Whether a closed cooling tower circulating water system requires an anti-aircraft pipe depends on the actual needs and system design.
First of all, the main function of the anti-aircraft pipe is to prevent air from entering the closed cooling tower circulating water system, affecting the normal operation of the system. Therefore, if the design of the system requires strict protection against the ingress of air, then it is necessary to install anti-aircraft pipes.
Secondly, if the circulating water system is closed and there is no possibility of contact with outside air, then there is no need to install anti-aircraft pipes. Because the containment system itself prevents the ingress of air, it does not affect the normal operation of the system.
In addition, if the circulating water system is semi-enclosed, or there are some special circumstances, such as the high height of the circulating water pool, which needs to flow by gravity, the pipes of the circulating water system are long, and there are many bends, etc., these situations may cause air to be trapped in the circulating water system. To prevent the influence of air on the operation of the system, the installation of anti-aircraft pipes can be considered.
To sum up, whether it is necessary to install anti-aircraft pipes needs to be determined according to the actual needs and system design of the closed cooling tower circulating water system. In general, if it is a carbon steel hot-dip galvanized cooling pipe bundle, a vent pipe is required. If the system design requires strict protection against air ingress, or if there are conditions that could lead to air entrapment, then anti-aircraft pipes need to be installed. Otherwise, it is possible that the installation of anti-aircraft pipes is not required.