat exchanger. It must be pointed out that the adhesive fixing method has no influence on the sealing function. Non-adhesive sealing ■ Alignment: Put the sealing ring in place ■ Put it in: Make the sealing ring enter the sealing groove correctly ■ Press: In the sealing groove, there is a groove structure with gradually decreasing cross section, so that the sealing ring can be positioned correctly. Adhesive sealing can use harmonic sealant and non-harmonic sealant from different manufacturers according to the purpose of gasket use and sealing quality requirements. Before bonding, the residual adhesive and gasket on the bonding surface should be thoroughly removed by steam flow. For the bonding of mixed sealant, the residual adhesive and gasket on the joint surface of plate heat exchanger must be burned out with fire. During large-scale bonding, it is necessary to prepare a liquid nitrogen pool for freezing the seal and a heating furnace for drying the plate heat exchanger with gasket, and the heating temperature reaches 160℃. If possible, the plate heat exchanger should be chemically cleaned to ensure that the gasket of the bonded parts remaining on the bonding surface of the plate heat exchanger is completely removed. According to the observation hole of the plate heat exchanger honeycomb, we can know whether the gasket is installed correctly. Chemical cleaning agent (such as acetone) should be used to clean the joint surface of plate heat exchanger. Similarly, chemical cleaners must be used to remove the softener and anti-blocking coating attached to the gasket. Apply adhesive in the middle of each bonding surface. According to the width of the gasket, the width of the adhesive is about the width of a match, and then the adhesive is evenly coated on the whole bonding surface with a brush, so that the whole bonding surface can be fully utilized. According to the different types of adhesives, wait for a certain ventilation and drying time, then put in the gasket, stack the plate heat exchangers together, tighten them with fastening screws, or press them with heavy objects on the stacked heat exchanger groups. Depending on the type of adhesive, the curing time is about 8 ~ 20 hours. For mixed adhesives, screw stretching and furnace heating hardening must be carried out. Table 2 compares the advantages and disadvantages of adhesive seal and non-adhesive seal. Cleaning and Cleaning Usually, people find the seal failure of heat exchanger by dripping water when the process equipment is in cold motion or during the cooling process. Some plate heat exchangers have the function of secondary adjustment, which allows the heat exchanger group to be tightened again when a small amount of leakage occurs. Thereby increasing the stress between gaskets and solving the dripping phenomenon in a short time. In the newly assembled heat exchanger, a larger combined length dimension can be used. After leakage occurs, each group of plate heat exchangers can be tightened and a longer combined length dimension can be used. The maximum combined length dimension and the minimum combined length dimension can usually be seen on the nameplate of the heat exchanger. It should be noted that it cannot be smaller than the minimum combined length dimension. When the combined heat exchanger reaches the minimum combined length and still leaks, it means that the gasket must be replaced. AKK Industrial Service Co., Ltd. is a professional enterprise that provides debugging services for plate heat exchangers, providing maintenance services for plate heat exchangers in various process enterprises. In cooperation with industrial users in different processes, AKK Company has developed its own unique, effective and low-cost heat exchanger, heat exchanger, cleaning, inspection and rubber seal replacement technology. The main steps of rubber parts replacement technology are: 1, inspection and testing of recycling performance. Check the wall thickness of heat exchanger and pipeline to prevent suspected corrosion. 2. Remove the aging seal. According to different dirt, the acid-base cleaning pool jointly developed with Hogg Chemical Company is used for chemical cleaning, so that the surface of the cleaned parts will not be corroded by chemical media (such as gasoline). 3. After chemical cleaning, the chemical medium remaining on the surface of the plate heat exchanger is completely removed by a high-pressure blower. 4, each heat exchanger plate coated with fluorescent testing agent, under the ultraviolet irradiation to check whether there are tiny cracks and corrosion holes, and clean again. In addition, it is also important to check the sealing groove and repair it if necessary. 5. For the bonded gasket, thoroughly remove the residual substances, re-bond with the prepared glue, and clamp the reassembled heat exchanger group in a special fixture to cure the glue; Heat and keep warm in a holding furnace to achieve the best bonding effect. For non-stick gaskets, different devices are used to fix the gasket in the radiator. 6. Check the bonding position and bonding quality of each plate radiator, classify them according to the installation order, and then carefully assemble the plate radiator group. After replacement according to the above method, the performance of plate heat exchanger will be the same as new. Conclusion: Plate heat exchanger is a kind of equipment with high safety requirements in process industrial equipment. When the gasket is damaged, external leakage can be seen. Heat exchanger, heat exchanger, etc. There will be slight leakage at first, and in the process equipment with large pressure impact, there may be large leakage due to gasket damage. Under the strong pressure impact, sometimes the gasket will be separated from the correct installation position of the plate heat exchanger, or even from the heat exchanger in serious cases. In this case, the operation of the equipment must be stopped immediately so as to cool the heat exchanger to room temperature without pressure. If the gasket has been deformed under the action of pressure impact, it can no longer restore its original shape and position, and it must be replaced with a new gasket. If there is no spare gasket, the fins on both sides of the damaged gasket must be removed from the whole plate heat exchanger group, and then the gasket joint surfaces of the remaining fins must be checked. Considering the stress and size of the recombined heat exchanger group, the pressure fastening is carried out again. The remaining heat exchangers must be installed in strict accordance with the requirements in the instruction manual. In order to ensure that the remaining heat exchangers have enough stress to resist the load, it is necessary to multiply the original allowable stress of each heat exchanger by the original number of heat exchangers, and divide the product by the current number of remaining heat exchangers to obtain the assembly stress value that each heat exchanger must bear now.