cooling towersClosed circuit
cooling towersClosed circuit
To ensure the performance established at the design stage, all cooling towers used in industrial, commercial and civil applications require routine maintenance. This is essential to preserve efficient heat transfer over time, which saves water and electricity. It is also very important to avoid or, at least, limit downtime at equipment.
To ensure the best cooling tower maintenance, DECSA provides a team of experienced and qualified service specialists capable of providing the best cooling tower maintenance plan according to the specific work context: industrial, commercial or civil. Each system and its components require a different maintenance programme. The supply of original spare parts, always carefully selected and studied by DECSA technicians, also plays a key role.
It is also essential to know the elements of the machinery, their functions, and the checks required for each unit. Let's see how to ensure proper cooling tower maintenance, starting with a general overview of the maintenance checks needed for each component.
The cooling tower has a relatively simple structure.
Each machinery consists of the following components:
- the main casing
- one or more intake or exhaust fans
- water distribution pipes
- air intake grilles
- spray nozzles
- heat exchange fill packs or coils
- drift eliminators
Although not these components need ordinary maintenance, you should bear in mind that - because of the "hostile" working environment always in contact with water - exposure to the risk of corrosion remains pretty high.
Also, cooling towers are subject to weather and pollution, which makes it necessary to carry out regular checks on all the most exposed parts. Finally, it is also important to remember the "moving" components of the cooling tower - such as the fans and their motors - which require regular checks.
As can be seen, the overall picture is pretty composite. We shall try to put things in order by dividing cooling tower maintenance into two "macro areas". :
- maintenance of the components in contact with water, which is essential for good machinery performance
- maintenance of the mechanical components, which handle the proper functioning of the cooling tower.
Let's look at them in detail.
Here we present the required cooling tower maintenance for components constantly exposed to water and humidity. Water quality plays a fundamental role in avoiding the deterioration of the elements of the equipment. For more information, please refer to Decsa's cooling tower maintenance manuals.
The exchange fill pack is essential for the cooling tower's performance. Specifically, the fill pack is where air and water meet to allow the water to evaporate and cool (for more information on this, see the article "I fill packs in cooling towers").
Therefore, keeping the heat exchanger in optimal condition - i.e. free of fouling or blockages of any kind - by checking it every three to six months at the latest is crucial. If this is not the case, you may need to request a replacement of the elements of the fill pack.
Decsa's evaporative cooling towers have a specific heat exchanger fill pack called DECSAPACK, made with water and air flow suitable for both industrial and civil cooling systems.
The drift eliminators are always in contact with warm air and humidity. Their purpose is to prevent the entrainment of droplets outside equipment and to prevent, if present, the spread of bacteria to the surrounding environment.
Drift eliminators must always be clean to preserve their high efficiency. Adequate cleaning is ensured by disassembling and washing with hot water or by "mechanically" cleaning the eliminators themselves and checking that they are completely intact (otherwise, you should replace them immediately).
Depending on how long the system has been in operation, you should check drift eliminators up to three times a year. Attention: you must fit them in the correct direction!
Besides the droplet separator, air intake grilles are the component that separates "the internal environment" of the cooling tower "from the external environment". Thus, like the drift eliminators, you should check periodically.
As the air intake grilles are close to the water basin tank, it is necessary to check that they are free of biofilm and encrustation. If damaged, you should replace them immediately, paying close attention to the correct way of reassembly.
We also recommend keeping them clean to allow the proper passage of air flow and ensure maximum heat exchange efficiency.
Depending on the water quality, the cold water collection basin of the cooling tower can be more or less prone to corrosion. For example, a high concentration of chlorides - which can come from the make-up water volume - almost always causes the metal of the evaporative cooling tower to corrode and its zinc protection.
Cleanliness of the cold water tank, filter and purge valve avoids the proliferation of biofilm and microorganisms. If the filter or purge valve is damaged, replacement is necessary.
Regular basin inspection can prevent the spread of corrosion and the formation of algae or biofilm in the water collection basin.
The nozzles and rubber seals should be checked periodically and replaced if necessary. To maintain the efficiency and thus the performance of the cooling tower, nozzles and the water distribution system should be in good condition, distributing the water evenly over the entire surface of the heat exchanger. If this is not the case, replacement of nozzle is necessary. Replacement or cleaning is easy and depends on the type of nozzle:
The distribution manifold also needs a minimum of maintenance: you should keep it free of fouling and, if broken, it must be replaced.
As part of cooling tower maintenance, you should regularly check mechanical components to avoid breakage due to wear and prevent machine downtime. In addition, some elements - such as fans - should be kept in perfect condition to ensure that cooling tower performance does not drop. Prevention is better than cure.
Pulleys, bearings, fan motor tie rods and transmissions must be greased regularly and kept in perfect condition at least every six months because of the cooling towers' exposure to the elements.
Belts should be kept tight and checked regularly, quarterly, or half-yearly. We recommend replacing them once a year.
Replacing belts is relatively simple: by loosening the motor tie rods, you can release the belt's tension, allowing for its replacement. You will then need to operate the motor tie rods again.
The vibrations caused by the cooling tower fans can lead to malfunctions or breakages. We recommend checking the fan's vibration every six months. DECSA technicians can carry out the eventual balancing of the cooling tower fans.
You should regularly check mechanical parts - such as the engine and driveshaft - and replace them before they cause unit downtime.
Decsa's after-sales service has become a benchmark in the cooling systems market. We provide maintenance and service for cooling towers and condensers for industrial refrigeration, HVAC and process cooling, even for equipment not of our manufacture.
In addition to supervising installation activities and offering genuine spare parts, our service includes short time interventions, repairs and ordinary or extra-ordinary maintenance programs.
This latter service consists of customized regular maintenance contracts (annual or multi-year, depending on customers' needs). It includes periodic interventions by Decsa's Service team for the various components of the evaporative tower cooling (e.g. greasing of bearings, correct tensioning of belts, ... ) and the periodic inspection of its perishable components (fill pack, drop separator, spray nozzles). This service guarantees the maintenance of performance and a longer machine lifetime. You can coordinate the service maintenance according to the downtime of your plant.
To simplify and safely carry out maintenance operations, we recommend equipping cooling towers with appropriate external ladders and walkways to facilitate access to all the components that need regular maintenance. These can also be purchased and installed at equipment installed and in operation for years.
Need more information about your cooling tower maintenance activities? Contact us
Stay up to date: subscribe to the newsletter to receive the latest Decsa news and updates in the field of evaporative cooling.