1. Backwash method: The heat transfer capacity of the plate heat exchanger suddenly drops. When the pressure drop increases, we will judge that the plate heat exchanger may be blocked.In some working conditions containing solid impurities, when the exclusion of external factors and the cleaning of imported hot and cold filters cannot be solved, the plate heat exchanger can be backwashed.The heat exchanger under this condition must be equipped with a backwash line before being put into use.From the opposite direction of the plate, backwash with refrigerant or heat medium 2-5 times higher than the operating pressure. At the same time, we recommend that the equipment with backwash pipelines should be equipped with special sewage outlets to discharge backwash obstructions to the system.Because backwashing requires early investment and its effects cannot be eradicated, it is less used for inspection and maintenance.
2. Disassembly cleaning method: Disassembly cleaning method is a more common cleaning method for plate heat exchangers. Generally, it is divided into two methods: (1) After removing the plate heat exchanger, it is not suitable to remove the plate, first hang it on the upper beam of the heat exchanger, and clean it piece by piece with water pressure. This is suitable for working conditions where plate fouling is not serious.(2) After opening the plate heat exchanger, remove the plate heat exchanger plate and gasket, and then beat the plate with a mallet to knock down the fouling of the sheet.If in winter, you can move the plate outdoors for a period of time. After the dirt on the plate freezes, it will be better to remove the dirt by tapping.Do not use a rigid brush or a wire brush to clean the surface of the steel plate, which will cause residue and corrosion to easily scale.Plates are usually cleaned with thick brushes and chemical methods. It cannot be removed with a sharp knife to avoid scratching the plate.When the debris or dirt on the plate is very thin and soluble in water, the plate can be placed in a special water tank and washed with a certain pressure of water or low pressure steam.Stainless steel plates are not allowed to use steel wire brushes. The cleaning water must be free of salt and sulfur, and the chloride ion content in the water should be less than 20ppm.