Methods for removing scale from condensers

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After long-term use, condensers are prone to the formation of scale in their pipes. If this scale is not removed in a timely manner, it will affect the heat exchange efficiency, leading to an increase in the condensation temperature of the unit. This, in turn, results in a reduced cooling capacity and increased electrical consumption of the unit. Therefore, the condenser should have its scale removed regularly. There are roughly three methods for preventing and removing scale: 1. Mechanical descaling: This method involves using a flexible shaft pipe cleaner to remove scale from the steel cooling tubes in condensers, and it is particularly suitable for vertical shell-and-tube condensers. The procedure is as follows: 1. Extract the refrigerant from the condenser. 2. Close all valves connecting the condenser to the refrigeration system. 3. The cooling water for the condenser is supplied properly. 4. The umbrella-gear-shaped scraper connected via a flexible shaft pipe cleaner rotates from top to bottom inside the vertical tubes of the condenser to scrape off scale; circulating cooling water is used to cool the heat generated by friction between the scraper and the tube walls, while the removed scale, rust, and other contaminants are flushed into the water tank. During the descaling process, the appropriate diameter of the roller cutter is determined based on the thickness of the scale buildup in the condenser, the degree of rust on the tube walls, and the length of time the equipment has been in use. For the first round of descaling, the diameter of the roller cutter used should be slightly smaller than the inner diameter of the cooling tubes, in order to prevent damage to the tube walls; subsequently, a roller cutter with a diameter close to that of the cooling tubes is used for the second round of descaling. These two rounds of descaling are sufficient to remove over 95% of the scale and rust from the condenser. This mechanical descaling method utilizes the rotation and vibration of an umbrella-shaped gear cutter as it moves inside the cooling tubes, thereby removing scale and rust from those tubes. After descaling is complete, all the water in the condenser tank is pumped out; the scale, rust, and other contaminants removed are cleaned from the bottom of the tank, after which water is refilled. 2. Chemical acid cleaning method: The condenser is cleaned using a prepared weakly acidic descaling agent to remove scale and improve its heat transfer efficiency. The procedure is as follows: 1. Prepare the descaling solution in the pickling tank, start the pickling pump to circulate the descaling solution through the condenser tubes for 24 hours; under normal circumstances, the scale is almost completely removed after 24 hours. 2. After stopping the pickling pump, use a circular steel brush to scrub back and forth inside the walls of the condenser tubes, and rinse away the scale and rust with clean water. 3. Then, rinse the scale-removing solution remaining in the pipe repeatedly with clean water until it is completely cleaned. The chemical acid cleaning method is suitable for vertical and horizontal shell-and-tube condensers. 3. Electronic magnetic water descaling method: The working principle of an electronic magnetic water device is to dissolve calcium, magnesium, and other salts present in the cooling water flowing through the condenser into the water in the form of positive and negative ions at room temperature. When cooling water flows at a certain speed through the transverse magnetic field of the magnetized water device, dissolved ions such as calcium and magnesium acquire induced electrical energy, causing a change in their charge state. The electrostatic attraction between these ions is disrupted, which alters their crystallization conditions; as a result, the crystal structure becomes looser, its tensile and compressive strength decreases, and it is no longer possible to form hard scale with strong adhesion. Instead, this material turns into loose sediment that is carried away by the flow of cooling water. This descaling method not only effectively prevents the formation of new scale but also removes existing scale, as the use of an electronic magnetic water treatment device eliminates the ability of ions to cause scaling, thereby removing the protective effect that such ions once provided against existing scale. Furthermore, the magnetized cooling water possesses a certain amount of induced electrical energy. Meanwhile, due to the different expansion coefficients of the steel pipes in the condenser and the scale, the existing scale gradually cracks, and the magnetized water continuously penetrates into these cracks, breaking down the adhesion of the scale so that it becomes loose and falls off on its own, being carried away by the circulating cooling water. The descaling method for electronic magnetic water heaters is simple and easy to implement, requires little labor, and enables descaling and scale prevention without affecting the normal operation of the cooling system. The importance of descaling and energy savings: Once scale forms on the condenser, the thermal conductivity resistance increases. As a result, the heat transfer coefficient decreases. Since the condensation temperature is inversely proportional to the heat transfer coefficient, this leads to an increase in the condenser temperature. The condensation pressure also rises accordingly, and the more severe the scaling on the condenser, the more significant the increase in condensation pressure. This results in higher power consumption by the refrigeration unit, as well as increased power usage by all the components in the refrigeration system, leading to waste of electrical energy.