Counterflow, airflow

System designers often think dampers bloek airflow and are suitable to prevent baek drafts in idle towers. This is not the ease. Airfoil dampers simply hamper fan housing efficiency- they do not block airflow. Air Inlet Screens are always part of blow through, counterflow towers to protect people from rotating equipment. Some designs can be a hazard when accessible from the underside and require the specifier to call out additional screening. They can be a worthwhile accessory when there are nearby trees even when not required for safety reasons. Air inlet screens should be eliminated on towers utilizing inlet ductwork. Inlet ductwork may also make it necessary to block extraneous air entry such as from the underside when towers are elevated. 

The towers are less thermally efficient than counterflow designs but offer less resistance to airflow. They are often used in large manufacturing industry, where risks of fouling from process leaks could shut down a counterflow system. 

The components of a tower that distribute hot water uniformly through the cooling tower, to the point where it meets the airflow. Includes headers, laterals, nozzles (esp. in counterflow designs), troughs, and flow controllers. 

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