Maintenance And Servicing Methods For Closed Cooling Towers​

 I. Maintenance of Closed Cooling Tower Spraying System: Solidifying the Foundation for Clean and Smooth Water Circulation​

As the "water circulation core" of a closed cooling tower, the spraying system's cleanliness and smoothness directly determine cooling efficiency. Maintenance shall focus on "water quality control + component inspection".​

Water Quality Precision Control​

Water Replenishment Standard: The water tank at the bottom of the cooling tower shall be filled with clean water, and softened water is preferred (to reduce scaling risks from calcium and magnesium ions at the source). The water pH value must be stably maintained within the range of 6-8 (to prevent corrosion of the water tank, pipelines, and nozzles by acidic or alkaline water).​

Regular Cleaning and Water Replacement: Conduct in-depth cleaning of the water tank at least once a week to completely remove sludge, impurities, and microbial plaques deposited at the tank bottom. After cleaning, fully replace the stagnant water in the tank to prevent accumulation of residual pollutants, which may cause pipeline blockage or water quality deterioration.​

Spraying Status Monitoring and Fault Handling​

During daily operation, continuously observe the spraying water distribution (which shall meet the requirements of "uniform coverage, no flow interruption, and no local excessive/insufficient water volume"). If spraying abnormalities occur, conduct troubleshooting in the following steps:​

Check whether the spraying pipelines are blocked, have loose or leaking joints, or are cracked;​

Disassemble and inspect the nozzles, remove scale, sediment, and other impurities inside to ensure unobstructed water flow channels of the nozzles;​

Timely replace damaged components identified (such as cracked pipelines and worn nozzles) to restore the normal operation of the spraying system.​

II. Anti-Freezing for Closed Cooling Tower Heat Exchanger: Core Protection Measures in Low-Temperature Environments​

When the ambient temperature is below 0°C, residual water in the heat exchanger coils is prone to freezing and expanding, which may cause coil cracking. Therefore, targeted anti-freezing measures shall be adopted based on the tower's operating conditions (long-term shutdown or normal operation) in low-temperature environments.​

Anti-Freezing Measures for Long-Term Shutdown in Winter​

If the cooling tower is not to be used for a long time after shutdown, use compressed air to completely blow dry the residual water in the coils, eliminating the risk of freezing and cracking.​

For the water tank in the circulation system, it is recommended to ensure during the installation phase that: when the system is shut down, the liquid level of the liquid medium in the tank is lower than the height of the heat exchanger, to prevent the medium from flowing back into the coils and causing freezing damage.​

Anti-Freezing Settings for Short-Term Shutdown or Low-Temperature Operation in Winter​

Switch the [Anti-Freezing/Normal] switch of the equipment to the [Anti-Freezing] position. By setting the parameters of the timer controller, enable the circulating water in the system to flow at regular intervals, preventing stagnant water in the coils from freezing.​

Multi-Dimensional Anti-Freezing Guarantee Scheme​

Protection Measures During Production​

The inner sides of the joints of the outer shell panels shall be tightly sealed with special rubber strips for cooling towers, to prevent water vapor penetration and subsequent freezing-induced water leakage;​

Adopt water collectors with excellent water-retaining performance, which can prevent even tiny water droplets from drifting out of the tower and freezing;​

When selecting fans, prioritize models that can reverse for a short period, as a backup plan for emergency de-icing;​

The nozzle layout has been optimized during the design phase: the distance between peripheral nozzles and the tower wall is appropriately increased, and the diameter of peripheral nozzles is 2 sizes smaller than that of internal nozzles, to reduce water flow along the wall (avoiding wall freezing).​

Anti-Freezing via Hot Water Spraying​

When the temperature of the medium in the internal circulation liquid pipe is lower than 8°C, the hot water spraying system will start automatically, spraying hot water evenly on the entire heat exchanger coils to increase the temperature of the medium in the pipes and the pipe material, ensuring the coils are not cracked by freezing.​

Hot Water Generation Control​

An electric heater is installed in the spraying water tank. When switched to the automatic gear: the electric heater starts automatically when the water temperature in the tank is ≤5°C, and stops automatically when the water temperature rises to 10°C. A liquid level switch is also equipped; if the liquid level is lower than the set value, the electric heating system will be automatically locked (to prevent damage caused by dry burning).​

