During the maintenance of the heat exchanger, the flushing water is discharged from the heat exchanger and connected to the local cleaning pump. The flushing water is discharged from the heat exchanger and connected to the local cleaning pump. Refer to the above "precautions for plate cleaning" for the selection of cleaning agent. In order to clean thoroughly, the on-site cleaning solution must flow from the bottom to the top of the plate to ensure that all the plate surfaces are wet with the cleaning solution. When cleaning the multi process heat exchanger, the cleaning solution must flow backward for at least 1 2 cleaning time to ensure that all plate surfaces of the multi process are wet. 5  the best cleaning scheme is to use the in-situ cleaning solution to wash at the maximum flow rate or to wash at the maximum flow rate allowed by the in-situ cleaning nozzle diameter  the maximum flow rate allowed by the nozzle diameter of 2 inches is 260 GPM, and the maximum flow rate allowed by the nozzle diameter of 1 inch is 67 GPM . If in-situ cleaning can be carried out according to the established regular cleaning plan before thorough pollution, the cleaning effect will be better. 6. After cleaning with local cleaning solution, rinse thoroughly with clean water. If the heat exchanger uses brine as the cooling medium, the brine shall be drained as clean as possible before the cleaning operation, and then the heat exchanger shall be rinsed with cold water. If all the salt water side bottoms are cleaned before cleaning both sides of the heat exchanger with hot in place cleaning solution, the corrosion to the equipment will be minimized. 4. Backwashing and mesh filter usually have obvious backwashing effect when there are fibrous and large particles in the heat exchanger. The purpose of backwashing can be achieved by one of the following two ways. 1. Flush the device with clean water in the opposite direction of normal operation.  2  arrange the pipeline and set valves on the pipeline  so as to operate in reverse mode at the product side within a fixed time. This special mode is especially suitable for the heat exchanger whose product is steam.  3  when the water flow contains a considerable amount of solid or fibrous substances, it is recommended to install a mesh filter on the water supply pipeline in front of the heat exchanger. This reduces the number of backwash. 5. Principle of on-site cleaning 1. Never open the heat exchanger when it is still hot, under pressure, carrying liquid or in operation.