Video: Cooling Towers: Operation Methods, Maintenance ＆ Usage Precautions
Figure 1: Large size cooling towers.
Cooling towers are critical equipment used in industrial and commercial areas to cool fluids. In order to ensure its effective operation, increase its lifespan and maintain safety, correct operation methods, maintenance and upkeep knowledge, and usage precautions are crucial. In this article, we will delve into these aspects.
1. Correct Operation Method of Cooling Tower
Although the cooling tower is an accessory equipment in the air conditioning and cooling system, it is responsible
for the important task of dissipating the total heat absorbed by the entire system. Therefore, the correct operation
of the cooling tower is directly related to the cooling effect and energy saving of the entire air conditioning
system.
Since misoperation of cooling towers is common and occurs throughout the entire process from startup to shutdown, it
is extremely harmful and relevant operators and managers should pay attention to it.
The correct operation methods and requirements for cooling towers are:
(1) The number of cooling towers used matches the number of machine units turned on.
(2) Close the inlet and outlet valves of the cooling tower that does not have the fan turned on to prevent cooling water from flowing through the
tower that is not in use.
(3) After turning off the cooling tower fan that is temporarily used, do not forget to close the inlet and outlet
valves of the tower.
(4) Check the operation of the cooling tower after turning it on each shift. If it is found that cooling water is
passing through the cooling tower without the fan running, the inlet and outlet valves of the tower should be closed
promptly and the water level in the water tray should be adjusted.
Figure 2: Working principle diagram of central air conditioning.
2. Cooling Tower Maintenance Knowledge
The cooling tower maintenance process is divided into three stages, namely cleaning and maintenance after shutdown, inspection and debugging before startup, and inspection during operation.
2.1 Cleaning and Maintenance of Cooling Tower after Shutdown
1. Water Distribution System
① Check whether the main water pipe, water distribution pipe, and sprinkler head of the cooling tower are damaged or
loose, and repair and fix them in time. Thoroughly remove the dirt inside the water distribution pipes and sprinkler
heads to ensure that the water pipes are smooth and the sprinkler heads distribute water evenly.
② Thoroughly rinse the cooling tower cold water basin and water outlet filter cover to prevent accumulation of scale
and dirt from clogging the pipes. After cleaning, the drain valve should be opened and the accumulated water in the
water pan should be drained to avoid freezing.
③ Check whether the cold water basin and other parts are leaking. If there are any leaks, recoat the glue in time.
Figure 3: Schematic diagram of cooling tower circulating water system.
2. Cooling System
① Clean all heat exchange materials (fill materials) in the cooling tower, thoroughly remove scale and dirt on the
surface and among the holes of the heat exchange materials, to ensure the cleanliness of the heat exchange
materials. Repair and replace heat exchange materials when disassembling and assembling them. When filling, pay
attention to placing it closely without leaving any gaps.
② Clean the water curtain and soundproof blanket to remove dirt. Repair damaged areas or replace. The water curtains
must be stacked closely to prevent water from drifting. Fill the cooling tower with water and check for water
leakage (especially at the tower connection). If leakage occurs, replace the seal.
3. Transmission System
① Motor: Check whether the wiring terminals of the
motor are intact, whether the motor rotates
normally, whether the motor junction box is sealed, lubricate the motor bearings, and repaint the motor casing.
② Reducer: Check whether the reducer rotates normally.
If there is any abnormal sound, replace the
reducer bearing immediately.
③ Belt and pulley: Adjust the screw, loosen the belt and extend
the service life of the belt.
Check whether the belt is damaged or cracked. If necessary, it is recommended to replace the belt with a new one.
Check the levelness of the pulley and motor frame, tighten loose bolts, and replace any corroded bolts.
④ Fan: Clean the dirt on the surface of the fan blades, check the angle of the fan blades, the gap between the fan
blades and the fan cylinder, and make adjustments.
4. Tower Appearance
① Thoroughly clean the fan cylinder, tower, and air inlet guide plate to ensure a clean appearance.
② Re-tighten the bolts in all parts and replace the rusty bolts.
③ Check the appearance of the tower body for damage and cracks, and repair them in time.