Operator Operation Specifications (Organizational Measures)​

Provide special training for operators: when the minimum temperature is lower than 5°C, completely drain the stagnant water in the system in a timely manner after equipment shutdown to avoid the risk of freezing and cracking.​

Medium Optimization (Technical Measures)​

Replace all original liquids in the system with antifreeze suitable for the local minimum temperature. A single modification can achieve permanent anti-freezing, eliminating concerns about freezing during production operation, shutdown, or equipment maintenance.​

III. Prevention and Control of Long-Term Performance Attenuation of Closed Cooling Towers: Focusing on Scaling Treatment and Efficiency Maintenance​

The cooling capacity of a closed cooling tower is ultimately determined by core parameters such as heat exchange area, ventilation speed, and heat transfer coefficient. During equipment operation, no scaling will form on the inner wall of the stainless steel pipes. However, ordinary tap water is used for spraying and cooling on the outer wall; as the spraying water continuously evaporates, the concentration of scaling ions (such as Ca²⁺ and Mg²⁺) in the water increases, which easily forms scale on the outer wall of the stainless steel pipes. This scale reduces the heat transfer coefficient and causes attenuation of cooling capacity.​

Therefore, the equipment instruction manual of our company emphasizes management requirements: on-site operators shall completely drain the spraying water and replace it with new water every week to reduce the concentration of scaling ions. Meanwhile, prominent reminders (spray-painted) are placed in the spraying water tank of the closed cooling tower, emphasizing "weekly replacement or cleaning" to minimize scaling.​

IV. Maintenance of Key Equipment of Closed Cooling Towers: Ensuring Stable Operation of Core Components​

During equipment operation, static equipment requires regular inspection and maintenance, while dynamic operating equipment requires focused maintenance and timely replacement. The core operating equipment of a closed cooling tower includes fans, water pumps, and electrical components, with specific maintenance requirements as follows:​

Fan Maintenance: Special fans for cooling towers are adopted, featuring high efficiency, low energy consumption, low noise, and large air volume. Conduct regular daily inspections: check whether the fan blades are worn, loose, or deformed, and whether the bearing lubrication status is good (add lubricating oil or grease as needed) to ensure smooth fan operation.​

Spraying Water Pump Maintenance: Special water pumps with low lift and large flow are equipped, which can increase the spraying flow, reduce power consumption, and extend the equipment service life. Conduct regular inspections: check whether the pump impeller is blocked or worn, and whether the pump shaft seal is leaking (to prevent water loss and efficiency reduction). If problems are found, conduct maintenance or replace components in a timely manner.​

Electrical Component Maintenance: Regularly inspect electrical components such as contactors, relays, and controllers: check whether the terminal blocks are loose, whether the wires are aging, and whether there is abnormal heating. At the same time, regularly clean the electrical control cabinet to prevent dust accumulation from causing short circuits or component failures.​

Spare Part Management Optimization: To facilitate user maintenance, our company adopts unified models for core components (such as fans and water pumps). This helps users reduce the backlog of spare parts inventory, simplify the maintenance process, and make equipment inspection and repair more standardized and efficient.​

V. Full-Process Maintenance Precautions for Closed Cooling Towers​

(I) General Safety Precautions for Closed Cooling Towers​

Power-Off Operation Principle: When maintaining live components such as fans, water pumps, and electrical components, the main power supply of the equipment must be cut off first, and a warning sign "Under Maintenance, No Switching On" shall be hung at the power switch to prevent personal injury or component damage caused by accidental startup.​

High-Altitude Operation Protection: If it is necessary to climb to the top of the cooling tower (e.g., to inspect fans or water collectors), wear anti-slip safety helmets and safety belts, and ensure the stability of climbing ladders. High-altitude operations are strictly prohibited in rainy, snowy, or slippery tower conditions.​

Chemical Use Specifications: If chemicals such as descaling agents or disinfectants are used during maintenance, wear acid- and alkali-resistant gloves and goggles to prevent chemicals from contacting the skin or splashing into the eyes. At the same time, ensure good ventilation in the operation area to prevent the accumulation of harmful gases.​

