In addition to the overhaul of the plate heat exchanger under special circumstances, regular maintenance should also be carried out.Because the plate heat exchanger seal is easy to assemble and disassemble, the maintenance is simple, and no special tools and equipment are needed.Keeping the plates clean is one of the important conditions for maintaining a high heat transfer coefficient.Between the plates, the medium moves along the narrow and tortuous flow channels. Even if the scale layer is not too thick, it will cause changes in the flow channels, significantly affect the movement of the fluid, increase the pressure drop, and reduce heat transfer. coefficient,For example, a sugar factory uses a plate heat exchanger in heating. Because the secondary water is not treated well, the flow channel is blocked in only two months during use and cannot continue to run. Precautions for cleaning plate gaskets of plate heat exchangers are as follows:
(1) During chemical cleaning of the plate heat exchanger, the solution should maintain a certain flow rate, which is generally 0.8 to 1.2 m / s. The aim is to increase the degree of turbulence of the solution.
(2) Carbon steel brushes are not allowed to scrub stainless steel sheets during mechanical (physical) cleaning, so as not to accelerate the corrosion of the sheet. At the same time, the surface of the plate cannot be scratched or deformed.
(3) Different chemical cleaning solutions should be used for different dirt. In addition to the commonly used dilute soda ash solution, a 5% nitric acid solution can be used for scale. The scale produced in the production of soda ash can be used as a 5% hydrochloric acid solution. However, do not use chemical detergents that cause corrosion to the plates.
(4) The cleaned heat exchanger plates should be washed with water and wiped dry, and the plates should be prevented from deforming when placed.