④ Check whether the seams of the tower wall panels are tight and re-glue them if necessary.
5. Cooling Tower Parts
① Check whether the automatic water replenishing device -- the float ball is damaged and whether it works normally.
Repair and replace in time if abnormalities are found.
② Re-tighten the bolts of the cooling tower iron parts, replace the rusty bolts, and paint the rusted iron parts.
③ Check whether the tower flanges of the inlet and outlet pipes and water supply pipe are damaged or leaking.
After the cooling tower has been cleaned and maintained, it is recommended to wrap and seal the cooling tower fan
cylinder with a cloth to prevent debris from entering the interior of the cooling tower.
Figure 4: Cooling tower cutaway view.
2.2 Inspection and Debugging before Starting the Cooling Tower
① Remove the fan cover (such as a cloth), adjust the top screw, and adjust the belt tightness.
② Carefully check whether the motor and reducer of the cooling tower transmission system are operating normally.
③ Check and clean the dirt on the cooling tower cold water basin and filter screen. Drain the water to check the
cold water basin, and adjust the position of the float so that the water level in the cold water basin meets the
usage requirements.
④ Adjust the fan blade angle and measure the motor current to make them reach the optimal working condition
standard.
⑤ Adjust the cooling tower water inlet and outlet valves to ensure the cooling tower water flow meets the
requirements. Once requirements are met, start the machine.
2.3 Inspection of Cooling Tower during Operation
① Regularly inspect the cooling tower in operation to understand the usage of the cooling tower.
② Carefully test the cooling tower inlet and outlet water temperatures, motor operating current and other technical
data.
③ Carefully check the operating conditions of the motor, reducer and other transmission devices.
④ Check the actual working conditions of the water distribution system. If a fault is found, deal with it
immediately.
Figure 5: Cooling tower fan maintenance.
3. Things to Note When Using Closed Circuit Cooling Towers in Winter
To prevent freezing of copper pipes (radiators) and water distribution system, please note the following:
1. Anti Freezing Measures: In cold temperatures, the water in the cooling tower may freeze, so
antifreezing measures
must be taken. Common methods are to use antifreeze liquid or a heating system to keep the water temperature in a
non-freezing range.
●After adding antifreeze liquid to the circulating water of the closed circuit cooling tower, the freezing
temperature drops and it is not easy to freeze.
●The higher the concentration of antifreeze liquid, the lower the freezing temperature will be, but the thermal
conductivity will decrease. Therefore, attention should be paid to this point when selecting the cooling tower.
●Also, if there is water leakage, please note that replenishing water will dilute the antifreeze solution and
increase the freezing temperature.
2. Pipe Maintenance: Cold temperatures can lead to an increased risk of pipes freezing and
cracking. Make sure the
piping system is well maintained, especially at the cooling tower inlet and drain lines.
3. Cleaning and Maintenance: Snow and ice may build up around cooling towers in cold winter. Clear
snow and ice
regularly to ensure the normal operation of the cooling tower. In addition, perform routine maintenance and upkeep
to check the health and performance of the equipment.
4. Safety Measures: Closed circuit cooling towers often contain rotating parts and high-voltage
equipment. When
operating or maintaining a cooling tower, it is important to follow safety procedures to ensure worker safety.
Please note that the above recommendations are general and may vary depending on the type, size, and design of the
cooling tower. In actual operation, please follow the use and maintenance guidelines provided by the manufacturer,
and make appropriate adjustments according to the specific situation.
Figure 6: Working principle diagram of closed circuit cooling tower.
4. Other Precautions When Using Closed Circuit Cooling Towers
① Read the operation and maintenance instructions before running and operating the cooling tower. Please abide by
the prohibited items and operating instructions.
② Never enter the cooling tower during its operation, and do not climb to the top of the tower body.
③ Never touch the fan when it may be running.
④ The antifreezing electric heater will generate heat, please do not touch it with your hands.
⑤ Please do not drink the water from the cooling tower. If it enters your eyes, please rinse immediately. After
working, please rinse your mouth and wash your hands.
⑥ Please follow the contents recorded on the warning labels posted on all parts of the tower.