Tool and Spare Part Management: Tools used for maintenance shall be placed neatly to avoid falling and damaging the equipment. Replaced waste components (such as aging wires and worn nozzles) shall be collected and disposed of centrally, and shall not be randomly discarded in the cooling tower water tank or the surrounding environment.​

(II) Special Precautions for Closed Cooling Tower Spraying System Maintenance​

Water Tank Cleaning Safety: When cleaning sludge in the water tank, drain the accumulated water first. If there is an odor or potential harmful gas (e.g., from microbial fermentation) in the water tank, ventilate the tank first before entering for operation. When entering the water tank for cleaning, a dedicated person shall be assigned to supervise outside to prevent personnel oxygen deficiency or trapping.​

Nozzle Replacement Details: Disassemble and install nozzles gently to avoid damaging the nozzle interfaces due to violent operations. After replacement, conduct a spraying test to ensure uniform water flow from the nozzles without dripping, leaking, or blockage, preventing local uneven heat exchange caused by improper nozzle installation.​

(III) Special Precautions for Closed Cooling Tower Heat Exchanger Anti-Freezing​

Water Drainage Requirements for Winter Shutdown: When draining water during shutdown in low-temperature environments, ensure that all pipelines in the system (including coils, connecting pipelines, and valves) are completely drained of accumulated water. The sewage valve at the lowest point of the pipeline can be opened to assist in water drainage, avoiding pipeline cracking caused by freezing and expansion of residual water.​

Antifreeze Replacement Specifications: Before replacing antifreeze, thoroughly clean the system pipelines to remove residual water and impurities, preventing precipitation or reduced anti-freezing effect caused by mixing different types of antifreeze. When adding antifreeze, follow the concentration ratio required in the equipment instruction manual to ensure the freezing point meets the local minimum temperature requirements (it is recommended to be 5-8°C lower than the local minimum temperature).​

Electric Heater Inspection: Regularly inspect whether the terminal blocks of the electric heater are loose and whether the insulation layer is damaged to prevent short circuits and electric leakage. Before starting in winter, test the linkage function of the liquid level switch to ensure that the electric heating system can be normally locked when the liquid level is too low, avoiding fire or equipment burnout caused by dry burning.​

(IV) Special Precautions for Closed Cooling Tower Key Equipment Maintenance​

Fan Bearing Lubrication: When adding lubricating oil, strictly follow the oil type specified in the equipment instruction manual (e.g., Grade 3 Lithium-Based Grease), and do not mix different types of lubricating oil. The lubrication amount shall be appropriate: excessive lubrication may cause bearing overheating, while insufficient lubrication may aggravate wear.​

Water Pump Seal Maintenance: If leakage is found at the water pump seal, replace the sealing components (such as mechanical seals and O-rings) in a timely manner to avoid pump shaft corrosion caused by long-term leakage. After replacing the sealing components, check the coaxiality of the pump body to prevent re-damage to the seal due to installation deviation.​

Moisture Prevention for Electrical Components: During the rainy season or in humid environments, strengthen moisture prevention measures for the electrical control cabinet (e.g., install dehumidifiers and place desiccants), and regularly check for condensation inside the cabinet to prevent short circuits of electrical components due to moisture. When cleaning the control cabinet, wipe it with a dry cloth; flushing with water is strictly prohibited.​

(V) Maintenance Record and Traceability Requirements for Closed Cooling Towers​

Maintenance Record Specifications: After each maintenance, record the maintenance date, maintenance items, identified problems, handling measures, and the model and quantity of replaced components (e.g., the specification of replaced nozzles and the type of added antifreeze) in detail to form a complete maintenance file, facilitating subsequent traceability and equipment status analysis.​

Abnormal Situation Reporting: If major hidden dangers are found during maintenance (such as coil cracking, severe deformation of fan blades, or burnout of electrical components), stop the equipment operation immediately and report to the equipment management department. Operation with faults is strictly prohibited. The equipment can only be restarted after the hidden dangers are completely eliminated and passed the inspection.